Red Hat Enterprise Linux 8 Security Technical Implementation Guide

Version

RHEL-08-010000

Vuln IDs

V-230221

Rule IDs

SV-230221r1017040_rule

An operating system release is considered "supported" if the vendor continues to provide security patches for the product. With an unsupported release, it will not be possible to resolve security issues discovered in the system software. Red Hat offers the Extended Update Support (EUS) add-on to a Red Hat Enterprise Linux subscription, for a fee, for those customers who wish to standardize on a specific minor release for an extended period. The RHEL 8 minor releases eligible for EUS are 8.1, 8.2, 8.4, 8.6, and 8.8. Each RHEL 8 EUS stream is available for 24 months from the availability of the minor release. RHEL 8.10 will be the final minor release overall. For more details on the Red Hat Enterprise Linux Life Cycle visit https://access.redhat.com/support/policy/updates/errata/. Note: The life-cycle time spans and dates are subject to adjustment.

Checks: C-32890r858733_chk

Verify the version of the operating system is vendor supported. Note: The lifecycle time spans and dates are subject to adjustment. Check the version of the operating system with the following command: $ sudo cat /etc/redhat-release Red Hat Enterprise Linux Server release 8.6 (Ootpa) Current End of Extended Update Support for RHEL 8.1 is 30 November 2021. Current End of Extended Update Support for RHEL 8.2 is 30 April 2022. Current End of Extended Update Support for RHEL 8.4 is 31 May 2023. Current End of Maintenance Support for RHEL 8.5 is 31 May 2022. Current End of Extended Update Support for RHEL 8.6 is 31 May 2024. Current End of Maintenance Support for RHEL 8.7 is 31 May 2023. Current End of Extended Update Support for RHEL 8.8 is 31 May 2025. Current End of Maintenance Support for RHEL 8.9 is 31 May 2024. Current End of Maintenance Support for RHEL 8.10 is 31 May 2029. If the release is not supported by the vendor, this is a finding.

Fix: F-32865r567410_fix

Upgrade to a supported version of RHEL 8.

b

RHEL 8 vendor packaged system security patches and updates must be installed and up to date.

CM-6 - Medium - CCI-000366 - V-230222 - SV-230222r1017041_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010010

Vuln IDs

V-230222

Rule IDs

SV-230222r1017041_rule

Timely patching is critical for maintaining the operational availability, confidentiality, and integrity of information technology (IT) systems. However, failure to keep operating system and application software patched is a common mistake made by IT professionals. New patches are released daily, and it is often difficult for even experienced System Administrators to keep abreast of all the new patches. When new weaknesses in an operating system exist, patches are usually made available by the vendor to resolve the problems. If the most recent security patches and updates are not installed, unauthorized users may take advantage of weaknesses in the unpatched software. The lack of prompt attention to patching could result in a system compromise.

Checks: C-32891r567412_chk

Verify the operating system security patches and updates are installed and up to date. Updates are required to be applied with a frequency determined by the site or Program Management Office (PMO). Obtain the list of available package security updates from Red Hat. The URL for updates is https://rhn.redhat.com/errata/. It is important to note that updates provided by Red Hat may not be present on the system if the underlying packages are not installed. Check that the available package security updates have been installed on the system with the following command: $ sudo yum history list | more Loaded plugins: langpacks, product-id, subscription-manager ID | Command line | Date and time | Action(s) | Altered ------------------------------------------------------------------------------- 70 | install aide | 2020-03-05 10:58 | Install | 1 69 | update -y | 2020-03-04 14:34 | Update | 18 EE 68 | install vlc | 2020-02-21 17:12 | Install | 21 67 | update -y | 2020-02-21 17:04 | Update | 7 EE If package updates have not been performed on the system within the timeframe the site/program documentation requires, this is a finding. Typical update frequency may be overridden by Information Assurance Vulnerability Alert (IAVA) notifications from CYBERCOM. If the operating system is in non-compliance with the Information Assurance Vulnerability Management (IAVM) process, this is a finding.

Fix: F-32866r567413_fix

Install the operating system patches or updated packages available from Red Hat within 30 days or sooner as local policy dictates.

c

RHEL 8 must implement NIST FIPS-validated cryptography for the following: To provision digital signatures, to generate cryptographic hashes, and to protect data requiring data-at-rest protections in accordance with applicable federal laws, Executive Orders, directives, policies, regulations, and standards.

AC-17 - High - CCI-000068 - V-230223 - SV-230223r1069327_rule

RMF Control

AC-17

Severity

H

CCI

CCI-000068

Version

RHEL-08-010020

Vuln IDs

V-230223

Rule IDs

SV-230223r1069327_rule

Use of weak or untested encryption algorithms undermines the purposes of using encryption to protect data. The operating system must implement cryptographic modules adhering to the higher standards approved by the federal government since this provides assurance they have been tested and validated. RHEL 8 utilizes GRUB 2 as the default bootloader. Note that GRUB 2 command-line parameters are defined in the "kernelopts" variable of the /boot/grub2/grubenv file for all kernel boot entries. The command "fips-mode-setup" modifies the "kernelopts" variable, which in turn updates all kernel boot entries. The fips=1 kernel option needs to be added to the kernel command line during system installation so that key generation is done with FIPS-approved algorithms and continuous monitoring tests in place. Users must also ensure the system has plenty of entropy during the installation process by moving the mouse around, or if no mouse is available, ensuring that many keystrokes are typed. The recommended amount of keystrokes is 256 and more. Less than 256 keystrokes may generate a nonunique key. Satisfies: SRG-OS-000033-GPOS-00014, SRG-OS-000125-GPOS-00065, SRG-OS-000396-GPOS-00176, SRG-OS-000423-GPOS-00187, SRG-OS-000478-GPOS-00223

Checks: C-32892r1069263_chk

Verify the operating system implements DOD-approved encryption to protect the confidentiality of remote access sessions. Show the configured systemwide cryptographic policy by running the following command: $ sudo update-crypto-policies --show FIPS If the main policy name is not "FIPS", this is a finding. If the AD-SUPPORT subpolicy module is included (e.g., "FIPS:AD-SUPPORT"), and Active Directory support is not documented as an operational requirement with the information system security officer (ISSO), this is a finding. If the NO-ENFORCE-EMS subpolicy module is included (e.g., "FIPS:NO-ENFORCE-EMS"), and not enforcing EMS is not documented as an operational requirement with the ISSO, this is a finding. If any other subpolicy module is included, this is a finding.

Fix: F-32867r928584_fix

Configure the operating system to implement DOD-approved encryption by following the steps below: To enable strict FIPS compliance, the fips=1 kernel option needs to be added to the kernel boot parameters during system installation so key generation is done with FIPS-approved algorithms and continuous monitoring tests in place. Enable FIPS mode after installation (not strict FIPS-compliant) with the following command: $ sudo fips-mode-setup --enable Reboot the system for the changes to take effect.

c

All RHEL 8 local disk partitions must implement cryptographic mechanisms to prevent unauthorized disclosure or modification of all information that requires at rest protection.

SC-28 - High - CCI-001199 - V-230224 - SV-230224r1044787_rule

RMF Control

SC-28

Severity

H

CCI

CCI-001199

Version

RHEL-08-010030

Vuln IDs

V-230224

Rule IDs

SV-230224r1044787_rule

RHEL 8 systems handling data requiring "data at rest" protections must employ cryptographic mechanisms to prevent unauthorized disclosure and modification of the information at rest. Selection of a cryptographic mechanism is based on the need to protect the integrity of organizational information. The strength of the mechanism is commensurate with the security category and/or classification of the information. Organizations have the flexibility to either encrypt all information on storage devices (i.e., full disk encryption) or encrypt specific data structures (e.g., files, records, or fields). Satisfies: SRG-OS-000185-GPOS-00079, SRG-OS-000404-GPOS-00183, SRG-OS-000405-GPOS-00184

Checks: C-32893r917863_chk

Verify RHEL 8 prevents unauthorized disclosure or modification of all information requiring at-rest protection by using disk encryption. If there is a documented and approved reason for not having data-at-rest encryption at the operating system level, such as encryption provided by a hypervisor or a disk storage array in a virtualized environment, this requirement is not applicable. Verify all system partitions are encrypted with the following command: $ sudo blkid /dev/mapper/rhel-root: UUID="67b7d7fe-de60-6fd0-befb-e6748cf97743" TYPE="crypto_LUKS" Every persistent disk partition present must be of type "crypto_LUKS". If any partitions other than the boot partition or pseudo file systems (such as /proc or /sys) are not type "crypto_LUKS", ask the administrator to indicate how the partitions are encrypted. If there is no evidence that these partitions are encrypted, this is a finding.

Fix: F-32868r567419_fix

Configure RHEL 8 to prevent unauthorized modification of all information at rest by using disk encryption. Encrypting a partition in an already installed system is more difficult, because existing partitions will need to be resized and changed. To encrypt an entire partition, dedicate a partition for encryption in the partition layout.

b

RHEL 8 must display the Standard Mandatory DOD Notice and Consent Banner before granting local or remote access to the system via a ssh logon.

AC-8 - Medium - CCI-000048 - V-230225 - SV-230225r1069297_rule

RMF Control

AC-8

Severity

M

CCI

Version

RHEL-08-010040

Vuln IDs

V-230225

Rule IDs

SV-230225r1069297_rule

Display of a standardized and approved use notification before granting access to the operating system ensures privacy and security notification verbiage used is consistent with applicable federal laws, Executive Orders, directives, policies, regulations, standards, and guidance. System use notifications are required only for access via logon interfaces with human users and are not required when such human interfaces do not exist. The banner must be formatted in accordance with applicable DOD policy. Use the following verbiage for operating systems that can accommodate banners of 1300 characters: "You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions: -The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations. -At any time, the USG may inspect and seize data stored on this IS. -Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG-authorized purpose. -This IS includes security measures (e.g., authentication and access controls) to protect USG interests--not for your personal benefit or privacy. -Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details." Use the following verbiage for operating systems that have severe limitations on the number of characters that can be displayed in the banner: "I've read & consent to terms in IS user agreem't." Satisfies: SRG-OS-000023-GPOS-00006, SRG-OS-000228-GPOS-00088

Checks: C-32894r1069203_chk

Verify any publicly accessible connection to the operating system displays the Standard Mandatory DOD Notice and Consent Banner before granting access to the system. Check for the location of the banner file being used with the following command: $ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH '^\s*banner' /etc/ssh/sshd_config:banner /etc/issue This command will return the banner keyword and the name of the file that contains the ssh banner (in this case "/etc/issue"). If the line is commented out, this is a finding. If conflicting results are returned, this is a finding. View the file specified by the banner keyword to check that it matches the text of the Standard Mandatory DOD Notice and Consent Banner: "You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions: -The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations. -At any time, the USG may inspect and seize data stored on this IS. -Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG-authorized purpose. -This IS includes security measures (e.g., authentication and access controls) to protect USG interests--not for your personal benefit or privacy. -Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details." If the system does not display a graphical logon banner or the banner does not match the Standard Mandatory DOD Notice and Consent Banner, this is a finding. If the text in the file does not match the Standard Mandatory DOD Notice and Consent Banner, this is a finding.

Fix: F-32869r951589_fix

Configure the operating system to display the Standard Mandatory DOD Notice and Consent Banner before granting access to the system via the ssh. Edit the "/etc/ssh/sshd_config" file to uncomment the banner keyword and configure it to point to a file that will contain the logon banner (this file may be named differently or be in a different location if using a version of SSH that is provided by a third-party vendor). An example configuration line is: banner /etc/issue Either create the file containing the banner or replace the text in the file with the Standard Mandatory DOD Notice and Consent Banner. The DOD-required text is: "You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions: -The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations. -At any time, the USG may inspect and seize data stored on this IS. -Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG-authorized purpose. -This IS includes security measures (e.g., authentication and access controls) to protect USG interests--not for your personal benefit or privacy. -Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details." The SSH service must be restarted for changes to take effect.

b

RHEL 8 must display the Standard Mandatory DoD Notice and Consent Banner before granting local or remote access to the system via a graphical user logon.

AC-8 - Medium - CCI-000048 - V-230226 - SV-230226r1069298_rule

RMF Control

AC-8

Severity

M

CCI

Version

RHEL-08-010050

Vuln IDs

V-230226

Rule IDs

SV-230226r1069298_rule

Display of a standardized and approved use notification before granting access to the operating system ensures privacy and security notification verbiage used is consistent with applicable federal laws, Executive Orders, directives, policies, regulations, standards, and guidance. System use notifications are required only for access via logon interfaces with human users and are not required when such human interfaces do not exist. The banner must be formatted in accordance with applicable DoD policy. Use the following verbiage for operating systems that can accommodate banners of 1300 characters: "You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions: -The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations. -At any time, the USG may inspect and seize data stored on this IS. -Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG-authorized purpose. -This IS includes security measures (e.g., authentication and access controls) to protect USG interests--not for your personal benefit or privacy. -Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details." Satisfies: SRG-OS-000023-GPOS-00006, SRG-OS-000228-GPOS-00088

Checks: C-32895r1069205_chk

Verify RHEL 8 displays the Standard Mandatory DoD Notice and Consent Banner before granting access to the operating system via a graphical user logon. Note: This requirement assumes the use of the RHEL 8 default graphical user interface, Gnome Shell. If the system does not have any graphical user interface installed, this requirement is Not Applicable. Check that the operating system displays the exact Standard Mandatory DoD Notice and Consent Banner text with the command: $ sudo grep -r banner-message-text /etc/dconf/db/local.d/* /etc/dconf/db/local.d/01-banner-message:banner-message-text='You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only.\nBy using this IS (which includes any device attached to this IS), you consent to the following conditions:\n-The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations.\n-At any time, the USG may inspect and seize data stored on this IS.\n-Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG-authorized purpose.\n-This IS includes security measures (e.g., authentication and access controls) to protect USG interests--not for your personal benefit or privacy.\n-Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details. ' Note: The "\n " characters are for formatting only. They will not be displayed on the graphical interface. If the banner does not match the Standard Mandatory DoD Notice and Consent Banner exactly, this is a finding.

Fix: F-32870r743915_fix

Configure the operating system to display the Standard Mandatory DoD Notice and Consent Banner before granting access to the system. Note: If the system does not have a graphical user interface installed, this requirement is Not Applicable. Add the following lines to the [org/gnome/login-screen] section of the "/etc/dconf/db/local.d/01-banner-message": banner-message-text='You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only.\nBy using this IS (which includes any device attached to this IS), you consent to the following conditions:\n-The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations.\n-At any time, the USG may inspect and seize data stored on this IS.\n-Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG-authorized purpose.\n-This IS includes security measures (e.g., authentication and access controls) to protect USG interests--not for your personal benefit or privacy.\n-Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details. ' Note: The "\n " characters are for formatting only. They will not be displayed on the graphical interface. Run the following command to update the database: $ sudo dconf update

b

RHEL 8 must display the Standard Mandatory DoD Notice and Consent Banner before granting local or remote access to the system via a command line user logon.

AC-8 - Medium - CCI-000048 - V-230227 - SV-230227r1017046_rule

RMF Control

AC-8

Severity

M

CCI

Version

RHEL-08-010060

Vuln IDs

V-230227

Rule IDs

SV-230227r1017046_rule

Display of a standardized and approved use notification before granting access to the operating system ensures privacy and security notification verbiage used is consistent with applicable federal laws, Executive Orders, directives, policies, regulations, standards, and guidance. System use notifications are required only for access via logon interfaces with human users and are not required when such human interfaces do not exist. The banner must be formatted in accordance with applicable DoD policy. Use the following verbiage for operating systems that can accommodate banners of 1300 characters: "You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions: -The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations. -At any time, the USG may inspect and seize data stored on this IS. -Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG-authorized purpose. -This IS includes security measures (e.g., authentication and access controls) to protect USG interests--not for your personal benefit or privacy. -Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details." Satisfies: SRG-OS-000023-GPOS-00006, SRG-OS-000228-GPOS-00088

Checks: C-32896r567427_chk

Verify RHEL 8 displays the Standard Mandatory DoD Notice and Consent Banner before granting access to the operating system via a command line user logon. Check that RHEL 8 displays a banner at the command line login screen with the following command: $ sudo cat /etc/issue If the banner is set correctly it will return the following text: “You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions: -The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations. -At any time, the USG may inspect and seize data stored on this IS. -Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG-authorized purpose. -This IS includes security measures (e.g., authentication and access controls) to protect USG interests--not for your personal benefit or privacy. -Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details.” If the banner text does not match the Standard Mandatory DoD Notice and Consent Banner exactly, this is a finding.

Fix: F-32871r567428_fix

Configure RHEL 8 to display the Standard Mandatory DoD Notice and Consent Banner before granting access to the system via command line logon. Edit the "/etc/issue" file to replace the default text with the Standard Mandatory DoD Notice and Consent Banner. The DoD-required text is: "You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions: -The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations. -At any time, the USG may inspect and seize data stored on this IS. -Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG-authorized purpose. -This IS includes security measures (e.g., authentication and access controls) to protect USG interests -- not for your personal benefit or privacy. -Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details."

b

All RHEL 8 remote access methods must be monitored.

AC-17 - Medium - CCI-000067 - V-230228 - SV-230228r1069299_rule

RMF Control

AC-17

Severity

M

CCI

CCI-000067

Version

RHEL-08-010070

Vuln IDs

V-230228

Rule IDs

SV-230228r1069299_rule

Remote access services, such as those providing remote access to network devices and information systems, which lack automated monitoring capabilities, increase risk and make remote user access management difficult at best. Remote access is access to DOD nonpublic information systems by an authorized user (or an information system) communicating through an external, nonorganization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless. Automated monitoring of remote access sessions allows organizations to detect cyber attacks and ensure ongoing compliance with remote access policies by auditing connection activities of remote access capabilities, such as Remote Desktop Protocol (RDP), on a variety of information system components (e.g., servers, workstations, notebook computers, smartphones, and tablets).

Checks: C-32897r1069207_chk

Verify that RHEL 8 monitors all remote access methods. Check that remote access methods are being logged by running the following command: $ sudo grep -E '(auth\.\*|authpriv\.\*|daemon\.\*)' /etc/rsyslog.conf /etc/rsyslog.d/*.conf /etc/rsyslog.d/*.conf auth.*;authpriv.*;daemon.* /var/log/secure If "auth.*", "authpriv.*" or "daemon.*" are not configured to be logged, this is a finding.

Fix: F-32872r567431_fix

Configure RHEL 8 to monitor all remote access methods by installing rsyslog with the following command: $ sudo yum install rsyslog Then add or update the following lines to the "/etc/rsyslog.conf" file: auth.*;authpriv.*;daemon.* /var/log/secure The "rsyslog" service must be restarted for the changes to take effect. To restart the "rsyslog" service, run the following command: $ sudo systemctl restart rsyslog.service

b

RHEL 8, for PKI-based authentication, must validate certificates by constructing a certification path (which includes status information) to an accepted trust anchor.

IA-5 - Medium - CCI-000185 - V-230229 - SV-230229r1017048_rule

RMF Control

IA-5

Severity

M

CCI

CCI-000185

Version

RHEL-08-010090

Vuln IDs

V-230229

Rule IDs

SV-230229r1017048_rule

Without path validation, an informed trust decision by the relying party cannot be made when presented with any certificate not already explicitly trusted. A trust anchor is an authoritative entity represented via a public key and associated data. It is used in the context of public key infrastructures, X.509 digital certificates, and DNSSEC. When there is a chain of trust, usually the top entity to be trusted becomes the trust anchor; it can be, for example, a Certification Authority (CA). A certification path starts with the subject certificate and proceeds through a number of intermediate certificates up to a trusted root certificate, typically issued by a trusted CA. This requirement verifies that a certification path to an accepted trust anchor is used for certificate validation and that the path includes status information. Path validation is necessary for a relying party to make an informed trust decision when presented with any certificate not already explicitly trusted. Status information for certification paths includes certificate revocation lists or online certificate status protocol responses. Validation of the certificate status information is out of scope for this requirement. Satisfies: SRG-OS-000066-GPOS-00034, SRG-OS-000384-GPOS-00167

Checks: C-32898r858738_chk

Verify RHEL 8 for PKI-based authentication has valid certificates by constructing a certification path (which includes status information) to an accepted trust anchor. Note: If the System Administrator demonstrates the use of an approved alternate multifactor authentication method, this requirement is not applicable. Check that the system has a valid DoD root CA installed with the following command: $ sudo openssl x509 -text -in /etc/sssd/pki/sssd_auth_ca_db.pem Certificate: Data: Version: 3 (0x2) Serial Number: 1 (0x1) Signature Algorithm: sha256WithRSAEncryption Issuer: C = US, O = U.S. Government, OU = DoD, OU = PKI, CN = DoD Root CA 3 Validity Not Before: Mar 20 18:46:41 2012 GMT Not After : Dec 30 18:46:41 2029 GMT Subject: C = US, O = U.S. Government, OU = DoD, OU = PKI, CN = DoD Root CA 3 Subject Public Key Info: Public Key Algorithm: rsaEncryption If the root ca file is not a DoD-issued certificate with a valid date and installed in the /etc/sssd/pki/sssd_auth_ca_db.pem location, this is a finding.

Fix: F-32873r809269_fix

Configure RHEL 8, for PKI-based authentication, to validate certificates by constructing a certification path (which includes status information) to an accepted trust anchor. Obtain a valid copy of the DoD root CA file from the PKI CA certificate bundle at cyber.mil and copy into the following file: /etc/sssd/pki/sssd_auth_ca_db.pem

b

RHEL 8, for certificate-based authentication, must enforce authorized access to the corresponding private key.

IA-5 - Medium - CCI-000186 - V-230230 - SV-230230r1069287_rule

RMF Control

IA-5

Severity

M

CCI

CCI-000186

Version

RHEL-08-010100

Vuln IDs

V-230230

Rule IDs

SV-230230r1069287_rule

If an unauthorized user obtains access to a private key without a passcode, that user would have unauthorized access to any system where the associated public key has been installed.

Checks: C-32899r1069182_chk

Verify the SSH private key files have a passcode. For each private key stored on the system, use the following command: $ sudo ssh-keygen -y -f /path/to/file Enter passphrase: If the contents of the key are displayed, this is a finding.

Fix: F-32874r1069183_fix

Create a new private and public key pair that utilizes a passcode with the following command: $ sudo ssh-keygen -p -f /path/to/file

b

RHEL 8 must encrypt all stored passwords with a FIPS 140-2 approved cryptographic hashing algorithm.

IA-5 - Medium - CCI-000196 - V-230231 - SV-230231r1017050_rule

RMF Control

IA-5

Severity

M

CCI

CCI-000196

Version

RHEL-08-010110

Vuln IDs

V-230231

Rule IDs

SV-230231r1017050_rule

Passwords need to be protected at all times, and encryption is the standard method for protecting passwords. If passwords are not encrypted, they can be plainly read (i.e., clear text) and easily compromised. Unapproved mechanisms that are used for authentication to the cryptographic module are not verified and therefore cannot be relied upon to provide confidentiality or integrity, and DoD data may be compromised. FIPS 140-2 is the current standard for validating that mechanisms used to access cryptographic modules utilize authentication that meets DoD requirements.

Checks: C-32900r567439_chk

Verify that the shadow password suite configuration is set to encrypt password with a FIPS 140-2 approved cryptographic hashing algorithm. Check the hashing algorithm that is being used to hash passwords with the following command: $ sudo grep -i crypt /etc/login.defs ENCRYPT_METHOD SHA512 If "ENCRYPT_METHOD" does not equal SHA512 or greater, this is a finding.

Fix: F-32875r567440_fix

Configure RHEL 8 to encrypt all stored passwords. Edit/Modify the following line in the "/etc/login.defs" file and set "[ENCRYPT_METHOD]" to SHA512. ENCRYPT_METHOD SHA512

b

RHEL 8 must employ FIPS 140-2 approved cryptographic hashing algorithms for all stored passwords.

IA-5 - Medium - CCI-000196 - V-230232 - SV-230232r1017051_rule

RMF Control

IA-5

Severity

M

CCI

CCI-000196

Version

RHEL-08-010120

Vuln IDs

V-230232

Rule IDs

SV-230232r1017051_rule

The system must use a strong hashing algorithm to store the password. Passwords need to be protected at all times, and encryption is the standard method for protecting passwords. If passwords are not encrypted, they can be plainly read (i.e., clear text) and easily compromised.

Checks: C-32901r567442_chk

Confirm that the interactive user account passwords are using a strong password hash with the following command: $ sudo cut -d: -f2 /etc/shadow $6$kcOnRq/5$NUEYPuyL.wghQwWssXRcLRFiiru7f5JPV6GaJhNC2aK5F3PZpE/BCCtwrxRc/AInKMNX3CdMw11m9STiql12f/ Password hashes "!" or "*" indicate inactive accounts not available for logon and are not evaluated. If any interactive user password hash does not begin with "$6$", this is a finding.

Fix: F-32876r567443_fix

Lock all interactive user accounts not using SHA-512 hashing until the passwords can be regenerated with SHA-512.

b

The RHEL 8 shadow password suite must be configured to use a sufficient number of hashing rounds.

IA-5 - Medium - CCI-000196 - V-230233 - SV-230233r1044790_rule

RMF Control

IA-5

Severity

M

CCI

CCI-000196

Version

RHEL-08-010130

Vuln IDs

V-230233

Rule IDs

SV-230233r1044790_rule

The system must use a strong hashing algorithm to store the password. The system must use a sufficient number of hashing rounds to ensure the required level of entropy. Passwords need to be protected at all times, and encryption is the standard method for protecting passwords. If passwords are not encrypted, they can be plainly read (i.e., clear text) and easily compromised.

Checks: C-32902r1044788_chk

Check that a minimum number of hash rounds is configured by running the following command: $ sudo grep -E "^SHA_CRYPT_" /etc/login.defs If only one of "SHA_CRYPT_MIN_ROUNDS" or "SHA_CRYPT_MAX_ROUNDS" is set, and this value is below "100000", this is a finding. If both "SHA_CRYPT_MIN_ROUNDS" and "SHA_CRYPT_MAX_ROUNDS" are set, and the highest value for either is below "100000", this is a finding.

Fix: F-32877r1044789_fix

Configure RHEL 8 to encrypt all stored passwords with a strong cryptographic hash. Edit/modify the following line in the "/etc/login.defs" file and set "SHA_CRYPT_MIN_ROUNDS" to a value no lower than "100000": SHA_CRYPT_MIN_ROUNDS 100000

c

RHEL 8 operating systems booted with United Extensible Firmware Interface (UEFI) must require authentication upon booting into single-user mode and maintenance.

AC-3 - High - CCI-000213 - V-230234 - SV-230234r1017053_rule

RMF Control

AC-3

Severity

H

CCI

Version

RHEL-08-010140

Vuln IDs

V-230234

Rule IDs

SV-230234r1017053_rule

If the system does not require valid authentication before it boots into single-user or maintenance mode, anyone who invokes single-user or maintenance mode is granted privileged access to all files on the system. GRUB 2 is the default boot loader for RHEL 8 and is designed to require a password to boot into single-user mode or make modifications to the boot menu.

Checks: C-32903r743920_chk

For systems that use BIOS, this is Not Applicable. Check to see if an encrypted grub superusers password is set. On systems that use UEFI, use the following command: $ sudo grep -iw grub2_password /boot/efi/EFI/redhat/user.cfg GRUB2_PASSWORD=grub.pbkdf2.sha512.[password_hash] If the grub superusers password does not begin with "grub.pbkdf2.sha512", this is a finding.

Fix: F-32878r743921_fix

Configure the system to require a grub bootloader password for the grub superusers account with the grub2-setpassword command, which creates/overwrites the /boot/efi/EFI/redhat/user.cfg file. Generate an encrypted grub2 password for the grub superusers account with the following command: $ sudo grub2-setpassword Enter password: Confirm password:

c

RHEL 8 operating systems booted with a BIOS must require authentication upon booting into single-user and maintenance modes.

AC-3 - High - CCI-000213 - V-230235 - SV-230235r1017054_rule

RMF Control

AC-3

Severity

H

CCI

Version

RHEL-08-010150

Vuln IDs

V-230235

Rule IDs

SV-230235r1017054_rule

If the system does not require valid authentication before it boots into single-user or maintenance mode, anyone who invokes single-user or maintenance mode is granted privileged access to all files on the system. GRUB 2 is the default boot loader for RHEL 8 and is designed to require a password to boot into single-user mode or make modifications to the boot menu.

Checks: C-32904r743923_chk

For systems that use UEFI, this is Not Applicable. Check to see if an encrypted grub superusers password is set. On systems that use a BIOS, use the following command: $ sudo grep -iw grub2_password /boot/grub2/user.cfg GRUB2_PASSWORD=grub.pbkdf2.sha512.[password_hash] If the grub superusers password does not begin with "grub.pbkdf2.sha512", this is a finding.

Fix: F-32879r743924_fix

Configure the system to require a grub bootloader password for the grub superusers account with the grub2-setpassword command, which creates/overwrites the /boot/grub2/user.cfg file. Generate an encrypted grub2 password for the grub superusers account with the following command: $ sudo grub2-setpassword Enter password: Confirm password:

b

RHEL 8 operating systems must require authentication upon booting into rescue mode.

AC-3 - Medium - CCI-000213 - V-230236 - SV-230236r1017055_rule

RMF Control

AC-3

Severity

M

CCI

Version

RHEL-08-010151

Vuln IDs

V-230236

Rule IDs

SV-230236r1017055_rule

If the system does not require valid root authentication before it boots into emergency or rescue mode, anyone who invokes emergency or rescue mode is granted privileged access to all files on the system.

Checks: C-32905r743926_chk

Check to see if the system requires authentication for rescue mode with the following command: $ sudo grep sulogin-shell /usr/lib/systemd/system/rescue.service ExecStart=-/usr/lib/systemd/systemd-sulogin-shell rescue If the "ExecStart" line is configured for anything other than "/usr/lib/systemd/systemd-sulogin-shell rescue", commented out, or missing, this is a finding.

Fix: F-32880r743927_fix

Configure the system to require authentication upon booting into rescue mode by adding the following line to the "/usr/lib/systemd/system/rescue.service" file. ExecStart=-/usr/lib/systemd/systemd-sulogin-shell rescue

b

The RHEL 8 pam_unix.so module must be configured in the password-auth file to use a FIPS 140-2 approved cryptographic hashing algorithm for system authentication.

IA-7 - Medium - CCI-000803 - V-230237 - SV-230237r1017056_rule

RMF Control

IA-7

Severity

M

CCI

Version

RHEL-08-010160

Vuln IDs

V-230237

Rule IDs

SV-230237r1017056_rule

Unapproved mechanisms that are used for authentication to the cryptographic module are not verified and therefore cannot be relied upon to provide confidentiality or integrity, and DoD data may be compromised. RHEL 8 systems utilizing encryption are required to use FIPS-compliant mechanisms for authenticating to cryptographic modules. FIPS 140-2 is the current standard for validating that mechanisms used to access cryptographic modules utilize authentication that meets DoD requirements. This allows for Security Levels 1, 2, 3, or 4 for use on a general-purpose computing system.

Checks: C-32906r809274_chk

Verify that the pam_unix.so module is configured to use sha512. Check that the pam_unix.so module is configured to use sha512 in /etc/pam.d/password-auth with the following command: $ sudo grep password /etc/pam.d/password-auth | grep pam_unix password sufficient pam_unix.so sha512 If "sha512" is missing, or is commented out, this is a finding.

Fix: F-32881r809275_fix

Configure RHEL 8 to use a FIPS 140-2 approved cryptographic hashing algorithm for system authentication. Edit/modify the following line in the "/etc/pam.d/password-auth" file to include the sha512 option for pam_unix.so: password sufficient pam_unix.so sha512

b

RHEL 8 must prevent system daemons from using Kerberos for authentication.

IA-7 - Medium - CCI-000803 - V-230238 - SV-230238r1017057_rule

RMF Control

IA-7

Severity

M

CCI

Version

RHEL-08-010161

Vuln IDs

V-230238

Rule IDs

SV-230238r1017057_rule

Unapproved mechanisms that are used for authentication to the cryptographic module are not verified and therefore cannot be relied upon to provide confidentiality or integrity, and DoD data may be compromised. RHEL 8 systems utilizing encryption are required to use FIPS-compliant mechanisms for authenticating to cryptographic modules. The key derivation function (KDF) in Kerberos is not FIPS compatible. Ensuring the system does not have any keytab files present prevents system daemons from using Kerberos for authentication. A keytab is a file containing pairs of Kerberos principals and encrypted keys. FIPS 140-2 is the current standard for validating that mechanisms used to access cryptographic modules utilize authentication that meets DoD requirements. This allows for Security Levels 1, 2, 3, or 4 for use on a general-purpose computing system.

Checks: C-32907r646861_chk

Verify that RHEL 8 prevents system daemons from using Kerberos for authentication. If the system is a server utilizing krb5-server-1.17-18.el8.x86_64 or newer, this requirement is not applicable. If the system is a workstation utilizing krb5-workstation-1.17-18.el8.x86_64 or newer, this requirement is not applicable. Check if there are available keytabs with the following command: $ sudo ls -al /etc/*.keytab If this command produces any file(s), this is a finding.

Fix: F-32882r567461_fix

Configure RHEL 8 to prevent system daemons from using Kerberos for authentication. Remove any files with the .keytab extension from the operating system.

b

The krb5-workstation package must not be installed on RHEL 8.

IA-7 - Medium - CCI-000803 - V-230239 - SV-230239r1017058_rule

RMF Control

IA-7

Severity

M

CCI

Version

RHEL-08-010162

Vuln IDs

V-230239

Rule IDs

SV-230239r1017058_rule

Unapproved mechanisms that are used for authentication to the cryptographic module are not verified and therefore cannot be relied upon to provide confidentiality or integrity, and DoD data may be compromised. RHEL 8 systems utilizing encryption are required to use FIPS-compliant mechanisms for authenticating to cryptographic modules. Currently, Kerberos does not utilize FIPS 140-2 cryptography. FIPS 140-2 is the current standard for validating that mechanisms used to access cryptographic modules utilize authentication that meets DoD requirements. This allows for Security Levels 1, 2, 3, or 4 for use on a general-purpose computing system.

Checks: C-32908r646863_chk

Verify the krb5-workstation package has not been installed on the system with the following commands: If the system is a server or is utilizing krb5-workstation-1.17-18.el8.x86_64 or newer, this is Not Applicable. $ sudo yum list installed krb5-workstation krb5-workstation.x86_64 1.17-9.el8 repository If the krb5-workstation package is installed and is not documented with the Information System Security Officer (ISSO) as an operational requirement, this is a finding.

Fix: F-32883r567464_fix

Document the krb5-workstation package with the ISSO as an operational requirement or remove it from the system with the following command: $ sudo yum remove krb5-workstation

b

RHEL 8 must use a Linux Security Module configured to enforce limits on system services.

SC-3 - Medium - CCI-001084 - V-230240 - SV-230240r1017059_rule

RMF Control

SC-3

Severity

M

CCI

Version

RHEL-08-010170

Vuln IDs

V-230240

Rule IDs

SV-230240r1017059_rule

Without verification of the security functions, security functions may not operate correctly and the failure may go unnoticed. Security function is defined as the hardware, software, and/or firmware of the information system responsible for enforcing the system security policy and supporting the isolation of code and data on which the protection is based. Security functionality includes, but is not limited to, establishing system accounts, configuring access authorizations (i.e., permissions, privileges), setting events to be audited, and setting intrusion detection parameters. This requirement applies to operating systems performing security function verification/testing and/or systems and environments that require this functionality.

Checks: C-32909r567466_chk

Verify the operating system verifies correct operation of all security functions. Check if "SELinux" is active and in "Enforcing" mode with the following command: $ sudo getenforce Enforcing If "SELinux" is not active and not in "Enforcing" mode, this is a finding.

Fix: F-32884r567467_fix

Configure the operating system to verify correct operation of all security functions. Set the "SELinux" status and the "Enforcing" mode by modifying the "/etc/selinux/config" file to have the following line: SELINUX=enforcing A reboot is required for the changes to take effect.

a

RHEL 8 must have policycoreutils package installed.

SC-3 - Low - CCI-001084 - V-230241 - SV-230241r1017060_rule

RMF Control

SC-3

Severity

L

CCI

Version

RHEL-08-010171

Vuln IDs

V-230241

Rule IDs

SV-230241r1017060_rule

Without verification of the security functions, security functions may not operate correctly and the failure may go unnoticed. Security function is defined as the hardware, software, and/or firmware of the information system responsible for enforcing the system security policy and supporting the isolation of code and data on which the protection is based. Security functionality includes, but is not limited to, establishing system accounts, configuring access authorizations (i.e., permissions, privileges), setting events to be audited, and setting intrusion detection parameters. Policycoreutils contains the policy core utilities that are required for basic operation of an SELinux-enabled system. These utilities include load_policy to load SELinux policies, setfile to label filesystems, newrole to switch roles, and run_init to run /etc/init.d scripts in the proper context.

Checks: C-32910r567469_chk

Verify the operating system has the policycoreutils package installed with the following command: $ sudo yum list installed policycoreutils policycoreutils.x86_64 2.9-3.el8 @anaconda If the policycoreutils package is not installed, this is a finding.

Fix: F-32885r567470_fix

Configure the operating system to have the policycoreutils package installed with the following command: $ sudo yum install policycoreutils

b

A sticky bit must be set on all RHEL 8 public directories to prevent unauthorized and unintended information transferred via shared system resources.

SC-4 - Medium - CCI-001090 - V-230243 - SV-230243r1069294_rule

RMF Control

SC-4

Severity

M

CCI

CCI-001090

Version

RHEL-08-010190

Vuln IDs

V-230243

Rule IDs

SV-230243r1069294_rule

Preventing unauthorized information transfers mitigates the risk of information, including encrypted representations of information, produced by the actions of prior users/roles (or the actions of processes acting on behalf of prior users/roles) from being available to any current users/roles (or current processes) that obtain access to shared system resources (e.g., registers, main memory, hard disks) after those resources have been released back to information systems. The control of information in shared resources is also commonly referred to as object reuse and residual information protection. This requirement generally applies to the design of an information technology product, but it can also apply to the configuration of particular information system components that are, or use, such products. This can be verified by acceptance/validation processes in DoD or other government agencies. There may be shared resources with configurable protections (e.g., files in storage) that may be assessed on specific information system components.

Checks: C-32912r1069197_chk

Verify that all world-writable directories have the sticky bit set. Check to see that all world-writable directories have the sticky bit set by running the following command: $ sudo find / -type d $ -perm -0002 -a ! -perm -1000 $ 2>/dev/null -exec ls -ald {} \; drwxrwxrwx. 14 root root 4096 Sep 13 15:13 /tmp If any of the returned directories are world-writable and do not have the sticky bit set, this is a finding.

Fix: F-32887r567476_fix

Configure all world-writable directories to have the sticky bit set to prevent unauthorized and unintended information transferred via shared system resources. Set the sticky bit on all world-writable directories using the command, replace "[World-Writable Directory]" with any directory path missing the sticky bit: $ sudo chmod 1777 [World-Writable Directory]

b

RHEL 8 must be configured so that all network connections associated with SSH traffic terminate after becoming unresponsive.

SC-10 - Medium - CCI-001133 - V-230244 - SV-230244r1069300_rule

RMF Control

SC-10

Severity

M

CCI

CCI-001133

Version

RHEL-08-010200

Vuln IDs

V-230244

Rule IDs

SV-230244r1069300_rule

Terminating an unresponsive SSH session within a short time period reduces the window of opportunity for unauthorized personnel to take control of a management session enabled on the console or console port that has been left unattended. In addition, quickly terminating an idle SSH session will also free up resources committed by the managed network element. Terminating network connections associated with communications sessions includes, for example, deallocating associated TCP/IP address/port pairs at the operating system level and deallocating networking assignments at the application level if multiple application sessions are using a single operating system-level network connection. This does not mean the operating system terminates all sessions or network access; it only ends the unresponsive session and releases the resources associated with that session. RHEL 8 uses /etc/ssh/sshd_config for configurations of OpenSSH. Within the sshd_config, the product of the values of "ClientAliveInterval" and "ClientAliveCountMax" is used to establish the inactivity threshold. The "ClientAliveInterval" is a timeout interval in seconds after which if no data has been received from the client, sshd will send a message through the encrypted channel to request a response from the client. The "ClientAliveCountMax" is the number of client alive messages that may be sent without sshd receiving any messages back from the client. If this threshold is met, sshd will disconnect the client. For more information on these settings and others, refer to the sshd_config man pages. Satisfies: SRG-OS-000163-GPOS-00072, SRG-OS-000126-GPOS-00066, SRG-OS-000279-GPOS-00109

Checks: C-32913r1069209_chk

Verify the SSH server automatically terminates a user session after the SSH client has become unresponsive. Check that the "ClientAliveCountMax" is set to "1" by performing the following command: $ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH '^\s*clientalivecountmax' /etc/ssh/sshd_config:ClientAliveCountMax 1 If "ClientAliveCountMax" do not exist, is not set to a value of "1" in "/etc/ssh/sshd_config", or is commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-32888r917866_fix

Note: This setting must be applied in conjunction with RHEL-08-010201 to function correctly. Configure the SSH server to terminate a user session automatically after the SSH client has become unresponsive. Modify or append the following lines in the "/etc/ssh/sshd_config" file: ClientAliveCountMax 1 For the changes to take effect, the SSH daemon must be restarted: $ sudo systemctl restart sshd.service

b

The RHEL 8 /var/log/messages file must have mode 0640 or less permissive.

SI-11 - Medium - CCI-001314 - V-230245 - SV-230245r1017063_rule

RMF Control

SI-11

Severity

M

CCI

Version

RHEL-08-010210

Vuln IDs

V-230245

Rule IDs

SV-230245r1017063_rule

Only authorized personnel should be aware of errors and the details of the errors. Error messages are an indicator of an organization's operational state or can identify the RHEL 8 system or platform. Additionally, Personally Identifiable Information (PII) and operational information must not be revealed through error messages to unauthorized personnel or their designated representatives. The structure and content of error messages must be carefully considered by the organization and development team. The extent to which the information system is able to identify and handle error conditions is guided by organizational policy and operational requirements.

Checks: C-32914r567481_chk

Verify that the "/var/log/messages" file has mode "0640" or less permissive with the following command: $ sudo stat -c "%a %n" /var/log/messages 640 /var/log/messages If a value of "0640" or less permissive is not returned, this is a finding.

Fix: F-32889r567482_fix

Change the permissions of the file "/var/log/messages" to "0640" by running the following command: $ sudo chmod 0640 /var/log/messages

b

The RHEL 8 /var/log/messages file must be owned by root.

SI-11 - Medium - CCI-001314 - V-230246 - SV-230246r1017064_rule

RMF Control

SI-11

Severity

M

CCI

Version

RHEL-08-010220

Vuln IDs

V-230246

Rule IDs

SV-230246r1017064_rule

Only authorized personnel should be aware of errors and the details of the errors. Error messages are an indicator of an organization's operational state or can identify the RHEL 8 system or platform. Additionally, Personally Identifiable Information (PII) and operational information must not be revealed through error messages to unauthorized personnel or their designated representatives. The structure and content of error messages must be carefully considered by the organization and development team. The extent to which the information system is able to identify and handle error conditions is guided by organizational policy and operational requirements.

Checks: C-32915r567484_chk

Verify that the /var/log/messages file is owned by root with the following command: $ sudo stat -c "%U" /var/log/messages root If "root" is not returned as a result, this is a finding.

Fix: F-32890r567485_fix

Change the owner of the file /var/log/messages to root by running the following command: $ sudo chown root /var/log/messages

b

The RHEL 8 /var/log/messages file must be group-owned by root.

SI-11 - Medium - CCI-001314 - V-230247 - SV-230247r1017065_rule

RMF Control

SI-11

Severity

M

CCI

Version

RHEL-08-010230

Vuln IDs

V-230247

Rule IDs

SV-230247r1017065_rule

Only authorized personnel should be aware of errors and the details of the errors. Error messages are an indicator of an organization's operational state or can identify the RHEL 8 system or platform. Additionally, Personally Identifiable Information (PII) and operational information must not be revealed through error messages to unauthorized personnel or their designated representatives. The structure and content of error messages must be carefully considered by the organization and development team. The extent to which the information system is able to identify and handle error conditions is guided by organizational policy and operational requirements.

Checks: C-32916r567487_chk

Verify the "/var/log/messages" file is group-owned by root with the following command: $ sudo stat -c "%G" /var/log/messages root If "root" is not returned as a result, this is a finding.

Fix: F-32891r567488_fix

Change the group of the file "/var/log/messages" to "root" by running the following command: $ sudo chgrp root /var/log/messages

b

The RHEL 8 /var/log directory must have mode 0755 or less permissive.

SI-11 - Medium - CCI-001314 - V-230248 - SV-230248r1069291_rule

RMF Control

SI-11

Severity

M

CCI

Version

RHEL-08-010240

Vuln IDs

V-230248

Rule IDs

SV-230248r1069291_rule

Only authorized personnel should be aware of errors and the details of the errors. Error messages are an indicator of an organization's operational state or can identify the RHEL 8 system or platform. Additionally, Personally Identifiable Information (PII) and operational information must not be revealed through error messages to unauthorized personnel or their designated representatives. The structure and content of error messages must be carefully considered by the organization and development team. The extent to which the information system is able to identify and handle error conditions is guided by organizational policy and operational requirements.

Checks: C-32917r1069191_chk

Verify that the "/var/log" directory has a mode of "0755" or less with the following command: $ sudo stat -c "%a %n" /var/log 755 /var/log If a value of "0755" or less permissive is not returned, this is a finding.

Fix: F-32892r567491_fix

Change the permissions of the directory "/var/log" to "0755" by running the following command: $ sudo chmod 0755 /var/log

b

The RHEL 8 /var/log directory must be owned by root.

SI-11 - Medium - CCI-001314 - V-230249 - SV-230249r1017067_rule

RMF Control

SI-11

Severity

M

CCI

Version

RHEL-08-010250

Vuln IDs

V-230249

Rule IDs

SV-230249r1017067_rule

Only authorized personnel should be aware of errors and the details of the errors. Error messages are an indicator of an organization's operational state or can identify the RHEL 8 system or platform. Additionally, Personally Identifiable Information (PII) and operational information must not be revealed through error messages to unauthorized personnel or their designated representatives. The structure and content of error messages must be carefully considered by the organization and development team. The extent to which the information system is able to identify and handle error conditions is guided by organizational policy and operational requirements.

Checks: C-32918r567493_chk

Verify the /var/log directory is owned by root with the following command: $ sudo stat -c "%U" /var/log root If "root" is not returned as a result, this is a finding.

Fix: F-32893r567494_fix

Change the owner of the directory /var/log to root by running the following command: $ sudo chown root /var/log

b

The RHEL 8 /var/log directory must be group-owned by root.

SI-11 - Medium - CCI-001314 - V-230250 - SV-230250r1017068_rule

RMF Control

SI-11

Severity

M

CCI

Version

RHEL-08-010260

Vuln IDs

V-230250

Rule IDs

SV-230250r1017068_rule

Only authorized personnel should be aware of errors and the details of the errors. Error messages are an indicator of an organization's operational state or can identify the RHEL 8 system or platform. Additionally, Personally Identifiable Information (PII) and operational information must not be revealed through error messages to unauthorized personnel or their designated representatives. The structure and content of error messages must be carefully considered by the organization and development team. The extent to which the information system is able to identify and handle error conditions is guided by organizational policy and operational requirements.

Checks: C-32919r567496_chk

Verify the "/var/log" directory is group-owned by root with the following command: $ sudo stat -c "%G" /var/log root If "root" is not returned as a result, this is a finding.

Fix: F-32894r567497_fix

Change the group of the directory "/var/log" to "root" by running the following command: $ sudo chgrp root /var/log

b

The RHEL 8 SSH server must be configured to use only Message Authentication Codes (MACs) employing FIPS 140-3 validated cryptographic hash algorithms.

AC-17 - Medium - CCI-001453 - V-230251 - SV-230251r1044814_rule

RMF Control

AC-17

Severity

M

CCI

Version

RHEL-08-010290

Vuln IDs

V-230251

Rule IDs

SV-230251r1044814_rule

Without cryptographic integrity protections, information can be altered by unauthorized users without detection. Remote access (e.g., RDP) is access to DOD nonpublic information systems by an authorized user (or an information system) communicating through an external, nonorganization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless. Cryptographic mechanisms used for protecting the integrity of information include, for example, signed hash functions using asymmetric cryptography enabling distribution of the public key to verify the hash information while maintaining the confidentiality of the secret key used to generate the hash. RHEL 8 incorporates systemwide crypto policies by default. The SSH configuration file has no effect on the ciphers, MACs, or algorithms unless specifically defined in the /etc/sysconfig/sshd file. The employed algorithms can be viewed in the /etc/crypto-policies/back-ends/opensshserver.config file. The system will attempt to use the first hash presented by the client that matches the server list. Listing the values "strongest to weakest" is a method to ensure the use of the strongest hash available to secure the SSH connection. Satisfies: SRG-OS-000250-GPOS-00093, SRG-OS-000393-GPOS-00173, SRG-OS-000394-GPOS-00174, SRG-OS-000125-GPOS-00065

Checks: C-32920r1044812_chk

Verify the RHEL 8 SSH server is configured to use only MACs employing FIPS 140-3 approved algorithms. To verify the MACs in the systemwide SSH configuration file, use the following command: $ sudo grep -i macs /etc/crypto-policies/back-ends/opensshserver.config -oMACs=hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512,hmac-sha2-256 If the MACs entries in the "opensshserver.config" file have any hashes other than "hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512,hmac-sha2-256", the order differs from the example above, or they are missing or commented out, this is a finding.

Fix: F-32895r1044813_fix

Configure the RHEL 8 SSH server to use only MACs employing FIPS 140-3 approved algorithms by updating the "/etc/crypto-policies/back-ends/opensshserver.config" file with the following commands. To manually update the MACs in the systemwide SSH configuration, use the following command: $ sudo sed -i -E 's/(-oMACs=)[^ ]*/\1hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512,hmac-sha2-256/' "$(readlink -f /etc/crypto-policies/back-ends/opensshserver.config)" A reboot is required for the changes to take effect.

b

The RHEL 8 operating system must implement DOD-approved encryption to protect the confidentiality of SSH server connections.

AC-17 - Medium - CCI-001453 - V-230252 - SV-230252r1067104_rule

RMF Control

AC-17

Severity

M

CCI

Version

RHEL-08-010291

Vuln IDs

V-230252

Rule IDs

SV-230252r1067104_rule

Without cryptographic integrity protections, information can be altered by unauthorized users without detection. Remote access (e.g., RDP) is access to DOD nonpublic information systems by an authorized user (or an information system) communicating through an external, nonorganization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless. Cryptographic mechanisms used for protecting the integrity of information include, for example, signed hash functions using asymmetric cryptography enabling distribution of the public key to verify the hash information while maintaining the confidentiality of the secret key used to generate the hash. RHEL 8 incorporates systemwide crypto policies by default. The SSH configuration file has no effect on the ciphers, MACs, or algorithms unless specifically defined in the /etc/sysconfig/sshd file. The employed algorithms can be viewed in the /etc/crypto-policies/back-ends/opensshserver.config file. The system will attempt to use the first hash presented by the client that matches the server list. Listing the values "strongest to weakest" is a method to ensure the use of the strongest hash available to secure the SSH connection. Satisfies: SRG-OS-000250-GPOS-00093, SRG-OS-000393-GPOS-00173, SRG-OS-000394-GPOS-00174, SRG-OS-000125-GPOS-00065

Checks: C-32921r1067104_chk

Verify the SSH server is configured to use only ciphers employing FIPS 140-3 approved algorithms. To verify the ciphers in the systemwide SSH configuration file, use the following command: $ sudo grep -i ciphers /etc/crypto-policies/back-ends/opensshserver.config -oCiphers=aes256-gcm@openssh.com,aes128-gcm@openssh.com,aes256-ctr,aes128-ctr If the ciphers entries in the "opensshserver.config" file have any hashes other than "aes256-gcm@openssh.com,aes128-gcm@openssh.com,aes256-ctr,aes128-ctr", the order differs from the example above, or they are missing or commented out, this is a finding.

Fix: F-32896r1044816_fix

Configure the RHEL 8 SSH server to use only ciphers employing FIPS 140-3 approved algorithms by updating the "/etc/crypto-policies/back-ends/opensshserver.config" file with the following commands. To manually update the ciphers in the systemwide SSH configuration, use the following command: $ sudo sed -i -E 's/(-oCiphers=)[^ ]*/\1aes256-gcm@openssh.com,aes128-gcm@openssh.com,aes256-ctr,aes128-ctr/' "$(readlink -f /etc/crypto-policies/back-ends/opensshserver.config)" A reboot is required for the changes to take effect.

a

RHEL 8 must ensure the SSH server uses strong entropy.

CM-6 - Low - CCI-000366 - V-230253 - SV-230253r1044799_rule

RMF Control

CM-6

Severity

L

CCI

Version

RHEL-08-010292

Vuln IDs

V-230253

Rule IDs

SV-230253r1044799_rule

The most important characteristic of a random number generator is its randomness, namely its ability to deliver random numbers that are impossible to predict. Entropy in computer security is associated with the unpredictability of a source of randomness. The random source with high entropy tends to achieve a uniform distribution of random values. Random number generators are one of the most important building blocks of cryptosystems. The SSH implementation in RHEL 8 uses the OPENSSL library, which does not use high-entropy sources by default. By using the SSH_USE_STRONG_RNG environment variable the OPENSSL random generator is reseeded from /dev/random. This setting is not recommended on computers without the hardware random generator because insufficient entropy causes the connection to be blocked until enough entropy is available.

Checks: C-32922r1044797_chk

Note: If the operating system is RHEL versions 8.0 or 8.1, this requirement is not applicable. Verify the operating system SSH server uses strong entropy with the following command: $ sudo grep -i ssh_use_strong_rng /etc/sysconfig/sshd SSH_USE_STRONG_RNG=32 If the "SSH_USE_STRONG_RNG" line does not equal "32", is commented out, or is missing, this is a finding.

Fix: F-32897r1044798_fix

Configure the operating system SSH server to use strong entropy. Add or modify the following line in the "/etc/sysconfig/sshd" file. SSH_USE_STRONG_RNG=32 The SSH service must be restarted for changes to take effect. Restart the SSH Daemon with the following command: $ sudo systemctl restart sshd.service

b

The RHEL 8 operating system must implement DoD-approved encryption in the OpenSSL package.

AC-17 - Medium - CCI-001453 - V-230254 - SV-230254r1017072_rule

RMF Control

AC-17

Severity

M

CCI

Version

RHEL-08-010293

Vuln IDs

V-230254

Rule IDs

SV-230254r1017072_rule

Without cryptographic integrity protections, information can be altered by unauthorized users without detection. Remote access (e.g., RDP) is access to DoD nonpublic information systems by an authorized user (or an information system) communicating through an external, non-organization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless. Cryptographic mechanisms used for protecting the integrity of information include, for example, signed hash functions using asymmetric cryptography enabling distribution of the public key to verify the hash information while maintaining the confidentiality of the secret key used to generate the hash. RHEL 8 incorporates system-wide crypto policies by default. The employed algorithms can be viewed in the /etc/crypto-policies/back-ends/openssl.config file. Satisfies: SRG-OS-000250-GPOS-00093, SRG-OS-000393-GPOS-00173, SRG-OS-000394-GPOS-00174, SRG-OS-000125-GPOS-00065

Checks: C-32923r567508_chk

Verify the OpenSSL library is configured to use only ciphers employing FIPS 140-2-approved algorithms: Verify that system-wide crypto policies are in effect: $ sudo grep -i opensslcnf.config /etc/pki/tls/openssl.cnf .include /etc/crypto-policies/back-ends/opensslcnf.config If the "opensslcnf.config" is not defined in the "/etc/pki/tls/openssl.cnf" file, this is a finding. Verify which system-wide crypto policy is in use: $ sudo update-crypto-policies --show FIPS If the system-wide crypto policy is set to anything other than "FIPS", this is a finding.

Fix: F-32898r567509_fix

Configure the RHEL 8 OpenSSL library to use only ciphers employing FIPS 140-2-approved algorithms with the following command: $ sudo fips-mode-setup --enable A reboot is required for the changes to take effect.

b

The RHEL 8 operating system must implement DoD-approved TLS encryption in the OpenSSL package.

AC-17 - Medium - CCI-001453 - V-230255 - SV-230255r1017075_rule

RMF Control

AC-17

Severity

M

CCI

Version

RHEL-08-010294

Vuln IDs

V-230255

Rule IDs

SV-230255r1017075_rule

Without cryptographic integrity protections, information can be altered by unauthorized users without detection. Remote access (e.g., RDP) is access to DoD nonpublic information systems by an authorized user (or an information system) communicating through an external, non-organization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless. Cryptographic mechanisms used for protecting the integrity of information include, for example, signed hash functions using asymmetric cryptography enabling distribution of the public key to verify the hash information while maintaining the confidentiality of the secret key used to generate the hash. RHEL 8 incorporates system-wide crypto policies by default. The employed algorithms can be viewed in the /etc/crypto-policies/back-ends/openssl.config file. Satisfies: SRG-OS-000250-GPOS-00093, SRG-OS-000393-GPOS-00173, SRG-OS-000394-GPOS-00174, SRG-OS-000125-GPOS-00065

Checks: C-32924r1017073_chk

Verify the OpenSSL library is configured to use only DoD-approved TLS encryption: For versions prior to crypto-policies-20210617-1.gitc776d3e.el8.noarch: $ sudo grep -i MinProtocol /etc/crypto-policies/back-ends/opensslcnf.config MinProtocol = TLSv1.2 If the "MinProtocol" is set to anything older than "TLSv1.2", this is a finding. For version crypto-policies-20210617-1.gitc776d3e.el8.noarch and newer: $ sudo grep -i MinProtocol /etc/crypto-policies/back-ends/opensslcnf.config TLS.MinProtocol = TLSv1.2 DTLS.MinProtocol = DTLSv1.2 If the "TLS.MinProtocol" is set to anything older than "TLSv1.2" or the "DTLS.MinProtocol" is set to anything older than DTLSv1.2, this is a finding.

Fix: F-32899r1017074_fix

Configure the RHEL 8 OpenSSL library to use only DoD-approved TLS encryption by editing the following line in the "/etc/crypto-policies/back-ends/opensslcnf.config" file: For versions prior to crypto-policies-20210617-1.gitc776d3e.el8.noarch: MinProtocol = TLSv1.2 For version crypto-policies-20210617-1.gitc776d3e.el8.noarch and newer: TLS.MinProtocol = TLSv1.2 DTLS.MinProtocol = DTLSv1.2 A reboot is required for the changes to take effect.

b

The RHEL 8 operating system must implement DoD-approved TLS encryption in the GnuTLS package.

AC-17 - Medium - CCI-001453 - V-230256 - SV-230256r1017076_rule

RMF Control

AC-17

Severity

M

CCI

Version

RHEL-08-010295

Vuln IDs

V-230256

Rule IDs

SV-230256r1017076_rule

Without cryptographic integrity protections, information can be altered by unauthorized users without detection. Transport Layer Security (TLS) encryption is a required security setting as a number of known vulnerabilities have been reported against Secure Sockets Layer (SSL) and earlier versions of TLS. Encryption of private information is essential to ensuring data confidentiality. If private information is not encrypted, it can be intercepted and easily read by an unauthorized party. SQL Server must use a minimum of FIPS 140-2-approved TLS version 1.2, and all non-FIPS-approved SSL and TLS versions must be disabled. NIST SP 800-52 specifies the preferred configurations for government systems. Cryptographic mechanisms used for protecting the integrity of information include, for example, signed hash functions using asymmetric cryptography enabling distribution of the public key to verify the hash information while maintaining the confidentiality of the secret key used to generate the hash. The GnuTLS library offers an API to access secure communications protocols. SSLv2 is not available in the GnuTLS library. The RHEL 8 system-wide crypto policy defines employed algorithms in the /etc/crypto-policies/back-ends/gnutls.config file. Satisfies: SRG-OS-000250-GPOS-00093, SRG-OS-000423-GPOS-00187

Checks: C-32925r792858_chk

Verify the GnuTLS library is configured to only allow DoD-approved SSL/TLS Versions: $ sudo grep -io +vers.* /etc/crypto-policies/back-ends/gnutls.config +VERS-ALL:-VERS-DTLS0.9:-VERS-SSL3.0:-VERS-TLS1.0:-VERS-TLS1.1:-VERS-DTLS1.0:+COMP-NULL:%PROFILE_MEDIUM If the "gnutls.config" does not list "-VERS-DTLS0.9:-VERS-SSL3.0:-VERS-TLS1.0:-VERS-TLS1.1:-VERS-DTLS1.0" to disable unapproved SSL/TLS versions, this is a finding.

Fix: F-32900r567515_fix

Configure the RHEL 8 GnuTLS library to use only DoD-approved encryption by adding the following line to "/etc/crypto-policies/back-ends/gnutls.config": +VERS-ALL:-VERS-DTLS0.9:-VERS-SSL3.0:-VERS-TLS1.0:-VERS-TLS1.1:-VERS-DTLS1.0 A reboot is required for the changes to take effect.

b

RHEL 8 system commands must have mode 755 or less permissive.

CM-5 - Medium - CCI-001499 - V-230257 - SV-230257r1017077_rule

RMF Control

CM-5

Severity

M

CCI

Version

RHEL-08-010300

Vuln IDs

V-230257

Rule IDs

SV-230257r1017077_rule

If RHEL 8 were to allow any user to make changes to software libraries, then those changes might be implemented without undergoing the appropriate testing and approvals that are part of a robust change management process. This requirement applies to RHEL 8 with software libraries that are accessible and configurable, as in the case of interpreted languages. Software libraries also include privileged programs that execute with escalated privileges. Only qualified and authorized individuals will be allowed to obtain access to information system components for purposes of initiating changes, including upgrades and modifications.

Checks: C-32926r792860_chk

Verify the system commands contained in the following directories have mode "755" or less permissive with the following command: $ sudo find -L /bin /sbin /usr/bin /usr/sbin /usr/local/bin /usr/local/sbin -perm /022 -exec ls -l {} \; If any system commands are found to be group-writable or world-writable, this is a finding.

Fix: F-32901r792861_fix

Configure the system commands to be protected from unauthorized access. Run the following command, replacing "[FILE]" with any system command with a mode more permissive than "755". $ sudo chmod 755 [FILE]

b

RHEL 8 system commands must be owned by root.

CM-5 - Medium - CCI-001499 - V-230258 - SV-230258r1017078_rule

RMF Control

CM-5

Severity

M

CCI

Version

RHEL-08-010310

Vuln IDs

V-230258

Rule IDs

SV-230258r1017078_rule

If RHEL 8 were to allow any user to make changes to software libraries, then those changes might be implemented without undergoing the appropriate testing and approvals that are part of a robust change management process. This requirement applies to RHEL 8 with software libraries that are accessible and configurable, as in the case of interpreted languages. Software libraries also include privileged programs that execute with escalated privileges. Only qualified and authorized individuals will be allowed to obtain access to information system components for purposes of initiating changes, including upgrades and modifications.

Checks: C-32927r567520_chk

Verify the system commands contained in the following directories are owned by "root" with the following command: $ sudo find -L /bin /sbin /usr/bin /usr/sbin /usr/local/bin /usr/local/sbin ! -user root -exec ls -l {} \; If any system commands are returned, this is a finding.

Fix: F-32902r567521_fix

Configure the system commands to be protected from unauthorized access. Run the following command, replacing "[FILE]" with any system command file not owned by "root". $ sudo chown root [FILE]

b

RHEL 8 system commands must be group-owned by root or a system account.

CM-5 - Medium - CCI-001499 - V-230259 - SV-230259r1017079_rule

RMF Control

CM-5

Severity

M

CCI

Version

RHEL-08-010320

Vuln IDs

V-230259

Rule IDs

SV-230259r1017079_rule

If RHEL 8 were to allow any user to make changes to software libraries, then those changes might be implemented without undergoing the appropriate testing and approvals that are part of a robust change management process. This requirement applies to RHEL 8 with software libraries that are accessible and configurable, as in the case of interpreted languages. Software libraries also include privileged programs that execute with escalated privileges. Only qualified and authorized individuals will be allowed to obtain access to information system components for purposes of initiating changes, including upgrades and modifications.

Checks: C-32928r792863_chk

Verify the system commands contained in the following directories are group-owned by "root", or a required system account, with the following command: $ sudo find -L /bin /sbin /usr/bin /usr/sbin /usr/local/bin /usr/local/sbin ! -group root -exec ls -l {} \; If any system commands are returned and is not group-owned by a required system account, this is a finding.

Fix: F-32903r567524_fix

Configure the system commands to be protected from unauthorized access. Run the following command, replacing "[FILE]" with any system command file not group-owned by "root" or a required system account. $ sudo chgrp root [FILE]

b

RHEL 8 library files must have mode 755 or less permissive.

CM-5 - Medium - CCI-001499 - V-230260 - SV-230260r1101888_rule

RMF Control

CM-5

Severity

M

CCI

Version

RHEL-08-010330

Vuln IDs

V-230260

Rule IDs

SV-230260r1101888_rule

If RHEL 8 were to allow any user to make changes to software libraries, then those changes might be implemented without undergoing the appropriate testing and approvals that are part of a robust change management process. This requirement applies to RHEL 8 with software libraries that are accessible and configurable, as in the case of interpreted languages. Software libraries also include privileged programs that execute with escalated privileges. Only qualified and authorized individuals will be allowed to obtain access to information system components for purposes of initiating changes, including upgrades and modifications.

Checks: C-32929r1101886_chk

Verify the systemwide shared library files contained in the directories "/lib", "/lib64", "/usr/lib", and "/usr/lib64" have mode 0755 or less permissive. Check that the systemwide shared library files have mode 0755 or less permissive with the following command: $ sudo find /lib /lib64 /usr/lib /usr/lib64 -type f -name '*.so*' -perm /022 -exec stat -c "%n %a" {} + If any output is returned, this is a finding.

Fix: F-32904r1101887_fix

Configure the systemwide shared library files contained in the directories "/lib", "/lib64", "/usr/lib", and "/usr/lib64" have mode 0755 or less permissive with the following command. $ sudo find /lib /lib64 /usr/lib /usr/lib64 -type f -name '*.so*' -perm /022 -exec chmod go-w {} +

b

RHEL 8 library files must be owned by root.

CM-5 - Medium - CCI-001499 - V-230261 - SV-230261r1101891_rule

RMF Control

CM-5

Severity

M

CCI

Version

RHEL-08-010340

Vuln IDs

V-230261

Rule IDs

SV-230261r1101891_rule

If RHEL 8 were to allow any user to make changes to software libraries, then those changes might be implemented without undergoing the appropriate testing and approvals that are part of a robust change management process. This requirement applies to RHEL 8 with software libraries that are accessible and configurable, as in the case of interpreted languages. Software libraries also include privileged programs that execute with escalated privileges. Only qualified and authorized individuals will be allowed to obtain access to information system components for purposes of initiating changes, including upgrades and modifications.

Checks: C-32930r1101889_chk

Verify the systemwide shared library files contained in the directories "/lib", "/lib64", "/usr/lib", and "/usr/lib64" are owned by root with the following command: $ sudo find /lib /lib64 /usr/lib /usr/lib64 -type f -name '*.so*' ! -user root -exec stat -c "%n %U" {} + If any output is returned, this is a finding.

Fix: F-32905r1101890_fix

Configure the systemwide shared library files contained in the directories "/lib", "/lib64", "/usr/lib", and "/usr/lib64" to be owned by root with the following command: $ sudo find /lib /lib64 /usr/lib /usr/lib64 -type f -name '*.so*' ! -user root -exec chown root {} +

b

RHEL 8 library files must be group-owned by root or a system account.

CM-5 - Medium - CCI-001499 - V-230262 - SV-230262r1101894_rule

RMF Control

CM-5

Severity

M

CCI

Version

RHEL-08-010350

Vuln IDs

V-230262

Rule IDs

SV-230262r1101894_rule

If RHEL 8 were to allow any user to make changes to software libraries, then those changes might be implemented without undergoing the appropriate testing and approvals that are part of a robust change management process. This requirement applies to RHEL 8 with software libraries that are accessible and configurable, as in the case of interpreted languages. Software libraries also include privileged programs that execute with escalated privileges. Only qualified and authorized individuals will be allowed to obtain access to information system components for purposes of initiating changes, including upgrades and modifications.

Checks: C-32931r1101892_chk

Verify the systemwide shared library files contained in the directories "/lib", "/lib64", "/usr/lib", and "/usr/lib64" are group owned by root with the following command: $ sudo find /lib /lib64 /usr/lib /usr/lib64 -type f -name '*.so*' ! -group root -exec stat -c "%n %G" {} + If any output is returned, this is a finding.

Fix: F-32906r1101893_fix

Configure the systemwide shared library files contained in the directories "/lib", "/lib64", "/usr/lib", and "/usr/lib64" are group owned by root with the following command: $ sudo find /lib /lib64 /usr/lib /usr/lib64 -type f -name '*.so*' ! -group root -exec chown :root {} +

b

The RHEL 8 file integrity tool must notify the system administrator when changes to the baseline configuration or anomalies in the operation of any security functions are discovered within an organizationally defined frequency.

CM-3 - Medium - CCI-001744 - V-230263 - SV-230263r1017083_rule

RMF Control

CM-3

Severity

M

CCI

CCI-001744

Version

RHEL-08-010360

Vuln IDs

V-230263

Rule IDs

SV-230263r1017083_rule

Unauthorized changes to the baseline configuration could make the system vulnerable to various attacks or allow unauthorized access to the operating system. Changes to operating system configurations can have unintended side effects, some of which may be relevant to security. Detecting such changes and providing an automated response can help avoid unintended, negative consequences that could ultimately affect the security state of the operating system. The operating system's Information System Security Manager (ISSM)/Information System Security Officer (ISSO) and System Administrators (SAs) must be notified via email and/or monitoring system trap when there is an unauthorized modification of a configuration item. Notifications provided by information systems include messages to local computer consoles, and/or hardware indications, such as lights. This capability must take into account operational requirements for availability for selecting an appropriate response. The organization may choose to shut down or restart the information system upon security function anomaly detection. RHEL 8 comes with many optional software packages. A file integrity tool called Advanced Intrusion Detection Environment (AIDE) is one of those optional packages. This requirement assumes the use of AIDE; however, a different tool may be used if the requirements are met. Note that AIDE does not have a configuration that will send a notification, so a cron job is recommended that uses the mail application on the system to email the results of the file integrity check. Satisfies: SRG-OS-000363-GPOS-00150, SRG-OS-000446-GPOS-00200, SRG-OS-000447-GPOS-00201

Checks: C-32932r902714_chk

Verify the operating system routinely checks the baseline configuration for unauthorized changes and notifies the system administrator when anomalies in the operation of any security functions are discovered. Check that RHEL 8 routinely executes a file integrity scan for changes to the system baseline. The command used in the example will use a daily occurrence. Check the cron directories for scripts controlling the execution and notification of results of the file integrity application. For example, if AIDE is installed on the system, use the following commands: $ sudo ls -al /etc/cron.* | grep aide -rwxr-xr-x 1 root root 29 Nov 22 2015 aide $ sudo grep aide /etc/crontab /var/spool/cron/root /etc/crontab: 30 04 * * * root /usr/sbin/aide /var/spool/cron/root: 30 04 * * * root /usr/sbin/aide $ sudo more /etc/cron.daily/aide #!/bin/bash /usr/sbin/aide --check | /bin/mail -s "$HOSTNAME - Daily AIDE integrity check run" root@example_server_name.mil If the file integrity application does not exist, or a script file controlling the execution of the file integrity application does not exist, or the file integrity application does not notify designated personnel of changes, this is a finding.

Fix: F-32907r902715_fix

Configure the file integrity tool to run automatically on the system at least weekly and to notify designated personnel if baseline configurations are changed in an unauthorized manner. The AIDE tool can be configured to email designated personnel with the use of the cron system. The following example output is generic. It will set cron to run AIDE daily and to send email at the completion of the analysis. $ sudo more /etc/cron.daily/aide #!/bin/bash /usr/sbin/aide --check | /bin/mail -s "$HOSTNAME - Daily AIDE integrity check run" root@example_server_name.mil Note: Per requirement RHEL-08-010358, the "mailx" package must be installed on the system to enable email functionality.

c

RHEL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components from a repository without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization.

CM-5 - High - CCI-001749 - V-230264 - SV-230264r1017377_rule

RMF Control

CM-5

Severity

H

CCI

Version

RHEL-08-010370

Vuln IDs

V-230264

Rule IDs

SV-230264r1017377_rule

Changes to any software components can have significant effects on the overall security of the operating system. This requirement ensures the software has not been tampered with and that it has been provided by a trusted vendor. Accordingly, patches, service packs, device drivers, or operating system components must be signed with a certificate recognized and approved by the organization. Verifying the authenticity of the software prior to installation validates the integrity of the patch or upgrade received from a vendor. This verifies the software has not been tampered with and that it has been provided by a trusted vendor. Self-signed certificates are disallowed by this requirement. The operating system should not have to verify the software again. This requirement does not mandate DoD certificates for this purpose; however, the certificate used to verify the software must be from an approved CA.

Checks: C-32933r880709_chk

Verify the operating system prevents the installation of patches, service packs, device drivers, or operating system components from a repository without verification that they have been digitally signed using a certificate that is recognized and approved by the organization. Check that YUM verifies the signature of packages from a repository prior to install with the following command: $ sudo grep -E '^\[.*\]|gpgcheck' /etc/yum.repos.d/*.repo /etc/yum.repos.d/appstream.repo:[appstream] /etc/yum.repos.d/appstream.repo:gpgcheck=1 /etc/yum.repos.d/baseos.repo:[baseos] /etc/yum.repos.d/baseos.repo:gpgcheck=1 If "gpgcheck" is not set to "1", or if options are missing or commented out, ask the System Administrator how the certificates for patches and other operating system components are verified. If there is no process to validate certificates that is approved by the organization, this is a finding.

Fix: F-32908r880710_fix

Configure the operating system to verify the signature of packages from a repository prior to install by setting the following option in the "/etc/yum.repos.d/[your_repo_name].repo" file: gpgcheck=1

c

RHEL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization.

CM-5 - High - CCI-001749 - V-230265 - SV-230265r1017378_rule

RMF Control

CM-5

Severity

H

CCI

Version

RHEL-08-010371

Vuln IDs

V-230265

Rule IDs

SV-230265r1017378_rule

Changes to any software components can have significant effects on the overall security of the operating system. This requirement ensures the software has not been tampered with and that it has been provided by a trusted vendor. Accordingly, patches, service packs, device drivers, or operating system components must be signed with a certificate recognized and approved by the organization. Verifying the authenticity of the software prior to installation validates the integrity of the patch or upgrade received from a vendor. This verifies the software has not been tampered with and that it has been provided by a trusted vendor. Self-signed certificates are disallowed by this requirement. The operating system should not have to verify the software again. This requirement does not mandate DoD certificates for this purpose; however, the certificate used to verify the software must be from an approved CA.

Checks: C-32934r567541_chk

Verify the operating system prevents the installation of patches, service packs, device drivers, or operating system components from a repository without verification that they have been digitally signed using a certificate that is recognized and approved by the organization. Check if YUM is configured to perform a signature check on local packages with the following command: $ sudo grep -i localpkg_gpgcheck /etc/dnf/dnf.conf localpkg_gpgcheck =True If "localpkg_gpgcheck" is not set to either "1", "True", or "yes", commented out, or is missing from "/etc/dnf/dnf.conf", this is a finding.

Fix: F-32909r567542_fix

Configure the operating system to remove all software components after updated versions have been installed. Set the "localpkg_gpgcheck" option to "True" in the "/etc/dnf/dnf.conf" file: localpkg_gpgcheck=True

b

RHEL 8 must prevent the loading of a new kernel for later execution.

CM-5 - Medium - CCI-001749 - V-230266 - SV-230266r1017084_rule

RMF Control

CM-5

Severity

M

CCI

Version

RHEL-08-010372

Vuln IDs

V-230266

Rule IDs

SV-230266r1017084_rule

Changes to any software components can have significant effects on the overall security of the operating system. This requirement ensures the software has not been tampered with and that it has been provided by a trusted vendor. Disabling kexec_load prevents an unsigned kernel image (that could be a windows kernel or modified vulnerable kernel) from being loaded. Kexec can be used subvert the entire secureboot process and should be avoided at all costs especially since it can load unsigned kernel images. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of which of the directories they reside in. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf

Checks: C-32935r858746_chk

Verify the operating system is configured to disable kernel image loading with the following commands: Check the status of the kernel.kexec_load_disabled kernel parameter. $ sudo sysctl kernel.kexec_load_disabled kernel.kexec_load_disabled = 1 If "kernel.kexec_load_disabled" is not set to "1" or is missing, this is a finding. Check that the configuration files are present to enable this kernel parameter. $ sudo grep -r kernel.kexec_load_disabled /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf:kernel.kexec_load_disabled = 1 If "kernel.kexec_load_disabled" is not set to "1", is missing or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-32910r858747_fix

Configure the operating system to disable kernel image loading. Add or edit the following line in a system configuration file, in the "/etc/sysctl.d/" directory: kernel.kexec_load_disabled = 1 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf Load settings from all system configuration files with the following command: $ sudo sysctl --system

b

RHEL 8 must enable kernel parameters to enforce discretionary access control on symlinks.

AC-3 - Medium - CCI-002165 - V-230267 - SV-230267r1017085_rule

RMF Control

AC-3

Severity

M

CCI

CCI-002165

Version

RHEL-08-010373

Vuln IDs

V-230267

Rule IDs

SV-230267r1017085_rule

Discretionary Access Control (DAC) is based on the notion that individual users are "owners" of objects and therefore have discretion over who should be authorized to access the object and in which mode (e.g., read or write). Ownership is usually acquired as a consequence of creating the object or via specified ownership assignment. DAC allows the owner to determine who will have access to objects they control. An example of DAC includes user-controlled file permissions. When discretionary access control policies are implemented, subjects are not constrained with regard to what actions they can take with information for which they have already been granted access. Thus, subjects that have been granted access to information are not prevented from passing (i.e., the subjects have the discretion to pass) the information to other subjects or objects. A subject that is constrained in its operation by Mandatory Access Control policies is still able to operate under the less rigorous constraints of this requirement. Thus, while Mandatory Access Control imposes constraints preventing a subject from passing information to another subject operating at a different sensitivity level, this requirement permits the subject to pass the information to any subject at the same sensitivity level. The policy is bounded by the information system boundary. Once the information is passed outside the control of the information system, additional means may be required to ensure the constraints remain in effect. While the older, more traditional definitions of discretionary access control require identity-based access control, that limitation is not required for this use of discretionary access control. By enabling the fs.protected_symlinks kernel parameter, symbolic links are permitted to be followed only when outside a sticky world-writable directory, or when the UID of the link and follower match, or when the directory owner matches the symlink's owner. Disallowing such symlinks helps mitigate vulnerabilities based on insecure file system accessed by privileged programs, avoiding an exploitation vector exploiting unsafe use of open() or creat(). The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of which of the directories they reside in. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf Satisfies: SRG-OS-000312-GPOS-00122, SRG-OS-000312-GPOS-00123, SRG-OS-000312-GPOS-00124, SRG-OS-000324-GPOS-00125

Checks: C-32936r858749_chk

Verify the operating system is configured to enable DAC on symlinks with the following commands: Check the status of the fs.protected_symlinks kernel parameter. $ sudo sysctl fs.protected_symlinks fs.protected_symlinks = 1 If "fs.protected_symlinks" is not set to "1" or is missing, this is a finding. Check that the configuration files are present to enable this kernel parameter. $ sudo grep -r fs.protected_symlinks /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf:fs.protected_symlinks = 1 If "fs.protected_symlinks" is not set to "1", is missing or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-32911r858750_fix

Configure the operating system to enable DAC on symlinks. Add or edit the following line in a system configuration file, in the "/etc/sysctl.d/" directory: fs.protected_symlinks = 1 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf Load settings from all system configuration files with the following command: $ sudo sysctl --system

b

RHEL 8 must enable kernel parameters to enforce discretionary access control on hardlinks.

AC-3 - Medium - CCI-002165 - V-230268 - SV-230268r1017086_rule

RMF Control

AC-3

Severity

M

CCI

CCI-002165

Version

RHEL-08-010374

Vuln IDs

V-230268

Rule IDs

SV-230268r1017086_rule

Discretionary Access Control (DAC) is based on the notion that individual users are "owners" of objects and therefore have discretion over who should be authorized to access the object and in which mode (e.g., read or write). Ownership is usually acquired as a consequence of creating the object or via specified ownership assignment. DAC allows the owner to determine who will have access to objects they control. An example of DAC includes user-controlled file permissions. When discretionary access control policies are implemented, subjects are not constrained with regard to what actions they can take with information for which they have already been granted access. Thus, subjects that have been granted access to information are not prevented from passing (i.e., the subjects have the discretion to pass) the information to other subjects or objects. A subject that is constrained in its operation by Mandatory Access Control policies is still able to operate under the less rigorous constraints of this requirement. Thus, while Mandatory Access Control imposes constraints preventing a subject from passing information to another subject operating at a different sensitivity level, this requirement permits the subject to pass the information to any subject at the same sensitivity level. The policy is bounded by the information system boundary. Once the information is passed outside the control of the information system, additional means may be required to ensure the constraints remain in effect. While the older, more traditional definitions of discretionary access control require identity-based access control, that limitation is not required for this use of discretionary access control. By enabling the fs.protected_hardlinks kernel parameter, users can no longer create soft or hard links to files they do not own. Disallowing such hardlinks mitigate vulnerabilities based on insecure file system accessed by privileged programs, avoiding an exploitation vector exploiting unsafe use of open() or creat(). The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of which of the directories they reside in. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf Satisfies: SRG-OS-000312-GPOS-00122, SRG-OS-000312-GPOS-00123, SRG-OS-000312-GPOS-00124, SRG-OS-000324-GPOS-00125

Checks: C-32937r858752_chk

Verify the operating system is configured to enable DAC on hardlinks with the following commands: Check the status of the fs.protected_hardlinks kernel parameter. $ sudo sysctl fs.protected_hardlinks fs.protected_hardlinks = 1 If "fs.protected_hardlinks" is not set to "1" or is missing, this is a finding. Check that the configuration files are present to enable this kernel parameter. $ sudo grep -r fs.protected_hardlinks /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf:fs.protected_hardlinks = 1 If "fs.protected_hardlinks" is not set to "1", is missing or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-32912r858753_fix

Configure the operating system to enable DAC on hardlinks. Add or edit the following line in a system configuration file, in the "/etc/sysctl.d/" directory: fs.protected_hardlinks = 1 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf Load settings from all system configuration files with the following command: $ sudo sysctl --system

a

RHEL 8 must restrict access to the kernel message buffer.

SC-4 - Low - CCI-001090 - V-230269 - SV-230269r1017087_rule

RMF Control

SC-4

Severity

L

CCI

CCI-001090

Version

RHEL-08-010375

Vuln IDs

V-230269

Rule IDs

SV-230269r1017087_rule

Preventing unauthorized information transfers mitigates the risk of information, including encrypted representations of information, produced by the actions of prior users/roles (or the actions of processes acting on behalf of prior users/roles) from being available to any current users/roles (or current processes) that obtain access to shared system resources (e.g., registers, main memory, hard disks) after those resources have been released back to information systems. The control of information in shared resources is also commonly referred to as object reuse and residual information protection. This requirement generally applies to the design of an information technology product, but it can also apply to the configuration of particular information system components that are, or use, such products. This can be verified by acceptance/validation processes in DoD or other government agencies. There may be shared resources with configurable protections (e.g., files in storage) that may be assessed on specific information system components. Restricting access to the kernel message buffer limits access to only root. This prevents attackers from gaining additional system information as a non-privileged user. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of which of the directories they reside in. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf

Checks: C-32938r833295_chk

Verify the operating system is configured to restrict access to the kernel message buffer with the following commands: Check the status of the kernel.dmesg_restrict kernel parameter. $ sudo sysctl kernel.dmesg_restrict kernel.dmesg_restrict = 1 If "kernel.dmesg_restrict" is not set to "1" or is missing, this is a finding. Check that the configuration files are present to enable this kernel parameter. $ sudo grep -r kernel.dmesg_restrict /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf:kernel.dmesg_restrict = 1 If "kernel.dmesg_restrict" is not set to "1", is missing or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-32913r858755_fix

Configure the operating system to restrict access to the kernel message buffer. Add or edit the following line in a system configuration file, in the "/etc/sysctl.d/" directory: kernel.dmesg_restrict = 1 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf Load settings from all system configuration files with the following command: $ sudo sysctl --system

a

RHEL 8 must prevent kernel profiling by unprivileged users.

SC-4 - Low - CCI-001090 - V-230270 - SV-230270r1017088_rule

RMF Control

SC-4

Severity

L

CCI

CCI-001090

Version

RHEL-08-010376

Vuln IDs

V-230270

Rule IDs

SV-230270r1017088_rule

Preventing unauthorized information transfers mitigates the risk of information, including encrypted representations of information, produced by the actions of prior users/roles (or the actions of processes acting on behalf of prior users/roles) from being available to any current users/roles (or current processes) that obtain access to shared system resources (e.g., registers, main memory, hard disks) after those resources have been released back to information systems. The control of information in shared resources is also commonly referred to as object reuse and residual information protection. This requirement generally applies to the design of an information technology product, but it can also apply to the configuration of particular information system components that are, or use, such products. This can be verified by acceptance/validation processes in DoD or other government agencies. There may be shared resources with configurable protections (e.g., files in storage) that may be assessed on specific information system components. Setting the kernel.perf_event_paranoid kernel parameter to "2" prevents attackers from gaining additional system information as a non-privileged user. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of which of the directories they reside in. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf

Checks: C-32939r833297_chk

Verify the operating system is configured to prevent kernel profiling by unprivileged users with the following commands: Check the status of the kernel.perf_event_paranoid kernel parameter. $ sudo sysctl kernel.perf_event_paranoid kernel.perf_event_paranoid = 2 If "kernel.perf_event_paranoid" is not set to "2" or is missing, this is a finding. Check that the configuration files are present to enable this kernel parameter. $ sudo grep -r kernel.perf_event_paranoid /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf:kernel.perf_event_paranoid = 2 If "kernel.perf_event_paranoid" is not set to "2", is missing or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-32914r858757_fix

Configure the operating system to prevent kernel profiling by unprivileged users. Add or edit the following line in a system configuration file, in the "/etc/sysctl.d/" directory: kernel.perf_event_paranoid = 2 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf Load settings from all system configuration files with the following command: $ sudo sysctl --system

b

RHEL 8 must require users to provide a password for privilege escalation.

IA-11 - Medium - CCI-002038 - V-230271 - SV-230271r1101896_rule

RMF Control

IA-11

Severity

M

CCI

Version

RHEL-08-010380

Vuln IDs

V-230271

Rule IDs

SV-230271r1101896_rule

Without reauthentication, users may access resources or perform tasks for which they do not have authorization. When operating systems provide the capability to escalate a functional capability, it is critical the user reauthenticate. Satisfies: SRG-OS-000373-GPOS-00156, SRG-OS-000373-GPOS-00157, SRG-OS-000373-GPOS-00158

Checks: C-32940r1101895_chk

Verify that "/etc/sudoers" has no occurrences of "NOPASSWD". Check that the "/etc/sudoers" file has no occurrences of "NOPASSWD" by running the following command: $ sudo grep -iR 'NOPASSWD' /etc/sudoers /etc/sudoers.d/ %admin ALL=(ALL) NOPASSWD: ALL If any occurrences of "NOPASSWD" are returned from the command and have not been documented with the information system security officer (ISSO) as an organizationally defined administrative group utilizing multifactor authentication (MFA), this is a finding.

Fix: F-32915r854025_fix

Remove any occurrence of "NOPASSWD" found in "/etc/sudoers" file or files in the "/etc/sudoers.d" directory.

b

RHEL 8 must require users to reauthenticate for privilege escalation.

IA-11 - Medium - CCI-002038 - V-230272 - SV-230272r1101898_rule

RMF Control

IA-11

Severity

M

CCI

Version

RHEL-08-010381

Vuln IDs

V-230272

Rule IDs

SV-230272r1101898_rule

Without reauthentication, users may access resources or perform tasks for which they do not have authorization. When operating systems provide the capability to escalate a functional capability, it is critical the user reauthenticate. Satisfies: SRG-OS-000373-GPOS-00156, SRG-OS-000373-GPOS-00157, SRG-OS-000373-GPOS-00158

Checks: C-32941r1101897_chk

Verify that "/etc/sudoers" has no occurrences of "!authenticate". Check that the "/etc/sudoers" file has no occurrences of "!authenticate" by running the following command: $ sudo egrep -iR '!authenticate' /etc/sudoers /etc/sudoers.d/ If any occurrences of "!authenticate" return from the command, this is a finding.

Fix: F-32916r567563_fix

Remove any occurrence of "!authenticate" found in "/etc/sudoers" file or files in the "/etc/sudoers.d" directory.

b

RHEL 8 must have the packages required for multifactor authentication installed.

IA-2 - Medium - CCI-001948 - V-230273 - SV-230273r1017381_rule

RMF Control

IA-2

Severity

M

CCI

CCI-001948

Version

RHEL-08-010390

Vuln IDs

V-230273

Rule IDs

SV-230273r1017381_rule

Using an authentication device, such as a DoD Common Access Card (CAC) or token that is separate from the information system, ensures that even if the information system is compromised, credentials stored on the authentication device will not be affected. Multifactor solutions that require devices separate from information systems gaining access include, for example, hardware tokens providing time-based or challenge-response authenticators and smart cards such as the U.S. Government Personal Identity Verification (PIV) card and the DoD CAC. A privileged account is defined as an information system account with authorizations of a privileged user. Remote access is access to DoD nonpublic information systems by an authorized user (or an information system) communicating through an external, non-organization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless. This requirement only applies to components where this is specific to the function of the device or has the concept of an organizational user (e.g., VPN, proxy capability). This does not apply to authentication for the purpose of configuring the device itself (management).

Checks: C-32942r743941_chk

Verify the operating system has the packages required for multifactor authentication installed with the following commands: $ sudo yum list installed openssl-pkcs11 openssl-pkcs11.x86_64 0.4.8-2.el8 @anaconda If the "openssl-pkcs11" package is not installed, ask the administrator to indicate what type of multifactor authentication is being utilized and what packages are installed to support it. If there is no evidence of multifactor authentication being used, this is a finding.

Fix: F-32917r743942_fix

Configure the operating system to implement multifactor authentication by installing the required package with the following command: $ sudo yum install openssl-pkcs11

b

RHEL 8 must implement certificate status checking for multifactor authentication.

IA-2 - Medium - CCI-001948 - V-230274 - SV-230274r1017089_rule

RMF Control

IA-2

Severity

M

CCI

CCI-001948

Version

RHEL-08-010400

Vuln IDs

V-230274

Rule IDs

SV-230274r1017089_rule

Using an authentication device, such as a DoD Common Access Card (CAC) or token that is separate from the information system, ensures that even if the information system is compromised, credentials stored on the authentication device will not be affected. Multifactor solutions that require devices separate from information systems gaining access include, for example, hardware tokens providing time-based or challenge-response authenticators and smart cards such as the U.S. Government Personal Identity Verification (PIV) card and the DoD CAC. RHEL 8 includes multiple options for configuring certificate status checking, but for this requirement focuses on the System Security Services Daemon (SSSD). By default, sssd performs Online Certificate Status Protocol (OCSP) checking and certificate verification using a sha256 digest function. Satisfies: SRG-OS-000375-GPOS-00160, SRG-OS-000377-GPOS-00162

Checks: C-32943r858740_chk

Verify the operating system implements certificate status checking for multifactor authentication. Note: If the System Administrator demonstrates the use of an approved alternate multifactor authentication method, this requirement is not applicable. Check to see if Online Certificate Status Protocol (OCSP) is enabled and using the proper digest value on the system with the following command: $ sudo grep certificate_verification /etc/sssd/sssd.conf /etc/sssd/conf.d/*.conf | grep -v "^#" certificate_verification = ocsp_dgst=sha1 If the certificate_verification line is missing from the [sssd] section, or is missing "ocsp_dgst=sha1", ask the administrator to indicate what type of multifactor authentication is being utilized and how the system implements certificate status checking. If there is no evidence of certificate status checking being used, this is a finding.

Fix: F-32918r809280_fix

Configure the operating system to implement certificate status checking for multifactor authentication. Review the "/etc/sssd/sssd.conf" file to determine if the system is configured to prevent OCSP or certificate verification. Add the following line to the [sssd] section of the "/etc/sssd/sssd.conf" file: certificate_verification = ocsp_dgst=sha1 The "sssd" service must be restarted for the changes to take effect. To restart the "sssd" service, run the following command: $ sudo systemctl restart sssd.service

b

RHEL 8 must accept Personal Identity Verification (PIV) credentials.

IA-2 - Medium - CCI-001953 - V-230275 - SV-230275r958816_rule

RMF Control

IA-2

Severity

M

CCI

CCI-001953

Version

RHEL-08-010410

Vuln IDs

V-230275

Rule IDs

SV-230275r958816_rule

The use of PIV credentials facilitates standardization and reduces the risk of unauthorized access. The DoD has mandated the use of the Common Access Card (CAC) to support identity management and personal authentication for systems covered under Homeland Security Presidential Directive (HSPD) 12, as well as making the CAC a primary component of layered protection for national security systems.

Checks: C-32944r567571_chk

Verify RHEL 8 accepts PIV credentials. Check that the "opensc" package is installed on the system with the following command: $ sudo yum list installed opensc opensc.x86_64 0.19.0-5.el8 @anaconda Check that "opensc" accepts PIV cards with the following command: $ sudo opensc-tool --list-drivers | grep -i piv PIV-II Personal Identity Verification Card If the "opensc" package is not installed and the "opensc-tool" driver list does not include "PIV-II", this is a finding.

Fix: F-32919r567572_fix

Configure RHEL 8 to accept PIV credentials. Install the "opensc" package using the following command: $ sudo yum install opensc

b

RHEL 8 must implement non-executable data to protect its memory from unauthorized code execution.

SI-16 - Medium - CCI-002824 - V-230276 - SV-230276r958928_rule

RMF Control

SI-16

Severity

M

CCI

CCI-002824

Version

RHEL-08-010420

Vuln IDs

V-230276

Rule IDs

SV-230276r958928_rule

Some adversaries launch attacks with the intent of executing code in non-executable regions of memory or in memory locations that are prohibited. Security safeguards employed to protect memory include, for example, data execution prevention and address space layout randomization. Data execution prevention safeguards can be either hardware-enforced or software-enforced with hardware providing the greater strength of mechanism. Examples of attacks are buffer overflow attacks.

Checks: C-32945r567574_chk

Verify the NX (no-execution) bit flag is set on the system. Check that the no-execution bit flag is set with the following commands: $ sudo dmesg | grep NX [ 0.000000] NX (Execute Disable) protection: active If "dmesg" does not show "NX (Execute Disable) protection" active, check the cpuinfo settings with the following command: $ sudo less /proc/cpuinfo | grep -i flags flags : fpu vme de pse tsc ms nx rdtscp lm constant_tsc If "flags" does not contain the "nx" flag, this is a finding.

Fix: F-32920r567575_fix

The NX bit execute protection must be enabled in the system BIOS.

b

RHEL 8 must clear the page allocator to prevent use-after-free attacks.

SC-3 - Medium - CCI-001084 - V-230277 - SV-230277r1017090_rule

RMF Control

SC-3

Severity

M

CCI

Version

RHEL-08-010421

Vuln IDs

V-230277

Rule IDs

SV-230277r1017090_rule

Some adversaries launch attacks with the intent of executing code in non-executable regions of memory or in memory locations that are prohibited. Security safeguards employed to protect memory include, for example, data execution prevention and address space layout randomization. Data execution prevention safeguards can be either hardware-enforced or software-enforced with hardware providing the greater strength of mechanism. Poisoning writes an arbitrary value to freed pages, so any modification or reference to that page after being freed or before being initialized will be detected and prevented. This prevents many types of use-after-free vulnerabilities at little performance cost. Also prevents leak of data and detection of corrupted memory. Satisfies: SRG-OS-000134-GPOS-00068, SRG-OS-000433-GPOS-00192

Checks: C-32946r792883_chk

Verify that GRUB 2 is configured to enable page poisoning to mitigate use-after-free vulnerabilities with the following commands: Check that the current GRUB 2 configuration has page poisoning enabled: $ sudo grub2-editenv list | grep page_poison kernelopts=root=/dev/mapper/rhel-root ro crashkernel=auto resume=/dev/mapper/rhel-swap rd.lvm.lv=rhel/root rd.lvm.lv=rhel/swap rhgb quiet fips=1 page_poison=1 vsyscall=none audit=1 audit_backlog_limit=8192 boot=UUID=8d171156-cd61-421c-ba41-1c021ac29e82 If "page_poison" is not set to "1" or is missing, this is a finding. Check that page poisoning is enabled by default to persist in kernel updates: $ sudo grep page_poison /etc/default/grub GRUB_CMDLINE_LINUX="page_poison=1" If "page_poison" is not set to "1", is missing or commented out, this is a finding.

Fix: F-32921r567578_fix

Configure RHEL 8 to enable page poisoning with the following commands: $ sudo grubby --update-kernel=ALL --args="page_poison=1" Add or modify the following line in "/etc/default/grub" to ensure the configuration survives kernel updates: GRUB_CMDLINE_LINUX="page_poison=1"

b

RHEL 8 must disable virtual syscalls.

SC-3 - Medium - CCI-001084 - V-230278 - SV-230278r1017091_rule

RMF Control

SC-3

Severity

M

CCI

Version

RHEL-08-010422

Vuln IDs

V-230278

Rule IDs

SV-230278r1017091_rule

Syscalls are special routines in the Linux kernel, which userspace applications ask to do privileged tasks. Invoking a system call is an expensive operation because the processor must interrupt the currently executing task and switch context to kernel mode and then back to userspace after the system call completes. Virtual Syscalls map into user space a page that contains some variables and the implementation of some system calls. This allows the system calls to be executed in userspace to alleviate the context switching expense. Virtual Syscalls provide an opportunity of attack for a user who has control of the return instruction pointer. Disabling vsyscalls help to prevent return oriented programming (ROP) attacks via buffer overflows and overruns. If the system intends to run containers based on RHEL 6 components, then virtual syscalls will need enabled so the components function properly. Satisfies: SRG-OS-000134-GPOS-00068, SRG-OS-000433-GPOS-00192

Checks: C-32947r792885_chk

Verify that GRUB 2 is configured to disable vsyscalls with the following commands: Check that the current GRUB 2 configuration disables vsyscalls: $ sudo grub2-editenv list | grep vsyscall kernelopts=root=/dev/mapper/rhel-root ro crashkernel=auto resume=/dev/mapper/rhel-swap rd.lvm.lv=rhel/root rd.lvm.lv=rhel/swap rhgb quiet fips=1 page_poison=1 vsyscall=none audit=1 audit_backlog_limit=8192 boot=UUID=8d171156-cd61-421c-ba41-1c021ac29e82 If "vsyscall" is not set to "none" or is missing, this is a finding. Check that vsyscalls are disabled by default to persist in kernel updates: $ sudo grep vsyscall /etc/default/grub GRUB_CMDLINE_LINUX="vsyscall=none" If "vsyscall" is not set to "none", is missing or commented out and is not documented with the Information System Security Officer (ISSO) as an operational requirement, this is a finding.

Fix: F-32922r743947_fix

Document the use of vsyscalls with the ISSO as an operational requirement or disable them with the following command: $ sudo grubby --update-kernel=ALL --args="vsyscall=none" Add or modify the following line in "/etc/default/grub" to ensure the configuration survives kernel updates: GRUB_CMDLINE_LINUX="vsyscall=none"

b

RHEL 8 must clear memory when it is freed to prevent use-after-free attacks.

SC-3 - Medium - CCI-001084 - V-230279 - SV-230279r1069286_rule

RMF Control

SC-3

Severity

M

CCI

Version

RHEL-08-010423

Vuln IDs

V-230279

Rule IDs

SV-230279r1069286_rule

Some adversaries launch attacks with the intent of executing code in nonexecutable regions of memory or in memory locations that are prohibited. Security safeguards employed to protect memory include, for example, data execution prevention and address space layout randomization. Data execution prevention safeguards can be either hardware-enforced or software-enforced with hardware providing the greater strength of mechanism. Poisoning writes an arbitrary value to freed pages, so any modification or reference to that page after being freed or before being initialized will be detected and prevented. This prevents many types of use-after-free vulnerabilities at little performance cost. Also prevents leak of data and detection of corrupted memory. init_on_free is a Linux kernel boot parameter that enhances security by initializing memory regions when they are freed, preventing data leakage. This process ensures that stale data in freed memory cannot be accessed by malicious programs. SLUB canaries add a randomized value (canary) at the end of SLUB-allocated objects to detect memory corruption caused by buffer overflows or underflows. Redzoning adds padding (red zones) around SLUB-allocated objects to detect overflows or underflows by triggering a fault when adjacent memory is accessed. SLUB canaries are often more efficient and provide stronger detection against buffer overflows compared to redzoning. SLUB canaries are supported in hardened Linux kernels like the ones provided by Linux-hardened. SLAB objects are blocks of physically contiguous memory. SLUB is the unqueued SLAB allocator. Satisfies: SRG-OS-000433-GPOS-00192, SRG-OS-000134-GPOS-00068

Checks: C-32948r1069179_chk

Verify that GRUB2 is configured to mitigate use-after-free vulnerabilities by employing memory poisoning. Inspect the "GRUB_CMDLINE_LINUX" entry of /etc/default/grub as follows: $ sudo grep -i grub_cmdline_linux /etc/default/grub GRUB_CMDLINE_LINUX="... init_on_free=1" If "init_on_free=1" is missing or commented out, this is a finding.

Fix: F-32923r1069180_fix

Configure RHEL 8 to enable init_on_free with the following command: $ sudo grubby --update-kernel=ALL --args="init_on_free=1" Regenerate the GRUB configuration: $ sudo grub2-mkconfig -o /boot/grub2/grub.cfg Reboot the system: $ sudo reboot

b

RHEL 8 must implement address space layout randomization (ASLR) to protect its memory from unauthorized code execution.

SI-16 - Medium - CCI-002824 - V-230280 - SV-230280r1017093_rule

RMF Control

SI-16

Severity

M

CCI

CCI-002824

Version

RHEL-08-010430

Vuln IDs

V-230280

Rule IDs

SV-230280r1017093_rule

Some adversaries launch attacks with the intent of executing code in non-executable regions of memory or in memory locations that are prohibited. Security safeguards employed to protect memory include, for example, data execution prevention and address space layout randomization. Data execution prevention safeguards can be either hardware-enforced or software-enforced with hardware providing the greater strength of mechanism. Examples of attacks are buffer overflow attacks. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of which of the directories they reside in. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf

Checks: C-32949r858765_chk

Verify RHEL 8 implements ASLR with the following command: $ sudo sysctl kernel.randomize_va_space kernel.randomize_va_space = 2 If "kernel.randomize_va_space" is not set to "2", this is a finding. Check that the configuration files are present to enable this kernel parameter. $ sudo grep -r kernel.randomize_va_space /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf:kernel.randomize_va_space = 2 If "kernel.randomize_va_space" is not set to "2", is missing or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-32924r858766_fix

Configure the operating system to implement virtual address space randomization. Add or edit the following line in a system configuration file, in the "/etc/sysctl.d/" directory: kernel.randomize_va_space=2 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf Issue the following command to make the changes take effect: $ sudo sysctl --system

a

YUM must remove all software components after updated versions have been installed on RHEL 8.

SI-2 - Low - CCI-002617 - V-230281 - SV-230281r958936_rule

RMF Control

SI-2

Severity

L

CCI

CCI-002617

Version

RHEL-08-010440

Vuln IDs

V-230281

Rule IDs

SV-230281r958936_rule

Previous versions of software components that are not removed from the information system after updates have been installed may be exploited by adversaries. Some information technology products may remove older versions of software automatically from the information system.

Checks: C-32950r567589_chk

Verify the operating system removes all software components after updated versions have been installed. Check if YUM is configured to remove unneeded packages with the following command: $ sudo grep -i clean_requirements_on_remove /etc/dnf/dnf.conf clean_requirements_on_remove=True If "clean_requirements_on_remove" is not set to either "1", "True", or "yes", commented out, or is missing from "/etc/dnf/dnf.conf", this is a finding.

Fix: F-32925r567590_fix

Configure the operating system to remove all software components after updated versions have been installed. Set the "clean_requirements_on_remove" option to "True" in the "/etc/dnf/dnf.conf" file: clean_requirements_on_remove=True

b

RHEL 8 must enable the SELinux targeted policy.

SI-6 - Medium - CCI-002696 - V-230282 - SV-230282r958944_rule

RMF Control

SI-6

Severity

M

CCI

CCI-002696

Version

RHEL-08-010450

Vuln IDs

V-230282

Rule IDs

SV-230282r958944_rule

Without verification of the security functions, security functions may not operate correctly and the failure may go unnoticed. Security function is defined as the hardware, software, and/or firmware of the information system responsible for enforcing the system security policy and supporting the isolation of code and data on which the protection is based. Security functionality includes, but is not limited to, establishing system accounts, configuring access authorizations (i.e., permissions, privileges), setting events to be audited, and setting intrusion detection parameters. This requirement applies to operating systems performing security function verification/testing and/or systems and environments that require this functionality.

Checks: C-32951r567592_chk

Ensure the operating system verifies correct operation of all security functions. Check if "SELinux" is active and is enforcing the targeted policy with the following command: $ sudo sestatus SELinux status: enabled SELinuxfs mount: /sys/fs/selinux SELinux root directory: /etc/selinux Loaded policy name: targeted Current mode: enforcing Mode from config file: enforcing Policy MLS status: enabled Policy deny_unknown status: allowed Memory protection checking: actual (secure) Max kernel policy version: 31 If the "Loaded policy name" is not set to "targeted", this is a finding. Verify that the /etc/selinux/config file is configured to the "SELINUXTYPE" to "targeted": $ sudo grep -i "selinuxtype" /etc/selinux/config | grep -v '^#' SELINUXTYPE = targeted If no results are returned or "SELINUXTYPE" is not set to "targeted", this is a finding.

Fix: F-32926r567593_fix

Configure the operating system to verify correct operation of all security functions. Set the "SELinuxtype" to the "targeted" policy by modifying the "/etc/selinux/config" file to have the following line: SELINUXTYPE=targeted A reboot is required for the changes to take effect.

c

There must be no shosts.equiv files on the RHEL 8 operating system.

CM-6 - High - CCI-000366 - V-230283 - SV-230283r1017094_rule

RMF Control

CM-6

Severity

H

CCI

Version

RHEL-08-010460

Vuln IDs

V-230283

Rule IDs

SV-230283r1017094_rule

The "shosts.equiv" files are used to configure host-based authentication for the system via SSH. Host-based authentication is not sufficient for preventing unauthorized access to the system, as it does not require interactive identification and authentication of a connection request, or for the use of two-factor authentication.

Checks: C-32952r567595_chk

Verify there are no "shosts.equiv" files on RHEL 8 with the following command: $ sudo find / -name shosts.equiv If a "shosts.equiv" file is found, this is a finding.

Fix: F-32927r567596_fix

Remove any found "shosts.equiv" files from the system. $ sudo rm /etc/ssh/shosts.equiv

c

There must be no .shosts files on the RHEL 8 operating system.

CM-6 - High - CCI-000366 - V-230284 - SV-230284r1017095_rule

RMF Control

CM-6

Severity

H

CCI

Version

RHEL-08-010470

Vuln IDs

V-230284

Rule IDs

SV-230284r1017095_rule

The ".shosts" files are used to configure host-based authentication for individual users or the system via SSH. Host-based authentication is not sufficient for preventing unauthorized access to the system, as it does not require interactive identification and authentication of a connection request, or for the use of two-factor authentication.

Checks: C-32953r567598_chk

Verify there are no ".shosts" files on RHEL 8 with the following command: $ sudo find / -name '*.shosts' If any ".shosts" files are found, this is a finding.

Fix: F-32928r567599_fix

Remove any found ".shosts" files from the system. $ sudo rm /[path]/[to]/[file]/.shosts

a

RHEL 8 must enable the hardware random number generator entropy gatherer service.

CM-6 - Low - CCI-000366 - V-230285 - SV-230285r1017096_rule

RMF Control

CM-6

Severity

L

CCI

Version

RHEL-08-010471

Vuln IDs

V-230285

Rule IDs

SV-230285r1017096_rule

The most important characteristic of a random number generator is its randomness, namely its ability to deliver random numbers that are impossible to predict. Entropy in computer security is associated with the unpredictability of a source of randomness. The random source with high entropy tends to achieve a uniform distribution of random values. Random number generators are one of the most important building blocks of cryptosystems. The rngd service feeds random data from hardware device to kernel random device. Quality (nonpredictable) random number generation is important for several security functions (i.e., ciphers).

Checks: C-32954r928586_chk

Note: For RHEL versions 8.4 and above running with kernel FIPS mode enabled as specified by RHEL-08-010020, this requirement is Not Applicable. Check that RHEL 8 has enabled the hardware random number generator entropy gatherer service. Verify the rngd service is enabled and active with the following commands: $ sudo systemctl is-enabled rngd enabled $ sudo systemctl is-active rngd active If the service is not "enabled" and "active", this is a finding.

Fix: F-32929r917875_fix

Start the rngd service and enable the rngd service with the following commands: $ sudo systemctl start rngd.service $ sudo systemctl enable rngd.service

b

The RHEL 8 SSH public host key files must have mode 0644 or less permissive.

CM-6 - Medium - CCI-000366 - V-230286 - SV-230286r1017097_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010480

Vuln IDs

V-230286

Rule IDs

SV-230286r1017097_rule

If a public host key file is modified by an unauthorized user, the SSH service may be compromised.

Checks: C-32955r567604_chk

Verify the SSH public host key files have mode "0644" or less permissive with the following command: $ sudo ls -l /etc/ssh/*.pub -rw-r--r-- 1 root root 618 Nov 28 06:43 ssh_host_dsa_key.pub -rw-r--r-- 1 root root 347 Nov 28 06:43 ssh_host_key.pub -rw-r--r-- 1 root root 238 Nov 28 06:43 ssh_host_rsa_key.pub If any key.pub file has a mode more permissive than "0644", this is a finding. Note: SSH public key files may be found in other directories on the system depending on the installation.

Fix: F-32930r567605_fix

Change the mode of public host key files under "/etc/ssh" to "0644" with the following command: $ sudo chmod 0644 /etc/ssh/*key.pub The SSH daemon must be restarted for the changes to take effect. To restart the SSH daemon, run the following command: $ sudo systemctl restart sshd.service

b

The RHEL 8 SSH private host key files must have mode 0640 or less permissive.

CM-6 - Medium - CCI-000366 - V-230287 - SV-230287r1017098_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010490

Vuln IDs

V-230287

Rule IDs

SV-230287r1017098_rule

If an unauthorized user obtains the private SSH host key file, the host could be impersonated.

Checks: C-32956r880712_chk

Verify the SSH private host key files have mode "0640" or less permissive with the following command: $ sudo ls -l /etc/ssh/ssh_host*key -rw-r----- 1 root ssh_keys 668 Nov 28 06:43 ssh_host_dsa_key -rw-r----- 1 root ssh_keys 582 Nov 28 06:43 ssh_host_key -rw-r----- 1 root ssh_keys 887 Nov 28 06:43 ssh_host_rsa_key If any private host key file has a mode more permissive than "0640", this is a finding.

Fix: F-32931r880713_fix

Configure the mode of SSH private host key files under "/etc/ssh" to "0640" with the following command: $ sudo chmod 0640 /etc/ssh/ssh_host*key The SSH daemon must be restarted for the changes to take effect. To restart the SSH daemon, run the following command: $ sudo systemctl restart sshd.service

b

The RHEL 8 SSH daemon must perform strict mode checking of home directory configuration files.

CM-6 - Medium - CCI-000366 - V-230288 - SV-230288r1069301_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010500

Vuln IDs

V-230288

Rule IDs

SV-230288r1069301_rule

If other users have access to modify user-specific SSH configuration files, they may be able to log on to the system as another user.

Checks: C-32957r1069211_chk

Verify the SSH daemon performs strict mode checking of home directory configuration files with the following command: $ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH '^\s*strictmodes' /etc/ssh/sshd_config:StrictModes yes If "StrictModes" is set to "no", is missing, or the returned line is commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-32932r567611_fix

Configure SSH to perform strict mode checking of home directory configuration files. Uncomment the "StrictModes" keyword in "/etc/ssh/sshd_config" and set the value to "yes": StrictModes yes The SSH daemon must be restarted for the changes to take effect. To restart the SSH daemon, run the following command: $ sudo systemctl restart sshd.service

b

The RHEL 8 SSH daemon must not allow authentication using known host’s authentication.

CM-6 - Medium - CCI-000366 - V-230290 - SV-230290r1069302_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010520

Vuln IDs

V-230290

Rule IDs

SV-230290r1069302_rule

Configuring this setting for the SSH daemon provides additional assurance that remote logon via SSH will require a password, even in the event of misconfiguration elsewhere.

Checks: C-32959r1069213_chk

Verify the SSH daemon does not allow authentication using known host’s authentication with the following command: $ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH '^\s*ignoreuserknownhosts' /etc/ssh/sshd_config:IgnoreUserKnownHosts yes If the value is returned as "no", the returned line is commented out, or no output is returned, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-32934r567617_fix

Configure the SSH daemon to not allow authentication using known host’s authentication. Add the following line in "/etc/ssh/sshd_config", or uncomment the line and set the value to "yes": IgnoreUserKnownHosts yes The SSH daemon must be restarted for the changes to take effect. To restart the SSH daemon, run the following command: $ sudo systemctl restart sshd.service

b

The RHEL 8 SSH daemon must not allow Kerberos authentication, except to fulfill documented and validated mission requirements.

CM-6 - Medium - CCI-000366 - V-230291 - SV-230291r1069303_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010521

Vuln IDs

V-230291

Rule IDs

SV-230291r1069303_rule

Configuring these settings for the SSH daemon provides additional assurance that remote logon via SSH will not use unused methods of authentication, even in the event of misconfiguration elsewhere.

Checks: C-32960r1069215_chk

Verify the SSH daemon does not allow Kerberos authentication with the following command: $ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH '^\s*kerberosauthentication' /etc/ssh/sshd_config:KerberosAuthentication no If the value is returned as "yes", the returned line is commented out, no output is returned, or has not been documented with the information system security officer (ISSO), this is a finding. If conflicting results are returned, this is a finding.

Fix: F-32935r743956_fix

Configure the SSH daemon to not allow Kerberos authentication. Add the following line in "/etc/ssh/sshd_config", or uncomment the line and set the value to "no": KerberosAuthentication no The SSH daemon must be restarted for the changes to take effect. To restart the SSH daemon, run the following command: $ sudo systemctl restart sshd.service

a

RHEL 8 must use a separate file system for /var.

CM-6 - Low - CCI-000366 - V-230292 - SV-230292r1017103_rule

RMF Control

CM-6

Severity

L

CCI

Version

RHEL-08-010540

Vuln IDs

V-230292

Rule IDs

SV-230292r1017103_rule

The use of separate file systems for different paths can protect the system from failures resulting from a file system becoming full or failing.

Checks: C-32961r902717_chk

Verify that a separate file system has been created for "/var". Check that a file system has been created for "/var" with the following command: $ sudo grep /var /etc/fstab /dev/mapper/... /var xfs defaults,nodev 0 0 If a separate entry for "/var" is not in use, this is a finding.

Fix: F-32936r567623_fix

Migrate the "/var" path onto a separate file system.

a

RHEL 8 must use a separate file system for /var/log.

CM-6 - Low - CCI-000366 - V-230293 - SV-230293r1017104_rule

RMF Control

CM-6

Severity

L

CCI

Version

RHEL-08-010541

Vuln IDs

V-230293

Rule IDs

SV-230293r1017104_rule

The use of separate file systems for different paths can protect the system from failures resulting from a file system becoming full or failing.

Checks: C-32962r902719_chk

Verify that a separate file system has been created for "/var/log". Check that a file system has been created for "/var/log" with the following command: $ sudo grep /var/log /etc/fstab /dev/mapper/... /var/log xfs defaults,nodev,noexec,nosuid 0 0 If a separate entry for "/var/log" is not in use, this is a finding.

Fix: F-32937r567626_fix

Migrate the "/var/log" path onto a separate file system.

a

RHEL 8 must use a separate file system for the system audit data path.

CM-6 - Low - CCI-000366 - V-230294 - SV-230294r1017105_rule

RMF Control

CM-6

Severity

L

CCI

Version

RHEL-08-010542

Vuln IDs

V-230294

Rule IDs

SV-230294r1017105_rule

The use of separate file systems for different paths can protect the system from failures resulting from a file system becoming full or failing.

Checks: C-32963r567628_chk

Verify that a separate file system/partition has been created for the system audit data path with the following command: Note: /var/log/audit is used as the example as it is a common location. $ sudo grep /var/log/audit /etc/fstab UUID=3645951a /var/log/audit xfs defaults 1 2 If an entry for "/var/log/audit" does not exist, ask the System Administrator if the system audit logs are being written to a different file system/partition on the system, then grep for that file system/partition. If a separate file system/partition does not exist for the system audit data path, this is a finding.

Fix: F-32938r567629_fix

Migrate the system audit data path onto a separate file system.

b

A separate RHEL 8 filesystem must be used for the /tmp directory.

CM-6 - Medium - CCI-000366 - V-230295 - SV-230295r1017106_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010543

Vuln IDs

V-230295

Rule IDs

SV-230295r1017106_rule

The use of separate file systems for different paths can protect the system from failures resulting from a file system becoming full or failing.

Checks: C-32964r567631_chk

Verify that a separate file system/partition has been created for non-privileged local interactive user home directories. $ sudo grep /tmp /etc/fstab /dev/mapper/rhel-tmp /tmp xfs defaults,nodev,nosuid,noexec 0 0 If a separate entry for the file system/partition "/tmp" does not exist, this is a finding.

Fix: F-32939r567632_fix

Migrate the "/tmp" directory onto a separate file system/partition.

b

RHEL 8 must not permit direct logons to the root account using remote access via SSH.

IA-2 - Medium - CCI-000770 - V-230296 - SV-230296r1069322_rule

RMF Control

IA-2

Severity

M

CCI

CCI-000770

Version

RHEL-08-010550

Vuln IDs

V-230296

Rule IDs

SV-230296r1069322_rule

Even though the communications channel may be encrypted, an additional layer of security is gained by extending the policy of not logging on directly as root. In addition, logging on with a user-specific account provides individual accountability of actions performed on the system.

Checks: C-32965r1069253_chk

Verify remote access using SSH prevents users from logging on directly as "root". Check that SSH prevents users from logging on directly as "root" with the following command: $ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH '^\s*permitrootlogin' PermitRootLogin no If the "PermitRootLogin" keyword is set to any value other than "no", is missing, or is commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-32940r567635_fix

Configure RHEL 8 to stop users from logging on remotely as the "root" user via SSH. Edit the appropriate "/etc/ssh/sshd_config" file to uncomment or add the line for the "PermitRootLogin" keyword and set its value to "no": PermitRootLogin no The SSH daemon must be restarted for the changes to take effect. To restart the SSH daemon, run the following command: $ sudo systemctl restart sshd.service

b

The rsyslog service must be running in RHEL 8.

CM-6 - Medium - CCI-000366 - V-230298 - SV-230298r1017108_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010561

Vuln IDs

V-230298

Rule IDs

SV-230298r1017108_rule

Configuring RHEL 8 to implement organization-wide security implementation guides and security checklists ensures compliance with federal standards and establishes a common security baseline across the DoD that reflects the most restrictive security posture consistent with operational requirements. Configuration settings are the set of parameters that can be changed in hardware, software, or firmware components of the system that affect the security posture and/or functionality of the system. Security-related parameters are those parameters impacting the security state of the system, including the parameters required to satisfy other security control requirements. Security-related parameters include, for example: registry settings; account, file, directory permission settings; and settings for functions, ports, protocols, services, and remote connections.

Checks: C-32967r567640_chk

Verify the rsyslog service is enabled and active with the following commands: $ sudo systemctl is-enabled rsyslog enabled $ sudo systemctl is-active rsyslog active If the service is not "enabled" and "active" this is a finding.

Fix: F-32942r567641_fix

Start the auditd service, and enable the rsyslog service with the following commands: $ sudo systemctl start rsyslog.service $ sudo systemctl enable rsyslog.service

b

RHEL 8 must prevent files with the setuid and setgid bit set from being executed on file systems that contain user home directories.

CM-6 - Medium - CCI-000366 - V-230299 - SV-230299r1017109_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010570

Vuln IDs

V-230299

Rule IDs

SV-230299r1017109_rule

The "nosuid" mount option causes the system not to execute "setuid" and "setgid" files with owner privileges. This option must be used for mounting any file system not containing approved "setuid" and "setguid" files. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access.

Checks: C-32968r567643_chk

Verify file systems that contain user home directories are mounted with the "nosuid" option. Note: If a separate file system has not been created for the user home directories (user home directories are mounted under "/"), this is automatically a finding as the "nosuid" option cannot be used on the "/" system. Find the file system(s) that contain the user home directories with the following command: $ sudo awk -F: '($3>=1000)&&($7 !~ /nologin/){print $1,$3,$6}' /etc/passwd smithj:1001: /home/smithj robinst:1002: /home/robinst Check the file systems that are mounted at boot time with the following command: $ sudo more /etc/fstab UUID=a411dc99-f2a1-4c87-9e05-184977be8539 /home xfs rw,relatime,discard,data=ordered,nosuid,nodev,noexec 0 0 If a file system found in "/etc/fstab" refers to the user home directory file system and it does not have the "nosuid" option set, this is a finding.

Fix: F-32943r567644_fix

Configure the "/etc/fstab" to use the "nosuid" option on file systems that contain user home directories for interactive users.

b

RHEL 8 must prevent files with the setuid and setgid bit set from being executed on the /boot directory.

CM-6 - Medium - CCI-000366 - V-230300 - SV-230300r1017110_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010571

Vuln IDs

V-230300

Rule IDs

SV-230300r1017110_rule

The "nosuid" mount option causes the system not to execute "setuid" and "setgid" files with owner privileges. This option must be used for mounting any file system not containing approved "setuid" and "setguid" files. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access.

Checks: C-32969r743958_chk

For systems that use UEFI, this is Not Applicable. Verify the /boot directory is mounted with the "nosuid" option with the following command: $ sudo mount | grep '\s/boot\s' /dev/sda1 on /boot type xfs (rw,nosuid,relatime,seclabe,attr2,inode64,noquota) If the /boot file system does not have the "nosuid" option set, this is a finding.

Fix: F-32944r567647_fix

Configure the "/etc/fstab" to use the "nosuid" option on the /boot directory.

b

RHEL 8 must prevent special devices on non-root local partitions.

CM-6 - Medium - CCI-000366 - V-230301 - SV-230301r1017111_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010580

Vuln IDs

V-230301

Rule IDs

SV-230301r1017111_rule

The "nodev" mount option causes the system to not interpret character or block special devices. Executing character or block special devices from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access. The only legitimate location for device files is the /dev directory located on the root partition.

Checks: C-32970r567649_chk

Verify all non-root local partitions are mounted with the "nodev" option with the following command: $ sudo mount | grep '^/dev\S* on /\S' | grep --invert-match 'nodev' If any output is produced, this is a finding.

Fix: F-32945r567650_fix

Configure the "/etc/fstab" to use the "nodev" option on all non-root local partitions.

b

RHEL 8 must prevent code from being executed on file systems that contain user home directories.

CM-6 - Medium - CCI-000366 - V-230302 - SV-230302r1017112_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010590

Vuln IDs

V-230302

Rule IDs

SV-230302r1017112_rule

The "noexec" mount option causes the system not to execute binary files. This option must be used for mounting any file system not containing approved binary files, as they may be incompatible. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access.

Checks: C-32971r567652_chk

Verify file systems that contain user home directories are mounted with the "noexec" option. Note: If a separate file system has not been created for the user home directories (user home directories are mounted under "/"), this is automatically a finding as the "noexec" option cannot be used on the "/" system. Find the file system(s) that contain the user home directories with the following command: $ sudo awk -F: '($3>=1000)&&($7 !~ /nologin/){print $1,$3,$6}' /etc/passwd smithj:1001: /home/smithj robinst:1002: /home/robinst Check the file systems that are mounted at boot time with the following command: $ sudo more /etc/fstab UUID=a411dc99-f2a1-4c87-9e05-184977be8539 /home ext4 rw,relatime,discard,data=ordered,nosuid,nodev,noexec 0 2 If a file system found in "/etc/fstab" refers to the user home directory file system and it does not have the "noexec" option set, this is a finding.

Fix: F-32946r567653_fix

Configure the "/etc/fstab" to use the "noexec" option on file systems that contain user home directories for interactive users.

b

RHEL 8 must prevent special devices on file systems that are used with removable media.

CM-6 - Medium - CCI-000366 - V-230303 - SV-230303r1017113_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010600

Vuln IDs

V-230303

Rule IDs

SV-230303r1017113_rule

The "nodev" mount option causes the system not to interpret character or block special devices. Executing character or block special devices from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access.

Checks: C-32972r567655_chk

Verify file systems that are used for removable media are mounted with the "nodev" option with the following command: $ sudo more /etc/fstab UUID=2bc871e4-e2a3-4f29-9ece-3be60c835222 /mnt/usbflash vfat noauto,owner,ro,nosuid,nodev,noexec 0 0 If a file system found in "/etc/fstab" refers to removable media and it does not have the "nodev" option set, this is a finding.

Fix: F-32947r567656_fix

Configure the "/etc/fstab" to use the "nodev" option on file systems that are associated with removable media.

b

RHEL 8 must prevent code from being executed on file systems that are used with removable media.

CM-6 - Medium - CCI-000366 - V-230304 - SV-230304r1017114_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010610

Vuln IDs

V-230304

Rule IDs

SV-230304r1017114_rule

The "noexec" mount option causes the system not to execute binary files. This option must be used for mounting any file system not containing approved binary files, as they may be incompatible. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access.

Checks: C-32973r567658_chk

Verify file systems that are used for removable media are mounted with the "noexec" option with the following command: $ sudo more /etc/fstab UUID=2bc871e4-e2a3-4f29-9ece-3be60c835222 /mnt/usbflash vfat noauto,owner,ro,nosuid,nodev,noexec 0 0 If a file system found in "/etc/fstab" refers to removable media and it does not have the "noexec" option set, this is a finding.

Fix: F-32948r567659_fix

Configure the "/etc/fstab" to use the "noexec" option on file systems that are associated with removable media.

b

RHEL 8 must prevent files with the setuid and setgid bit set from being executed on file systems that are used with removable media.

CM-6 - Medium - CCI-000366 - V-230305 - SV-230305r1017115_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010620

Vuln IDs

V-230305

Rule IDs

SV-230305r1017115_rule

The "nosuid" mount option causes the system not to execute "setuid" and "setgid" files with owner privileges. This option must be used for mounting any file system not containing approved "setuid" and "setguid" files. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access.

Checks: C-32974r567661_chk

Verify file systems that are used for removable media are mounted with the "nosuid" option with the following command: $ sudo more /etc/fstab UUID=2bc871e4-e2a3-4f29-9ece-3be60c835222 /mnt/usbflash vfat noauto,owner,ro,nosuid,nodev,noexec 0 0 If a file system found in "/etc/fstab" refers to removable media and it does not have the "nosuid" option set, this is a finding.

Fix: F-32949r567662_fix

Configure the "/etc/fstab" to use the "nosuid" option on file systems that are associated with removable media.

b

RHEL 8 must prevent code from being executed on file systems that are imported via Network File System (NFS).

CM-6 - Medium - CCI-000366 - V-230306 - SV-230306r1017116_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010630

Vuln IDs

V-230306

Rule IDs

SV-230306r1017116_rule

The "noexec" mount option causes the system not to execute binary files. This option must be used for mounting any file system not containing approved binary as they may be incompatible. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access.

Checks: C-32975r567664_chk

Verify that file systems being imported via NFS are mounted with the "noexec" option with the following command: $ sudo grep nfs /etc/fstab | grep noexec UUID=e06097bb-cfcd-437b-9e4d-a691f5662a7d /store nfs rw,nosuid,nodev,noexec 0 0 If a file system found in "/etc/fstab" refers to NFS and it does not have the "noexec" option set, this is a finding.

Fix: F-32950r567665_fix

Configure the "/etc/fstab" to use the "noexec" option on file systems that are being imported via NFS.

b

RHEL 8 must prevent special devices on file systems that are imported via Network File System (NFS).

CM-6 - Medium - CCI-000366 - V-230307 - SV-230307r1017117_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010640

Vuln IDs

V-230307

Rule IDs

SV-230307r1017117_rule

The "nodev" mount option causes the system to not interpret character or block special devices. Executing character or block special devices from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access.

Checks: C-32976r567667_chk

Verify file systems that are being NFS-imported are mounted with the "nodev" option with the following command: $ sudo grep nfs /etc/fstab | grep nodev UUID=e06097bb-cfcd-437b-9e4d-a691f5662a7d /store nfs rw,nosuid,nodev,noexec 0 0 If a file system found in "/etc/fstab" refers to NFS and it does not have the "nodev" option set, this is a finding.

Fix: F-32951r567668_fix

Configure the "/etc/fstab" to use the "nodev" option on file systems that are being imported via NFS.

b

RHEL 8 must prevent files with the setuid and setgid bit set from being executed on file systems that are imported via Network File System (NFS).

CM-6 - Medium - CCI-000366 - V-230308 - SV-230308r1017118_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010650

Vuln IDs

V-230308

Rule IDs

SV-230308r1017118_rule

The "nosuid" mount option causes the system not to execute "setuid" and "setgid" files with owner privileges. This option must be used for mounting any file system not containing approved "setuid" and "setguid" files. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access.

Checks: C-32977r567670_chk

Verify that file systems being imported via NFS are mounted with the "nosuid" option with the following command: $ sudo grep nfs /etc/fstab | grep nosuid UUID=e06097bb-cfcd-437b-9e4d-a691f5662a7d /store nfs rw,nosuid,nodev,noexec 0 0 If a file system found in "/etc/fstab" refers to NFS and it does not have the "nosuid" option set, this is a finding.

Fix: F-32952r567671_fix

Configure the "/etc/fstab" to use the "nosuid" option on file systems that are being imported via NFS.

b

Local RHEL 8 initialization files must not execute world-writable programs.

CM-6 - Medium - CCI-000366 - V-230309 - SV-230309r1017119_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010660

Vuln IDs

V-230309

Rule IDs

SV-230309r1017119_rule

If user start-up files execute world-writable programs, especially in unprotected directories, they could be maliciously modified to destroy user files or otherwise compromise the system at the user level. If the system is compromised at the user level, it is easier to elevate privileges to eventually compromise the system at the root and network level.

Checks: C-32978r567673_chk

Verify that local initialization files do not execute world-writable programs. Check the system for world-writable files. The following command will discover and print world-writable files. Run it once for each local partition [PART]: $ sudo find [PART] -xdev -type f -perm -0002 -print For all files listed, check for their presence in the local initialization files with the following commands: Note: The example will be for a system that is configured to create user home directories in the "/home" directory. $ sudo grep <file> /home/*/.* If any local initialization files are found to reference world-writable files, this is a finding.

Fix: F-32953r567674_fix

Set the mode on files being executed by the local initialization files with the following command: $ sudo chmod 0755 <file>

b

RHEL 8 must disable kernel dumps unless needed.

CM-6 - Medium - CCI-000366 - V-230310 - SV-230310r1017120_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010670

Vuln IDs

V-230310

Rule IDs

SV-230310r1017120_rule

Kernel core dumps may contain the full contents of system memory at the time of the crash. Kernel core dumps may consume a considerable amount of disk space and may result in denial of service by exhausting the available space on the target file system partition. RHEL 8 installation media presents the option to enable or disable the kdump service at the time of system installation.

Checks: C-32979r567676_chk

Verify that kernel core dumps are disabled unless needed with the following command: $ sudo systemctl status kdump.service kdump.service - Crash recovery kernel arming Loaded: loaded (/usr/lib/systemd/system/kdump.service; enabled; vendor preset: enabled) Active: active (exited) since Mon 2020-05-04 16:08:09 EDT; 3min ago Main PID: 1130 (code=exited, status=0/SUCCESS) If the "kdump" service is active, ask the System Administrator if the use of the service is required and documented with the Information System Security Officer (ISSO). If the service is active and is not documented, this is a finding.

Fix: F-32954r567677_fix

If kernel core dumps are not required, disable the "kdump" service with the following command: # systemctl disable kdump.service If kernel core dumps are required, document the need with the ISSO.

b

RHEL 8 must disable the kernel.core_pattern.

CM-6 - Medium - CCI-000366 - V-230311 - SV-230311r1017121_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010671

Vuln IDs

V-230311

Rule IDs

SV-230311r1017121_rule

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of which of the directories they reside in. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf

Checks: C-32980r833304_chk

Verify RHEL 8 disables storing core dumps with the following commands: $ sudo sysctl kernel.core_pattern kernel.core_pattern = |/bin/false If the returned line does not have a value of "|/bin/false", or a line is not returned and the need for core dumps is not documented with the Information System Security Officer (ISSO) as an operational requirement, this is a finding. Check that the configuration files are present to enable this kernel parameter. $ sudo grep -r kernel.core_pattern /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf:kernel.core_pattern = |/bin/false If "kernel.core_pattern" is not set to "|/bin/false", is missing or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-32955r858768_fix

Configure RHEL 8 to disable storing core dumps. Add or edit the following line in a system configuration file, in the "/etc/sysctl.d/" directory: kernel.core_pattern = |/bin/false Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf The system configuration files need to be reloaded for the changes to take effect. To reload the contents of the files, run the following command: $ sudo sysctl --system

b

RHEL 8 must disable acquiring, saving, and processing core dumps.

CM-6 - Medium - CCI-000366 - V-230312 - SV-230312r1017122_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010672

Vuln IDs

V-230312

Rule IDs

SV-230312r1017122_rule

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. A core dump includes a memory image taken at the time the operating system terminates an application. The memory image could contain sensitive data and is generally useful only for developers trying to debug problems. When the kernel invokes systemd-coredumpt to handle a core dump, it runs in privileged mode, and will connect to the socket created by the systemd-coredump.socket unit. This, in turn, will spawn an unprivileged systemd-coredump@.service instance to process the core dump.

Checks: C-32981r833306_chk

Verify RHEL 8 is not configured to acquire, save, or process core dumps with the following command: $ sudo systemctl status systemd-coredump.socket systemd-coredump.socket Loaded: masked (Reason: Unit systemd-coredump.socket is masked.) Active: inactive (dead) If the "systemd-coredump.socket" is loaded and not masked and the need for core dumps is not documented with the Information System Security Officer (ISSO) as an operational requirement, this is a finding.

Fix: F-32956r833307_fix

Configure the system to disable the systemd-coredump.socket with the following commands: $ sudo systemctl disable --now systemd-coredump.socket $ sudo systemctl mask systemd-coredump.socket Created symlink /etc/systemd/system/systemd-coredump.socket -> /dev/null Reload the daemon for this change to take effect. $ sudo systemctl daemon-reload

b

RHEL 8 must disable core dumps for all users.

CM-6 - Medium - CCI-000366 - V-230313 - SV-230313r1069304_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010673

Vuln IDs

V-230313

Rule IDs

SV-230313r1069304_rule

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. A core dump includes a memory image taken at the time the operating system terminates an application. The memory image could contain sensitive data and is generally useful only for developers trying to debug problems.

Checks: C-32982r1069217_chk

Verify the operating system disables core dumps for all users by issuing the following command: $ sudo grep -r -s '^[^#].*core' /etc/security/limits.conf /etc/security/limits.d/*.conf /etc/security/limits.d/core_dumps.conf:* hard core 0 This can be set as a global domain (with the * wildcard) but may be set differently for multiple domains. If the "core" item is missing, commented out, or the value is anything other than "0" and the need for core dumps is not documented with the Information System Security Officer (ISSO) as an operational requirement for all domains that have the "core" item assigned, this is a finding.

Fix: F-32957r1017123_fix

Configure the operating system to disable core dumps for all users. Add the following line to the top of the /etc/security/limits.conf or in a ".conf" file defined in /etc/security/limits.d/: * hard core 0

b

RHEL 8 must disable storing core dumps.

CM-6 - Medium - CCI-000366 - V-230314 - SV-230314r1017125_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010674

Vuln IDs

V-230314

Rule IDs

SV-230314r1017125_rule

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. A core dump includes a memory image taken at the time the operating system terminates an application. The memory image could contain sensitive data and is generally useful only for developers trying to debug problems.

Checks: C-32983r567688_chk

Verify the operating system disables storing core dumps for all users by issuing the following command: $ sudo grep -i storage /etc/systemd/coredump.conf Storage=none If the "Storage" item is missing, commented out, or the value is anything other than "none" and the need for core dumps is not documented with the Information System Security Officer (ISSO) as an operational requirement for all domains that have the "core" item assigned, this is a finding.

Fix: F-32958r567689_fix

Configure the operating system to disable storing core dumps for all users. Add or modify the following line in /etc/systemd/coredump.conf: Storage=none

b

RHEL 8 must disable core dump backtraces.

CM-6 - Medium - CCI-000366 - V-230315 - SV-230315r1017126_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010675

Vuln IDs

V-230315

Rule IDs

SV-230315r1017126_rule

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. A core dump includes a memory image taken at the time the operating system terminates an application. The memory image could contain sensitive data and is generally useful only for developers trying to debug problems.

Checks: C-32984r567691_chk

Verify the operating system disables core dump backtraces by issuing the following command: $ sudo grep -i ProcessSizeMax /etc/systemd/coredump.conf ProcessSizeMax=0 If the "ProcessSizeMax" item is missing, commented out, or the value is anything other than "0" and the need for core dumps is not documented with the Information System Security Officer (ISSO) as an operational requirement for all domains that have the "core" item assigned, this is a finding.

Fix: F-32959r567692_fix

Configure the operating system to disable core dump backtraces. Add or modify the following line in /etc/systemd/coredump.conf: ProcessSizeMax=0

b

For RHEL 8 systems using Domain Name Servers (DNS) resolution, at least two name servers must be configured.

CM-6 - Medium - CCI-000366 - V-230316 - SV-230316r1044801_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010680

Vuln IDs

V-230316

Rule IDs

SV-230316r1044801_rule

To provide availability for name resolution services, multiple redundant name servers are mandated. A failure in name resolution could lead to the failure of security functions requiring name resolution, which may include time synchronization, centralized authentication, and remote system logging.

Checks: C-32985r1044800_chk

Note: If the system is running in a cloud platform and the cloud provider gives a single, highly available IP address for DNS configuration, this is not applicable. Determine whether the system is using local or DNS name resolution with the following command: $ sudo grep hosts /etc/nsswitch.conf hosts: files dns If the DNS entry is missing from the host's line in the "/etc/nsswitch.conf" file, the "/etc/resolv.conf" file must be empty. Verify the "/etc/resolv.conf" file is empty with the following command: $ sudo ls -al /etc/resolv.conf -rw-r--r-- 1 root root 0 Aug 19 08:31 resolv.conf If local host authentication is being used and the "/etc/resolv.conf" file is not empty, this is a finding. If the DNS entry is found on the host's line of the "/etc/nsswitch.conf" file, verify the operating system is configured to use two or more name servers for DNS resolution. Determine the name servers used by the system with the following command: $ sudo grep nameserver /etc/resolv.conf nameserver 192.168.1.2 nameserver 192.168.1.3 If fewer than two lines are returned that are not commented out, this is a finding.

Fix: F-32960r567695_fix

Configure the operating system to use two or more name servers for DNS resolution. By default, "NetworkManager" on RHEL 8 dynamically updates the /etc/resolv.conf file with the DNS settings from active "NetworkManager" connection profiles. However, this feature can be disabled to allow manual configurations. If manually configuring DNS, edit the "/etc/resolv.conf" file to uncomment or add the two or more "nameserver" option lines with the IP address of local authoritative name servers. If local host resolution is being performed, the "/etc/resolv.conf" file must be empty. An empty "/etc/resolv.conf" file can be created as follows: $ sudo echo -n > /etc/resolv.conf

b

Executable search paths within the initialization files of all local interactive RHEL 8 users must only contain paths that resolve to the system default or the users home directory.

CM-6 - Medium - CCI-000366 - V-230317 - SV-230317r1069320_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010690

Vuln IDs

V-230317

Rule IDs

SV-230317r1069320_rule

The executable search path (typically the PATH environment variable) contains a list of directories for the shell to search to find executables. If this path includes the current working directory (other than the user's home directory), executables in these directories may be executed instead of system commands. This variable is formatted as a colon-separated list of directories. If there is an empty entry, such as a leading or trailing colon or two consecutive colons, this is interpreted as the current working directory. If deviations from the default system search path for the local interactive user are required, they must be documented with the Information System Security Officer (ISSO).

Checks: C-32986r1069249_chk

Verify that all local interactive user initialization file executable search path statements do not contain statements that will reference a working directory other than user home directories with the following commands: $ sudo grep -irw path= /home/*/.* /home/[localinteractiveuser]/.bash_profile:PATH=$PATH:$HOME/.local/bin:$HOME/bin If any local interactive user initialization files have executable search path statements that include directories outside of their home directory and is not documented with the ISSO as an operational requirement, this is a finding.

Fix: F-32961r567698_fix

Edit the local interactive user initialization files to change any PATH variable statements that reference directories other than their home directory. If a local interactive user requires path variables to reference a directory owned by the application, it must be documented with the ISSO.

b

All RHEL 8 world-writable directories must be owned by root, sys, bin, or an application user.

CM-6 - Medium - CCI-000366 - V-230318 - SV-230318r1017129_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010700

Vuln IDs

V-230318

Rule IDs

SV-230318r1017129_rule

If a world-writable directory is not owned by root, sys, bin, or an application User Identifier (UID), unauthorized users may be able to modify files created by others. The only authorized public directories are those temporary directories supplied with the system or those designed to be temporary file repositories. The setting is normally reserved for directories used by the system and by users for temporary file storage, (e.g., /tmp), and for directories requiring global read/write access.

Checks: C-32987r567700_chk

The following command will discover and print world-writable directories that are not owned by a system account, given the assumption that only system accounts have a uid lower than 1000. Run it once for each local partition [PART]: $ sudo find [PART] -xdev -type d -perm -0002 -uid +999 -print If there is output, this is a finding.

Fix: F-32962r567701_fix

All directories in local partitions which are world-writable should be owned by root or another system account. If any world-writable directories are not owned by a system account, this should be investigated. Following this, the files should be deleted or assigned to an appropriate group.

b

All RHEL 8 world-writable directories must be group-owned by root, sys, bin, or an application group.

CM-6 - Medium - CCI-000366 - V-230319 - SV-230319r1017130_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010710

Vuln IDs

V-230319

Rule IDs

SV-230319r1017130_rule

If a world-writable directory is not group-owned by root, sys, bin, or an application Group Identifier (GID), unauthorized users may be able to modify files created by others. The only authorized public directories are those temporary directories supplied with the system or those designed to be temporary file repositories. The setting is normally reserved for directories used by the system and by users for temporary file storage, (e.g., /tmp), and for directories requiring global read/write access.

Checks: C-32988r567703_chk

The following command will discover and print world-writable directories that are not group-owned by a system account, given the assumption that only system accounts have a gid lower than 1000. Run it once for each local partition [PART]: $ sudo find [PART] -xdev -type d -perm -0002 -gid +999 -print If there is output, this is a finding.

Fix: F-32963r567704_fix

All directories in local partitions which are world-writable must be group-owned by root or another system account. If any world-writable directories are not group-owned by a system account, this must be investigated. Following this, the directories must be deleted or assigned to an appropriate group.

b

All RHEL 8 local interactive users must have a home directory assigned in the /etc/passwd file.

CM-6 - Medium - CCI-000366 - V-230320 - SV-230320r1017131_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010720

Vuln IDs

V-230320

Rule IDs

SV-230320r1017131_rule

If local interactive users are not assigned a valid home directory, there is no place for the storage and control of files they should own.

Checks: C-32989r567706_chk

Verify local interactive users on RHEL 8 have a home directory assigned with the following command: $ sudo pwck -r user 'lp': directory '/var/spool/lpd' does not exist user 'news': directory '/var/spool/news' does not exist user 'uucp': directory '/var/spool/uucp' does not exist user 'www-data': directory '/var/www' does not exist Ask the System Administrator (SA) if any users found without home directories are local interactive users. If the SA is unable to provide a response, check for users with a User Identifier (UID) of 1000 or greater with the following command: $ sudo awk -F: '($3>=1000)&&($7 !~ /nologin/){print $1, $3, $6}' /etc/passwd If any interactive users do not have a home directory assigned, this is a finding.

Fix: F-32964r567707_fix

Assign home directories to all local interactive users on RHEL 8 that currently do not have a home directory assigned.

b

All RHEL 8 local interactive user home directories must have mode 0750 or less permissive.

CM-6 - Medium - CCI-000366 - V-230321 - SV-230321r1017132_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010730

Vuln IDs

V-230321

Rule IDs

SV-230321r1017132_rule

Excessive permissions on local interactive user home directories may allow unauthorized access to user files by other users.

Checks: C-32990r567709_chk

Verify the assigned home directory of all local interactive users has a mode of "0750" or less permissive with the following command: Note: This may miss interactive users that have been assigned a privileged User Identifier (UID). Evidence of interactive use may be obtained from a number of log files containing system logon information. $ sudo ls -ld $(awk -F: '($3>=1000)&&($7 !~ /nologin/){print $6}' /etc/passwd) drwxr-x--- 2 smithj admin 4096 Jun 5 12:41 smithj If home directories referenced in "/etc/passwd" do not have a mode of "0750" or less permissive, this is a finding.

Fix: F-32965r567710_fix

Change the mode of interactive user’s home directories to "0750". To change the mode of a local interactive user’s home directory, use the following command: Note: The example will be for the user "smithj". $ sudo chmod 0750 /home/smithj

b

All RHEL 8 local interactive user home directories must be group-owned by the home directory owner’s primary group.

CM-6 - Medium - CCI-000366 - V-230322 - SV-230322r1017133_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010740

Vuln IDs

V-230322

Rule IDs

SV-230322r1017133_rule

If the Group Identifier (GID) of a local interactive user’s home directory is not the same as the primary GID of the user, this would allow unauthorized access to the user’s files, and users that share the same group may not be able to access files that they legitimately should.

Checks: C-32991r880715_chk

Verify the assigned home directory of all local interactive users is group-owned by that user’s primary GID with the following command: Note: This may miss local interactive users that have been assigned a privileged UID. Evidence of interactive use may be obtained from a number of log files containing system logon information. The returned directory "/home/smithj" is used as an example. $ sudo ls -ld $(awk -F: '($3>=1000)&&($7 !~ /nologin/){print $6}' /etc/passwd) drwxr-x--- 2 smithj admin 4096 Jun 5 12:41 smithj Check the user's primary group with the following command: $ sudo grep $(grep smithj /etc/passwd | awk -F: '{print $4}') /etc/group admin:x:250:smithj,jonesj,jacksons If the user home directory referenced in "/etc/passwd" is not group-owned by that user’s primary GID, this is a finding.

Fix: F-32966r880716_fix

Change the group owner of a local interactive user’s home directory to the group found in "/etc/passwd". To change the group owner of a local interactive user’s home directory, use the following command: Note: The example will be for the user "smithj", who has a home directory of "/home/smithj", and has a primary group of users. $ sudo chgrp users /home/smithj

b

All RHEL 8 local interactive user home directories defined in the /etc/passwd file must exist.

CM-6 - Medium - CCI-000366 - V-230323 - SV-230323r1017134_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010750

Vuln IDs

V-230323

Rule IDs

SV-230323r1017134_rule

If a local interactive user has a home directory defined that does not exist, the user may be given access to the "/" directory as the current working directory upon logon. This could create a denial of service because the user would not be able to access their logon configuration files, and it may give them visibility to system files they normally would not be able to access.

Checks: C-32992r567715_chk

Verify the assigned home directory of all local interactive users on RHEL 8 exists with the following command: $ sudo ls -ld $(awk -F: '($3>=1000)&&($7 !~ /nologin/){print $6}' /etc/passwd) drwxr-xr-x 2 smithj admin 4096 Jun 5 12:41 smithj Note: This may miss interactive users that have been assigned a privileged User ID (UID). Evidence of interactive use may be obtained from a number of log files containing system logon information. Check that all referenced home directories exist with the following command: $ sudo pwck -r user 'smithj': directory '/home/smithj' does not exist If any home directories referenced in "/etc/passwd" are returned as not defined, this is a finding.

Fix: F-32967r567716_fix

Create home directories to all local interactive users that currently do not have a home directory assigned. Use the following commands to create the user home directory assigned in "/etc/ passwd": Note: The example will be for the user smithj, who has a home directory of "/home/smithj", a UID of "smithj", and a Group Identifier (GID) of "users assigned" in "/etc/passwd". $ sudo mkdir /home/smithj $ sudo chown smithj /home/smithj $ sudo chgrp users /home/smithj $ sudo chmod 0750 /home/smithj

b

All RHEL 8 local interactive user accounts must be assigned a home directory upon creation.

CM-6 - Medium - CCI-000366 - V-230324 - SV-230324r1017135_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010760

Vuln IDs

V-230324

Rule IDs

SV-230324r1017135_rule

If local interactive users are not assigned a valid home directory, there is no place for the storage and control of files they should own.

Checks: C-32993r567718_chk

Verify all local interactive users on RHEL 8 are assigned a home directory upon creation with the following command: $ sudo grep -i create_home /etc/login.defs CREATE_HOME yes If the value for "CREATE_HOME" parameter is not set to "yes", the line is missing, or the line is commented out, this is a finding.

Fix: F-32968r567719_fix

Configure RHEL 8 to assign home directories to all new local interactive users by setting the "CREATE_HOME" parameter in "/etc/login.defs" to "yes" as follows. CREATE_HOME yes

b

All RHEL 8 local initialization files must have mode 0740 or less permissive.

CM-6 - Medium - CCI-000366 - V-230325 - SV-230325r1017136_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010770

Vuln IDs

V-230325

Rule IDs

SV-230325r1017136_rule

Local initialization files are used to configure the user's shell environment upon logon. Malicious modification of these files could compromise accounts upon logon.

Checks: C-32994r917877_chk

Verify that all local initialization files have a mode of "0740" or less permissive with the following command: Note: The example will be for the "smithj" user, who has a home directory of "/home/smithj". $ sudo ls -al /home/smithj/.[^.]* | more -rw-------. 1 smithj users 2984 Apr 27 19:02 .bash_history -rw-r--r--. 1 smithj users 18 Aug 21 2019 .bash_logout -rw-r--r--. 1 smithj users 193 Aug 21 2019 .bash_profile If any local initialization files have a mode more permissive than "0740", this is a finding.

Fix: F-32969r917878_fix

Set the mode of the local initialization files to "0740" with the following command: Note: The example will be for the smithj user, who has a home directory of "/home/smithj". $ sudo chmod 0740 /home/smithj/.<INIT_FILE>

b

All RHEL 8 local files and directories must have a valid owner.

CM-6 - Medium - CCI-000366 - V-230326 - SV-230326r1069284_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010780

Vuln IDs

V-230326

Rule IDs

SV-230326r1069284_rule

Unowned files and directories may be unintentionally inherited if a user is assigned the same User Identifier "UID" as the UID of the un-owned files.

Checks: C-32995r1069175_chk

Verify all local files and directories on RHEL 8 have a valid owner with the following command: $ df --local -P | awk {'if (NR!=1) print $6'} | sudo xargs -I '{}' find '{}' -xdev -nouser If any files on the system do not have an assigned owner, this is a finding.

Fix: F-32970r567725_fix

Either remove all files and directories from the system that do not have a valid user, or assign a valid user to all unowned files and directories on RHEL 8 with the "chown" command: $ sudo chown <user> <file>

b

All RHEL 8 local files and directories must have a valid group owner.

CM-6 - Medium - CCI-000366 - V-230327 - SV-230327r1069285_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010790

Vuln IDs

V-230327

Rule IDs

SV-230327r1069285_rule

Files without a valid group owner may be unintentionally inherited if a group is assigned the same Group Identifier (GID) as the GID of the files without a valid group owner.

Checks: C-32996r1069177_chk

Verify all local files and directories on RHEL 8 have a valid group with the following command: $ df --local -P | awk {'if (NR!=1) print $6'} | sudo xargs -I '{}' find '{}' -xdev -nogroup If any files on the system do not have an assigned group, this is a finding.

Fix: F-32971r567728_fix

Either remove all files and directories from RHEL 8 that do not have a valid group, or assign a valid group to all files and directories on the system with the "chgrp" command: $ sudo chgrp <group> <file>

b

A separate RHEL 8 filesystem must be used for user home directories (such as /home or an equivalent).

CM-6 - Medium - CCI-000366 - V-230328 - SV-230328r1017139_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010800

Vuln IDs

V-230328

Rule IDs

SV-230328r1017139_rule

The use of separate file systems for different paths can protect the system from failures resulting from a file system becoming full or failing.

Checks: C-32997r902721_chk

Verify that a separate file system has been created for non-privileged local interactive user home directories. Check the home directory assignment for all non-privileged users, users with a User Identifier (UID) greater than 1000, on the system with the following command: $ sudo awk -F: '($3>=1000)&&($7 !~ /nologin/){print $1,$3,$6}' /etc/passwd doej 1001 /home/doej publicj 1002 /home/publicj smithj 1003 /home/smithj The output of the command will give the directory/partition that contains the home directories for the non-privileged users on the system (in this example, "/home") and users’ shell. All accounts with a valid shell (such as /bin/bash) are considered interactive users. Check that a file system/partition has been created for the nonprivileged interactive users with the following command: Note: The partition of "/home" is used in the example. $ sudo grep /home /etc/fstab /dev/mapper/... /home xfs defaults,noexec,nosuid,nodev 0 0 If a separate entry for the file system/partition containing the nonprivileged interactive user home directories does not exist, this is a finding.

Fix: F-32972r902722_fix

Migrate the "/home" directory onto a separate file system.

c

Unattended or automatic logon via the RHEL 8 graphical user interface must not be allowed.

CM-6 - High - CCI-000366 - V-230329 - SV-230329r1017140_rule

RMF Control

CM-6

Severity

H

CCI

Version

RHEL-08-010820

Vuln IDs

V-230329

Rule IDs

SV-230329r1017140_rule

Failure to restrict system access to authenticated users negatively impacts operating system security.

Checks: C-32998r567733_chk

Verify the operating system does not allow an unattended or automatic logon to the system via a graphical user interface. Note: This requirement assumes the use of the RHEL 8 default graphical user interface, Gnome Shell. If the system does not have any graphical user interface installed, this requirement is Not Applicable. Check for the value of the "AutomaticLoginEnable" in the "/etc/gdm/custom.conf" file with the following command: $ sudo grep -i automaticloginenable /etc/gdm/custom.conf AutomaticLoginEnable=false If the value of "AutomaticLoginEnable" is not set to "false", this is a finding.

Fix: F-32973r567734_fix

Configure the operating system to not allow an unattended or automatic logon to the system via a graphical user interface. Add or edit the line for the "AutomaticLoginEnable" parameter in the [daemon] section of the "/etc/gdm/custom.conf" file to "false": [daemon] AutomaticLoginEnable=false

b

RHEL 8 must not allow users to override SSH environment variables.

CM-6 - Medium - CCI-000366 - V-230330 - SV-230330r1069305_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010830

Vuln IDs

V-230330

Rule IDs

SV-230330r1069305_rule

SSH environment options potentially allow users to bypass access restriction in some configurations.

Checks: C-32999r1069219_chk

Verify that unattended or automatic logon via ssh is disabled with the following command: $ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH '^\s*permituserenvironment' /etc/ssh/sshd_config:PermitUserEnvironment no If "PermitUserEnvironment" is set to "yes", is missing completely, or is commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-32974r567737_fix

Configure RHEL 8 to allow the SSH daemon to not allow unattended or automatic logon to the system. Add or edit the following line in the "/etc/ssh/sshd_config" file: PermitUserEnvironment no The SSH daemon must be restarted for the changes to take effect. To restart the SSH daemon, run the following command: $ sudo systemctl restart sshd.service

b

RHEL 8 temporary user accounts must be provisioned with an expiration time of 72 hours or less.

AC-2 - Medium - CCI-000016 - V-230331 - SV-230331r1017143_rule

RMF Control

AC-2

Severity

M

CCI

CCI-000016

Version

RHEL-08-020000

Vuln IDs

V-230331

Rule IDs

SV-230331r1017143_rule

If temporary user accounts remain active when no longer needed or for an excessive period, these accounts may be used to gain unauthorized access. To mitigate this risk, automated termination of all temporary accounts must be set upon account creation. Temporary accounts are established as part of normal account activation procedures when there is a need for short-term accounts without the demand for immediacy in account activation. If temporary accounts are used, RHEL 8 must be configured to automatically terminate these types of accounts after a DoD-defined time period of 72 hours. To address access requirements, many RHEL 8 operating systems may be integrated with enterprise-level authentication/access mechanisms that meet or exceed access control policy requirements.

Checks: C-33000r1017142_chk

Verify that temporary accounts have been provisioned with an expiration date of 72 hours. For every existing temporary account, run the following command to obtain its account expiration information. $ sudo chage -l system_account_name Verify each of these accounts has an expiration date set within 72 hours. If any temporary accounts have no expiration date set or do not expire within 72 hours, this is a finding.

Fix: F-32975r567740_fix

If a temporary account must be created configure the system to terminate the account after a 72 hour time period with the following command to set an expiration date on it. Substitute "system_account_name" with the account to be created. $ sudo chage -E `date -d "+3 days" +%Y-%m-%d` system_account_name

b

RHEL 8 must automatically lock an account when three unsuccessful logon attempts occur.

AC-7 - Medium - CCI-000044 - V-230332 - SV-230332r1017144_rule

RMF Control

AC-7

Severity

M

CCI

Version

RHEL-08-020010

Vuln IDs

V-230332

Rule IDs

SV-230332r1017144_rule

By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, otherwise known as brute-force attacks, is reduced. Limits are imposed by locking the account. RHEL 8 can utilize the "pam_faillock.so" for this purpose. Note that manual changes to the listed files may be overwritten by the "authselect" program. From "Pam_Faillock" man pages: Note that the default directory that "pam_faillock" uses is usually cleared on system boot so the access will be reenabled after system reboot. If that is undesirable a different tally directory must be set with the "dir" option. Satisfies: SRG-OS-000021-GPOS-00005, SRG-OS-000329-GPOS-00128

Checks: C-33001r567742_chk

Check that the system locks an account after three unsuccessful logon attempts with the following commands: Note: If the System Administrator demonstrates the use of an approved centralized account management method that locks an account after three unsuccessful logon attempts within a period of 15 minutes, this requirement is not applicable. Note: This check applies to RHEL versions 8.0 and 8.1, if the system is RHEL version 8.2 or newer, this check is not applicable. $ sudo grep pam_faillock.so /etc/pam.d/password-auth auth required pam_faillock.so preauth dir=/var/log/faillock silent audit deny=3 even_deny_root fail_interval=900 unlock_time=0 auth required pam_faillock.so authfail dir=/var/log/faillock unlock_time=0 account required pam_faillock.so If the "deny" option is not set to "3" or less (but not "0") on the "preauth" line with the "pam_faillock.so" module, or is missing from this line, this is a finding. If any line referencing the "pam_faillock.so" module is commented out, this is a finding. $ sudo grep pam_faillock.so /etc/pam.d/system-auth auth required pam_faillock.so preauth dir=/var/log/faillock silent audit deny=3 even_deny_root fail_interval=900 unlock_time=0 auth required pam_faillock.so authfail dir=/var/log/faillock unlock_time=0 account required pam_faillock.so If the "deny" option is not set to "3" or less (but not "0") on the "preauth" line with the "pam_faillock.so" module, or is missing from this line, this is a finding. If any line referencing the "pam_faillock.so" module is commented out, this is a finding.

Fix: F-32976r567743_fix

Configure the operating system to lock an account when three unsuccessful logon attempts occur. Add/Modify the appropriate sections of the "/etc/pam.d/system-auth" and "/etc/pam.d/password-auth" files to match the following lines: auth required pam_faillock.so preauth dir=/var/log/faillock silent audit deny=3 even_deny_root fail_interval=900 unlock_time=0 auth required pam_faillock.so authfail dir=/var/log/faillock unlock_time=0 account required pam_faillock.so The "sssd" service must be restarted for the changes to take effect. To restart the "sssd" service, run the following command: $ sudo systemctl restart sssd.service

b

RHEL 8 must automatically lock an account when three unsuccessful logon attempts occur.

AC-7 - Medium - CCI-000044 - V-230333 - SV-230333r1017145_rule

RMF Control

AC-7

Severity

M

CCI

Version

RHEL-08-020011

Vuln IDs

V-230333

Rule IDs

SV-230333r1017145_rule

By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, otherwise known as brute-force attacks, is reduced. Limits are imposed by locking the account. In RHEL 8.2 the "/etc/security/faillock.conf" file was incorporated to centralize the configuration of the pam_faillock.so module. Also introduced is a "local_users_only" option that will only track failed user authentication attempts for local users in /etc/passwd and ignore centralized (AD, IdM, LDAP, etc.) users to allow the centralized platform to solely manage user lockout. From "faillock.conf" man pages: Note that the default directory that "pam_faillock" uses is usually cleared on system boot so the access will be reenabled after system reboot. If that is undesirable a different tally directory must be set with the "dir" option. Satisfies: SRG-OS-000021-GPOS-00005, SRG-OS-000329-GPOS-00128

Checks: C-33002r743964_chk

Note: This check applies to RHEL versions 8.2 or newer, if the system is RHEL version 8.0 or 8.1, this check is not applicable. Verify the "/etc/security/faillock.conf" file is configured to lock an account after three unsuccessful logon attempts: $ sudo grep 'deny =' /etc/security/faillock.conf deny = 3 If the "deny" option is not set to "3" or less (but not "0"), is missing or commented out, this is a finding.

Fix: F-32977r743965_fix

Configure the operating system to lock an account when three unsuccessful logon attempts occur. Add/Modify the "/etc/security/faillock.conf" file to match the following line: deny = 3

b

RHEL 8 must automatically lock an account when three unsuccessful logon attempts occur during a 15-minute time period.

AC-7 - Medium - CCI-000044 - V-230334 - SV-230334r1017146_rule

RMF Control

AC-7

Severity

M

CCI

Version

RHEL-08-020012

Vuln IDs

V-230334

Rule IDs

SV-230334r1017146_rule

By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, otherwise known as brute-force attacks, is reduced. Limits are imposed by locking the account. RHEL 8 can utilize the "pam_faillock.so" for this purpose. Note that manual changes to the listed files may be overwritten by the "authselect" program. From "Pam_Faillock" man pages: Note that the default directory that "pam_faillock" uses is usually cleared on system boot so the access will be reenabled after system reboot. If that is undesirable a different tally directory must be set with the "dir" option. Satisfies: SRG-OS-000021-GPOS-00005, SRG-OS-000329-GPOS-00128

Checks: C-33003r567748_chk

Check that the system locks an account after three unsuccessful logon attempts within a period of 15 minutes with the following commands: Note: If the System Administrator demonstrates the use of an approved centralized account management method that locks an account after three unsuccessful logon attempts within a period of 15 minutes, this requirement is not applicable. Note: This check applies to RHEL versions 8.0 and 8.1, if the system is RHEL version 8.2 or newer, this check is not applicable. $ sudo grep pam_faillock.so /etc/pam.d/password-auth auth required pam_faillock.so preauth dir=/var/log/faillock silent audit deny=3 even_deny_root fail_interval=900 unlock_time=0 auth required pam_faillock.so authfail dir=/var/log/faillock unlock_time=0 account required pam_faillock.so If the "fail_interval" option is not set to "900" or less (but not "0") on the "preauth" lines with the "pam_faillock.so" module, or is missing from this line, this is a finding. $ sudo grep pam_faillock.so /etc/pam.d/system-auth auth required pam_faillock.so preauth dir=/var/log/faillock silent audit deny=3 even_deny_root fail_interval=900 unlock_time=0 auth required pam_faillock.so authfail dir=/var/log/faillock unlock_time=0 account required pam_faillock.so If the "fail_interval" option is not set to "900" or less (but not "0") on the "preauth" lines with the "pam_faillock.so" module, or is missing from this line, this is a finding.

Fix: F-32978r567749_fix

Configure the operating system to lock an account when three unsuccessful logon attempts occur in 15 minutes. Add/Modify the appropriate sections of the "/etc/pam.d/system-auth" and "/etc/pam.d/password-auth" files to match the following lines: auth required pam_faillock.so preauth dir=/var/log/faillock silent audit deny=3 even_deny_root fail_interval=900 unlock_time=0 auth required pam_faillock.so authfail dir=/var/log/faillock unlock_time=0 account required pam_faillock.so The "sssd" service must be restarted for the changes to take effect. To restart the "sssd" service, run the following command: $ sudo systemctl restart sssd.service

b

RHEL 8 must automatically lock an account when three unsuccessful logon attempts occur during a 15-minute time period.

AC-7 - Medium - CCI-000044 - V-230335 - SV-230335r1017147_rule

RMF Control

AC-7

Severity

M

CCI

Version

RHEL-08-020013

Vuln IDs

V-230335

Rule IDs

SV-230335r1017147_rule

By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, otherwise known as brute-force attacks, is reduced. Limits are imposed by locking the account. In RHEL 8.2 the "/etc/security/faillock.conf" file was incorporated to centralize the configuration of the pam_faillock.so module. Also introduced is a "local_users_only" option that will only track failed user authentication attempts for local users in /etc/passwd and ignore centralized (AD, IdM, LDAP, etc.) users to allow the centralized platform to solely manage user lockout. From "faillock.conf" man pages: Note that the default directory that "pam_faillock" uses is usually cleared on system boot so the access will be reenabled after system reboot. If that is undesirable a different tally directory must be set with the "dir" option. Satisfies: SRG-OS-000021-GPOS-00005, SRG-OS-000329-GPOS-00128

Checks: C-33004r743967_chk

Note: This check applies to RHEL versions 8.2 or newer, if the system is RHEL version 8.0 or 8.1, this check is not applicable. Verify the "/etc/security/faillock.conf" file is configured to lock an account after three unsuccessful logon attempts within 15 minutes: $ sudo grep 'fail_interval =' /etc/security/faillock.conf fail_interval = 900 If the "fail_interval" option is not set to "900" or more, is missing or commented out, this is a finding.

Fix: F-32979r743968_fix

Configure the operating system to lock an account when three unsuccessful logon attempts occur in 15 minutes. Add/Modify the "/etc/security/faillock.conf" file to match the following line: fail_interval = 900

b

RHEL 8 must automatically lock an account until the locked account is released by an administrator when three unsuccessful logon attempts occur during a 15-minute time period.

AC-7 - Medium - CCI-000044 - V-230336 - SV-230336r1017148_rule

RMF Control

AC-7

Severity

M

CCI

Version

RHEL-08-020014

Vuln IDs

V-230336

Rule IDs

SV-230336r1017148_rule

By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, otherwise known as brute-force attacks, is reduced. Limits are imposed by locking the account. RHEL 8 can utilize the "pam_faillock.so" for this purpose. Note that manual changes to the listed files may be overwritten by the "authselect" program. From "Pam_Faillock" man pages: Note that the default directory that "pam_faillock" uses is usually cleared on system boot so the access will be reenabled after system reboot. If that is undesirable a different tally directory must be set with the "dir" option. Satisfies: SRG-OS-000021-GPOS-00005, SRG-OS-000329-GPOS-00128

Checks: C-33005r567754_chk

Check that the system locks an account after three unsuccessful logon attempts within a period of 15 minutes until released by an administrator with the following commands: Note: If the System Administrator demonstrates the use of an approved centralized account management method that locks an account after three unsuccessful logon attempts within a period of 15 minutes, this requirement is not applicable. Note: This check applies to RHEL versions 8.0 and 8.1, if the system is RHEL version 8.2 or newer, this check is not applicable. $ sudo grep pam_faillock.so /etc/pam.d/password-auth auth required pam_faillock.so preauth dir=/var/log/faillock silent audit deny=3 even_deny_root fail_interval=900 unlock_time=0 auth required pam_faillock.so authfail dir=/var/log/faillock unlock_time=0 account required pam_faillock.so If the "unlock_time" option is not set to "0" on the "preauth" and "authfail" lines with the "pam_faillock.so" module, or is missing from these lines, this is a finding. $ sudo grep pam_faillock.so /etc/pam.d/system-auth auth required pam_faillock.so preauth dir=/var/log/faillock silent audit deny=3 even_deny_root fail_interval=900 unlock_time=0 auth required pam_faillock.so authfail dir=/var/log/faillock unlock_time=0 account required pam_faillock.so If the "unlock_time" option is not set to "0" on the "preauth" and "authfail" lines with the "pam_faillock.so" module, or is missing from these lines, this is a finding.

Fix: F-32980r567755_fix

Configure the operating system to lock an account until released by an administrator when three unsuccessful logon attempts occur in 15 minutes. Add/Modify the appropriate sections of the "/etc/pam.d/system-auth" and "/etc/pam.d/password-auth" files to match the following lines: auth required pam_faillock.so preauth dir=/var/log/faillock silent audit deny=3 even_deny_root fail_interval=900 unlock_time=0 auth required pam_faillock.so authfail dir=/var/log/faillock unlock_time=0 account required pam_faillock.so The "sssd" service must be restarted for the changes to take effect. To restart the "sssd" service, run the following command: $ sudo systemctl restart sssd.service

b

RHEL 8 must automatically lock an account until the locked account is released by an administrator when three unsuccessful logon attempts occur during a 15-minute time period.

AC-7 - Medium - CCI-000044 - V-230337 - SV-230337r1069292_rule

RMF Control

AC-7

Severity

M

CCI

Version

RHEL-08-020015

Vuln IDs

V-230337

Rule IDs

SV-230337r1069292_rule

By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, otherwise known as brute-force attacks, is reduced. Limits are imposed by locking the account. In RHEL 8.2 the "/etc/security/faillock.conf" file was incorporated to centralize the configuration of the pam_faillock.so module. Also introduced is a "local_users_only" option that will only track failed user authentication attempts for local users in /etc/passwd and ignore centralized (AD, IdM, LDAP, etc.) users to allow the centralized platform to solely manage user lockout. From "faillock.conf" man pages: Note that the default directory that "pam_faillock" uses is usually cleared on system boot so the access will be reenabled after system reboot. If that is undesirable a different tally directory must be set with the "dir" option. Satisfies: SRG-OS-000021-GPOS-00005, SRG-OS-000329-GPOS-00128

Checks: C-33006r1069193_chk

Note: If temporary accounts do not exist or are not used this is not applicable. This check applies to RHEL versions 8.2 or newer, if the system is RHEL version 8.0 or 8.1, this check is not applicable. Verify the "/etc/security/faillock.conf" file is configured to lock an account until released by an administrator after three unsuccessful logon attempts: $ sudo grep 'unlock_time =' /etc/security/faillock.conf unlock_time = 0 If the "unlock_time" option is not set to "0", is missing or commented out, this is a finding.

Fix: F-32981r743971_fix

Configure the operating system to lock an account until released by an administrator when three unsuccessful logon attempts occur in 15 minutes. Add/Modify the "/etc/security/faillock.conf" file to match the following line: unlock_time = 0

b

RHEL 8 must ensure account lockouts persist.

AC-7 - Medium - CCI-000044 - V-230338 - SV-230338r1017150_rule

RMF Control

AC-7

Severity

M

CCI

Version

RHEL-08-020016

Vuln IDs

V-230338

Rule IDs

SV-230338r1017150_rule

By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, otherwise known as brute-force attacks, is reduced. Limits are imposed by locking the account. RHEL 8 can utilize the "pam_faillock.so" for this purpose. Note that manual changes to the listed files may be overwritten by the "authselect" program. From "Pam_Faillock" man pages: Note that the default directory that "pam_faillock" uses is usually cleared on system boot so the access will be reenabled after system reboot. If that is undesirable a different tally directory must be set with the "dir" option. Satisfies: SRG-OS-000021-GPOS-00005, SRG-OS-000329-GPOS-00128

Checks: C-33007r567760_chk

Check that the faillock directory contents persists after a reboot with the following commands: Note: If the System Administrator demonstrates the use of an approved centralized account management method that locks an account after three unsuccessful logon attempts within a period of 15 minutes, this requirement is not applicable. Note: This check applies to RHEL versions 8.0 and 8.1, if the system is RHEL version 8.2 or newer, this check is not applicable. $ sudo grep pam_faillock.so /etc/pam.d/password-auth auth required pam_faillock.so preauth dir=/var/log/faillock silent audit deny=3 even_deny_root fail_interval=900 unlock_time=0 auth required pam_faillock.so authfail dir=/var/log/faillock unlock_time=0 account required pam_faillock.so If the "dir" option is not set to a non-default documented tally log directory on the "preauth" and "authfail" lines with the "pam_faillock.so" module, or is missing from these lines, this is a finding. $ sudo grep pam_faillock.so /etc/pam.d/system-auth auth required pam_faillock.so preauth dir=/var/log/faillock silent audit deny=3 even_deny_root fail_interval=900 unlock_time=0 auth required pam_faillock.so authfail dir=/var/log/faillock unlock_time=0 account required pam_faillock.so If the "dir" option is not set to a non-default documented tally log directory on the "preauth" and "authfail" lines with the "pam_faillock.so" module, or is missing from these lines, this is a finding.

Fix: F-32982r567761_fix

Configure the operating system maintain the contents of the faillock directory after a reboot. Add/Modify the appropriate sections of the "/etc/pam.d/system-auth" and "/etc/pam.d/password-auth" files to match the following lines: Note: Using the default faillock directory of /var/run/faillock will result in the contents being cleared in the event of a reboot. auth required pam_faillock.so preauth dir=/var/log/faillock silent audit deny=3 even_deny_root fail_interval=900 unlock_time=0 auth required pam_faillock.so authfail dir=/var/log/faillock unlock_time=0 account required pam_faillock.so The "sssd" service must be restarted for the changes to take effect. To restart the "sssd" service, run the following command: $ sudo systemctl restart sssd.service

b

RHEL 8 must ensure account lockouts persist.

AC-7 - Medium - CCI-000044 - V-230339 - SV-230339r1017151_rule

RMF Control

AC-7

Severity

M

CCI

Version

RHEL-08-020017

Vuln IDs

V-230339

Rule IDs

SV-230339r1017151_rule

By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, otherwise known as brute-force attacks, is reduced. Limits are imposed by locking the account. In RHEL 8.2 the "/etc/security/faillock.conf" file was incorporated to centralize the configuration of the pam_faillock.so module. Also introduced is a "local_users_only" option that will only track failed user authentication attempts for local users in /etc/passwd and ignore centralized (AD, IdM, LDAP, etc.) users to allow the centralized platform to solely manage user lockout. From "faillock.conf" man pages: Note that the default directory that "pam_faillock" uses is usually cleared on system boot so the access will be reenabled after system reboot. If that is undesirable a different tally directory must be set with the "dir" option. Satisfies: SRG-OS-000021-GPOS-00005, SRG-OS-000329-GPOS-00128

Checks: C-33008r743973_chk

Note: This check applies to RHEL versions 8.2 or newer. If the system is RHEL version 8.0 or 8.1, this check is not applicable. Verify the "/etc/security/faillock.conf" file is configured use a non-default faillock directory to ensure contents persist after reboot: $ sudo grep 'dir =' /etc/security/faillock.conf dir = /var/log/faillock If the "dir" option is not set to a non-default documented tally log directory, is missing or commented out, this is a finding.

Fix: F-32983r743974_fix

Configure the operating system maintain the contents of the faillock directory after a reboot. Add/Modify the "/etc/security/faillock.conf" file to match the following line: dir = /var/log/faillock

b

RHEL 8 must prevent system messages from being presented when three unsuccessful logon attempts occur.

AC-7 - Medium - CCI-000044 - V-230340 - SV-230340r1017152_rule

RMF Control

AC-7

Severity

M

CCI

Version

RHEL-08-020018

Vuln IDs

V-230340

Rule IDs

SV-230340r1017152_rule

By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, otherwise known as brute-force attacks, is reduced. Limits are imposed by locking the account. RHEL 8 can utilize the "pam_faillock.so" for this purpose. Note that manual changes to the listed files may be overwritten by the "authselect" program. From "Pam_Faillock" man pages: Note that the default directory that "pam_faillock" uses is usually cleared on system boot so the access will be reenabled after system reboot. If that is undesirable a different tally directory must be set with the "dir" option. Satisfies: SRG-OS-000021-GPOS-00005, SRG-OS-000329-GPOS-00128

Checks: C-33009r567766_chk

Check that the system prevents informative messages from being presented to the user pertaining to logon information with the following commands: Note: If the System Administrator demonstrates the use of an approved centralized account management method that locks an account after three unsuccessful logon attempts within a period of 15 minutes, this requirement is not applicable. Note: This check applies to RHEL versions 8.0 and 8.1, if the system is RHEL version 8.2 or newer, this check is not applicable. $ sudo grep pam_faillock.so /etc/pam.d/password-auth auth required pam_faillock.so preauth dir=/var/log/faillock silent audit deny=3 even_deny_root fail_interval=900 unlock_time=0 auth required pam_faillock.so authfail dir=/var/log/faillock unlock_time=0 account required pam_faillock.so If the "silent" option is missing from the "preauth" line with the "pam_faillock.so" module, this is a finding. $ sudo grep pam_faillock.so /etc/pam.d/system-auth auth required pam_faillock.so preauth dir=/var/log/faillock silent audit deny=3 even_deny_root fail_interval=900 unlock_time=0 auth required pam_faillock.so authfail dir=/var/log/faillock unlock_time=0 account required pam_faillock.so If the "silent" option is missing from the "preauth" line with the "pam_faillock.so" module, this is a finding.

Fix: F-32984r567767_fix

Configure the operating system to prevent informative messages from being presented at logon attempts. Add/Modify the appropriate sections of the "/etc/pam.d/system-auth" and "/etc/pam.d/password-auth" files to match the following lines: auth required pam_faillock.so preauth dir=/var/log/faillock silent audit deny=3 even_deny_root fail_interval=900 unlock_time=0 auth required pam_faillock.so authfail dir=/var/log/faillock unlock_time=0 account required pam_faillock.so The "sssd" service must be restarted for the changes to take effect. To restart the "sssd" service, run the following command: $ sudo systemctl restart sssd.service

b

RHEL 8 must prevent system messages from being presented when three unsuccessful logon attempts occur.

AC-7 - Medium - CCI-000044 - V-230341 - SV-230341r1017153_rule

RMF Control

AC-7

Severity

M

CCI

Version

RHEL-08-020019

Vuln IDs

V-230341

Rule IDs

SV-230341r1017153_rule

By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, otherwise known as brute-force attacks, is reduced. Limits are imposed by locking the account. In RHEL 8.2 the "/etc/security/faillock.conf" file was incorporated to centralize the configuration of the pam_faillock.so module. Also introduced is a "local_users_only" option that will only track failed user authentication attempts for local users in /etc/passwd and ignore centralized (AD, IdM, LDAP, etc.) users to allow the centralized platform to solely manage user lockout. From "faillock.conf" man pages: Note that the default directory that "pam_faillock" uses is usually cleared on system boot so the access will be reenabled after system reboot. If that is undesirable a different tally directory must be set with the "dir" option. Satisfies: SRG-OS-000021-GPOS-00005, SRG-OS-000329-GPOS-00128

Checks: C-33010r743976_chk

Note: This check applies to RHEL versions 8.2 or newer, if the system is RHEL version 8.0 or 8.1, this check is not applicable. Verify the "/etc/security/faillock.conf" file is configured to prevent informative messages from being presented at logon attempts: $ sudo grep silent /etc/security/faillock.conf silent If the "silent" option is not set, is missing or commented out, this is a finding.

Fix: F-32985r743977_fix

Configure the operating system to prevent informative messages from being presented at logon attempts. Add/Modify the "/etc/security/faillock.conf" file to match the following line: silent

b

RHEL 8 must log user name information when unsuccessful logon attempts occur.

AC-7 - Medium - CCI-000044 - V-230342 - SV-230342r1017154_rule

RMF Control

AC-7

Severity

M

CCI

Version

RHEL-08-020020

Vuln IDs

V-230342

Rule IDs

SV-230342r1017154_rule

By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, otherwise known as brute-force attacks, is reduced. Limits are imposed by locking the account. RHEL 8 can utilize the "pam_faillock.so" for this purpose. Note that manual changes to the listed files may be overwritten by the "authselect" program. From "Pam_Faillock" man pages: Note that the default directory that "pam_faillock" uses is usually cleared on system boot so the access will be reenabled after system reboot. If that is undesirable a different tally directory must be set with the "dir" option. In RHEL 8.2 the "/etc/security/faillock.conf" file was incorporated to centralize the configuration of the pam_faillock.so module. Also introduced is a "local_users_only" option that will only track failed user authentication attempts for local users in /etc/passwd and ignore centralized (AD, IdM, LDAP, etc.) users to allow the centralized platform to solely manage user lockout. Satisfies: SRG-OS-000021-GPOS-00005, SRG-OS-000329-GPOS-00128

Checks: C-33011r646871_chk

Check that the system logs user name information when unsuccessful logon attempts occur with the following commands: If the system is RHEL version 8.2 or newer, this check is not applicable. Note: If the System Administrator demonstrates the use of an approved centralized account management method that locks an account after three unsuccessful logon attempts within a period of 15 minutes, this requirement is not applicable. $ sudo grep pam_faillock.so /etc/pam.d/password-auth auth required pam_faillock.so preauth dir=/var/log/faillock silent audit deny=3 even_deny_root fail_interval=900 unlock_time=0 auth required pam_faillock.so authfail dir=/var/log/faillock unlock_time=0 account required pam_faillock.so If the "audit" option is missing from the "preauth" line with the "pam_faillock.so" module, this is a finding. $ sudo grep pam_faillock.so /etc/pam.d/system-auth auth required pam_faillock.so preauth dir=/var/log/faillock silent audit deny=3 even_deny_root fail_interval=900 unlock_time=0 auth required pam_faillock.so authfail dir=/var/log/faillock unlock_time=0 account required pam_faillock.so If the "audit" option is missing from the "preauth" line with the "pam_faillock.so" module, this is a finding.

Fix: F-32986r567773_fix

Configure the operating system to log user name information when unsuccessful logon attempts occur. Add/Modify the appropriate sections of the "/etc/pam.d/system-auth" and "/etc/pam.d/password-auth" files to match the following lines: auth required pam_faillock.so preauth dir=/var/log/faillock silent audit deny=3 even_deny_root fail_interval=900 unlock_time=0 auth required pam_faillock.so authfail dir=/var/log/faillock unlock_time=0 account required pam_faillock.so The "sssd" service must be restarted for the changes to take effect. To restart the "sssd" service, run the following command: $ sudo systemctl restart sssd.service

b

RHEL 8 must log user name information when unsuccessful logon attempts occur.

AC-7 - Medium - CCI-000044 - V-230343 - SV-230343r1017155_rule

RMF Control

AC-7

Severity

M

CCI

Version

RHEL-08-020021

Vuln IDs

V-230343

Rule IDs

SV-230343r1017155_rule

By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, otherwise known as brute-force attacks, is reduced. Limits are imposed by locking the account. In RHEL 8.2 the "/etc/security/faillock.conf" file was incorporated to centralize the configuration of the pam_faillock.so module. Also introduced is a "local_users_only" option that will only track failed user authentication attempts for local users in /etc/passwd and ignore centralized (AD, IdM, LDAP, etc.) users to allow the centralized platform to solely manage user lockout. From "faillock.conf" man pages: Note that the default directory that "pam_faillock" uses is usually cleared on system boot so the access will be reenabled after system reboot. If that is undesirable a different tally directory must be set with the "dir" option. Satisfies: SRG-OS-000021-GPOS-00005, SRG-OS-000329-GPOS-00128

Checks: C-33012r743979_chk

Note: This check applies to RHEL versions 8.2 or newer, if the system is RHEL version 8.0 or 8.1, this check is not applicable. Verify the "/etc/security/faillock.conf" file is configured to log user name information when unsuccessful logon attempts occur: $ sudo grep audit /etc/security/faillock.conf audit If the "audit" option is not set, is missing or commented out, this is a finding.

Fix: F-32987r743980_fix

Configure the operating system to log user name information when unsuccessful logon attempts occur. Add/Modify the "/etc/security/faillock.conf" file to match the following line: audit

b

RHEL 8 must include root when automatically locking an account until the locked account is released by an administrator when three unsuccessful logon attempts occur during a 15-minute time period.

AC-7 - Medium - CCI-000044 - V-230344 - SV-230344r1017156_rule

RMF Control

AC-7

Severity

M

CCI

Version

RHEL-08-020022

Vuln IDs

V-230344

Rule IDs

SV-230344r1017156_rule

By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, otherwise known as brute-force attacks, is reduced. Limits are imposed by locking the account. RHEL 8 can utilize the "pam_faillock.so" for this purpose. Note that manual changes to the listed files may be overwritten by the "authselect" program. From "Pam_Faillock" man pages: Note that the default directory that "pam_faillock" uses is usually cleared on system boot so the access will be reenabled after system reboot. If that is undesirable a different tally directory must be set with the "dir" option. In RHEL 8.2 the "/etc/security/faillock.conf" file was incorporated to centralize the configuration of the pam_faillock.so module. Also introduced is a "local_users_only" option that will only track failed user authentication attempts for local users in /etc/passwd and ignore centralized (AD, IdM, LDAP, etc.) users to allow the centralized platform to solely manage user lockout. Satisfies: SRG-OS-000021-GPOS-00005, SRG-OS-000329-GPOS-00128

Checks: C-33013r646873_chk

Check that the system includes the root account when locking an account after three unsuccessful logon attempts within a period of 15 minutes with the following commands: If the system is RHEL version 8.2 or newer, this check is not applicable. Note: If the System Administrator demonstrates the use of an approved centralized account management method that locks an account after three unsuccessful logon attempts within a period of 15 minutes, this requirement is not applicable. $ sudo grep pam_faillock.so /etc/pam.d/password-auth auth required pam_faillock.so preauth dir=/var/log/faillock silent audit deny=3 even_deny_root fail_interval=900 unlock_time=0 auth required pam_faillock.so authfail dir=/var/log/faillock unlock_time=0 account required pam_faillock.so If the "even_deny_root" option is missing from the "preauth" line with the "pam_faillock.so" module, this is a finding. $ sudo grep pam_faillock.so /etc/pam.d/system-auth auth required pam_faillock.so preauth dir=/var/log/faillock silent audit deny=3 even_deny_root fail_interval=900 unlock_time=0 auth required pam_faillock.so authfail dir=/var/log/faillock unlock_time=0 account required pam_faillock.so If the "even_deny_root" option is missing from the "preauth" line with the "pam_faillock.so" module, this is a finding.

Fix: F-32988r567779_fix

Configure the operating system to include root when locking an account after three unsuccessful logon attempts occur in 15 minutes. Add/Modify the appropriate sections of the "/etc/pam.d/system-auth" and "/etc/pam.d/password-auth" files to match the following lines: auth required pam_faillock.so preauth dir=/var/log/faillock silent audit deny=3 even_deny_root fail_interval=900 unlock_time=0 auth required pam_faillock.so authfail dir=/var/log/faillock unlock_time=0 account required pam_faillock.so The "sssd" service must be restarted for the changes to take effect. To restart the "sssd" service, run the following command: $ sudo systemctl restart sssd.service

b

RHEL 8 must include root when automatically locking an account until the locked account is released by an administrator when three unsuccessful logon attempts occur during a 15-minute time period.

AC-7 - Medium - CCI-000044 - V-230345 - SV-230345r1017157_rule

RMF Control

AC-7

Severity

M

CCI

Version

RHEL-08-020023

Vuln IDs

V-230345

Rule IDs

SV-230345r1017157_rule

By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, otherwise known as brute-force attacks, is reduced. Limits are imposed by locking the account. In RHEL 8.2 the "/etc/security/faillock.conf" file was incorporated to centralize the configuration of the pam_faillock.so module. Also introduced is a "local_users_only" option that will only track failed user authentication attempts for local users in /etc/passwd and ignore centralized (AD, IdM, LDAP, etc.) users to allow the centralized platform to solely manage user lockout. From "faillock.conf" man pages: Note that the default directory that "pam_faillock" uses is usually cleared on system boot so the access will be reenabled after system reboot. If that is undesirable a different tally directory must be set with the "dir" option. Satisfies: SRG-OS-000021-GPOS-00005, SRG-OS-000329-GPOS-00128

Checks: C-33014r743982_chk

Note: This check applies to RHEL versions 8.2 or newer, if the system is RHEL version 8.0 or 8.1, this check is not applicable. Verify the "/etc/security/faillock.conf" file is configured to log user name information when unsuccessful logon attempts occur: $ sudo grep even_deny_root /etc/security/faillock.conf even_deny_root If the "even_deny_root" option is not set, is missing or commented out, this is a finding.

Fix: F-32989r743983_fix

Configure the operating system to include root when locking an account after three unsuccessful logon attempts occur in 15 minutes. Add/Modify the "/etc/security/faillock.conf" file to match the following line: even_deny_root

a

RHEL 8 must limit the number of concurrent sessions to ten for all accounts and/or account types.

AC-10 - Low - CCI-000054 - V-230346 - SV-230346r1069306_rule

RMF Control

AC-10

Severity

L

CCI

CCI-000054

Version

RHEL-08-020024

Vuln IDs

V-230346

Rule IDs

SV-230346r1069306_rule

Operating system management includes the ability to control the number of users and user sessions that utilize an operating system. Limiting the number of allowed users and sessions per user is helpful in reducing the risks related to DoS attacks. This requirement addresses concurrent sessions for information system accounts and does not address concurrent sessions by single users via multiple system accounts. The maximum number of concurrent sessions should be defined based on mission needs and the operational environment for each system.

Checks: C-33015r1069221_chk

Verify the operating system limits the number of concurrent sessions to "10" for all accounts and/or account types by issuing the following command: $ sudo grep -r -s '^[^#].*maxlogins' /etc/security/limits.conf /etc/security/limits.d/*.conf /etc/security/limits.d/maxlogins.conf:* hard maxlogins 10 This can be set as a global domain (with the * wildcard) but may be set differently for multiple domains. If the "maxlogins" item is missing, commented out, or the value is set greater than "10" and is not documented with the Information System Security Officer (ISSO) as an operational requirement for all domains that have the "maxlogins" item assigned, this is a finding.

Fix: F-32990r1017158_fix

Configure the operating system to limit the number of concurrent sessions to "10" for all accounts and/or account types. Add the following line to the top of the /etc/security/limits.conf or in a ".conf" file defined in /etc/security/limits.d/: * hard maxlogins 10

b

RHEL 8 must enable a user session lock until that user re-establishes access using established identification and authentication procedures for graphical user sessions.

AC-11 - Medium - CCI-000056 - V-230347 - SV-230347r1017160_rule

RMF Control

AC-11

Severity

M

CCI

CCI-000056

Version

RHEL-08-020030

Vuln IDs

V-230347

Rule IDs

SV-230347r1017160_rule

A session lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not want to log out because of the temporary nature of the absence. The session lock is implemented at the point where session activity can be determined. Regardless of where the session lock is determined and implemented, once invoked, the session lock must remain in place until the user reauthenticates. No other activity aside from reauthentication must unlock the system. Satisfies: SRG-OS-000028-GPOS-00009, SRG-OS-000030-GPOS-00011

Checks: C-33016r567787_chk

Verify the operating system enables a user's session lock until that user re-establishes access using established identification and authentication procedures with the following command: $ sudo gsettings get org.gnome.desktop.screensaver lock-enabled true If the setting is "false", this is a finding. Note: This requirement assumes the use of the RHEL 8 default graphical user interface, Gnome Shell. If the system does not have any graphical user interface installed, this requirement is Not Applicable.

Fix: F-32991r567788_fix

Configure the operating system to enable a user's session lock until that user re-establishes access using established identification and authentication procedures. Create a database to contain the system-wide screensaver settings (if it does not already exist) with the following example: $ sudo vi /etc/dconf/db/local.d/00-screensaver Edit the "[org/gnome/desktop/screensaver]" section of the database file and add or update the following lines: # Set this to true to lock the screen when the screensaver activates lock-enabled=true Update the system databases: $ sudo dconf update

b

RHEL 8 must be able to initiate directly a session lock for all connection types using smartcard when the smartcard is removed.

AC-11 - Medium - CCI-000056 - V-230351 - SV-230351r1017164_rule

RMF Control

AC-11

Severity

M

CCI

CCI-000056

Version

RHEL-08-020050

Vuln IDs

V-230351

Rule IDs

SV-230351r1017164_rule

A session lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not want to log out because of the temporary nature of the absence. The session lock is implemented at the point where session activity can be determined. Rather than be forced to wait for a period of time to expire before the user session can be locked, RHEL 8 needs to provide users with the ability to manually invoke a session lock so users can secure their session if it is necessary to temporarily vacate the immediate physical vicinity. Satisfies: SRG-OS-000028-GPOS-00009, SRG-OS-000030-GPOS-00011

Checks: C-33020r792897_chk

Verify the operating system enables a user's session lock until that user re-establishes access using established identification and authentication procedures with the following command: This requirement assumes the use of the RHEL 8 default graphical user interface, Gnome Shell. If the system does not have any graphical user interface installed, this requirement is Not Applicable. $ sudo grep -R removal-action /etc/dconf/db/* /etc/dconf/db/distro.d/20-authselect:removal-action='lock-screen' If the "removal-action='lock-screen'" setting is missing or commented out from the dconf database files, this is a finding.

Fix: F-32995r792898_fix

Configure the operating system to enable a user's session lock until that user re-establishes access using established identification and authentication procedures. Select/Create an authselect profile and incorporate the "with-smartcard-lock-on-removal" feature with the following example: $ sudo authselect select sssd with-smartcard with-smartcard-lock-on-removal Alternatively, the dconf settings can be edited in the /etc/dconf/db/* location. Edit or add the "[org/gnome/settings-daemon/peripherals/smartcard]" section of the database file and add or update the following lines: removal-action='lock-screen' Update the system databases: $ sudo dconf update

b

RHEL 8 must automatically lock graphical user sessions after 15 minutes of inactivity.

AC-11 - Medium - CCI-000057 - V-230352 - SV-230352r1017165_rule

RMF Control

AC-11

Severity

M

CCI

Version

RHEL-08-020060

Vuln IDs

V-230352

Rule IDs

SV-230352r1017165_rule

A session lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not want to log out because of the temporary nature of the absence. The session lock is implemented at the point where session activity can be determined. Rather than be forced to wait for a period of time to expire before the user session can be locked, RHEL 8 needs to provide users with the ability to manually invoke a session lock so users can secure their session if it is necessary to temporarily vacate the immediate physical vicinity. Satisfies: SRG-OS-000029-GPOS-00010, SRG-OS-000031-GPOS-00012

Checks: C-33021r646875_chk

Verify the operating system initiates a session lock after a 15-minute period of inactivity for graphical user interfaces with the following commands: This requirement assumes the use of the RHEL 8 default graphical user interface, Gnome Shell. If the system does not have any graphical user interface installed, this requirement is Not Applicable. $ sudo gsettings get org.gnome.desktop.session idle-delay uint32 900 If "idle-delay" is set to "0" or a value greater than "900", this is a finding.

Fix: F-32996r567803_fix

Configure the operating system to initiate a screensaver after a 15-minute period of inactivity for graphical user interfaces. Create a database to contain the system-wide screensaver settings (if it does not already exist) with the following command: $ sudo touch /etc/dconf/db/local.d/00-screensaver Edit /etc/dconf/db/local.d/00-screensaver and add or update the following lines: [org/gnome/desktop/session] # Set the lock time out to 900 seconds before the session is considered idle idle-delay=uint32 900 Update the system databases: $ sudo dconf update

b

RHEL 8 must prevent a user from overriding the session lock-delay setting for the graphical user interface.

AC-11 - Medium - CCI-000057 - V-230354 - SV-230354r1069323_rule

RMF Control

AC-11

Severity

M

CCI

Version

RHEL-08-020080

Vuln IDs

V-230354

Rule IDs

SV-230354r1069323_rule

A session time-out lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not log out because of the temporary nature of the absence. Rather than relying on the user to manually lock their operating system session prior to vacating the vicinity, operating systems need to be able to identify when a user's session has idled and take action to initiate the session lock. The session lock is implemented at the point where session activity can be determined and/or controlled. Implementing session settings will have little value if a user is able to manipulate these settings from the defaults prescribed in the other requirements of this implementation guide. Locking these settings from non-privileged users is crucial to maintaining a protected baseline. Satisfies: SRG-OS-000029-GPOS-00010, SRG-OS-000031-GPOS-00012, SRG-OS-000480-GPOS-00227

Checks: C-33023r743988_chk

Verify the operating system prevents a user from overriding settings for graphical user interfaces. Note: This requirement assumes the use of the RHEL 8 default graphical user interface, Gnome Shell. If the system does not have any graphical user interface installed, this requirement is Not Applicable. Determine which profile the system database is using with the following command: $ sudo grep system-db /etc/dconf/profile/user system-db:local Check that graphical settings are locked from non-privileged user modification with the following command: Note: The example below is using the database "local" for the system, so the path is "/etc/dconf/db/local.d". This path must be modified if a database other than "local" is being used. $ sudo grep -i lock-delay /etc/dconf/db/local.d/locks/* /org/gnome/desktop/screensaver/lock-delay If the command does not return at least the example result, this is a finding.

Fix: F-32998r1069255_fix

Configure the operating system to prevent a user from overriding settings for graphical user interfaces. Create a database to contain the system-wide screensaver settings (if it does not already exist) with the following command: Note: The example below is using the database "local" for the system, so if the system is using another database in "/etc/dconf/profile/user", the file should be created under the appropriate subdirectory. $ sudo touch /etc/dconf/db/local.d/locks/session Add the following setting to prevent non-privileged users from modifying it: /org/gnome/desktop/screensaver/lock-delay Run the following command to update the database: $ sudo dconf update

b

RHEL 8 must map the authenticated identity to the user or group account for PKI-based authentication.

IA-5 - Medium - CCI-000187 - V-230355 - SV-230355r1017168_rule

RMF Control

IA-5

Severity

M

CCI

CCI-000187

Version

RHEL-08-020090

Vuln IDs

V-230355

Rule IDs

SV-230355r1017168_rule

Without mapping the certificate used to authenticate to the user account, the ability to determine the identity of the individual user or group will not be available for forensic analysis. There are various methods of mapping certificates to user/group accounts for RHEL 8. For the purposes of this requirement, the check and fix will account for Active Directory mapping. Some of the other possible methods include joining the system to a domain and utilizing a Red Hat idM server, or a local system mapping, where the system is not part of a domain.

Checks: C-33024r858742_chk

Verify the certificate of the user or group is mapped to the corresponding user or group in the "sssd.conf" file with the following command: Note: If the System Administrator demonstrates the use of an approved alternate multifactor authentication method, this requirement is not applicable. $ sudo cat /etc/sssd/sssd.conf [sssd] config_file_version = 2 services = pam, sudo, ssh domains = testing.test [pam] pam_cert_auth = True [domain/testing.test] id_provider = ldap [certmap/testing.test/rule_name] matchrule =<SAN>.*EDIPI@mil maprule = (userCertificate;binary={cert!bin}) domains = testing.test If the certmap section does not exist, ask the System Administrator to indicate how certificates are mapped to accounts. If there is no evidence of certificate mapping, this is a finding.

Fix: F-32999r818835_fix

Configure the operating system to map the authenticated identity to the user or group account by adding or modifying the certmap section of the "/etc/sssd/sssd.conf file based on the following example: [certmap/testing.test/rule_name] matchrule =<SAN>.*EDIPI@mil maprule = (userCertificate;binary={cert!bin}) domains = testing.test The "sssd" service must be restarted for the changes to take effect. To restart the "sssd" service, run the following command: $ sudo systemctl restart sssd.service

b

RHEL 8 must ensure the password complexity module is enabled in the password-auth file.

CM-6 - Medium - CCI-000366 - V-230356 - SV-230356r982195_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-020100

Vuln IDs

V-230356

Rule IDs

SV-230356r982195_rule

Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. "pwquality" enforces complex password construction configuration and has the ability to limit brute-force attacks on the system. RHEL 8 utilizes "pwquality" as a mechanism to enforce password complexity. This is set in both: /etc/pam.d/password-auth /etc/pam.d/system-auth

Checks: C-33025r902726_chk

Verify the operating system uses "pwquality" to enforce the password complexity rules. Check for the use of "pwquality" in the password-auth file with the following command: $ sudo cat /etc/pam.d/password-auth | grep pam_pwquality password requisite pam_pwquality.so If the command does not return a line containing the value "pam_pwquality.so" as shown, or the line is commented out, this is a finding.

Fix: F-33000r902727_fix

Configure the operating system to use "pwquality" to enforce password complexity rules. Add the following line to the "/etc/pam.d/password-auth" file (or modify the line to have the required value): password requisite pam_pwquality.so

b

RHEL 8 must enforce password complexity by requiring that at least one uppercase character be used.

IA-5 - Medium - CCI-000192 - V-230357 - SV-230357r1017169_rule

RMF Control

IA-5

Severity

M

CCI

CCI-000192

Version

RHEL-08-020110

Vuln IDs

V-230357

Rule IDs

SV-230357r1017169_rule

Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Password complexity is one factor of several that determines how long it takes to crack a password. The more complex the password, the greater the number of possible combinations that need to be tested before the password is compromised. RHEL 8 utilizes pwquality as a mechanism to enforce password complexity. Note that in order to require uppercase characters, without degrading the "minlen" value, the credit value must be expressed as a negative number in "/etc/security/pwquality.conf".

Checks: C-33026r833312_chk

Verify the value for "ucredit" with the following command: $ sudo grep -r ucredit /etc/security/pwquality.conf* /etc/security/pwquality.conf:ucredit = -1 If the value of "ucredit" is a positive number or is commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-33001r858770_fix

Configure the operating system to enforce password complexity by requiring that at least one uppercase character be used by setting the "ucredit" option. Add the following line to /etc/security/pwquality.conf (or modify the line to have the required value): ucredit = -1 Remove any configurations that conflict with the above value.

b

RHEL 8 must enforce password complexity by requiring that at least one lower-case character be used.

IA-5 - Medium - CCI-000193 - V-230358 - SV-230358r1017170_rule

RMF Control

IA-5

Severity

M

CCI

CCI-000193

Version

RHEL-08-020120

Vuln IDs

V-230358

Rule IDs

SV-230358r1017170_rule

Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Password complexity is one factor of several that determines how long it takes to crack a password. The more complex the password, the greater the number of possible combinations that need to be tested before the password is compromised. RHEL 8 utilizes pwquality as a mechanism to enforce password complexity. Note that in order to require lower-case characters without degrading the "minlen" value, the credit value must be expressed as a negative number in "/etc/security/pwquality.conf".

Checks: C-33027r833314_chk

Verify the value for "lcredit" with the following command: $ sudo grep -r lcredit /etc/security/pwquality.conf* /etc/security/pwquality.conf:lcredit = -1 If the value of "lcredit" is a positive number or is commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-33002r858772_fix

Configure the operating system to enforce password complexity by requiring that at least one lower-case character be used by setting the "lcredit" option. Add the following line to /etc/security/pwquality.conf (or modify the line to have the required value): lcredit = -1 Remove any configurations that conflict with the above value.

b

RHEL 8 must enforce password complexity by requiring that at least one numeric character be used.

IA-5 - Medium - CCI-000194 - V-230359 - SV-230359r1017171_rule

RMF Control

IA-5

Severity

M

CCI

CCI-000194

Version

RHEL-08-020130

Vuln IDs

V-230359

Rule IDs

SV-230359r1017171_rule

Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Password complexity is one factor of several that determines how long it takes to crack a password. The more complex the password, the greater the number of possible combinations that need to be tested before the password is compromised. RHEL 8 utilizes "pwquality" as a mechanism to enforce password complexity. Note that in order to require numeric characters, without degrading the minlen value, the credit value must be expressed as a negative number in "/etc/security/pwquality.conf".

Checks: C-33028r833316_chk

Verify the value for "dcredit" with the following command: $ sudo grep -r dcredit /etc/security/pwquality.conf* /etc/security/pwquality.conf:dcredit = -1 If the value of "dcredit" is a positive number or is commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-33003r858774_fix

Configure the operating system to enforce password complexity by requiring that at least one numeric character be used by setting the "dcredit" option. Add the following line to /etc/security/pwquality.conf (or modify the line to have the required value): dcredit = -1 Remove any configurations that conflict with the above value.

b

RHEL 8 must require the maximum number of repeating characters of the same character class be limited to four when passwords are changed.

IA-5 - Medium - CCI-000195 - V-230360 - SV-230360r1017172_rule

RMF Control

IA-5

Severity

M

CCI

Version

RHEL-08-020140

Vuln IDs

V-230360

Rule IDs

SV-230360r1017172_rule

Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Password complexity is one factor of several that determines how long it takes to crack a password. The more complex the password, the greater the number of possible combinations that need to be tested before the password is compromised. RHEL 8 utilizes "pwquality" as a mechanism to enforce password complexity. The "maxclassrepeat" option sets the maximum number of allowed same consecutive characters in the same class in the new password.

Checks: C-33029r833318_chk

Check for the value of the "maxclassrepeat" option with the following command: $ sudo grep -r maxclassrepeat /etc/security/pwquality.conf* /etc/security/pwquality.conf:maxclassrepeat = 4 If the value of "maxclassrepeat" is set to "0", more than "4" or is commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-33004r858776_fix

Configure the operating system to require the change of the number of repeating characters of the same character class when passwords are changed by setting the "maxclassrepeat" option. Add the following line to "/etc/security/pwquality.conf" conf (or modify the line to have the required value): maxclassrepeat = 4 Remove any configurations that conflict with the above value.

b

RHEL 8 must require the maximum number of repeating characters be limited to three when passwords are changed.

IA-5 - Medium - CCI-000195 - V-230361 - SV-230361r1017173_rule

RMF Control

IA-5

Severity

M

CCI

Version

RHEL-08-020150

Vuln IDs

V-230361

Rule IDs

SV-230361r1017173_rule

Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Password complexity is one factor of several that determines how long it takes to crack a password. The more complex the password, the greater the number of possible combinations that need to be tested before the password is compromised. RHEL 8 utilizes "pwquality" as a mechanism to enforce password complexity. The "maxrepeat" option sets the maximum number of allowed same consecutive characters in a new password.

Checks: C-33030r833320_chk

Check for the value of the "maxrepeat" option with the following command: $ sudo grep -r maxrepeat /etc/security/pwquality.conf* /etc/security/pwquality.conf:maxrepeat = 3 If the value of "maxrepeat" is set to more than "3" or is commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-33005r858778_fix

Configure the operating system to require the change of the number of repeating consecutive characters when passwords are changed by setting the "maxrepeat" option. Add the following line to "/etc/security/pwquality.conf conf" (or modify the line to have the required value): maxrepeat = 3 Remove any configurations that conflict with the above value.

b

RHEL 8 must require the change of at least four character classes when passwords are changed.

IA-5 - Medium - CCI-000195 - V-230362 - SV-230362r1017174_rule

RMF Control

IA-5

Severity

M

CCI

Version

RHEL-08-020160

Vuln IDs

V-230362

Rule IDs

SV-230362r1017174_rule

Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Password complexity is one factor of several that determines how long it takes to crack a password. The more complex the password, the greater the number of possible combinations that need to be tested before the password is compromised. RHEL 8 utilizes "pwquality" as a mechanism to enforce password complexity. The "minclass" option sets the minimum number of required classes of characters for the new password (digits, uppercase, lowercase, others).

Checks: C-33031r833322_chk

Verify the value of the "minclass" option with the following command: $ sudo grep -r minclass /etc/security/pwquality.conf* /etc/security/pwquality.conf:minclass = 4 If the value of "minclass" is set to less than "4" or is commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-33006r858780_fix

Configure the operating system to require the change of at least four character classes when passwords are changed by setting the "minclass" option. Add the following line to "/etc/security/pwquality.conf conf" (or modify the line to have the required value): minclass = 4 Remove any configurations that conflict with the above value.

b

RHEL 8 must require the change of at least 8 characters when passwords are changed.

IA-5 - Medium - CCI-000195 - V-230363 - SV-230363r1017175_rule

RMF Control

IA-5

Severity

M

CCI

Version

RHEL-08-020170

Vuln IDs

V-230363

Rule IDs

SV-230363r1017175_rule

Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Password complexity is one factor of several that determines how long it takes to crack a password. The more complex the password, the greater the number of possible combinations that need to be tested before the password is compromised. RHEL 8 utilizes "pwquality" as a mechanism to enforce password complexity. The "difok" option sets the number of characters in a password that must not be present in the old password.

Checks: C-33032r833324_chk

Verify the value of the "difok" option with the following command: $ sudo grep -r difok /etc/security/pwquality.conf* /etc/security/pwquality.conf:difok = 8 If the value of "difok" is set to less than "8" or is commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-33007r858782_fix

Configure the operating system to require the change of at least eight of the total number of characters when passwords are changed by setting the "difok" option. Add the following line to "/etc/security/pwquality.conf" (or modify the line to have the required value): difok = 8 Remove any configurations that conflict with the above value.

b

RHEL 8 passwords must have a 24 hours/1 day minimum password lifetime restriction in /etc/shadow.

IA-5 - Medium - CCI-000198 - V-230364 - SV-230364r1017176_rule

RMF Control

IA-5

Severity

M

CCI

CCI-000198

Version

RHEL-08-020180

Vuln IDs

V-230364

Rule IDs

SV-230364r1017176_rule

Enforcing a minimum password lifetime helps to prevent repeated password changes to defeat the password reuse or history enforcement requirement. If users are allowed to immediately and continually change their password, the password could be repeatedly changed in a short period of time to defeat the organization's policy regarding password reuse.

Checks: C-33033r567838_chk

Check whether the minimum time period between password changes for each user account is one day or greater. $ sudo awk -F: '$4 < 1 {print $1 " " $4}' /etc/shadow If any results are returned that are not associated with a system account, this is a finding.

Fix: F-33008r567839_fix

Configure non-compliant accounts to enforce a 24 hours/1 day minimum password lifetime: $ sudo chage -m 1 [user]

b

RHEL 8 passwords for new users or password changes must have a 24 hours/1 day minimum password lifetime restriction in /etc/login.defs.

IA-5 - Medium - CCI-000198 - V-230365 - SV-230365r1017177_rule

RMF Control

IA-5

Severity

M

CCI

CCI-000198

Version

RHEL-08-020190

Vuln IDs

V-230365

Rule IDs

SV-230365r1017177_rule

Enforcing a minimum password lifetime helps to prevent repeated password changes to defeat the password reuse or history enforcement requirement. If users are allowed to immediately and continually change their password, the password could be repeatedly changed in a short period of time to defeat the organization's policy regarding password reuse.

Checks: C-33034r567841_chk

Verify the operating system enforces 24 hours/1 day as the minimum password lifetime for new user accounts. Check for the value of "PASS_MIN_DAYS" in "/etc/login.defs" with the following command: $ sudo grep -i pass_min_days /etc/login.defs PASS_MIN_DAYS 1 If the "PASS_MIN_DAYS" parameter value is not "1" or greater, or is commented out, this is a finding.

Fix: F-33009r567842_fix

Configure the operating system to enforce 24 hours/1 day as the minimum password lifetime. Add the following line in "/etc/login.defs" (or modify the line to have the required value): PASS_MIN_DAYS 1

b

RHEL 8 user account passwords must have a 60-day maximum password lifetime restriction.

IA-5 - Medium - CCI-000199 - V-230366 - SV-230366r1038967_rule

RMF Control

IA-5

Severity

M

CCI

CCI-000199

Version

RHEL-08-020200

Vuln IDs

V-230366

Rule IDs

SV-230366r1038967_rule

Any password, no matter how complex, can eventually be cracked. Therefore, passwords need to be changed periodically. If RHEL 8 does not limit the lifetime of passwords and force users to change their passwords, there is the risk that RHEL 8 passwords could be compromised.

Checks: C-33035r646877_chk

Verify that RHEL 8 enforces a 60-day maximum password lifetime for new user accounts by running the following command: $ sudo grep -i pass_max_days /etc/login.defs PASS_MAX_DAYS 60 If the "PASS_MAX_DAYS" parameter value is greater than "60", or commented out, this is a finding.

Fix: F-33010r567845_fix

Configure RHEL 8 to enforce a 60-day maximum password lifetime. Add, or modify the following line in the "/etc/login.defs" file: PASS_MAX_DAYS 60

b

RHEL 8 user account passwords must be configured so that existing passwords are restricted to a 60-day maximum lifetime.

IA-5 - Medium - CCI-000199 - V-230367 - SV-230367r1038967_rule

RMF Control

IA-5

Severity

M

CCI

CCI-000199

Version

RHEL-08-020210

Vuln IDs

V-230367

Rule IDs

SV-230367r1038967_rule

Any password, no matter how complex, can eventually be cracked. Therefore, passwords need to be changed periodically. If RHEL 8 does not limit the lifetime of passwords and force users to change their passwords, there is the risk that RHEL 8 passwords could be compromised.

Checks: C-33036r567847_chk

Check whether the maximum time period for existing passwords is restricted to 60 days with the following commands: $ sudo awk -F: '$5 > 60 {print $1 " " $5}' /etc/shadow $ sudo awk -F: '$5 <= 0 {print $1 " " $5}' /etc/shadow If any results are returned that are not associated with a system account, this is a finding.

Fix: F-33011r567848_fix

Configure non-compliant accounts to enforce a 60-day maximum password lifetime restriction. $ sudo chage -M 60 [user]

b

RHEL 8 passwords must have a minimum of 15 characters.

IA-5 - Medium - CCI-000205 - V-230369 - SV-230369r1017181_rule

RMF Control

IA-5

Severity

M

CCI

CCI-000205

Version

RHEL-08-020230

Vuln IDs

V-230369

Rule IDs

SV-230369r1017181_rule

The shorter the password, the lower the number of possible combinations that need to be tested before the password is compromised. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Password length is one factor of several that helps to determine strength and how long it takes to crack a password. Use of more characters in a password helps to increase exponentially the time and/or resources required to compromise the password. RHEL 8 utilizes "pwquality" as a mechanism to enforce password complexity. Configurations are set in the "etc/security/pwquality.conf" file. The "minlen", sometimes noted as minimum length, acts as a "score" of complexity based on the credit components of the "pwquality" module. By setting the credit components to a negative value, not only will those components be required, they will not count towards the total "score" of "minlen". This will enable "minlen" to require a 15-character minimum. The DoD minimum password requirement is 15 characters.

Checks: C-33038r833326_chk

Verify the operating system enforces a minimum 15-character password length. The "minlen" option sets the minimum number of characters in a new password. Check for the value of the "minlen" option with the following command: $ sudo grep -r minlen /etc/security/pwquality.conf* /etc/security/pwquality.conf:minlen = 15 If the command does not return a "minlen" value of 15 or greater, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-33013r858784_fix

Configure operating system to enforce a minimum 15-character password length. Add the following line to "/etc/security/pwquality.conf" (or modify the line to have the required value): minlen = 15 Remove any configurations that conflict with the above value.

b

RHEL 8 passwords for new users must have a minimum of 15 characters.

IA-5 - Medium - CCI-000205 - V-230370 - SV-230370r1017182_rule

RMF Control

IA-5

Severity

M

CCI

CCI-000205

Version

RHEL-08-020231

Vuln IDs

V-230370

Rule IDs

SV-230370r1017182_rule

The shorter the password, the lower the number of possible combinations that need to be tested before the password is compromised. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Password length is one factor of several that helps to determine strength and how long it takes to crack a password. Use of more characters in a password helps to increase exponentially the time and/or resources required to compromise the password. The DoD minimum password requirement is 15 characters.

Checks: C-33039r567856_chk

Verify that RHEL 8 enforces a minimum 15-character password length for new user accounts by running the following command: $ sudo grep -i pass_min_len /etc/login.defs PASS_MIN_LEN 15 If the "PASS_MIN_LEN" parameter value is less than "15", or commented out, this is a finding.

Fix: F-33014r567857_fix

Configure operating system to enforce a minimum 15-character password length for new user accounts. Add, or modify the following line in the "/etc/login.defs" file: PASS_MIN_LEN 15

b

RHEL 8 duplicate User IDs (UIDs) must not exist for interactive users.

IA-2 - Medium - CCI-000764 - V-230371 - SV-230371r1017183_rule

RMF Control

IA-2

Severity

M

CCI

CCI-000764

Version

RHEL-08-020240

Vuln IDs

V-230371

Rule IDs

SV-230371r1017183_rule

To ensure accountability and prevent unauthenticated access, interactive users must be identified and authenticated to prevent potential misuse and compromise of the system. Interactive users include organizational employees or individuals the organization deems to have equivalent status of employees (e.g., contractors). Interactive users (and processes acting on behalf of users) must be uniquely identified and authenticated to all accesses, except for the following: 1) Accesses explicitly identified and documented by the organization. Organizations document specific user actions that can be performed on the information system without identification or authentication; and 2) Accesses that occur through authorized use of group authenticators without individual authentication. Organizations may require unique identification of individuals in group accounts (e.g., shared privilege accounts) or for detailed accountability of individual activity. Satisfies: SRG-OS-000104-GPOS-00051, SRG-OS-000121-GPOS-00062, SRG-OS-000042-GPOS-00020

Checks: C-33040r567859_chk

Verify that RHEL 8 contains no duplicate User IDs (UIDs) for interactive users. Check that the operating system contains no duplicate UIDs for interactive users with the following command: $ sudo awk -F ":" 'list[$3]++{print $1, $3}' /etc/passwd If output is produced, and the accounts listed are interactive user accounts, this is a finding.

Fix: F-33015r567860_fix

Edit the file "/etc/passwd" and provide each interactive user account that has a duplicate User ID (UID) with a unique UID.

b

RHEL 8 must implement smart card logon for multifactor authentication for access to interactive accounts.

IA-2 - Medium - CCI-000765 - V-230372 - SV-230372r1017184_rule

RMF Control

IA-2

Severity

M

CCI

CCI-000765

Version

RHEL-08-020250

Vuln IDs

V-230372

Rule IDs

SV-230372r1017184_rule

Using an authentication device, such as a Common Access Card (CAC) or token that is separate from the information system, ensures that even if the information system is compromised, that compromise will not affect credentials stored on the authentication device. Multifactor solutions that require devices separate from information systems gaining access include, for example, hardware tokens providing time-based or challenge-response authenticators and smart cards such as the U.S. Government Personal Identity Verification card and the DoD CAC. There are various methods of implementing multifactor authentication for RHEL 8. Some methods include a local system multifactor account mapping or joining the system to a domain and utilizing a Red Hat idM server or Microsoft Windows Active Directory server. Any of these methods will require that the client operating system handle the multifactor authentication correctly. Satisfies: SRG-OS-000105-GPOS-00052, SRG-OS-000106-GPOS-00053, SRG-OS-000107-GPOS-00054, SRG-OS-000108-GPOS-00055

Checks: C-33041r942943_chk

Verify RHEL 8 uses multifactor authentication for local access to accounts. Note: If the System Administrator demonstrates the use of an approved alternate multifactor authentication method, this requirement is not applicable. Check that the "pam_cert_auth" setting is set to "true" in the "/etc/sssd/sssd.conf" file. Check that the "try_cert_auth" or "require_cert_auth" options are configured in both "/etc/pam.d/system-auth" and "/etc/pam.d/smartcard-auth" files with the following command: $ sudo grep -ir cert_auth /etc/sssd/sssd.conf /etc/sssd/conf.d/*.conf /etc/pam.d/* /etc/sssd/sssd.conf:pam_cert_auth = True /etc/pam.d/smartcard-auth:auth sufficient pam_sss.so try_cert_auth /etc/pam.d/system-auth:auth [success=done authinfo_unavail=ignore ignore=ignore default=die] pam_sss.so try_cert_auth If "pam_cert_auth" is not set to "true" in "/etc/sssd/sssd.conf", this is a finding. If "pam_sss.so" is not set to "try_cert_auth" or "require_cert_auth" in both the "/etc/pam.d/smartcard-auth" and "/etc/pam.d/system-auth" files, this is a finding.

Fix: F-33016r942944_fix

Configure RHEL 8 to use multifactor authentication for local access to accounts. Add or update the "pam_cert_auth" setting in the "/etc/sssd/sssd.conf" file to match the following line: [pam] pam_cert_auth = True Add or update "pam_sss.so" with "try_cert_auth" or "require_cert_auth" in the "/etc/pam.d/system-auth" and "/etc/pam.d/smartcard-auth" files based on the following examples: /etc/pam.d/smartcard-auth:auth sufficient pam_sss.so try_cert_auth /etc/pam.d/system-auth:auth [success=done authinfo_unavail=ignore ignore=ignore default=die] pam_sss.so try_cert_auth The "sssd" service must be restarted for the changes to take effect. To restart the "sssd" service, run the following command: $ sudo systemctl restart sssd.service

b

RHEL 8 account identifiers (individuals, groups, roles, and devices) must be disabled after 35 days of inactivity.

IA-4 - Medium - CCI-000795 - V-230373 - SV-230373r1017185_rule

RMF Control

IA-4

Severity

M

CCI

CCI-000795

Version

RHEL-08-020260

Vuln IDs

V-230373

Rule IDs

SV-230373r1017185_rule

Inactive identifiers pose a risk to systems and applications because attackers may exploit an inactive identifier and potentially obtain undetected access to the system. Owners of inactive accounts will not notice if unauthorized access to their user account has been obtained. RHEL 8 needs to track periods of inactivity and disable application identifiers after 35 days of inactivity.

Checks: C-33042r567865_chk

Verify the account identifiers (individuals, groups, roles, and devices) are disabled after 35 days of inactivity with the following command: Check the account inactivity value by performing the following command: $ sudo grep -i inactive /etc/default/useradd INACTIVE=35 If "INACTIVE" is set to "-1", a value greater than "35", or is commented out, this is a finding.

Fix: F-33017r567866_fix

Configure RHEL 8 to disable account identifiers after 35 days of inactivity after the password expiration. Run the following command to change the configuration for useradd: $ sudo useradd -D -f 35 DoD recommendation is 35 days, but a lower value is acceptable. The value "-1" will disable this feature, and "0" will disable the account immediately after the password expires.

b

RHEL 8 must automatically expire temporary accounts within 72 hours.

AC-2 - Medium - CCI-001682 - V-230374 - SV-230374r1069293_rule

RMF Control

AC-2

Severity

M

CCI

CCI-001682

Version

RHEL-08-020270

Vuln IDs

V-230374

Rule IDs

SV-230374r1069293_rule

Temporary accounts are privileged or nonprivileged accounts that are established during pressing circumstances, such as new software or hardware configuration or an incident response, where the need for prompt account activation requires bypassing normal account authorization procedures. If any inactive temporary accounts are left enabled on the system and are not either manually removed or automatically expired within 72 hours, the security posture of the system will be degraded and exposed to exploitation by unauthorized users or insider threat actors. Temporary accounts are different from emergency accounts. Emergency accounts, also known as "last resort" or "break glass" accounts, are local logon accounts enabled on the system for emergency use by authorized system administrators to manage a system when standard logon methods are failing or not available. Emergency accounts are not subject to manual removal or scheduled expiration requirements. The automatic expiration of temporary accounts may be extended as needed by the circumstances but it must not be extended indefinitely. A documented permanent account should be established for privileged users who need long-term maintenance accounts.

Checks: C-33043r1069195_chk

Note: If temporary accounts do not exist or are not used this is not applicable. Verify temporary accounts have been provisioned with an expiration date of 72 hours. For every existing temporary account, run the following command to obtain its account expiration information: $ sudo chage -l <temporary_account_name> | grep -i "account expires" Verify each of these accounts has an expiration date set within 72 hours. If any temporary accounts have no expiration date set or do not expire within 72 hours, this is a finding.

Fix: F-33018r902730_fix

Configure the operating system to expire temporary accounts after 72 hours with the following command: $ sudo chage -E $(date -d +3days +%Y-%m-%d) <temporary_account_name>

b

All RHEL 8 passwords must contain at least one special character.

IA-5 - Medium - CCI-001619 - V-230375 - SV-230375r1017187_rule

RMF Control

IA-5

Severity

M

CCI

CCI-001619

Version

RHEL-08-020280

Vuln IDs

V-230375

Rule IDs

SV-230375r1017187_rule

Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Password complexity is one factor of several that determines how long it takes to crack a password. The more complex the password, the greater the number of possible combinations that need to be tested before the password is compromised. RHEL 8 utilizes "pwquality" as a mechanism to enforce password complexity. Note that to require special characters without degrading the "minlen" value, the credit value must be expressed as a negative number in "/etc/security/pwquality.conf".

Checks: C-33044r833328_chk

Verify the value for "ocredit" with the following command: $ sudo grep -r ocredit /etc/security/pwquality.conf* /etc/security/pwquality.conf:ocredit = -1 If the value of "ocredit" is a positive number or is commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-33019r858786_fix

Configure the operating system to enforce password complexity by requiring that at least one special character be used by setting the "ocredit" option. Add the following line to /etc/security/pwquality.conf (or modify the line to have the required value): ocredit = -1 Remove any configurations that conflict with the above value.

b

RHEL 8 must prohibit the use of cached authentications after one day.

IA-5 - Medium - CCI-002007 - V-230376 - SV-230376r1069307_rule

RMF Control

IA-5

Severity

M

CCI

CCI-002007

Version

RHEL-08-020290

Vuln IDs

V-230376

Rule IDs

SV-230376r1069307_rule

If cached authentication information is out-of-date, the validity of the authentication information may be questionable. RHEL 8 includes multiple options for configuring authentication, but this requirement will be focus on the System Security Services Daemon (SSSD). By default sssd does not cache credentials.

Checks: C-33045r1069223_chk

Note: If smart card authentication is not being used on the system this item is Not Applicable. Verify that the SSSD prohibits the use of cached authentications after one day. Check that SSSD allows cached authentications with the following command: $ sudo grep cache_credentials /etc/sssd/sssd.conf /etc/sssd/sssd.conf:cache_credentials = true If "cache_credentials" is set to "false" or missing from the configuration file, this is not a finding, and no further checks are required. If "cache_credentials" is set to "true", check that SSSD prohibits the use of cached authentications after one day with the following command: $ sudo grep offline_credentials_expiration /etc/sssd/sssd.conf /etc/sssd/sssd.conf:offline_credentials_expiration = 1 If "offline_credentials_expiration" is not set to a value of "1", this is a finding.

Fix: F-33020r942947_fix

Configure the SSSD to prohibit the use of cached authentications after one day. Add or change the following line in "/etc/sssd/sssd.conf" just below the line "[pam]". offline_credentials_expiration = 1

b

RHEL 8 must prevent the use of dictionary words for passwords.

CM-6 - Medium - CCI-000366 - V-230377 - SV-230377r1017188_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-020300

Vuln IDs

V-230377

Rule IDs

SV-230377r1017188_rule

If RHEL 8 allows the user to select passwords based on dictionary words, this increases the chances of password compromise by increasing the opportunity for successful guesses, and brute-force attacks.

Checks: C-33046r833330_chk

Verify RHEL 8 prevents the use of dictionary words for passwords. Determine if the field "dictcheck" is set with the following command: $ sudo grep -r dictcheck /etc/security/pwquality.conf* /etc/security/pwquality.conf:dictcheck=1 If the "dictcheck" parameter is not set to "1", or is commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-33021r858788_fix

Configure RHEL 8 to prevent the use of dictionary words for passwords. Add or update the following line in the "/etc/security/pwquality.conf" file or a configuration file in the /etc/pwquality.conf.d/ directory to contain the "dictcheck" parameter: dictcheck=1 Remove any configurations that conflict with the above value.

b

RHEL 8 must enforce a delay of at least four seconds between logon prompts following a failed logon attempt.

CM-6 - Medium - CCI-000366 - V-230378 - SV-230378r1017189_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-020310

Vuln IDs

V-230378

Rule IDs

SV-230378r1017189_rule

Configuring the operating system to implement organization-wide security implementation guides and security checklists verifies compliance with federal standards and establishes a common security baseline across the DoD that reflects the most restrictive security posture consistent with operational requirements. Configuration settings are the set of parameters that can be changed in hardware, software, or firmware components of the system that affect the security posture and/or functionality of the system. Security-related parameters are those parameters impacting the security state of the system, including the parameters required to satisfy other security control requirements. Security-related parameters include, for example, registry settings; account, file, and directory permission settings; and settings for functions, ports, protocols, services, and remote connections.

Checks: C-33047r567880_chk

Verify the operating system enforces a delay of at least four seconds between console logon prompts following a failed logon attempt with the following command: $ sudo grep -i fail_delay /etc/login.defs FAIL_DELAY 4 If the value of "FAIL_DELAY" is not set to "4" or greater, or the line is commented out, this is a finding.

Fix: F-33022r567881_fix

Configure the operating system to enforce a delay of at least four seconds between logon prompts following a failed console logon attempt. Modify the "/etc/login.defs" file to set the "FAIL_DELAY" parameter to "4" or greater: FAIL_DELAY 4

b

RHEL 8 must not have unnecessary accounts.

CM-6 - Medium - CCI-000366 - V-230379 - SV-230379r1017190_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-020320

Vuln IDs

V-230379

Rule IDs

SV-230379r1017190_rule

Accounts providing no operational purpose provide additional opportunities for system compromise. Unnecessary accounts include user accounts for individuals not requiring access to the system and application accounts for applications not installed on the system.

Checks: C-33048r1014799_chk

Verify that there are no unauthorized interactive user accounts with the following command: $ less /etc/passwd root:x:0:0:root:/root:/bin/bash ... games:x:12:100:games:/usr/games:/sbin/nologin scsaustin:x:1001:1001:scsaustin:/home/scsaustin:/bin/bash djohnson:x:1002:1002:djohnson:/home/djohnson:/bin/bash Interactive user account, generally will have a user identifier (UID) of 1000 or greater, a home directory in a specific partition, and an interactive shell. Obtain the list of interactive user accounts authorized to be on the system from the system administrator or information system security officer (ISSO) and compare it to the list of local interactive user accounts on the system. If there are unauthorized local user accounts on the system, this is a finding.

Fix: F-33023r1014800_fix

Remove unauthorized local interactive user accounts with the following command where <unauthorized_user> is the unauthorized account: $ sudo userdel <unauthorized_user>

c

RHEL 8 must not allow accounts configured with blank or null passwords.

CM-6 - High - CCI-000366 - V-230380 - SV-230380r1069308_rule

RMF Control

CM-6

Severity

H

CCI

Version

RHEL-08-020330

Vuln IDs

V-230380

Rule IDs

SV-230380r1069308_rule

If an account has an empty password, anyone could log on and run commands with the privileges of that account. Accounts with empty passwords should never be used in operational environments.

Checks: C-33049r1069225_chk

To verify that null passwords cannot be used, run the following command: $ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH '^\s*permitemptypasswords' /etc/ssh/sshd_config:PermitEmptyPasswords no If "PermitEmptyPasswords" is set to "yes", this is a finding. If conflicting results are returned, this is a finding.

Fix: F-33024r743992_fix

Edit the following line in "etc/ssh/sshd_config" to prevent logons with empty passwords. PermitEmptyPasswords no The SSH daemon must be restarted for the changes to take effect. To restart the SSH daemon, run the following command: $ sudo systemctl restart sshd.service

a

RHEL 8 must display the date and time of the last successful account logon upon logon.

AC-9 - Low - CCI-000052 - V-230381 - SV-230381r1069295_rule

RMF Control

AC-9

Severity

L

CCI

CCI-000052

Version

RHEL-08-020340

Vuln IDs

V-230381

Rule IDs

SV-230381r1069295_rule

Providing users with feedback on when account accesses last occurred facilitates user recognition and reporting of unauthorized account use.

Checks: C-33050r1069199_chk

Verify users are provided with feedback on when account accesses last occurred with the following command: $ sudo grep pam_lastlog /etc/pam.d/postlogin session required pam_lastlog.so showfailed If "pam_lastlog.so" is missing from "/etc/pam.d/postlogin" file, or the silent option is present, this is a finding.

Fix: F-33025r567890_fix

Configure the operating system to provide users with feedback on when account accesses last occurred by setting the required configuration options in "/etc/pam.d/postlogin". Add the following line to the top of "/etc/pam.d/postlogin": session required pam_lastlog.so showfailed

b

RHEL 8 must display the date and time of the last successful account logon upon an SSH logon.

AC-9 - Medium - CCI-000052 - V-230382 - SV-230382r1069309_rule

RMF Control

AC-9

Severity

M

CCI

CCI-000052

Version

RHEL-08-020350

Vuln IDs

V-230382

Rule IDs

SV-230382r1069309_rule

Providing users with feedback on when account accesses via SSH last occurred facilitates user recognition and reporting of unauthorized account use.

Checks: C-33051r1069227_chk

Verify SSH provides users with feedback on when account accesses last occurred with the following command: $ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH '^\s*printlastlog' /etc/ssh/sshd_config:PrintLastLog yes If the "PrintLastLog" keyword is set to "no", is missing, or is commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-33026r567893_fix

Configure SSH to provide users with feedback on when account accesses last occurred by setting the required configuration options in "/etc/pam.d/sshd" or in the "sshd_config" file used by the system ("/etc/ssh/sshd_config" will be used in the example) (this file may be named differently or be in a different location if using a version of SSH that is provided by a third-party vendor). Modify the "PrintLastLog" line in "/etc/ssh/sshd_config" to match the following: PrintLastLog yes The SSH service must be restarted for changes to "sshd_config" to take effect.

b

RHEL 8 must define default permissions for all authenticated users in such a way that the user can only read and modify their own files.

CM-6 - Medium - CCI-000366 - V-230383 - SV-230383r1017192_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-020351

Vuln IDs

V-230383

Rule IDs

SV-230383r1017192_rule

Setting the most restrictive default permissions ensures that when new accounts are created, they do not have unnecessary access.

Checks: C-33052r567895_chk

Verify the operating system defines default permissions for all authenticated users in such a way that the user can only read and modify their own files. Check for the value of the "UMASK" parameter in "/etc/login.defs" file with the following command: Note: If the value of the "UMASK" parameter is set to "000" in "/etc/login.defs" file, the Severity is raised to a CAT I. # grep -i umask /etc/login.defs UMASK 077 If the value for the "UMASK" parameter is not "077", or the "UMASK" parameter is missing or is commented out, this is a finding.

Fix: F-33027r567896_fix

Configure the operating system to define default permissions for all authenticated users in such a way that the user can only read and modify their own files. Add or edit the line for the "UMASK" parameter in "/etc/login.defs" file to "077": UMASK 077

b

RHEL 8 must set the umask value to 077 for all local interactive user accounts.

CM-6 - Medium - CCI-000366 - V-230384 - SV-230384r1017193_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-020352

Vuln IDs

V-230384

Rule IDs

SV-230384r1017193_rule

The umask controls the default access mode assigned to newly created files. A umask of 077 limits new files to mode 600 or less permissive. Although umask can be represented as a four-digit number, the first digit representing special access modes is typically ignored or required to be "0". This requirement applies to the globally configured system defaults and the local interactive user defaults for each account on the system.

Checks: C-33053r858731_chk

Verify that the default umask for all local interactive users is "077". Identify the locations of all local interactive user home directories by looking at the "/etc/passwd" file. Check all local interactive user initialization files for interactive users with the following command: Note: The example is for a system that is configured to create users home directories in the "/home" directory. $ sudo grep -ir ^umask /home | grep -v '.bash_history' If any local interactive user initialization files are found to have a umask statement that has a value less restrictive than "077", this is a finding.

Fix: F-33028r567899_fix

Remove the umask statement from all local interactive user's initialization files. If the account is for an application, the requirement for a umask less restrictive than "077" can be documented with the Information System Security Officer, but the user agreement for access to the account must specify that the local interactive user must log on to their account first and then switch the user to the application account with the correct option to gain the account's environment variables.

b

RHEL 8 must define default permissions for logon and non-logon shells.

CM-6 - Medium - CCI-000366 - V-230385 - SV-230385r1017194_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-020353

Vuln IDs

V-230385

Rule IDs

SV-230385r1017194_rule

The umask controls the default access mode assigned to newly created files. A umask of 077 limits new files to mode 600 or less permissive. Although umask can be represented as a four-digit number, the first digit representing special access modes is typically ignored or required to be "0". This requirement applies to the globally configured system defaults and the local interactive user defaults for each account on the system.

Checks: C-33054r792900_chk

Verify that the umask default for installed shells is "077". Check for the value of the "UMASK" parameter in the "/etc/bashrc", "/etc/csh.cshrc" and "/etc/profile" files with the following command: Note: If the value of the "UMASK" parameter is set to "000" in the "/etc/bashrc" the "/etc/csh.cshrc" or the "/etc/profile" files, the Severity is raised to a CAT I. # grep -i umask /etc/bashrc /etc/csh.cshrc /etc/profile /etc/bashrc: umask 077 /etc/bashrc: umask 077 /etc/csh.cshrc: umask 077 /etc/csh.cshrc: umask 077 /etc/profile: umask 077 /etc/profile: umask 077 If the value for the "UMASK" parameter is not "077", or the "UMASK" parameter is missing or is commented out, this is a finding.

Fix: F-33029r792901_fix

Configure the operating system to define default permissions for all authenticated users in such a way that the user can only read and modify their own files. Add or edit the lines for the "UMASK" parameter in the "/etc/bashrc", "/etc/csh.cshrc" and "/etc/profile"files to "077": UMASK 077

b

The RHEL 8 audit system must be configured to audit the execution of privileged functions and prevent all software from executing at higher privilege levels than users executing the software.

AC-6 - Medium - CCI-002233 - V-230386 - SV-230386r958730_rule

RMF Control

AC-6

Severity

M

CCI

CCI-002233

Version

RHEL-08-030000

Vuln IDs

V-230386

Rule IDs

SV-230386r958730_rule

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised information system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider threats and the advanced persistent threat. Satisfies: SRG-OS-000326-GPOS-00126, SRG-OS-000327-GPOS-00127

Checks: C-33055r567904_chk

Verify RHEL 8 audits the execution of privileged functions. Check if RHEL 8 is configured to audit the execution of the "execve" system call, by running the following command: $ sudo grep execve /etc/audit/audit.rules -a always,exit -F arch=b32 -S execve -C uid!=euid -F euid=0 -k execpriv -a always,exit -F arch=b64 -S execve -C uid!=euid -F euid=0 -k execpriv -a always,exit -F arch=b32 -S execve -C gid!=egid -F egid=0 -k execpriv -a always,exit -F arch=b64 -S execve -C gid!=egid -F egid=0 -k execpriv If the command does not return all lines, or the lines are commented out, this is a finding.

Fix: F-33030r567905_fix

Configure RHEL 8 to audit the execution of the "execve" system call. Add or update the following file system rules to "/etc/audit/rules.d/audit.rules": -a always,exit -F arch=b32 -S execve -C uid!=euid -F euid=0 -k execpriv -a always,exit -F arch=b64 -S execve -C uid!=euid -F euid=0 -k execpriv -a always,exit -F arch=b32 -S execve -C gid!=egid -F egid=0 -k execpriv -a always,exit -F arch=b64 -S execve -C gid!=egid -F egid=0 -k execpriv The audit daemon must be restarted for the changes to take effect.

b

Cron logging must be implemented in RHEL 8.

CM-6 - Medium - CCI-000366 - V-230387 - SV-230387r1017195_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-030010

Vuln IDs

V-230387

Rule IDs

SV-230387r1017195_rule

Cron logging can be used to trace the successful or unsuccessful execution of cron jobs. It can also be used to spot intrusions into the use of the cron facility by unauthorized and malicious users.

Checks: C-33056r743994_chk

Verify that "rsyslog" is configured to log cron events with the following command: Note: If another logging package is used, substitute the utility configuration file for "/etc/rsyslog.conf" or "/etc/rsyslog.d/*.conf" files. $ sudo grep -s cron /etc/rsyslog.conf /etc/rsyslog.d/*.conf /etc/rsyslog.conf:*.info;mail.none;authpriv.none;cron.none /var/log/messages /etc/rsyslog.conf:# Log cron stuff /etc/rsyslog.conf:cron.* /var/log/cron If the command does not return a response, check for cron logging all facilities with the following command. $ sudo grep -s /var/log/messages /etc/rsyslog.conf /etc/rsyslog.d/*.conf /etc/rsyslog.conf:*.info;mail.none;authpriv.none;cron.none /var/log/messages If "rsyslog" is not logging messages for the cron facility or all facilities, this is a finding.

Fix: F-33031r743995_fix

Configure "rsyslog" to log all cron messages by adding or updating the following line to "/etc/rsyslog.conf" or a configuration file in the /etc/rsyslog.d/ directory: cron.* /var/log/cron The rsyslog daemon must be restarted for the changes to take effect: $ sudo systemctl restart rsyslog.service

b

The RHEL 8 System Administrator (SA) and Information System Security Officer (ISSO) (at a minimum) must be alerted of an audit processing failure event.

AU-5 - Medium - CCI-000139 - V-230388 - SV-230388r1017196_rule

RMF Control

AU-5

Severity

M

CCI

CCI-000139

Version

RHEL-08-030020

Vuln IDs

V-230388

Rule IDs

SV-230388r1017196_rule

It is critical for the appropriate personnel to be aware if a system is at risk of failing to process audit logs as required. Without this notification, the security personnel may be unaware of an impending failure of the audit capability, and system operation may be adversely affected. Audit processing failures include software/hardware errors, failures in the audit capturing mechanisms, and audit storage capacity being reached or exceeded. This requirement applies to each audit data storage repository (i.e., distinct information system component where audit records are stored), the centralized audit storage capacity of organizations (i.e., all audit data storage repositories combined), or both.

Checks: C-33057r567910_chk

Verify that the SA and ISSO (at a minimum) are notified in the event of an audit processing failure. Check that RHEL 8 notifies the SA and ISSO (at a minimum) in the event of an audit processing failure with the following command: $ sudo grep action_mail_acct /etc/audit/auditd.conf action_mail_acct = root If the value of the "action_mail_acct" keyword is not set to "root" and/or other accounts for security personnel, the "action_mail_acct" keyword is missing, or the retuned line is commented out, ask the system administrator to indicate how they and the ISSO are notified of an audit process failure. If there is no evidence of the proper personnel being notified of an audit processing failure, this is a finding.

Fix: F-33032r567911_fix

Configure "auditd" service to notify the SA and ISSO in the event of an audit processing failure. Edit the following line in "/etc/audit/auditd.conf" to ensure that administrators are notified via email for those situations: action_mail_acct = root

b

The RHEL 8 Information System Security Officer (ISSO) and System Administrator (SA) (at a minimum) must have mail aliases to be notified of an audit processing failure.

AU-5 - Medium - CCI-000139 - V-230389 - SV-230389r1017197_rule

RMF Control

AU-5

Severity

M

CCI

CCI-000139

Version

RHEL-08-030030

Vuln IDs

V-230389

Rule IDs

SV-230389r1017197_rule

It is critical for the appropriate personnel to be aware if a system is at risk of failing to process audit logs as required. Without this notification, the security personnel may be unaware of an impending failure of the audit capability, and system operation may be adversely affected. Audit processing failures include software/hardware errors, failures in the audit capturing mechanisms, and audit storage capacity being reached or exceeded. This requirement applies to each audit data storage repository (i.e., distinct information system component where audit records are stored), the centralized audit storage capacity of organizations (i.e., all audit data storage repositories combined), or both.

Checks: C-33058r567913_chk

Verify that the administrators are notified in the event of an audit processing failure. Check that the "/etc/aliases" file has a defined value for "root". $ sudo grep "postmaster:\s*root$" /etc/aliases If the command does not return a line, or the line is commented out, ask the system administrator to indicate how they and the ISSO are notified of an audit process failure. If there is no evidence of the proper personnel being notified of an audit processing failure, this is a finding.

Fix: F-33033r567914_fix

Configure RHEL 8 to notify administrators in the event of an audit processing failure. Add/update the following line in "/etc/aliases": postmaster: root

b

The RHEL 8 System must take appropriate action when an audit processing failure occurs.

AU-5 - Medium - CCI-000140 - V-230390 - SV-230390r1038966_rule

RMF Control

AU-5

Severity

M

CCI

CCI-000140

Version

RHEL-08-030040

Vuln IDs

V-230390

Rule IDs

SV-230390r1038966_rule

It is critical for the appropriate personnel to be aware if a system is at risk of failing to process audit logs as required. Without this notification, the security personnel may be unaware of an impending failure of the audit capability, and system operation may be adversely affected. Audit processing failures include software/hardware errors, failures in the audit capturing mechanisms, and audit storage capacity being reached or exceeded. This requirement applies to each audit data storage repository (i.e., distinct information system component where audit records are stored), the centralized audit storage capacity of organizations (i.e., all audit data storage repositories combined), or both.

Checks: C-33059r567916_chk

Verify RHEL 8 takes the appropriate action when an audit processing failure occurs. Check that RHEL 8 takes the appropriate action when an audit processing failure occurs with the following command: $ sudo grep disk_error_action /etc/audit/auditd.conf disk_error_action = HALT If the value of the "disk_error_action" option is not "SYSLOG", "SINGLE", or "HALT", or the line is commented out, ask the system administrator to indicate how the system takes appropriate action when an audit process failure occurs. If there is no evidence of appropriate action, this is a finding.

Fix: F-33034r567917_fix

Configure RHEL 8 to shut down by default upon audit failure (unless availability is an overriding concern). Add or update the following line (depending on configuration "disk_error_action" can be set to "SYSLOG" or "SINGLE" depending on configuration) in "/etc/audit/auditd.conf" file: disk_error_action = HALT If availability has been determined to be more important, and this decision is documented with the ISSO, configure the operating system to notify system administration staff and ISSO staff in the event of an audit processing failure by setting the "disk_error_action" to "SYSLOG".

b

The RHEL 8 audit system must take appropriate action when the audit storage volume is full.

AU-5 - Medium - CCI-000140 - V-230392 - SV-230392r1038966_rule

RMF Control

AU-5

Severity

M

CCI

CCI-000140

Version

RHEL-08-030060

Vuln IDs

V-230392

Rule IDs

SV-230392r1038966_rule

It is critical that when RHEL 8 is at risk of failing to process audit logs as required, it takes action to mitigate the failure. Audit processing failures include software/hardware errors; failures in the audit capturing mechanisms; and audit storage capacity being reached or exceeded. Responses to audit failure depend upon the nature of the failure mode. When availability is an overriding concern, other approved actions in response to an audit failure are as follows: 1) If the failure was caused by the lack of audit record storage capacity, RHEL 8 must continue generating audit records if possible (automatically restarting the audit service if necessary) and overwriting the oldest audit records in a first-in-first-out manner. 2) If audit records are sent to a centralized collection server and communication with this server is lost or the server fails, RHEL 8 must queue audit records locally until communication is restored or until the audit records are retrieved manually. Upon restoration of the connection to the centralized collection server, action should be taken to synchronize the local audit data with the collection server.

Checks: C-33061r567922_chk

Verify RHEL 8 takes the appropriate action when the audit storage volume is full. Check that RHEL 8 takes the appropriate action when the audit storage volume is full with the following command: $ sudo grep disk_full_action /etc/audit/auditd.conf disk_full_action = HALT If the value of the "disk_full_action" option is not "SYSLOG", "SINGLE", or "HALT", or the line is commented out, ask the system administrator to indicate how the system takes appropriate action when an audit storage volume is full. If there is no evidence of appropriate action, this is a finding.

Fix: F-33036r567923_fix

Configure RHEL 8 to shut down by default upon audit failure (unless availability is an overriding concern). Add or update the following line (depending on configuration "disk_full_action" can be set to "SYSLOG" or "SINGLE" depending on configuration) in "/etc/audit/auditd.conf" file: disk_full_action = HALT If availability has been determined to be more important, and this decision is documented with the ISSO, configure the operating system to notify system administration staff and ISSO staff in the event of an audit processing failure by setting the "disk_full_action" to "SYSLOG".

b

The RHEL 8 audit system must audit local events.

CM-6 - Medium - CCI-000366 - V-230393 - SV-230393r1017200_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-030061

Vuln IDs

V-230393

Rule IDs

SV-230393r1017200_rule

Without establishing what type of events occurred, the source of events, where events occurred, and the outcome of events, it would be difficult to establish, correlate, and investigate the events leading up to an outage or attack. Audit record content that may be necessary to satisfy this requirement includes, for example, time stamps, source and destination addresses, user/process identifiers, event descriptions, success/fail indications, filenames involved, and access control or flow control rules invoked.

Checks: C-33062r567925_chk

Verify the RHEL 8 Audit Daemon is configured to include local events, with the following command: $ sudo grep local_events /etc/audit/auditd.conf local_events = yes If the value of the "local_events" option is not set to "yes", or the line is commented out, this is a finding.

Fix: F-33037r567926_fix

Configure RHEL 8 to audit local events on the system. Add or update the following line in "/etc/audit/auditd.conf" file: local_events = yes

b

RHEL 8 must label all off-loaded audit logs before sending them to the central log server.

AU-4 - Medium - CCI-001851 - V-230394 - SV-230394r958754_rule

RMF Control

AU-4

Severity

M

CCI

Version

RHEL-08-030062

Vuln IDs

V-230394

Rule IDs

SV-230394r958754_rule

Without establishing what type of events occurred, the source of events, where events occurred, and the outcome of events, it would be difficult to establish, correlate, and investigate the events leading up to an outage or attack. Audit record content that may be necessary to satisfy this requirement includes, for example, time stamps, source and destination addresses, user/process identifiers, event descriptions, success/fail indications, filenames involved, and access control or flow control rules invoked. Enriched logging is needed to determine who, what, and when events occur on a system. Without this, determining root cause of an event will be much more difficult. When audit logs are not labeled before they are sent to a central log server, the audit data will not be able to be analyzed and tied back to the correct system.

Checks: C-33063r567928_chk

Verify the RHEL 8 Audit Daemon is configured to label all off-loaded audit logs, with the following command: $ sudo grep "name_format" /etc/audit/auditd.conf name_format = hostname If the "name_format" option is not "hostname", "fqd", or "numeric", or the line is commented out, this is a finding.

Fix: F-33038r567929_fix

Edit the /etc/audit/auditd.conf file and add or update the "name_format" option: name_format = hostname The audit daemon must be restarted for changes to take effect.

a

RHEL 8 must resolve audit information before writing to disk.

CM-6 - Low - CCI-000366 - V-230395 - SV-230395r1017201_rule

RMF Control

CM-6

Severity

L

CCI

Version

RHEL-08-030063

Vuln IDs

V-230395

Rule IDs

SV-230395r1017201_rule

Without establishing what type of events occurred, the source of events, where events occurred, and the outcome of events, it would be difficult to establish, correlate, and investigate the events leading up to an outage or attack. Audit record content that may be necessary to satisfy this requirement includes, for example, time stamps, source and destination addresses, user/process identifiers, event descriptions, success/fail indications, filenames involved, and access control or flow control rules invoked. Enriched logging aids in making sense of who, what, and when events occur on a system. Without this, determining root cause of an event will be much more difficult.

Checks: C-33064r567931_chk

Verify the RHEL 8 Audit Daemon is configured to resolve audit information before writing to disk, with the following command: $ sudo grep "log_format" /etc/audit/auditd.conf log_format = ENRICHED If the "log_format" option is not "ENRICHED", or the line is commented out, this is a finding.

Fix: F-33039r567932_fix

Edit the /etc/audit/auditd.conf file and add or update the "log_format" option: log_format = ENRICHED The audit daemon must be restarted for changes to take effect.

b

RHEL 8 audit logs must have a mode of 0600 or less permissive to prevent unauthorized read access.

AU-9 - Medium - CCI-000162 - V-230396 - SV-230396r1017202_rule

RMF Control

AU-9

Severity

M

CCI

Version

RHEL-08-030070

Vuln IDs

V-230396

Rule IDs

SV-230396r1017202_rule

Only authorized personnel should be aware of errors and the details of the errors. Error messages are an indicator of an organization's operational state or can identify the RHEL 8 system or platform. Additionally, Personally Identifiable Information (PII) and operational information must not be revealed through error messages to unauthorized personnel or their designated representatives. The structure and content of error messages must be carefully considered by the organization and development team. The extent to which the information system is able to identify and handle error conditions is guided by organizational policy and operational requirements. Satisfies: SRG-OS-000057-GPOS-00027, SRG-OS-000058-GPOS-00028, SRG-OS-000059-GPOS-00029, SRG-OS-000206-GPOS-00084

Checks: C-33065r567934_chk

Verify the audit logs have a mode of "0600" or less permissive. First, determine where the audit logs are stored with the following command: $ sudo grep -iw log_file /etc/audit/auditd.conf log_file = /var/log/audit/audit.log Using the location of the audit log file, check if the audit log has a mode of "0600" or less permissive with the following command: $ sudo stat -c "%a %n" /var/log/audit/audit.log 600 /var/log/audit/audit.log If the audit log has a mode more permissive than "0600", this is a finding.

Fix: F-33040r902732_fix

Configure the audit log to be protected from unauthorized read access by setting the correct permissive mode with the following command: $ sudo chmod 0600 /var/log/audit/audit.log

b

RHEL 8 audit logs must be owned by root to prevent unauthorized read access.

AU-9 - Medium - CCI-000162 - V-230397 - SV-230397r1017203_rule

RMF Control

AU-9

Severity

M

CCI

Version

RHEL-08-030080

Vuln IDs

V-230397

Rule IDs

SV-230397r1017203_rule

Only authorized personnel should be aware of errors and the details of the errors. Error messages are an indicator of an organization's operational state or can identify the RHEL 8 system or platform. Additionally, Personally Identifiable Information (PII) and operational information must not be revealed through error messages to unauthorized personnel or their designated representatives. The structure and content of error messages must be carefully considered by the organization and development team. The extent to which the information system is able to identify and handle error conditions is guided by organizational policy and operational requirements. Satisfies: SRG-OS-000057-GPOS-00027, SRG-OS-000058-GPOS-00028, SRG-OS-000059-GPOS-00029, SRG-OS-000206-GPOS-00084

Checks: C-33066r567937_chk

Verify the audit logs are owned by "root". First, determine where the audit logs are stored with the following command: $ sudo grep -iw log_file /etc/audit/auditd.conf log_file = /var/log/audit/audit.log Using the location of the audit log file, determine if the audit log is owned by "root" using the following command: $ sudo ls -al /var/log/audit/audit.log rw------- 2 root root 23 Jun 11 11:56 /var/log/audit/audit.log If the audit log is not owned by "root", this is a finding.

Fix: F-33041r567938_fix

Configure the audit log to be protected from unauthorized read access, by setting the correct owner as "root" with the following command: $ sudo chown root [audit_log_file] Replace "[audit_log_file]" to the correct audit log path, by default this location is "/var/log/audit/audit.log".

b

RHEL 8 audit logs must be group-owned by root to prevent unauthorized read access.

AU-9 - Medium - CCI-000162 - V-230398 - SV-230398r1017204_rule

RMF Control

AU-9

Severity

M

CCI

Version

RHEL-08-030090

Vuln IDs

V-230398

Rule IDs

SV-230398r1017204_rule

Unauthorized disclosure of audit records can reveal system and configuration data to attackers, thus compromising its confidentiality. Audit information includes all information (e.g., audit records, audit settings, audit reports) needed to successfully audit RHEL 8 activity. Satisfies: SRG-OS-000057-GPOS-00027, SRG-OS-000058-GPOS-00028, SRG-OS-000059-GPOS-00029

Checks: C-33067r567940_chk

Verify the audit logs are group-owned by "root". First determine where the audit logs are stored with the following command: $ sudo grep -iw log_file /etc/audit/auditd.conf log_file = /var/log/audit/audit.log Using the location of the audit log file, determine if the audit log is group-owned by "root" using the following command: $ sudo ls -al /var/log/audit/audit.log rw------- 2 root root 23 Jun 11 11:56 /var/log/audit/audit.log If the audit log is not group-owned by "root", this is a finding.

Fix: F-33042r567941_fix

Configure the audit log to be owned by root by configuring the log group in the /etc/audit/auditd.conf file: log_group = root

b

RHEL 8 audit log directory must be owned by root to prevent unauthorized read access.

AU-9 - Medium - CCI-000162 - V-230399 - SV-230399r1017205_rule

RMF Control

AU-9

Severity

M

CCI

Version

RHEL-08-030100

Vuln IDs

V-230399

Rule IDs

SV-230399r1017205_rule

Unauthorized disclosure of audit records can reveal system and configuration data to attackers, thus compromising its confidentiality. Audit information includes all information (e.g., audit records, audit settings, audit reports) needed to successfully audit RHEL 8 activity. Satisfies: SRG-OS-000057-GPOS-00027, SRG-OS-000058-GPOS-00028, SRG-OS-000059-GPOS-00029

Checks: C-33068r567943_chk

Verify the audit log directory is owned by "root" to prevent unauthorized read access. Determine where the audit logs are stored with the following command: $ sudo grep -iw log_file /etc/audit/auditd.conf log_file = /var/log/audit/audit.log Determine the owner of the audit log directory by using the output of the above command (ex: "/var/log/audit/"). Run the following command with the correct audit log directory path: $ sudo ls -ld /var/log/audit drw------- 2 root root 23 Jun 11 11:56 /var/log/audit If the audit log directory is not owned by "root", this is a finding.

Fix: F-33043r567944_fix

Configure the audit log to be protected from unauthorized read access, by setting the correct owner as "root" with the following command: $ sudo chown root [audit_log_directory] Replace "[audit_log_directory]" with the correct audit log directory path, by default this location is usually "/var/log/audit".

b

RHEL 8 audit log directory must be group-owned by root to prevent unauthorized read access.

AU-9 - Medium - CCI-000162 - V-230400 - SV-230400r1017206_rule

RMF Control

AU-9

Severity

M

CCI

Version

RHEL-08-030110

Vuln IDs

V-230400

Rule IDs

SV-230400r1017206_rule

Unauthorized disclosure of audit records can reveal system and configuration data to attackers, thus compromising its confidentiality. Audit information includes all information (e.g., audit records, audit settings, audit reports) needed to successfully audit RHEL 8 activity. Satisfies: SRG-OS-000057-GPOS-00027, SRG-OS-000058-GPOS-00028, SRG-OS-000059-GPOS-00029

Checks: C-33069r567946_chk

Verify the audit log directory is group-owned by "root" to prevent unauthorized read access. Determine where the audit logs are stored with the following command: $ sudo grep -iw log_file /etc/audit/auditd.conf log_file = /var/log/audit/audit.log Determine the group owner of the audit log directory by using the output of the above command (ex: "/var/log/audit/"). Run the following command with the correct audit log directory path: $ sudo ls -ld /var/log/audit drw------- 2 root root 23 Jun 11 11:56 /var/log/audit If the audit log directory is not group-owned by "root", this is a finding.

Fix: F-33044r567947_fix

Configure the audit log to be protected from unauthorized read access by setting the correct group-owner as "root" with the following command: $ sudo chgrp root [audit_log_directory] Replace "[audit_log_directory]" with the correct audit log directory path, by default this location is usually "/var/log/audit".

b

RHEL 8 audit log directory must have a mode of 0700 or less permissive to prevent unauthorized read access.

AU-9 - Medium - CCI-000162 - V-230401 - SV-230401r1017207_rule

RMF Control

AU-9

Severity

M

CCI

Version

RHEL-08-030120

Vuln IDs

V-230401

Rule IDs

SV-230401r1017207_rule

Unauthorized disclosure of audit records can reveal system and configuration data to attackers, thus compromising its confidentiality. Audit information includes all information (e.g., audit records, audit settings, audit reports) needed to successfully audit RHEL 8 system activity. Satisfies: SRG-OS-000057-GPOS-00027, SRG-OS-000058-GPOS-00028, SRG-OS-000059-GPOS-00029

Checks: C-33070r567949_chk

Verify the audit log directories have a mode of "0700" or less permissive by first determining where the audit logs are stored with the following command: $ sudo grep -iw log_file /etc/audit/auditd.conf log_file = /var/log/audit/audit.log Using the location of the audit log, determine the directory where the audit logs are stored (ex: "/var/log/audit"). Run the following command to determine the permissions for the audit log folder: $ sudo stat -c "%a %n" /var/log/audit 700 /var/log/audit If the audit log directory has a mode more permissive than "0700", this is a finding.

Fix: F-33045r567950_fix

Configure the audit log directory to be protected from unauthorized read access by setting the correct permissive mode with the following command: $ sudo chmod 0700 [audit_log_directory] Replace "[audit_log_directory]" to the correct audit log directory path, by default this location is "/var/log/audit".

b

RHEL 8 audit system must protect auditing rules from unauthorized change.

AU-9 - Medium - CCI-000162 - V-230402 - SV-230402r1017208_rule

RMF Control

AU-9

Severity

M

CCI

Version

RHEL-08-030121

Vuln IDs

V-230402

Rule IDs

SV-230402r1017208_rule

Unauthorized disclosure of audit records can reveal system and configuration data to attackers, thus compromising its confidentiality. Audit information includes all information (e.g., audit records, audit settings, audit reports) needed to successfully audit RHEL 8 system activity. In immutable mode, unauthorized users cannot execute changes to the audit system to potentially hide malicious activity and then put the audit rules back. A system reboot would be noticeable and a system administrator could then investigate the unauthorized changes. Satisfies: SRG-OS-000057-GPOS-00027, SRG-OS-000058-GPOS-00028, SRG-OS-000059-GPOS-00029

Checks: C-33071r567952_chk

Verify the audit system prevents unauthorized changes with the following command: $ sudo grep "^\s*[^#]" /etc/audit/audit.rules | tail -1 -e 2 If the audit system is not set to be immutable by adding the "-e 2" option to the "/etc/audit/audit.rules", this is a finding.

Fix: F-33046r567953_fix

Configure the audit system to set the audit rules to be immutable by adding the following line to "/etc/audit/rules.d/audit.rules" -e 2 Note: Once set, the system must be rebooted for auditing to be changed. It is recommended to add this option as the last step in securing the system.

b

RHEL 8 audit system must protect logon UIDs from unauthorized change.

AU-9 - Medium - CCI-000162 - V-230403 - SV-230403r1017209_rule

RMF Control

AU-9

Severity

M

CCI

Version

RHEL-08-030122

Vuln IDs

V-230403

Rule IDs

SV-230403r1017209_rule

Unauthorized disclosure of audit records can reveal system and configuration data to attackers, thus compromising its confidentiality. Audit information includes all information (e.g., audit records, audit settings, audit reports) needed to successfully audit RHEL 8 system activity. In immutable mode, unauthorized users cannot execute changes to the audit system to potentially hide malicious activity and then put the audit rules back. A system reboot would be noticeable and a system administrator could then investigate the unauthorized changes. Satisfies: SRG-OS-000057-GPOS-00027, SRG-OS-000058-GPOS-00028, SRG-OS-000059-GPOS-00029

Checks: C-33072r567955_chk

Verify the audit system prevents unauthorized changes to logon UIDs with the following command: $ sudo grep -i immutable /etc/audit/audit.rules --loginuid-immutable If the login UIDs are not set to be immutable by adding the "--loginuid-immutable" option to the "/etc/audit/audit.rules", this is a finding.

Fix: F-33047r567956_fix

Configure the audit system to set the logon UIDs to be immutable by adding the following line to "/etc/audit/rules.d/audit.rules" --loginuid-immutable

b

RHEL 8 must generate audit records for all account creations, modifications, disabling, and termination events that affect /etc/shadow.

AU-12 - Medium - CCI-000169 - V-230404 - SV-230404r1017210_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030130

Vuln IDs

V-230404

Rule IDs

SV-230404r1017210_rule

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000304-GPOS-00121, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221

Checks: C-33073r567958_chk

Verify RHEL 8 generates audit records for all account creations, modifications, disabling, and termination events that affect "/etc/shadow". Check the auditing rules in "/etc/audit/audit.rules" with the following command: $ sudo grep /etc/shadow /etc/audit/audit.rules -w /etc/shadow -p wa -k identity If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-33048r567959_fix

Configure RHEL 8 to generate audit records for all account creations, modifications, disabling, and termination events that affect "/etc/shadow". Add or update the following file system rule to "/etc/audit/rules.d/audit.rules": -w /etc/shadow -p wa -k identity The audit daemon must be restarted for the changes to take effect.

b

RHEL 8 must generate audit records for all account creations, modifications, disabling, and termination events that affect /etc/security/opasswd.

AU-12 - Medium - CCI-000169 - V-230405 - SV-230405r1017211_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030140

Vuln IDs

V-230405

Rule IDs

SV-230405r1017211_rule

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000304-GPOS-00121, SRG-OS-000476-GPOS-00221

Checks: C-33074r567961_chk

Verify RHEL 8 generates audit records for all account creations, modifications, disabling, and termination events that affect "/etc/security/opasswd". Check the auditing rules in "/etc/audit/audit.rules" with the following command: $ sudo grep /etc/security/opasswd /etc/audit/audit.rules -w /etc/security/opasswd -p wa -k identity If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-33049r567962_fix

Configure RHEL 8 to generate audit records for all account creations, modifications, disabling, and termination events that affect "/etc/security/opasswd". Add or update the following file system rule to "/etc/audit/rules.d/audit.rules": -w /etc/security/opasswd -p wa -k identity The audit daemon must be restarted for the changes to take effect.

b

RHEL 8 must generate audit records for all account creations, modifications, disabling, and termination events that affect /etc/passwd.

AU-12 - Medium - CCI-000169 - V-230406 - SV-230406r1017212_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030150

Vuln IDs

V-230406

Rule IDs

SV-230406r1017212_rule

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000304-GPOS-00121, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221

Checks: C-33075r567964_chk

Verify RHEL 8 generates audit records for all account creations, modifications, disabling, and termination events that affect "/etc/passwd". Check the auditing rules in "/etc/audit/audit.rules" with the following command: $ sudo grep /etc/passwd /etc/audit/audit.rules -w /etc/passwd -p wa -k identity If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-33050r567965_fix

Configure RHEL 8 to generate audit records for all account creations, modifications, disabling, and termination events that affect "/etc/passwd". Add or update the following file system rule to "/etc/audit/rules.d/audit.rules": -w /etc/passwd -p wa -k identity The audit daemon must be restarted for the changes to take effect.

b

RHEL 8 must generate audit records for all account creations, modifications, disabling, and termination events that affect /etc/gshadow.

AU-12 - Medium - CCI-000169 - V-230407 - SV-230407r1017213_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030160

Vuln IDs

V-230407

Rule IDs

SV-230407r1017213_rule

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000304-GPOS-00121, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221

Checks: C-33076r567967_chk

Verify RHEL 8 generates audit records for all account creations, modifications, disabling, and termination events that affect "/etc/gshadow". Check the auditing rules in "/etc/audit/audit.rules" with the following command: $ sudo grep /etc/gshadow /etc/audit/audit.rules -w /etc/gshadow -p wa -k identity If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-33051r567968_fix

Configure RHEL 8 to generate audit records for all account creations, modifications, disabling, and termination events that affect "/etc/gshadow". Add or update the following file system rule to "/etc/audit/rules.d/audit.rules": -w /etc/gshadow -p wa -k identity The audit daemon must be restarted for the changes to take effect.

b

RHEL 8 must generate audit records for all account creations, modifications, disabling, and termination events that affect /etc/group.

AU-12 - Medium - CCI-000169 - V-230408 - SV-230408r1017214_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030170

Vuln IDs

V-230408

Rule IDs

SV-230408r1017214_rule

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000304-GPOS-00121, CCI-002884, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221

Checks: C-33077r567970_chk

Verify RHEL 8 generates audit records for all account creations, modifications, disabling, and termination events that affect "/etc/group". Check the auditing rules in "/etc/audit/audit.rules" with the following command: $ sudo grep /etc/group /etc/audit/audit.rules -w /etc/group -p wa -k identity If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-33052r567971_fix

Configure RHEL 8 to generate audit records for all account creations, modifications, disabling, and termination events that affect "/etc/group". Add or update the following file system rule to "/etc/audit/rules.d/audit.rules": -w /etc/group -p wa -k identity The audit daemon must be restarted for the changes to take effect.

b

RHEL 8 must generate audit records for all account creations, modifications, disabling, and termination events that affect /etc/sudoers.

AU-12 - Medium - CCI-000169 - V-230409 - SV-230409r1017215_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030171

Vuln IDs

V-230409

Rule IDs

SV-230409r1017215_rule

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000304-GPOS-00121, CCI-002884, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221

Checks: C-33078r567973_chk

Verify RHEL 8 generates audit records for all account creations, modifications, disabling, and termination events that affect "/etc/sudoers". Check the auditing rules in "/etc/audit/audit.rules" with the following command: $ sudo grep /etc/sudoers /etc/audit/audit.rules -w /etc/sudoers -p wa -k identity If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-33053r567974_fix

Configure RHEL 8 to generate audit records for all account creations, modifications, disabling, and termination events that affect "/etc/sudoers". Add or update the following file system rule to "/etc/audit/rules.d/audit.rules": -w /etc/sudoers -p wa -k identity The audit daemon must be restarted for the changes to take effect.

b

RHEL 8 must generate audit records for all account creations, modifications, disabling, and termination events that affect /etc/sudoers.d/.

AU-12 - Medium - CCI-000169 - V-230410 - SV-230410r1017216_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030172

Vuln IDs

V-230410

Rule IDs

SV-230410r1017216_rule

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000304-GPOS-00121, CCI-002884, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221

Checks: C-33079r567976_chk

Verify RHEL 8 generates audit records for all account creations, modifications, disabling, and termination events that affect "/etc/sudoers.d/". Check the auditing rules in "/etc/audit/audit.rules" with the following command: $ sudo grep /etc/sudoers.d/ /etc/audit/audit.rules -w /etc/sudoers.d/ -p wa -k identity If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-33054r567977_fix

Configure RHEL 8 to generate audit records for all account creations, modifications, disabling, and termination events that affect "/etc/sudoers.d/". Add or update the following file system rule to "/etc/audit/rules.d/audit.rules": -w /etc/sudoers.d/ -p wa -k identity The audit daemon must be restarted for the changes to take effect.

b

The RHEL 8 audit package must be installed.

AU-12 - Medium - CCI-000169 - V-230411 - SV-230411r1017217_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030180

Vuln IDs

V-230411

Rule IDs

SV-230411r1017217_rule

Without establishing what type of events occurred, the source of events, where events occurred, and the outcome of events, it would be difficult to establish, correlate, and investigate the events leading up to an outage or attack. Audit record content that may be necessary to satisfy this requirement includes, for example, time stamps, source and destination addresses, user/process identifiers, event descriptions, success/fail indications, filenames involved, and access control or flow control rules invoked. Associating event types with detected events in RHEL 8 audit logs provides a means of investigating an attack, recognizing resource utilization or capacity thresholds, or identifying an improperly configured RHEL 8 system. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000038-GPOS-00016, SRG-OS-000039-GPOS-00017, SRG-OS-000040-GPOS-00018, SRG-OS-000041-GPOS-00019, SRG-OS-000042-GPOS-00021, SRG-OS-000051-GPOS-00024, SRG-OS-000054-GPOS-00025, SRG-OS-000122-GPOS-00063, SRG-OS-000254-GPOS-00095, SRG-OS-000255-GPOS-00096, SRG-OS-000337-GPOS-00129, SRG-OS-000348-GPOS-00136, SRG-OS-000349-GPOS-00137, SRG-OS-000350-GPOS-00138, SRG-OS-000351-GPOS-00139, SRG-OS-000352-GPOS-00140, SRG-OS-000353-GPOS-00141, SRG-OS-000354-GPOS-00142, SRG-OS-000358-GPOS-00145, SRG-OS-000365-GPOS-00152, SRG-OS-000392-GPOS-00172, SRG-OS-000475-GPOS-00220

Checks: C-33080r743999_chk

Verify the audit service is configured to produce audit records. Check that the audit service is installed with the following command: $ sudo yum list installed audit If the "audit" package is not installed, this is a finding.

Fix: F-33055r646880_fix

Configure the audit service to produce audit records containing the information needed to establish when (date and time) an event occurred. Install the audit service (if the audit service is not already installed) with the following command: $ sudo yum install audit

b

Successful/unsuccessful uses of the su command in RHEL 8 must generate an audit record.

AU-12 - Medium - CCI-000169 - V-230412 - SV-230412r1017218_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030190

Vuln IDs

V-230412

Rule IDs

SV-230412r1017218_rule

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). The "su" command allows a user to run commands with a substitute user and group ID. When a user logs on, the AUID is set to the UID of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to "-1". The AUID representation is an unsigned 32-bit integer, which equals "4294967295". The audit system interprets "-1", "4294967295", and "unset" in the same way. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000064-GPOS-0003, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210

Checks: C-33081r567982_chk

Verify RHEL 8 generates audit records when successful/unsuccessful attempts to use the "su" command by performing the following command to check the file system rules in "/etc/audit/audit.rules": $ sudo grep -w /usr/bin/su /etc/audit/audit.rules -a always,exit -F path=/usr/bin/su -F perm=x -F auid>=1000 -F auid!=unset -k privileged-priv_change If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-33056r567983_fix

Configure RHEL 8 to generate audit records when successful/unsuccessful attempts to use the "su" command occur by adding or updating the following rule in "/etc/audit/rules.d/audit.rules": -a always,exit -F path=/usr/bin/su -F perm=x -F auid>=1000 -F auid!=unset -k privileged-priv_change The audit daemon must be restarted for the changes to take effect.

b

The RHEL 8 audit system must be configured to audit any usage of the setxattr, fsetxattr, lsetxattr, removexattr, fremovexattr, and lremovexattr system calls.

AU-12 - Medium - CCI-000169 - V-230413 - SV-230413r1017219_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030200

Vuln IDs

V-230413

Rule IDs

SV-230413r1017219_rule

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). "Setxattr" is a system call used to set an extended attribute value. "Fsetxattr" is a system call used to set an extended attribute value. This is used to set extended attributes on a file. "Lsetxattr" is a system call used to set an extended attribute value. This is used to set extended attributes on a symbolic link. "Removexattr" is a system call that removes extended attributes. "Fremovexattr" is a system call that removes extended attributes. This is used for removal of extended attributes from a file. "Lremovexattr" is a system call that removes extended attributes. This is used for removal of extended attributes from symbolic links. When a user logs on, the AUID is set to the UID of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to "-1". The AUID representation is an unsigned 32-bit integer, which equals "4294967295". The audit system interprets "-1", "4294967295", and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each syscall made by all programs on the system. Therefore, it is very important to use syscall rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance can be helped, however, by combining syscalls into one rule whenever possible. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000462-GPOS-00206, SRG-OS-000463-GPOS-00207, SRG-OS-000468-GPOS-00212, SRG-OS-000471-GPOS-00215, SRG-OS-000474-GPOS-00219, SRG-OS-000466-GPOS-00210

Checks: C-33082r809293_chk

Verify if RHEL 8 is configured to audit the execution of the "setxattr", "fsetxattr", "lsetxattr", "removexattr", "fremovexattr", and "lremovexattr" system calls by running the following command: $ sudo grep xattr /etc/audit/audit.rules -a always,exit -F arch=b32 -S setxattr,fsetxattr,lsetxattr,removexattr,fremovexattr,lremovexattr -F auid>=1000 -F auid!=unset -k perm_mod -a always,exit -F arch=b64 -S setxattr,fsetxattr,lsetxattr,removexattr,fremovexattr,lremovexattr -F auid>=1000 -F auid!=unset -k perm_mod -a always,exit -F arch=b32 -S setxattr,fsetxattr,lsetxattr,removexattr,fremovexattr,lremovexattr -F auid=0 -k perm_mod -a always,exit -F arch=b64 -S setxattr,fsetxattr,lsetxattr,removexattr,fremovexattr,lremovexattr -F auid=0 -k perm_mod If the command does not return an audit rule for "setxattr", "fsetxattr", "lsetxattr", "removexattr", "fremovexattr", and "lremovexattr" or any of the lines returned are commented out, this is a finding.

Fix: F-33057r809294_fix

Configure RHEL 8 to audit the execution of the "setxattr", "fsetxattr", "lsetxattr", "removexattr", "fremovexattr", and "lremovexattr" system calls by adding or updating the following lines to "/etc/audit/rules.d/audit.rules": -a always,exit -F arch=b32 -S setxattr,fsetxattr,lsetxattr,removexattr,fremovexattr,lremovexattr -F auid>=1000 -F auid!=unset -k perm_mod -a always,exit -F arch=b64 -S setxattr,fsetxattr,lsetxattr,removexattr,fremovexattr,lremovexattr -F auid>=1000 -F auid!=unset -k perm_mod -a always,exit -F arch=b32 -S setxattr,fsetxattr,lsetxattr,removexattr,fremovexattr,lremovexattr -F auid=0 -k perm_mod -a always,exit -F arch=b64 -S setxattr,fsetxattr,lsetxattr,removexattr,fremovexattr,lremovexattr -F auid=0 -k perm_mod The audit daemon must be restarted for the changes to take effect.

b

Successful/unsuccessful uses of the chage command in RHEL 8 must generate an audit record.

AU-12 - Medium - CCI-000169 - V-230418 - SV-230418r1017220_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030250

Vuln IDs

V-230418

Rule IDs

SV-230418r1017220_rule

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). The "chage" command is used to change or view user password expiry information. When a user logs on, the AUID is set to the UID of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to "-1". The AUID representation is an unsigned 32-bit integer, which equals "4294967295". The audit system interprets "-1", "4294967295", and "unset" in the same way. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000468-GPOS-00212, SRG-OS-000471-GPOS-00215

Checks: C-33087r568000_chk

Verify that an audit event is generated for any successful/unsuccessful use of the "chage" command by performing the following command to check the file system rules in "/etc/audit/audit.rules": $ sudo grep -w chage /etc/audit/audit.rules -a always,exit -F path=/usr/bin/chage -F perm=x -F auid>=1000 -F auid!=unset -k privileged-chage If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-33062r568001_fix

Configure the audit system to generate an audit event for any successful/unsuccessful uses of the "chage" command by adding or updating the following rule in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F path=/usr/bin/chage -F perm=x -F auid>=1000 -F auid!=unset -k privileged-chage The audit daemon must be restarted for the changes to take effect.

b

Successful/unsuccessful uses of the chcon command in RHEL 8 must generate an audit record.

AU-12 - Medium - CCI-000169 - V-230419 - SV-230419r1017221_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030260

Vuln IDs

V-230419

Rule IDs

SV-230419r1017221_rule

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). The "chcon" command is used to change file SELinux security context. When a user logs on, the AUID is set to the UID of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to "-1". The AUID representation is an unsigned 32-bit integer, which equals "4294967295". The audit system interprets "-1", "4294967295", and "unset" in the same way. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000468-GPOS-00212, SRG-OS-000471-GPOS-00215

Checks: C-33088r568003_chk

Verify RHEL 8 generates an audit record when successful/unsuccessful attempts to use the "chcon" command by performing the following command to check the file system rules in "/etc/audit/audit.rules": $ sudo grep -w chcon /etc/audit/audit.rules -a always,exit -F path=/usr/bin/chcon -F perm=x -F auid>=1000 -F auid!=unset -k perm_mod If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-33063r568004_fix

Configure the audit system to generate an audit event for any successful/unsuccessful use of the "chcon" command by adding or updating the following rule in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F path=/usr/bin/chcon -F perm=x -F auid>=1000 -F auid!=unset -k perm_mod The audit daemon must be restarted for the changes to take effect.

b

Successful/unsuccessful uses of the ssh-agent in RHEL 8 must generate an audit record.

AU-12 - Medium - CCI-000169 - V-230421 - SV-230421r1017222_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030280

Vuln IDs

V-230421

Rule IDs

SV-230421r1017222_rule

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). The "ssh-agent" is a program to hold private keys used for public key authentication. When a user logs on, the AUID is set to the UID of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to "-1". The AUID representation is an unsigned 32-bit integer, which equals "4294967295". The audit system interprets "-1", "4294967295", and "unset" in the same way. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-33090r568009_chk

Verify RHEL 8 generates an audit record when successful/unsuccessful attempts to use the "ssh-agent" by performing the following command to check the file system rules in "/etc/audit/audit.rules": $ sudo grep ssh-agent /etc/audit/audit.rules -a always,exit -F path=/usr/bin/ssh-agent -F perm=x -F auid>=1000 -F auid!=unset -k privileged-ssh If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-33065r568010_fix

Configure the audit system to generate an audit event for any successful/unsuccessful use of the "ssh-agent" by adding or updating the following rule in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F path=/usr/bin/ssh-agent -F perm=x -F auid>=1000 -F auid!=unset -k privileged-ssh The audit daemon must be restarted for the changes to take effect.

b

Successful/unsuccessful uses of the passwd command in RHEL 8 must generate an audit record.

AU-12 - Medium - CCI-000169 - V-230422 - SV-230422r1017223_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030290

Vuln IDs

V-230422

Rule IDs

SV-230422r1017223_rule

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). The "passwd" command is used to change passwords for user accounts. When a user logs on, the AUID is set to the UID of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to "-1". The AUID representation is an unsigned 32-bit integer, which equals "4294967295". The audit system interprets "-1", "4294967295", and "unset" in the same way. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-33091r568012_chk

Verify that an audit event is generated for any successful/unsuccessful use of the "passwd" command by performing the following command to check the file system rules in "/etc/audit/audit.rules": $ sudo grep -w passwd /etc/audit/audit.rules -a always,exit -F path=/usr/bin/passwd -F perm=x -F auid>=1000 -F auid!=unset -k privileged-passwd If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-33066r568013_fix

Configure the audit system to generate an audit event for any successful/unsuccessful uses of the "passwd" command by adding or updating the following rule in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F path=/usr/bin/passwd -F perm=x -F auid>=1000 -F auid!=unset -k privileged-passwd The audit daemon must be restarted for the changes to take effect.

b

Successful/unsuccessful uses of the mount command in RHEL 8 must generate an audit record.

AU-12 - Medium - CCI-000169 - V-230423 - SV-230423r1017224_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030300

Vuln IDs

V-230423

Rule IDs

SV-230423r1017224_rule

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). The "mount" command is used to mount a filesystem. When a user logs on, the AUID is set to the UID of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to "-1". The AUID representation is an unsigned 32-bit integer, which equals "4294967295". The audit system interprets "-1", "4294967295", and "unset" in the same way. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-33092r568015_chk

Verify that an audit event is generated for any successful/unsuccessful use of the "mount" command by performing the following command to check the file system rules in "/etc/audit/audit.rules": $ sudo grep -w /usr/bin/mount /etc/audit/audit.rules -a always,exit -F path=/usr/bin/mount -F perm=x -F auid>=1000 -F auid!=unset -k privileged-mount If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-33067r568016_fix

Configure the audit system to generate an audit event for any successful/unsuccessful use of the "mount" command by adding or updating the following rules in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F path=/usr/bin/mount -F perm=x -F auid>=1000 -F auid!=unset -k privileged-mount The audit daemon must be restarted for the changes to take effect.

b

Successful/unsuccessful uses of the umount command in RHEL 8 must generate an audit record.

AU-12 - Medium - CCI-000169 - V-230424 - SV-230424r1017225_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030301

Vuln IDs

V-230424

Rule IDs

SV-230424r1017225_rule

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). The "umount" command is used to unmount a filesystem. When a user logs on, the AUID is set to the UID of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to "-1". The AUID representation is an unsigned 32-bit integer, which equals "4294967295". The audit system interprets "-1", "4294967295", and "unset" in the same way. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-33093r568018_chk

Verify that an audit event is generated for any successful/unsuccessful use of the "umount" command by performing the following command to check the file system rules in "/etc/audit/audit.rules": $ sudo grep -w /usr/bin/umount /etc/audit/audit.rules -a always,exit -F path=/usr/bin/umount -F perm=x -F auid>=1000 -F auid!=unset -k privileged-mount If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-33068r568019_fix

Configure the audit system to generate an audit event for any successful/unsuccessful use of the "umount" command by adding or updating the following rules in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F path=/usr/bin/umount -F perm=x -F auid>=1000 -F auid!=unset -k privileged-mount The audit daemon must be restarted for the changes to take effect.

b

Successful/unsuccessful uses of the mount syscall in RHEL 8 must generate an audit record.

AU-12 - Medium - CCI-000169 - V-230425 - SV-230425r1017226_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030302

Vuln IDs

V-230425

Rule IDs

SV-230425r1017226_rule

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). The "mount" syscall is used to mount a filesystem. When a user logs on, the AUID is set to the UID of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to "-1". The AUID representation is an unsigned 32-bit integer, which equals "4294967295". The audit system interprets "-1", "4294967295", and "unset" in the same way. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-33094r568021_chk

Verify that an audit event is generated for any successful/unsuccessful use of the "mount" syscall by performing the following command to check the file system rules in "/etc/audit/audit.rules": $ sudo grep -w "\-S mount" /etc/audit/audit.rules -a always,exit -F arch=b32 -S mount -F auid>=1000 -F auid!=unset -k privileged-mount -a always,exit -F arch=b64 -S mount -F auid>=1000 -F auid!=unset -k privileged-mount If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-33069r568022_fix

Configure the audit system to generate an audit event for any successful/unsuccessful use of the "mount" syscall by adding or updating the following rules in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F arch=b32 -S mount -F auid>=1000 -F auid!=unset -k privileged-mount -a always,exit -F arch=b64 -S mount -F auid>=1000 -F auid!=unset -k privileged-mount The audit daemon must be restarted for the changes to take effect.

b

Successful/unsuccessful uses of the unix_update in RHEL 8 must generate an audit record.

AU-12 - Medium - CCI-000169 - V-230426 - SV-230426r1017227_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030310

Vuln IDs

V-230426

Rule IDs

SV-230426r1017227_rule

Reconstruction of harmful events or forensic analysis is not possible if audit records do not contain enough information. At a minimum, the organization must audit the full-text recording of privileged commands. The organization must maintain audit trails in sufficient detail to reconstruct events to determine the cause and impact of compromise. "Unix_update" is a helper program for the "pam_unix" module that updates the password for a given user. It is not intended to be run directly from the command line and logs a security violation if done so. When a user logs on, the AUID is set to the UID of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to "-1". The AUID representation is an unsigned 32-bit integer, which equals "4294967295". The audit system interprets "-1", "4294967295", and "unset" in the same way. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-33095r568024_chk

Verify that an audit event is generated for any successful/unsuccessful use of the "unix_update" by performing the following command to check the file system rules in "/etc/audit/audit.rules": $ sudo grep -w "unix_update" /etc/audit/audit.rules -a always,exit -F path=/usr/sbin/unix_update -F perm=x -F auid>=1000 -F auid!=unset -k privileged-unix-update If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-33070r568025_fix

Configure the audit system to generate an audit event for any successful/unsuccessful uses of the "unix_update" by adding or updating the following rule in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F path=/usr/sbin/unix_update -F perm=x -F auid>=1000 -F auid!=unset -k privileged-unix-update The audit daemon must be restarted for the changes to take effect.

b

Successful/unsuccessful uses of postdrop in RHEL 8 must generate an audit record.

AU-12 - Medium - CCI-000169 - V-230427 - SV-230427r1017228_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030311

Vuln IDs

V-230427

Rule IDs

SV-230427r1017228_rule

Reconstruction of harmful events or forensic analysis is not possible if audit records do not contain enough information. At a minimum, the organization must audit the full-text recording of privileged commands. The organization must maintain audit trails in sufficient detail to reconstruct events to determine the cause and impact of compromise. The "postdrop" command creates a file in the maildrop directory and copies its standard input to the file. When a user logs on, the AUID is set to the UID of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to "-1". The AUID representation is an unsigned 32-bit integer, which equals "4294967295". The audit system interprets "-1", "4294967295", and "unset" in the same way. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-33096r568027_chk

Verify that an audit event is generated for any successful/unsuccessful use of "postdrop" by performing the following command to check the file system rules in "/etc/audit/audit.rules": $ sudo grep -w "postdrop" /etc/audit/audit.rules -a always,exit -F path=/usr/sbin/postdrop -F perm=x -F auid>=1000 -F auid!=unset -k privileged-unix-update If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-33071r568028_fix

Configure the audit system to generate an audit event for any successful/unsuccessful uses of the "postdrop" by adding or updating the following rule in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F path=/usr/sbin/postdrop -F perm=x -F auid>=1000 -F auid!=unset -k privileged-unix-update The audit daemon must be restarted for the changes to take effect.

b

Successful/unsuccessful uses of postqueue in RHEL 8 must generate an audit record.

AU-12 - Medium - CCI-000169 - V-230428 - SV-230428r1017229_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030312

Vuln IDs

V-230428

Rule IDs

SV-230428r1017229_rule

Reconstruction of harmful events or forensic analysis is not possible if audit records do not contain enough information. At a minimum, the organization must audit the full-text recording of privileged commands. The organization must maintain audit trails in sufficient detail to reconstruct events to determine the cause and impact of compromise. The "postqueue" command implements the Postfix user interface for queue management. When a user logs on, the AUID is set to the UID of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to "-1". The AUID representation is an unsigned 32-bit integer, which equals "4294967295". The audit system interprets "-1", "4294967295", and "unset" in the same way. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-33097r568030_chk

Verify that an audit event is generated for any successful/unsuccessful use of "postqueue" by performing the following command to check the file system rules in "/etc/audit/audit.rules": $ sudo grep -w "postqueue" /etc/audit/audit.rules -a always,exit -F path=/usr/sbin/postqueue -F perm=x -F auid>=1000 -F auid!=unset -k privileged-unix-update If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-33072r568031_fix

Configure the audit system to generate an audit event for any successful/unsuccessful uses of the "postqueue" by adding or updating the following rule in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F path=/usr/sbin/postqueue -F perm=x -F auid>=1000 -F auid!=unset -k privileged-unix-update The audit daemon must be restarted for the changes to take effect.

b

Successful/unsuccessful uses of semanage in RHEL 8 must generate an audit record.

AU-12 - Medium - CCI-000169 - V-230429 - SV-230429r1017230_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030313

Vuln IDs

V-230429

Rule IDs

SV-230429r1017230_rule

Reconstruction of harmful events or forensic analysis is not possible if audit records do not contain enough information. At a minimum, the organization must audit the full-text recording of privileged commands. The organization must maintain audit trails in sufficient detail to reconstruct events to determine the cause and impact of compromise. The "semanage" command is used to configure certain elements of SELinux policy without requiring modification to or recompilation from policy sources. When a user logs on, the AUID is set to the UID of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to "-1". The AUID representation is an unsigned 32-bit integer, which equals "4294967295". The audit system interprets "-1", "4294967295", and "unset" in the same way. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-33098r568033_chk

Verify that an audit event is generated for any successful/unsuccessful use of "semanage" by performing the following command to check the file system rules in "/etc/audit/audit.rules": $ sudo grep -w "semanage" /etc/audit/audit.rules -a always,exit -F path=/usr/sbin/semanage -F perm=x -F auid>=1000 -F auid!=unset -k privileged-unix-update If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-33073r568034_fix

Configure the audit system to generate an audit event for any successful/unsuccessful uses of the "semanage" by adding or updating the following rule in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F path=/usr/sbin/semanage -F perm=x -F auid>=1000 -F auid!=unset -k privileged-unix-update The audit daemon must be restarted for the changes to take effect.

b

Successful/unsuccessful uses of setfiles in RHEL 8 must generate an audit record.

AU-12 - Medium - CCI-000169 - V-230430 - SV-230430r1017231_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030314

Vuln IDs

V-230430

Rule IDs

SV-230430r1017231_rule

Reconstruction of harmful events or forensic analysis is not possible if audit records do not contain enough information. At a minimum, the organization must audit the full-text recording of privileged commands. The organization must maintain audit trails in sufficient detail to reconstruct events to determine the cause and impact of compromise. The "setfiles" command is primarily used to initialize the security context fields (extended attributes) on one or more filesystems (or parts of them). Usually it is initially run as part of the SELinux installation process (a step commonly known as labeling). When a user logs on, the AUID is set to the UID of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to "-1". The AUID representation is an unsigned 32-bit integer, which equals "4294967295". The audit system interprets "-1", "4294967295", and "unset" in the same way. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-33099r568036_chk

Verify that an audit event is generated for any successful/unsuccessful use of "setfiles" by performing the following command to check the file system rules in "/etc/audit/audit.rules": $ sudo grep -w "setfiles" /etc/audit/audit.rules -a always,exit -F path=/usr/sbin/setfiles -F perm=x -F auid>=1000 -F auid!=unset -k privileged-unix-update If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-33074r568037_fix

Configure the audit system to generate an audit event for any successful/unsuccessful uses of the "setfiles" by adding or updating the following rule in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F path=/usr/sbin/setfiles -F perm=x -F auid>=1000 -F auid!=unset -k privileged-unix-update The audit daemon must be restarted for the changes to take effect.

b

Successful/unsuccessful uses of userhelper in RHEL 8 must generate an audit record.

AU-12 - Medium - CCI-000169 - V-230431 - SV-230431r1017232_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030315

Vuln IDs

V-230431

Rule IDs

SV-230431r1017232_rule

Reconstruction of harmful events or forensic analysis is not possible if audit records do not contain enough information. At a minimum, the organization must audit the full-text recording of privileged commands. The organization must maintain audit trails in sufficient detail to reconstruct events to determine the cause and impact of compromise. The "userhelper" command is not intended to be run interactively. "Userhelper" provides a basic interface to change a user's password, gecos information, and shell. The main difference between this program and its traditional equivalents (passwd, chfn, chsh) is that prompts are written to standard out to make it easy for a graphical user interface wrapper to interface to it as a child process. When a user logs on, the AUID is set to the UID of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to "-1". The AUID representation is an unsigned 32-bit integer, which equals "4294967295". The audit system interprets "-1", "4294967295", and "unset" in the same way. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-33100r568039_chk

Verify that an audit event is generated for any successful/unsuccessful use of "userhelper" by performing the following command to check the file system rules in "/etc/audit/audit.rules": $ sudo grep -w "userhelper" /etc/audit/audit.rules -a always,exit -F path=/usr/sbin/userhelper -F perm=x -F auid>=1000 -F auid!=unset -k privileged-unix-update If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-33075r568040_fix

Configure the audit system to generate an audit event for any successful/unsuccessful uses of the "userhelper" by adding or updating the following rule in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F path=/usr/sbin/userhelper -F perm=x -F auid>=1000 -F auid!=unset -k privileged-unix-update The audit daemon must be restarted for the changes to take effect.

b

Successful/unsuccessful uses of setsebool in RHEL 8 must generate an audit record.

AU-12 - Medium - CCI-000169 - V-230432 - SV-230432r1017233_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030316

Vuln IDs

V-230432

Rule IDs

SV-230432r1017233_rule

Reconstruction of harmful events or forensic analysis is not possible if audit records do not contain enough information. At a minimum, the organization must audit the full-text recording of privileged commands. The organization must maintain audit trails in sufficient detail to reconstruct events to determine the cause and impact of compromise. The "setsebool" command sets the current state of a particular SELinux boolean or a list of booleans to a given value. When a user logs on, the AUID is set to the UID of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to "-1". The AUID representation is an unsigned 32-bit integer, which equals "4294967295". The audit system interprets "-1", "4294967295", and "unset" in the same way. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-33101r568042_chk

Verify that an audit event is generated for any successful/unsuccessful use of "setsebool" by performing the following command to check the file system rules in "/etc/audit/audit.rules": $ sudo grep -w "setsebool" /etc/audit/audit.rules -a always,exit -F path=/usr/sbin/setsebool -F perm=x -F auid>=1000 -F auid!=unset -k privileged-unix-update If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-33076r568043_fix

Configure the audit system to generate an audit event for any successful/unsuccessful uses of the "setsebool" by adding or updating the following rule in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F path=/usr/sbin/setsebool -F perm=x -F auid>=1000 -F auid!=unset -k privileged-unix-update The audit daemon must be restarted for the changes to take effect.

b

Successful/unsuccessful uses of unix_chkpwd in RHEL 8 must generate an audit record.

AU-12 - Medium - CCI-000169 - V-230433 - SV-230433r1017234_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030317

Vuln IDs

V-230433

Rule IDs

SV-230433r1017234_rule

Reconstruction of harmful events or forensic analysis is not possible if audit records do not contain enough information. At a minimum, the organization must audit the full-text recording of privileged commands. The organization must maintain audit trails in sufficient detail to reconstruct events to determine the cause and impact of compromise. The "unix_chkpwd" command is a helper program for the pam_unix module that verifies the password of the current user. It also checks password and account expiration dates in shadow. It is not intended to be run directly from the command line and logs a security violation if done so. When a user logs on, the AUID is set to the UID of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to "-1". The AUID representation is an unsigned 32-bit integer, which equals "4294967295". The audit system interprets "-1", "4294967295", and "unset" in the same way. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-33102r568045_chk

Verify that an audit event is generated for any successful/unsuccessful use of "unix_chkpwd" by performing the following command to check the file system rules in "/etc/audit/audit.rules": $ sudo grep -w "unix_chkpwd" /etc/audit/audit.rules -a always,exit -F path=/usr/sbin/unix_chkpwd -F perm=x -F auid>=1000 -F auid!=unset -k privileged-unix-update If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-33077r568046_fix

Configure the audit system to generate an audit event for any successful/unsuccessful uses of the "unix_chkpwd" by adding or updating the following rule in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F path=/usr/sbin/unix_chkpwd -F perm=x -F auid>=1000 -F auid!=unset -k privileged-unix-update The audit daemon must be restarted for the changes to take effect.

b

Successful/unsuccessful uses of the ssh-keysign in RHEL 8 must generate an audit record.

AU-12 - Medium - CCI-000169 - V-230434 - SV-230434r1017235_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030320

Vuln IDs

V-230434

Rule IDs

SV-230434r1017235_rule

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). The "ssh-keysign" program is an SSH helper program for host-based authentication. When a user logs on, the AUID is set to the UID of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to "-1". The AUID representation is an unsigned 32-bit integer, which equals "4294967295". The audit system interprets "-1", "4294967295", and "unset" in the same way. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-33103r568048_chk

Verify RHEL 8 generates an audit record when successful/unsuccessful attempts to use the "ssh-keysign" by performing the following command to check the file system rules in "/etc/audit/audit.rules": $ sudo grep ssh-keysign /etc/audit/audit.rules -a always,exit -F path=/usr/libexec/openssh/ssh-keysign -F perm=x -F auid>=1000 -F auid!=unset -k privileged-ssh If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-33078r744001_fix

Configure the audit system to generate an audit event for any successful/unsuccessful use of the "ssh-keysign" by adding or updating the following rule in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F path=/usr/libexec/openssh/ssh-keysign -F perm=x -F auid>=1000 -F auid!=unset -k privileged-ssh The audit daemon must be restarted for the changes to take effect.

b

Successful/unsuccessful uses of the setfacl command in RHEL 8 must generate an audit record.

AU-12 - Medium - CCI-000169 - V-230435 - SV-230435r1017236_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030330

Vuln IDs

V-230435

Rule IDs

SV-230435r1017236_rule

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). The "setfacl" command is used to set file access control lists. When a user logs on, the AUID is set to the UID of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to "-1". The AUID representation is an unsigned 32-bit integer, which equals "4294967295". The audit system interprets "-1", "4294967295", and "unset" in the same way. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-33104r568051_chk

Verify RHEL 8 generates an audit record when successful/unsuccessful attempts to use the "setfacl" command by performing the following command to check the file system rules in "/etc/audit/audit.rules": $ sudo grep -w setfacl /etc/audit/audit.rules -a always,exit -F path=/usr/bin/setfacl -F perm=x -F auid>=1000 -F auid!=unset -k perm_mod If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-33079r568052_fix

Configure the audit system to generate an audit event for any successful/unsuccessful use of the "setfacl" command by adding or updating the following rule in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F path=/usr/bin/setfacl -F perm=x -F auid>=1000 -F auid!=unset -k perm_mod The audit daemon must be restarted for the changes to take effect.

b

Successful/unsuccessful uses of the pam_timestamp_check command in RHEL 8 must generate an audit record.

AU-12 - Medium - CCI-000169 - V-230436 - SV-230436r1017237_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030340

Vuln IDs

V-230436

Rule IDs

SV-230436r1017237_rule

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). The "pam_timestamp_check" command is used to check if the default timestamp is valid. When a user logs on, the AUID is set to the UID of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to "-1". The AUID representation is an unsigned 32-bit integer, which equals "4294967295". The audit system interprets "-1", "4294967295", and "unset" in the same way. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-33105r568054_chk

Verify that an audit event is generated for any successful/unsuccessful use of the "pam_timestamp_check" command by performing the following command to check the file system rules in "/etc/audit/audit.rules": $ sudo grep -w pam_timestamp_check /etc/audit/audit.rules -a always,exit -F path=/usr/sbin/pam_timestamp_check -F perm=x -F auid>=1000 -F auid!=unset -k privileged-pam_timestamp_check If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-33080r568055_fix

Configure the audit system to generate an audit event for any successful/unsuccessful uses of the "pam_timestamp_check" command by adding or updating the following rule in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F path=/usr/sbin/pam_timestamp_check -F perm=x -F auid>=1000 -F auid!=unset -k privileged-pam_timestamp_check The audit daemon must be restarted for the changes to take effect.

b

Successful/unsuccessful uses of the newgrp command in RHEL 8 must generate an audit record.

AU-12 - Medium - CCI-000169 - V-230437 - SV-230437r1017238_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030350

Vuln IDs

V-230437

Rule IDs

SV-230437r1017238_rule

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). The "newgrp" command is used to change the current group ID during a login session. When a user logs on, the AUID is set to the UID of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to "-1". The AUID representation is an unsigned 32-bit integer, which equals "4294967295". The audit system interprets "-1", "4294967295", and "unset" in the same way. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-33106r568057_chk

Verify RHEL 8 generates an audit record when successful/unsuccessful attempts to use the "newgrp" command by performing the following command to check the file system rules in "/etc/audit/audit.rules": $ sudo grep -w newgrp /etc/audit/audit.rules -a always,exit -F path=/usr/bin/newgrp -F perm=x -F auid>=1000 -F auid!=unset -k priv_cmd If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-33081r568058_fix

Configure the audit system to generate an audit event for any successful/unsuccessful use of the "newgrp" command by adding or updating the following rule in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F path=/usr/bin/newgrp -F perm=x -F auid>=1000 -F auid!=unset -k priv_cmd The audit daemon must be restarted for the changes to take effect.

b

Successful/unsuccessful uses of the init_module and finit_module system calls in RHEL 8 must generate an audit record.

AU-12 - Medium - CCI-000169 - V-230438 - SV-230438r1017241_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030360

Vuln IDs

V-230438

Rule IDs

SV-230438r1017241_rule

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). The "init_module" and "finit_module" system calls are used to load a kernel module. When a user logs on, the AUID is set to the UID of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to "-1". The AUID representation is an unsigned 32-bit integer, which equals "4294967295". The audit system interprets "-1", "4294967295", and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each syscall made by all programs on the system. Therefore, it is very important to use syscall rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance can be helped, however, by combining syscalls into one rule whenever possible. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-33107r1017239_chk

Verify RHEL 8 generates an audit record upon successful/unsuccessful attempts to use the "init_module" and "finit_module" system calls by using the following command to check the file system rules in "/etc/audit/audit.rules": $ sudo grep init_module /etc/audit/audit.rules -a always,exit -F arch=b32 -S init_module,finit_module -F auid>=1000 -F auid!=unset -k module_chng -a always,exit -F arch=b64 -S init_module,finit_module -F auid>=1000 -F auid!=unset -k module_chng If the command does not return an audit rule for "init_module" and "finit_module" or any of the lines returned are commented out, this is a finding.

Fix: F-33082r1017240_fix

Configure the audit system to generate an audit event for any successful/unsuccessful use of the "init_module" and "finit_module" system calls by adding or updating the following rules in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F arch=b32 -S init_module,finit_module -F auid>=1000 -F auid!=unset -k module_chng -a always,exit -F arch=b64 -S init_module,finit_module -F auid>=1000 -F auid!=unset -k module_chng The audit daemon must be restarted for the changes to take effect.

b

Successful/unsuccessful uses of the rename, unlink, rmdir, renameat, and unlinkat system calls in RHEL 8 must generate an audit record.

AU-12 - Medium - CCI-000169 - V-230439 - SV-230439r1017243_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030361

Vuln IDs

V-230439

Rule IDs

SV-230439r1017243_rule

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). The "rename" system call will rename the specified files by replacing the first occurrence of expression in their name by replacement. The "unlink" system call deletes a name from the filesystem. If that name was the last link to a file and no processes have the file open, the file is deleted and the space it was using is made available for reuse. The "rmdir" system call removes empty directories. The "renameat" system call renames a file, moving it between directories if required. The "unlinkat" system call operates in exactly the same way as either "unlink" or "rmdir" except for the differences described in the manual page. When a user logs on, the AUID is set to the UID of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to "-1". The AUID representation is an unsigned 32-bit integer, which equals "4294967295". The audit system interprets "-1", "4294967295", and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each syscall made by all programs on the system. Therefore, it is very important to use syscall rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. Performance can be helped, however, by combining syscalls into one rule whenever possible. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-33108r1017242_chk

Verify RHEL 8 generates an audit record upon successful/unsuccessful attempts to use the "rename", "unlink", "rmdir", "renameat", and "unlinkat" system calls by using the following command to check the file system rules in "/etc/audit/audit.rules": $ sudo grep 'rename\|unlink\|rmdir' /etc/audit/audit.rules -a always,exit -F arch=b32 -S rename,unlink,rmdir,renameat,unlinkat -F auid>=1000 -F auid!=unset -k delete -a always,exit -F arch=b64 -S rename,unlink,rmdir,renameat,unlinkat -F auid>=1000 -F auid!=unset -k delete If the command does not return an audit rule for "rename", "unlink", "rmdir", "renameat", and "unlinkat" or any of the lines returned are commented out, this is a finding.

Fix: F-33083r809301_fix

Configure the audit system to generate an audit event for any successful/unsuccessful use of the "rename", "unlink", "rmdir", "renameat", and "unlinkat" system calls by adding or updating the following rules in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F arch=b32 -S rename,unlink,rmdir,renameat,unlinkat -F auid>=1000 -F auid!=unset -k delete -a always,exit -F arch=b64 -S rename,unlink,rmdir,renameat,unlinkat -F auid>=1000 -F auid!=unset -k delete The audit daemon must be restarted for the changes to take effect.

b

Successful/unsuccessful uses of the gpasswd command in RHEL 8 must generate an audit record.

AU-12 - Medium - CCI-000169 - V-230444 - SV-230444r1017244_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030370

Vuln IDs

V-230444

Rule IDs

SV-230444r1017244_rule

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). The "gpasswd" command is used to administer /etc/group and /etc/gshadow. Every group can have administrators, members and a password. When a user logs on, the AUID is set to the UID of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to "-1". The AUID representation is an unsigned 32-bit integer, which equals "4294967295". The audit system interprets "-1", "4294967295", and "unset" in the same way. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-33113r568078_chk

Verify that an audit event is generated for any successful/unsuccessful use of the "gpasswd" command by performing the following command to check the file system rules in "/etc/audit/audit.rules": $ sudo grep -w gpasswd /etc/audit/audit.rules -a always,exit -F path=/usr/bin/gpasswd -F perm=x -F auid>=1000 -F auid!=unset -k privileged-gpasswd If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-33088r568079_fix

Configure the audit system to generate an audit event for any successful/unsuccessful uses of the "gpasswd" command by adding or updating the following rule in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F path=/usr/bin/gpasswd -F perm=x -F auid>=1000 -F auid!=unset -k privileged-gpasswd The audit daemon must be restarted for the changes to take effect.

b

Successful/unsuccessful uses of the delete_module command in RHEL 8 must generate an audit record.

AU-12 - Medium - CCI-000169 - V-230446 - SV-230446r1017245_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030390

Vuln IDs

V-230446

Rule IDs

SV-230446r1017245_rule

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). The "delete_module" command is used to unload a kernel module. When a user logs on, the AUID is set to the UID of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to "-1". The AUID representation is an unsigned 32-bit integer, which equals "4294967295". The audit system interprets "-1", "4294967295", and "unset" in the same way. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-33115r568084_chk

Verify RHEL 8 generates an audit record when successful/unsuccessful attempts to use the "delete_module" command by performing the following command to check the file system rules in "/etc/audit/audit.rules": $ sudo grep -w "delete_module" /etc/audit/audit.rules -a always,exit -F arch=b32 -S delete_module -F auid>=1000 -F auid!=unset -k module_chng -a always,exit -F arch=b64 -S delete_module -F auid>=1000 -F auid!=unset -k module_chng If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-33090r568085_fix

Configure the audit system to generate an audit event for any successful/unsuccessful use of the "delete_module" command by adding or updating the following rules in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F arch=b32 -S delete_module -F auid>=1000 -F auid!=unset -k module_chng -a always,exit -F arch=b64 -S delete_module -F auid>=1000 -F auid!=unset -k module_chng The audit daemon must be restarted for the changes to take effect.

b

Successful/unsuccessful uses of the crontab command in RHEL 8 must generate an audit record.

AU-12 - Medium - CCI-000169 - V-230447 - SV-230447r1017246_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030400

Vuln IDs

V-230447

Rule IDs

SV-230447r1017246_rule

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). The "crontab" command is used to maintain crontab files for individual users. Crontab is the program used to install, remove, or list the tables used to drive the cron daemon. This is similar to the task scheduler used in other operating systems. When a user logs on, the AUID is set to the UID of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to "-1". The AUID representation is an unsigned 32-bit integer, which equals "4294967295". The audit system interprets "-1", "4294967295", and "unset" in the same way. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-33116r568087_chk

Verify that an audit event is generated for any successful/unsuccessful use of the "crontab" command by performing the following command to check the file system rules in "/etc/audit/audit.rules": $ sudo grep -w crontab /etc/audit/audit.rules -a always,exit -F path=/usr/bin/crontab -F perm=x -F auid>=1000 -F auid!=unset -k privileged-crontab If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-33091r568088_fix

Configure the audit system to generate an audit event for any successful/unsuccessful uses of the "crontab" command by adding or updating the following rule in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F path=/usr/bin/crontab -F perm=x -F auid>=1000 -F auid!=unset -k privileged-crontab The audit daemon must be restarted for the changes to take effect.

b

Successful/unsuccessful uses of the chsh command in RHEL 8 must generate an audit record.

AU-12 - Medium - CCI-000169 - V-230448 - SV-230448r1017247_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030410

Vuln IDs

V-230448

Rule IDs

SV-230448r1017247_rule

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). The "chsh" command is used to change the login shell. When a user logs on, the AUID is set to the UID of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to "-1". The AUID representation is an unsigned 32-bit integer, which equals "4294967295". The audit system interprets "-1", "4294967295", and "unset" in the same way. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-33117r568090_chk

Verify RHEL 8 generates an audit record when successful/unsuccessful attempts to use the "chsh" command by performing the following command to check the file system rules in "/etc/audit/audit.rules": $ sudo grep -w chsh /etc/audit/audit.rules -a always,exit -F path=/usr/bin/chsh -F perm=x -F auid>=1000 -F auid!=unset -k priv_cmd If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-33092r568091_fix

Configure the audit system to generate an audit event for any successful/unsuccessful use of the "chsh" command by adding or updating the following rule in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F path=/usr/bin/chsh -F perm=x -F auid>=1000 -F auid!=unset -k priv_cmd The audit daemon must be restarted for the changes to take effect.

b

Successful/unsuccessful uses of the truncate, ftruncate, creat, open, openat, and open_by_handle_at system calls in RHEL 8 must generate an audit record.

AU-12 - Medium - CCI-000169 - V-230449 - SV-230449r1017249_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030420

Vuln IDs

V-230449

Rule IDs

SV-230449r1017249_rule

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). The "truncate" and "ftruncate" functions are used to truncate a file to a specified length. The "creat" system call is used to open and possibly create a file or device. The "open" system call opens a file specified by a pathname. If the specified file does not exist, it may optionally be created by "open". The "openat" system call opens a file specified by a relative pathname. The "name_to_handle_at" and "open_by_handle_at" system calls split the functionality of "openat" into two parts: "name_to_handle_at" returns an opaque handle that corresponds to a specified file; "open_by_handle_at" opens the file corresponding to a handle returned by a previous call to "name_to_handle_at" and returns an open file descriptor. When a user logs on, the AUID is set to the UID of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to "-1". The AUID representation is an unsigned 32-bit integer, which equals "4294967295". The audit system interprets "-1", "4294967295", and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each syscall made by all programs on the system. Therefore, it is very important to use syscall rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance can be helped, however, by combining syscalls into one rule whenever possible. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033

Checks: C-33118r1017248_chk

Verify RHEL 8 generates an audit record upon successful/unsuccessful attempts to use the "truncate", "ftruncate", "creat", "open", "openat", and "open_by_handle_at" system calls by using the following command to check the file system rules in "/etc/audit/audit.rules": $ sudo grep 'open\|truncate\|creat' /etc/audit/audit.rules -a always,exit -F arch=b32 -S truncate,ftruncate,creat,open,openat,open_by_handle_at -F exit=-EPERM -F auid>=1000 -F auid!=unset -k perm_access -a always,exit -F arch=b64 -S truncate,ftruncate,creat,open,openat,open_by_handle_at -F exit=-EPERM -F auid>=1000 -F auid!=unset -k perm_access -a always,exit -F arch=b32 -S truncate,ftruncate,creat,open,openat,open_by_handle_at -F exit=-EACCES -F auid>=1000 -F auid!=unset -k perm_access -a always,exit -F arch=b64 -S truncate,ftruncate,creat,open,openat,open_by_handle_at -F exit=-EACCES -F auid>=1000 -F auid!=unset -k perm_access If the output does not produce rules containing "-F exit=-EPERM", this is a finding. If the output does not produce rules containing "-F exit=-EACCES", this is a finding. If the command does not return an audit rule for "truncate", "ftruncate", "creat", "open", "openat", and "open_by_handle_at" or any of the lines returned are commented out, this is a finding.

Fix: F-33093r809304_fix

Configure the audit system to generate an audit event for any successful/unsuccessful use of the "truncate", "ftruncate", "creat", "open", "openat", and "open_by_handle_at" system calls by adding or updating the following rules in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F arch=b32 -S truncate,ftruncate,creat,open,openat,open_by_handle_at -F exit=-EPERM -F auid>=1000 -F auid!=unset -k perm_access -a always,exit -F arch=b64 -S truncate,ftruncate,creat,open,openat,open_by_handle_at -F exit=-EPERM -F auid>=1000 -F auid!=unset -k perm_access -a always,exit -F arch=b32 -S truncate,ftruncate,creat,open,openat,open_by_handle_at -F exit=-EACCES -F auid>=1000 -F auid!=unset -k perm_access -a always,exit -F arch=b64 -S truncate,ftruncate,creat,open,openat,open_by_handle_at -F exit=-EACCES -F auid>=1000 -F auid!=unset -k perm_access The audit daemon must be restarted for the changes to take effect.

b

Successful/unsuccessful uses of the chown, fchown, fchownat, and lchown system calls in RHEL 8 must generate an audit record.

AU-12 - Medium - CCI-000169 - V-230455 - SV-230455r1017251_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030480

Vuln IDs

V-230455

Rule IDs

SV-230455r1017251_rule

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). The "chown" command is used to change file owner and group. The "fchown" system call is used to change the ownership of a file referred to by the open file descriptor. The "fchownat" system call is used to change ownership of a file relative to a directory file descriptor. The "lchown" system call is used to change the ownership of the file specified by a path, which does not dereference symbolic links. When a user logs on, the AUID is set to the UID of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to "-1". The AUID representation is an unsigned 32-bit integer, which equals "4294967295". The audit system interprets "-1", "4294967295", and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each syscall made by all programs on the system. Therefore, it is very important to use syscall rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance can be helped, however, by combining syscalls into one rule whenever possible. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210

Checks: C-33124r1017250_chk

Verify RHEL 8 generates an audit record upon successful/unsuccessful attempts to use the "chown", "fchown", "fchownat" and "lchown" system calls by using the following command to check the file system rules in "/etc/audit/audit.rules": $ sudo grep chown /etc/audit/audit.rules -a always,exit -F arch=b32 -S chown,fchown,fchownat,lchown -F auid>=1000 -F auid!=unset -k perm_mod -a always,exit -F arch=b64 -S chown,fchown,fchownat,lchown -F auid>=1000 -F auid!=unset -k perm_mod If audit rules are not defined for "chown", "fchown", "fchownat", and "lchown" or any of the lines returned are commented out, this is a finding.

Fix: F-33099r809307_fix

Configure the audit system to generate an audit event for any successful/unsuccessful use of the "chown", "fchown", "fchownat", and "lchown" system calls by adding or updating the following line to "/etc/audit/rules.d/audit.rules": -a always,exit -F arch=b32 -S chown,fchown,fchownat,lchown -F auid>=1000 -F auid!=unset -k perm_mod -a always,exit -F arch=b64 -S chown,fchown,fchownat,lchown -F auid>=1000 -F auid!=unset -k perm_mod The audit daemon must be restarted for the changes to take effect.

b

Successful/unsuccessful uses of the chmod, fchmod, and fchmodat system calls in RHEL 8 must generate an audit record.

AU-12 - Medium - CCI-000169 - V-230456 - SV-230456r1017253_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030490

Vuln IDs

V-230456

Rule IDs

SV-230456r1017253_rule

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). The "chmod" system call changes the file mode bits of each given file according to mode, which can be either a symbolic representation of changes to make, or an octal number representing the bit pattern for the new mode bits. The "fchmod" system call is used to change permissions of a file. The "fchmodat" system call is used to change permissions of a file relative to a directory file descriptor. When a user logs on, the AUID is set to the UID of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to "-1". The AUID representation is an unsigned 32-bit integer, which equals "4294967295". The audit system interprets "-1", "4294967295", and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each syscall made by all programs on the system. Therefore, it is very important to use syscall rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. Performance can be helped, however, by combining syscalls into one rule whenever possible. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210

Checks: C-33125r1017252_chk

Verify RHEL 8 generates an audit record upon successful/unsuccessful attempts to use the "chmod", "fchmod", and "fchmodat" syscalls by using the following command to check the file system rules in "/etc/audit/audit.rules": $ sudo grep chmod /etc/audit/audit.rules -a always,exit -F arch=b32 -S chmod,fchmod,fchmodat -F auid>=1000 -F auid!=unset -k perm_mod -a always,exit -F arch=b64 -S chmod,fchmod,fchmodat -F auid>=1000 -F auid!=unset -k perm_mod If the command does not return an audit rule for "chmod", "fchmod", and "fchmodat", or any of the lines returned are commented out, this is a finding.

Fix: F-33100r809310_fix

Configure the audit system to generate an audit event for any successful/unsuccessful use of the "chmod", "fchmod", and "fchmodat" syscalls by adding or updating the following line to "/etc/audit/rules.d/audit.rules": -a always,exit -F arch=b32 -S chmod,fchmod,fchmodat -F auid>=1000 -F auid!=unset -k perm_mod -a always,exit -F arch=b64 -S chmod,fchmod,fchmodat -F auid>=1000 -F auid!=unset -k perm_mod The audit daemon must be restarted for the changes to take effect.

b

Successful/unsuccessful uses of the sudo command in RHEL 8 must generate an audit record.

AU-12 - Medium - CCI-000169 - V-230462 - SV-230462r1017254_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030550

Vuln IDs

V-230462

Rule IDs

SV-230462r1017254_rule

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). The "sudo" command allows a permitted user to execute a command as the superuser or another user, as specified by the security policy. When a user logs on, the AUID is set to the UID of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to "-1". The AUID representation is an unsigned 32-bit integer, which equals "4294967295". The audit system interprets "-1", "4294967295", and "unset" in the same way. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210

Checks: C-33131r568132_chk

Verify that an audit event is generated for any successful/unsuccessful use of the "sudo" command by performing the following command to check the file system rules in "/etc/audit/audit.rules": $ sudo grep -w sudo /etc/audit/audit.rules -a always,exit -F path=/usr/bin/sudo -F perm=x -F auid>=1000 -F auid!=unset -k priv_cmd If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-33106r568133_fix

Configure the audit system to generate an audit event for any successful/unsuccessful use of the "sudo" command by adding or updating the following rule in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F path=/usr/bin/sudo -F perm=x -F auid>=1000 -F auid!=unset -k priv_cmd The audit daemon must be restarted for the changes to take effect.

b

Successful/unsuccessful uses of the usermod command in RHEL 8 must generate an audit record.

AU-12 - Medium - CCI-000169 - V-230463 - SV-230463r1017255_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030560

Vuln IDs

V-230463

Rule IDs

SV-230463r1017255_rule

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). The "usermod" command modifies the system account files to reflect the changes that are specified on the command line. When a user logs on, the AUID is set to the UID of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to "-1". The AUID representation is an unsigned 32-bit integer, which equals "4294967295". The audit system interprets "-1", "4294967295", and "unset" in the same way. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210

Checks: C-33132r568135_chk

Verify that an audit event is generated for any successful/unsuccessful use of the "usermod" command by performing the following command to check the file system rules in "/etc/audit/audit.rules": $ sudo grep -w usermod /etc/audit/audit.rules -a always,exit -F path=/usr/sbin/usermod -F perm=x -F auid>=1000 -F auid!=unset -k privileged-usermod If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-33107r568136_fix

Configure the audit system to generate an audit event for any successful/unsuccessful uses of the "usermod" command by adding or updating the following rule in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F path=/usr/sbin/usermod -F perm=x -F auid>=1000 -F auid!=unset -k privileged-usermod The audit daemon must be restarted for the changes to take effect.

b

Successful/unsuccessful uses of the chacl command in RHEL 8 must generate an audit record.

AU-12 - Medium - CCI-000169 - V-230464 - SV-230464r1017256_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030570

Vuln IDs

V-230464

Rule IDs

SV-230464r1017256_rule

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). The "chacl" command is used to change the access control list of a file or directory. When a user logs on, the AUID is set to the UID of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to "-1". The AUID representation is an unsigned 32-bit integer, which equals "4294967295". The audit system interprets "-1", "4294967295", and "unset" in the same way. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210

Checks: C-33133r568138_chk

Verify RHEL 8 generates an audit record when successful/unsuccessful attempts to use the "chacl" command by performing the following command to check the file system rules in "/etc/audit/audit.rules": $ sudo grep -w chacl /etc/audit/audit.rules -a always,exit -F path=/usr/bin/chacl -F perm=x -F auid>=1000 -F auid!=unset -k perm_mod If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-33108r568139_fix

Configure the audit system to generate an audit event for any successful/unsuccessful use of the "chacl" command by adding or updating the following rule in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F path=/usr/bin/chacl -F perm=x -F auid>=1000 -F auid!=unset -k perm_mod The audit daemon must be restarted for the changes to take effect.

b

Successful/unsuccessful uses of the kmod command in RHEL 8 must generate an audit record.

AU-12 - Medium - CCI-000169 - V-230465 - SV-230465r1017257_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030580

Vuln IDs

V-230465

Rule IDs

SV-230465r1017257_rule

Without the capability to generate audit records, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). The "kmod" command is used to control Linux Kernel modules. The list of audited events is the set of events for which audits are to be generated. This set of events is typically a subset of the list of all events for which the system is capable of generating audit records. DoD has defined the list of events for which RHEL 8 will provide an audit record generation capability as the following: 1) Successful and unsuccessful attempts to access, modify, or delete privileges, security objects, security levels, or categories of information (e.g., classification levels); 2) Access actions, such as successful and unsuccessful logon attempts, privileged activities or other system-level access, starting and ending time for user access to the system, concurrent logons from different workstations, successful and unsuccessful accesses to objects, all program initiations, and all direct access to the information system; 3) All account creations, modifications, disabling, and terminations; and 4) All kernel module load, unload, and restart actions. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000471-GPOS-00216, SRG-OS-000477-GPOS-00222

Checks: C-33134r568141_chk

Verify if RHEL 8 is configured to audit the execution of the module management program "kmod", by running the following command: $ sudo grep "/usr/bin/kmod" /etc/audit/audit.rules -a always,exit -F path=/usr/bin/kmod -F perm=x -F auid>=1000 -F auid!=unset -k modules If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-33109r568142_fix

Configure RHEL 8 to audit the execution of the module management program "kmod" by adding or updating the following line to "/etc/audit/rules.d/audit.rules": -a always,exit -F path=/usr/bin/kmod -F perm=x -F auid>=1000 -F auid!=unset -k modules The audit daemon must be restarted for the changes to take effect.

b

Successful/unsuccessful modifications to the faillock log file in RHEL 8 must generate an audit record.

AU-12 - Medium - CCI-000169 - V-230466 - SV-230466r1017258_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030590

Vuln IDs

V-230466

Rule IDs

SV-230466r1017258_rule

Without the capability to generate audit records, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). The list of audited events is the set of events for which audits are to be generated. This set of events is typically a subset of the list of all events for which the system is capable of generating audit records. DoD has defined the list of events for which RHEL 8 will provide an audit record generation capability as the following: 1) Successful and unsuccessful attempts to access, modify, or delete privileges, security objects, security levels, or categories of information (e.g., classification levels); 2) Access actions, such as successful and unsuccessful logon attempts, privileged activities or other system-level access, starting and ending time for user access to the system, concurrent logons from different workstations, successful and unsuccessful accesses to objects, all program initiations, and all direct access to the information system; 3) All account creations, modifications, disabling, and terminations; and 4) All kernel module load, unload, and restart actions. From "Pam_Faillock man" pages: Note the default directory that pam_faillock uses is usually cleared on system boot so the access will be reenabled after system reboot. If that is undesirable a different tally directory must be set with the "dir" option. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000473-GPOS-00218

Checks: C-33135r568144_chk

Verify RHEL 8 generates an audit record when successful/unsuccessful modifications to the "faillock" file occur. First, determine where the faillock tallies are stored with the following commands: For RHEL versions 8.0 and 8.1: $ sudo grep -i pam_faillock.so /etc/pam.d/system-auth auth required pam_faillock.so preauth dir=/var/log/faillock silent deny=3 fail_interval=900 even_deny_root For RHEL versions 8.2 and newer: $ sudo grep dir /etc/security/faillock.conf dir=/var/log/faillock Using the location of the faillock log file, check that the following calls are being audited by performing the following command to check the file system rules in "/etc/audit/audit.rules": $ sudo grep -w faillock /etc/audit/audit.rules -w /var/log/faillock -p wa -k logins If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-33110r568145_fix

Configure the audit system to generate an audit event for any successful/unsuccessful modifications to the "faillock" file by adding or updating the following rules in the "/etc/audit/rules.d/audit.rules" file: -w /var/log/faillock -p wa -k logins The audit daemon must be restarted for the changes to take effect.

b

Successful/unsuccessful modifications to the lastlog file in RHEL 8 must generate an audit record.

AU-12 - Medium - CCI-000169 - V-230467 - SV-230467r1017259_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030600

Vuln IDs

V-230467

Rule IDs

SV-230467r1017259_rule

Without the capability to generate audit records, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). The list of audited events is the set of events for which audits are to be generated. This set of events is typically a subset of the list of all events for which the system is capable of generating audit records. DoD has defined the list of events for which RHEL 8 will provide an audit record generation capability as the following: 1) Successful and unsuccessful attempts to access, modify, or delete privileges, security objects, security levels, or categories of information (e.g., classification levels); 2) Access actions, such as successful and unsuccessful logon attempts, privileged activities or other system-level access, starting and ending time for user access to the system, concurrent logons from different workstations, successful and unsuccessful accesses to objects, all program initiations, and all direct access to the information system; 3) All account creations, modifications, disabling, and terminations; and 4) All kernel module load, unload, and restart actions. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000473-GPOS-00218

Checks: C-33136r568147_chk

Verify RHEL 8 generates an audit record when successful/unsuccessful modifications to the "lastlog" file by performing the following command to check the file system rules in "/etc/audit/audit.rules": $ sudo grep -w lastlog /etc/audit/audit.rules -w /var/log/lastlog -p wa -k logins If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-33111r568148_fix

Configure the audit system to generate an audit event for any successful/unsuccessful modifications to the "lastlog" file by adding or updating the following rules in the "/etc/audit/rules.d/audit.rules" file: -w /var/log/lastlog -p wa -k logins The audit daemon must be restarted for the changes to take effect.

a

RHEL 8 must enable auditing of processes that start prior to the audit daemon.

AU-12 - Low - CCI-000169 - V-230468 - SV-230468r1017260_rule

RMF Control

AU-12

Severity

L

CCI

Version

RHEL-08-030601

Vuln IDs

V-230468

Rule IDs

SV-230468r1017260_rule

Without the capability to generate audit records, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. If auditing is enabled late in the startup process, the actions of some startup processes may not be audited. Some audit systems also maintain state information only available if auditing is enabled before a given process is created. Audit records can be generated from various components within the information system (e.g., module or policy filter). The list of audited events is the set of events for which audits are to be generated. This set of events is typically a subset of the list of all events for which the system is capable of generating audit records. DoD has defined the list of events for which RHEL 8 will provide an audit record generation capability as the following: 1) Successful and unsuccessful attempts to access, modify, or delete privileges, security objects, security levels, or categories of information (e.g., classification levels); 2) Access actions, such as successful and unsuccessful logon attempts, privileged activities or other system-level access, starting and ending time for user access to the system, concurrent logons from different workstations, successful and unsuccessful accesses to objects, all program initiations, and all direct access to the information system; 3) All account creations, modifications, disabling, and terminations; and 4) All kernel module load, unload, and restart actions. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000473-GPOS-00218

Checks: C-33137r792903_chk

Verify RHEL 8 enables auditing of processes that start prior to the audit daemon with the following commands: $ sudo grub2-editenv list | grep audit kernelopts=root=/dev/mapper/rhel-root ro crashkernel=auto resume=/dev/mapper/rhel-swap rd.lvm.lv=rhel/root rd.lvm.lv=rhel/swap rhgb quiet fips=1 audit=1 audit_backlog_limit=8192 boot=UUID=8d171156-cd61-421c-ba41-1c021ac29e82 If the "audit" entry does not equal "1", is missing, or the line is commented out, this is a finding. Check that auditing is enabled by default to persist in kernel updates: $ sudo grep audit /etc/default/grub GRUB_CMDLINE_LINUX="audit=1" If "audit" is not set to "1", is missing or commented out, this is a finding.

Fix: F-33112r568151_fix

Configure RHEL 8 to audit processes that start prior to the audit daemon with the following command: $ sudo grubby --update-kernel=ALL --args="audit=1" Add or modify the following line in "/etc/default/grub" to ensure the configuration survives kernel updates: GRUB_CMDLINE_LINUX="audit=1"

a

RHEL 8 must allocate an audit_backlog_limit of sufficient size to capture processes that start prior to the audit daemon.

AU-4 - Low - CCI-001849 - V-230469 - SV-230469r958752_rule

RMF Control

AU-4

Severity

L

CCI

CCI-001849

Version

RHEL-08-030602

Vuln IDs

V-230469

Rule IDs

SV-230469r958752_rule

Without the capability to generate audit records, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. If auditing is enabled late in the startup process, the actions of some startup processes may not be audited. Some audit systems also maintain state information only available if auditing is enabled before a given process is created. Audit records can be generated from various components within the information system (e.g., module or policy filter). Allocating an audit_backlog_limit of sufficient size is critical in maintaining a stable boot process. With an insufficient limit allocated, the system is susceptible to boot failures and crashes.

Checks: C-33138r792905_chk

Verify RHEL 8 allocates a sufficient audit_backlog_limit to capture processes that start prior to the audit daemon with the following commands: $ sudo grub2-editenv list | grep audit kernelopts=root=/dev/mapper/rhel-root ro crashkernel=auto resume=/dev/mapper/rhel-swap rd.lvm.lv=rhel/root rd.lvm.lv=rhel/swap rhgb quiet fips=1 audit=1 audit_backlog_limit=8192 boot=UUID=8d171156-cd61-421c-ba41-1c021ac29e82 If the "audit_backlog_limit" entry does not equal "8192" or greater, is missing, or the line is commented out, this is a finding. Check the audit_backlog_limit is set to persist in kernel updates: $ sudo grep audit /etc/default/grub GRUB_CMDLINE_LINUX="audit_backlog_limit=8192" If "audit_backlog_limit" is not set to "8192" or greater, is missing or commented out, this is a finding.

Fix: F-33113r568154_fix

Configure RHEL 8 to allocate sufficient audit_backlog_limit to capture processes that start prior to the audit daemon with the following command: $ sudo grubby --update-kernel=ALL --args="audit_backlog_limit=8192" Add or modify the following line in "/etc/default/grub" to ensure the configuration survives kernel updates: GRUB_CMDLINE_LINUX="audit_backlog_limit=8192"

a

RHEL 8 must enable Linux audit logging for the USBGuard daemon.

AU-12 - Low - CCI-000169 - V-230470 - SV-230470r1017261_rule

RMF Control

AU-12

Severity

L

CCI

Version

RHEL-08-030603

Vuln IDs

V-230470

Rule IDs

SV-230470r1017261_rule

Without the capability to generate audit records, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. If auditing is enabled late in the startup process, the actions of some startup processes may not be audited. Some audit systems also maintain state information only available if auditing is enabled before a given process is created. Audit records can be generated from various components within the information system (e.g., module or policy filter). The list of audited events is the set of events for which audits are to be generated. This set of events is typically a subset of the list of all events for which the system is capable of generating audit records. DoD has defined the list of events for which RHEL 8 will provide an audit record generation capability as the following: 1) Successful and unsuccessful attempts to access, modify, or delete privileges, security objects, security levels, or categories of information (e.g., classification levels); 2) Access actions, such as successful and unsuccessful logon attempts, privileged activities or other system-level access, starting and ending time for user access to the system, concurrent logons from different workstations, successful and unsuccessful accesses to objects, all program initiations, and all direct access to the information system; 3) All account creations, modifications, disabling, and terminations; and 4) All kernel module load, unload, and restart actions. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000471-GPOS-00215

Checks: C-33139r1014802_chk

Verify RHEL 8 enables Linux audit logging of the USBGuard daemon with the following commands: Note: If the USBGuard daemon is not installed and enabled, this requirement is Not Applicable. $ sudo grep -i auditbackend /etc/usbguard/usbguard-daemon.conf AuditBackend=LinuxAudit If the "AuditBackend" entry does not equal "LinuxAudit", is missing, or the line is commented out, this is a finding. If the system is a virtual machine with no virtual or physical USB peripherals attached, this is not a finding.

Fix: F-33114r744005_fix

Configure RHEL 8 to enable Linux audit logging of the USBGuard daemon by adding or modifying the following line in "/etc/usbguard/usbguard-daemon.conf": AuditBackend=LinuxAudit

b

RHEL 8 must allow only the Information System Security Manager (ISSM) (or individuals or roles appointed by the ISSM) to select which auditable events are to be audited.

AU-12 - Medium - CCI-000171 - V-230471 - SV-230471r1069296_rule

RMF Control

AU-12

Severity

M

CCI

CCI-000171

Version

RHEL-08-030610

Vuln IDs

V-230471

Rule IDs

SV-230471r1069296_rule

Without the capability to restrict the roles and individuals that can select which events are audited, unauthorized personnel may be able to prevent the auditing of critical events. Misconfigured audits may degrade the system's performance by overwhelming the audit log. Misconfigured audits may also make it more difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one.

Checks: C-33140r1069201_chk

Verify that the files in directory "/etc/audit/rules.d/" and "/etc/audit/auditd.conf" file have a mode of "0640" or less permissive by using the following commands: $ sudo find /etc/audit/rules.d/ -type f -name *.rules -exec ls -al {} \; -rw-r-----. 1 root root 284 May 1 20:30 /etc/audit/rules.d/audit.rules $ sudo ls -l /etc/audit/auditd.conf -rw-r----- 1 root root 621 Sep 22 17:19 auditd.conf If the files in the "/etc/audit/rules.d/" directory or the "/etc/audit/auditd.conf" file have a mode more permissive than "0640", this is a finding.

Fix: F-33115r568160_fix

Configure the files in directory "/etc/audit/rules.d/" and the "/etc/audit/auditd.conf" file to have a mode of "0640" with the following commands: $ sudo chmod 0640 /etc/audit/rules.d/audit.rules $ sudo chmod 0640 /etc/audit/rules.d/[customrulesfile].rules $ sudo chmod 0640 /etc/audit/auditd.conf

b

RHEL 8 audit tools must have a mode of 0755 or less permissive.

AU-9 - Medium - CCI-001493 - V-230472 - SV-230472r1017263_rule

RMF Control

AU-9

Severity

M

CCI

CCI-001493

Version

RHEL-08-030620

Vuln IDs

V-230472

Rule IDs

SV-230472r1017263_rule

Protecting audit information also includes identifying and protecting the tools used to view and manipulate log data. Therefore, protecting audit tools is necessary to prevent unauthorized operation on audit information. RHEL 8 systems providing tools to interface with audit information will leverage user permissions and roles identifying the user accessing the tools, and the corresponding rights the user enjoys, to make access decisions regarding the access to audit tools. Audit tools include, but are not limited to, vendor-provided and open source audit tools needed to successfully view and manipulate audit information system activity and records. Audit tools include custom queries and report generators.

Checks: C-33141r568162_chk

Verify the audit tools are protected from unauthorized access, deletion, or modification by checking the permissive mode. Check the octal permission of each audit tool by running the following command: $ sudo stat -c "%a %n" /sbin/auditctl /sbin/aureport /sbin/ausearch /sbin/autrace /sbin/auditd /sbin/rsyslogd /sbin/augenrules 755 /sbin/auditctl 755 /sbin/aureport 755 /sbin/ausearch 750 /sbin/autrace 755 /sbin/auditd 755 /sbin/rsyslogd 755 /sbin/augenrules If any of the audit tools has a mode more permissive than "0755", this is a finding.

Fix: F-33116r568163_fix

Configure the audit tools to be protected from unauthorized access by setting the correct permissive mode using the following command: $ sudo chmod 0755 [audit_tool] Replace "[audit_tool]" with the audit tool that does not have the correct permissive mode.

b

RHEL 8 audit tools must be owned by root.

AU-9 - Medium - CCI-001493 - V-230473 - SV-230473r1017264_rule

RMF Control

AU-9

Severity

M

CCI

CCI-001493

Version

RHEL-08-030630

Vuln IDs

V-230473

Rule IDs

SV-230473r1017264_rule

Protecting audit information also includes identifying and protecting the tools used to view and manipulate log data. Therefore, protecting audit tools is necessary to prevent unauthorized operation on audit information. RHEL 8 systems providing tools to interface with audit information will leverage user permissions and roles identifying the user accessing the tools, and the corresponding rights the user enjoys, to make access decisions regarding the access to audit tools. Audit tools include, but are not limited to, vendor-provided and open source audit tools needed to successfully view and manipulate audit information system activity and records. Audit tools include custom queries and report generators. Satisfies: SRG-OS-000256-GPOS-00097, SRG-OS-000257-GPOS-00098, SRG-OS-000258-GPOS-00099

Checks: C-33142r744007_chk

Verify the audit tools are owned by "root" to prevent any unauthorized access, deletion, or modification. Check the owner of each audit tool by running the following command: $ sudo stat -c "%U %n" /sbin/auditctl /sbin/aureport /sbin/ausearch /sbin/autrace /sbin/auditd /sbin/rsyslogd /sbin/augenrules root /sbin/auditctl root /sbin/aureport root /sbin/ausearch root /sbin/autrace root /sbin/auditd root /sbin/rsyslogd root /sbin/augenrules If any of the audit tools are not owned by "root", this is a finding.

Fix: F-33117r568166_fix

Configure the audit tools to be owned by "root", by running the following command: $ sudo chown root [audit_tool] Replace "[audit_tool]" with each audit tool not owned by "root".

b

RHEL 8 audit tools must be group-owned by root.

AU-9 - Medium - CCI-001493 - V-230474 - SV-230474r1017265_rule

RMF Control

AU-9

Severity

M

CCI

CCI-001493

Version

RHEL-08-030640

Vuln IDs

V-230474

Rule IDs

SV-230474r1017265_rule

Protecting audit information also includes identifying and protecting the tools used to view and manipulate log data. Therefore, protecting audit tools is necessary to prevent unauthorized operation on audit information. RHEL 8 systems providing tools to interface with audit information will leverage user permissions and roles identifying the user accessing the tools, and the corresponding rights the user enjoys, to make access decisions regarding the access to audit tools. Audit tools include, but are not limited to, vendor-provided and open source audit tools needed to successfully view and manipulate audit information system activity and records. Audit tools include custom queries and report generators. Satisfies: SRG-OS-000256-GPOS-00097, SRG-OS-000257-GPOS-00098, SRG-OS-000258-GPOS-00099

Checks: C-33143r568168_chk

Verify the audit tools are group-owned by "root" to prevent any unauthorized access, deletion, or modification. Check the owner of each audit tool by running the following commands: $ sudo stat -c "%G %n" /sbin/auditctl /sbin/aureport /sbin/ausearch /sbin/autrace /sbin/auditd /sbin/rsyslogd /sbin/augenrules root /sbin/auditctl root /sbin/aureport root /sbin/ausearch root /sbin/autrace root /sbin/auditd root /sbin/rsyslogd root /sbin/augenrules If any of the audit tools are not group-owned by "root", this is a finding.

Fix: F-33118r568169_fix

Configure the audit tools to be group-owned by "root", by running the following command: $ sudo chgrp root [audit_tool] Replace "[audit_tool]" with each audit tool not group-owned by "root".

b

RHEL 8 must use cryptographic mechanisms to protect the integrity of audit tools.

AU-9 - Medium - CCI-001496 - V-230475 - SV-230475r1017266_rule

RMF Control

AU-9

Severity

M

CCI

CCI-001496

Version

RHEL-08-030650

Vuln IDs

V-230475

Rule IDs

SV-230475r1017266_rule

Protecting the integrity of the tools used for auditing purposes is a critical step toward ensuring the integrity of audit information. Audit information includes all information (e.g., audit records, audit settings, and audit reports) needed to successfully audit information system activity. Audit tools include, but are not limited to, vendor-provided and open source audit tools needed to successfully view and manipulate audit information system activity and records. Audit tools include custom queries and report generators. It is not uncommon for attackers to replace the audit tools or inject code into the existing tools with the purpose of providing the capability to hide or erase system activity from the audit logs. To address this risk, audit tools must be cryptographically signed to provide the capability to identify when the audit tools have been modified, manipulated, or replaced. An example is a checksum hash of the file or files.

Checks: C-33144r880721_chk

Verify that Advanced Intrusion Detection Environment (AIDE) is properly configured to use cryptographic mechanisms to protect the integrity of audit tools. If AIDE is not installed, ask the System Administrator how file integrity checks are performed on the system. Check the selection lines to ensure AIDE is configured to add/check with the following command: $ sudo grep -E '(\/usr\/sbin\/(audit|au|rsys))' /etc/aide.conf /usr/sbin/auditctl p+i+n+u+g+s+b+acl+xattrs+sha512 /usr/sbin/auditd p+i+n+u+g+s+b+acl+xattrs+sha512 /usr/sbin/ausearch p+i+n+u+g+s+b+acl+xattrs+sha512 /usr/sbin/aureport p+i+n+u+g+s+b+acl+xattrs+sha512 /usr/sbin/autrace p+i+n+u+g+s+b+acl+xattrs+sha512 /usr/sbin/rsyslogd p+i+n+u+g+s+b+acl+xattrs+sha512 /usr/sbin/augenrules p+i+n+u+g+s+b+acl+xattrs+sha512 If any of the audit tools listed above do not have an appropriate selection line, ask the system administrator to indicate what cryptographic mechanisms are being used to protect the integrity of the audit tools. If there is no evidence of integrity protection, this is a finding.

Fix: F-33119r568172_fix

Add or update the following lines to "/etc/aide.conf", to protect the integrity of the audit tools. # Audit Tools /usr/sbin/auditctl p+i+n+u+g+s+b+acl+xattrs+sha512 /usr/sbin/auditd p+i+n+u+g+s+b+acl+xattrs+sha512 /usr/sbin/ausearch p+i+n+u+g+s+b+acl+xattrs+sha512 /usr/sbin/aureport p+i+n+u+g+s+b+acl+xattrs+sha512 /usr/sbin/autrace p+i+n+u+g+s+b+acl+xattrs+sha512 /usr/sbin/rsyslogd p+i+n+u+g+s+b+acl+xattrs+sha512 /usr/sbin/augenrules p+i+n+u+g+s+b+acl+xattrs+sha512

b

RHEL 8 must allocate audit record storage capacity to store at least one week of audit records, when audit records are not immediately sent to a central audit record storage facility.

AU-4 - Medium - CCI-001849 - V-230476 - SV-230476r958752_rule

RMF Control

AU-4

Severity

M

CCI

CCI-001849

Version

RHEL-08-030660

Vuln IDs

V-230476

Rule IDs

SV-230476r958752_rule

To ensure RHEL 8 systems have a sufficient storage capacity in which to write the audit logs, RHEL 8 needs to be able to allocate audit record storage capacity. The task of allocating audit record storage capacity is usually performed during initial installation of RHEL 8.

Checks: C-33145r809312_chk

Verify RHEL 8 allocates audit record storage capacity to store at least one week of audit records when audit records are not immediately sent to a central audit record storage facility. Determine to which partition the audit records are being written with the following command: $ sudo grep -iw log_file /etc/audit/auditd.conf log_file = /var/log/audit/audit.log Check the size of the partition to which audit records are written (with the example being /var/log/audit/) with the following command: $ sudo df -h /var/log/audit/ /dev/sda2 24G 10.4G 13.6G 43% /var/log/audit If the audit records are not written to a partition made specifically for audit records (/var/log/audit is a separate partition), determine the amount of space being used by other files in the partition with the following command: $ sudo du -sh [audit_partition] 1.8G /var/log/audit If the audit record partition is not allocated for sufficient storage capacity, this is a finding. Note: The partition size needed to capture a week of audit records is based on the activity level of the system and the total storage capacity available. Typically 10.0 GB of storage space for audit records should be sufficient.

Fix: F-33120r568175_fix

Allocate enough storage capacity for at least one week of audit records when audit records are not immediately sent to a central audit record storage facility. If audit records are stored on a partition made specifically for audit records, resize the partition with sufficient space to contain one week of audit records. If audit records are not stored on a partition made specifically for audit records, a new partition with sufficient space will need be to be created.

b

RHEL 8 must have the packages required for offloading audit logs installed.

CM-6 - Medium - CCI-000366 - V-230477 - SV-230477r1017267_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-030670

Vuln IDs

V-230477

Rule IDs

SV-230477r1017267_rule

Information stored in one location is vulnerable to accidental or incidental deletion or alteration. Off-loading is a common process in information systems with limited audit storage capacity. RHEL 8 installation media provides "rsyslogd". "rsyslogd" is a system utility providing support for message logging. Support for both internet and UNIX domain sockets enables this utility to support both local and remote logging. Couple this utility with "gnutls" (which is a secure communications library implementing the SSL, TLS and DTLS protocols), and you have a method to securely encrypt and off-load auditing. Rsyslog provides three ways to forward message: the traditional UDP transport, which is extremely lossy but standard; the plain TCP based transport, which loses messages only during certain situations but is widely available; and the RELP transport, which does not lose messages but is currently available only as part of the rsyslogd 3.15.0 and above. Examples of each configuration: UDP *.* @remotesystemname TCP *.* @@remotesystemname RELP *.* :omrelp:remotesystemname:2514 Note that a port number was given as there is no standard port for RELP.

Checks: C-33146r568177_chk

Verify the operating system has the packages required for offloading audit logs installed with the following commands: $ sudo yum list installed rsyslog rsyslog.x86_64 8.1911.0-3.el8 @AppStream If the "rsyslog" package is not installed, ask the administrator to indicate how audit logs are being offloaded and what packages are installed to support it. If there is no evidence of audit logs being offloaded, this is a finding.

Fix: F-33121r568178_fix

Configure the operating system to offload audit logs by installing the required packages with the following command: $ sudo yum install rsyslog

b

RHEL 8 must have the packages required for encrypting offloaded audit logs installed.

CM-6 - Medium - CCI-000366 - V-230478 - SV-230478r1017268_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-030680

Vuln IDs

V-230478

Rule IDs

SV-230478r1017268_rule

Information stored in one location is vulnerable to accidental or incidental deletion or alteration. Off-loading is a common process in information systems with limited audit storage capacity. RHEL 8 installation media provides "rsyslogd". "rsyslogd" is a system utility providing support for message logging. Support for both internet and UNIX domain sockets enables this utility to support both local and remote logging. Couple this utility with "rsyslog-gnutls" (which is a secure communications library implementing the SSL, TLS and DTLS protocols), and you have a method to securely encrypt and off-load auditing. Rsyslog provides three ways to forward message: the traditional UDP transport, which is extremely lossy but standard; the plain TCP based transport, which loses messages only during certain situations but is widely available; and the RELP transport, which does not lose messages but is currently available only as part of the rsyslogd 3.15.0 and above. Examples of each configuration: UDP *.* @remotesystemname TCP *.* @@remotesystemname RELP *.* :omrelp:remotesystemname:2514 Note that a port number was given as there is no standard port for RELP.

Checks: C-33147r744009_chk

Verify the operating system has the packages required for encrypting offloaded audit logs installed with the following commands: $ sudo yum list installed rsyslog-gnutls rsyslog-gnutls.x86_64 8.1911.0-3.el8 @AppStream If the "rsyslog-gnutls" package is not installed, ask the administrator to indicate how audit logs are being encrypted during offloading and what packages are installed to support it. If there is no evidence of audit logs being encrypted during offloading, this is a finding.

Fix: F-33122r744010_fix

Configure the operating system to encrypt offloaded audit logs by installing the required packages with the following command: $ sudo yum install rsyslog-gnutls

b

The RHEL 8 audit records must be off-loaded onto a different system or storage media from the system being audited.

AU-4 - Medium - CCI-001851 - V-230479 - SV-230479r958754_rule

RMF Control

AU-4

Severity

M

CCI

Version

RHEL-08-030690

Vuln IDs

V-230479

Rule IDs

SV-230479r958754_rule

Information stored in one location is vulnerable to accidental or incidental deletion or alteration. Off-loading is a common process in information systems with limited audit storage capacity. RHEL 8 installation media provides "rsyslogd". "rsyslogd" is a system utility providing support for message logging. Support for both internet and UNIX domain sockets enables this utility to support both local and remote logging. Couple this utility with "gnutls" (which is a secure communications library implementing the SSL, TLS and DTLS protocols), and you have a method to securely encrypt and off-load auditing. Rsyslog provides three ways to forward message: the traditional UDP transport, which is extremely lossy but standard; the plain TCP based transport, which loses messages only during certain situations but is widely available; and the RELP transport, which does not lose messages but is currently available only as part of the rsyslogd 3.15.0 and above. Examples of each configuration: UDP *.* @remotesystemname TCP *.* @@remotesystemname RELP *.* :omrelp:remotesystemname:2514 Note that a port number was given as there is no standard port for RELP. Satisfies: SRG-OS-000342-GPOS-00133, SRG-OS-000479-GPOS-00224

Checks: C-33148r917881_chk

Verify the audit system offloads audit records onto a different system or media from the system being audited with the following command: $ sudo grep @@ /etc/rsyslog.conf /etc/rsyslog.d/*.conf /etc/rsyslog.conf:*.* @@[logaggregationserver.example.mil]:[port] If a remote server is not configured, or the line is commented out, ask the system administrator to indicate how the audit logs are offloaded to a different system or media. If there is no evidence that the audit logs are being offloaded to another system or media, this is a finding.

Fix: F-33123r917882_fix

Configure the operating system to offload audit records onto a different system or media from the system being audited by specifying the remote logging server in "/etc/rsyslog.conf" or "/etc/rsyslog.d/[customfile].conf" with the name or IP address of the log aggregation server. For UDP: *.* @[logaggregationserver.example.mil]:[port] For TCP: *.* @@[logaggregationserver.example.mil]:[port]

b

RHEL 8 must take appropriate action when the internal event queue is full.

AU-4 - Medium - CCI-001851 - V-230480 - SV-230480r958754_rule

RMF Control

AU-4

Severity

M

CCI

Version

RHEL-08-030700

Vuln IDs

V-230480

Rule IDs

SV-230480r958754_rule

Information stored in one location is vulnerable to accidental or incidental deletion or alteration. Off-loading is a common process in information systems with limited audit storage capacity. RHEL 8 installation media provides "rsyslogd". "rsyslogd" is a system utility providing support for message logging. Support for both internet and UNIX domain sockets enables this utility to support both local and remote logging. Couple this utility with "gnutls" (which is a secure communications library implementing the SSL, TLS and DTLS protocols), and you have a method to securely encrypt and off-load auditing. Satisfies: SRG-OS-000342-GPOS-00133, SRG-OS-000479-GPOS-00224

Checks: C-33149r568186_chk

Verify the audit system is configured to take an appropriate action when the internal event queue is full: $ sudo grep -i overflow_action /etc/audit/auditd.conf overflow_action = syslog If the value of the "overflow_action" option is not set to "syslog", "single", "halt", or the line is commented out, ask the System Administrator to indicate how the audit logs are off-loaded to a different system or media. If there is no evidence that the transfer of the audit logs being off-loaded to another system or media takes appropriate action if the internal event queue becomes full, this is a finding.

Fix: F-33124r568187_fix

Edit the /etc/audit/auditd.conf file and add or update the "overflow_action" option: overflow_action = syslog The audit daemon must be restarted for changes to take effect.

b

RHEL 8 must encrypt the transfer of audit records off-loaded onto a different system or media from the system being audited.

AU-4 - Medium - CCI-001851 - V-230481 - SV-230481r958754_rule

RMF Control

AU-4

Severity

M

CCI

Version

RHEL-08-030710

Vuln IDs

V-230481

Rule IDs

SV-230481r958754_rule

Information stored in one location is vulnerable to accidental or incidental deletion or alteration. Off-loading is a common process in information systems with limited audit storage capacity. RHEL 8 installation media provides "rsyslogd". "rsyslogd" is a system utility providing support for message logging. Support for both internet and UNIX domain sockets enables this utility to support both local and remote logging. Couple this utility with "gnutls" (which is a secure communications library implementing the SSL, TLS and DTLS protocols), and you have a method to securely encrypt and off-load auditing. Satisfies: SRG-OS-000342-GPOS-00133, SRG-OS-000479-GPOS-00224

Checks: C-33150r818839_chk

Verify the operating system encrypts audit records off-loaded onto a different system or media from the system being audited with the following commands: $ sudo grep -i '$DefaultNetstreamDriver' /etc/rsyslog.conf /etc/rsyslog.d/*.conf /etc/rsyslog.conf:$DefaultNetstreamDriver gtls If the value of the "$DefaultNetstreamDriver" option is not set to "gtls" or the line is commented out, this is a finding. $ sudo grep -i '$ActionSendStreamDriverMode' /etc/rsyslog.conf /etc/rsyslog.d/*.conf /etc/rsyslog.conf:$ActionSendStreamDriverMode 1 If the value of the "$ActionSendStreamDriverMode" option is not set to "1" or the line is commented out, this is a finding. If neither of the definitions above are set, ask the System Administrator to indicate how the audit logs are off-loaded to a different system or media. If there is no evidence that the transfer of the audit logs being off-loaded to another system or media is encrypted, this is a finding.

Fix: F-33125r568190_fix

Configure the operating system to encrypt off-loaded audit records by setting the following options in "/etc/rsyslog.conf" or "/etc/rsyslog.d/[customfile].conf": $DefaultNetstreamDriver gtls $ActionSendStreamDriverMode 1

b

RHEL 8 must authenticate the remote logging server for off-loading audit logs.

AU-4 - Medium - CCI-001851 - V-230482 - SV-230482r1069330_rule

RMF Control

AU-4

Severity

M

CCI

Version

RHEL-08-030720

Vuln IDs

V-230482

Rule IDs

SV-230482r1069330_rule

Information stored in one location is vulnerable to accidental or incidental deletion or alteration. Off-loading is a common process in information systems with limited audit storage capacity. RHEL 8 installation media provides "rsyslogd". "rsyslogd" is a system utility providing support for message logging. Support for both internet and UNIX domain sockets enables this utility to support both local and remote logging. Couple this utility with "gnutls" (which is a secure communications library implementing the SSL, TLS and DTLS protocols), and you have a method to securely encrypt and off-load auditing. "Rsyslog" supported authentication modes include: anon - anonymous authentication x509/fingerprint - certificate fingerprint authentication x509/certvalid - certificate validation only x509/name - certificate validation and subject name authentication. Satisfies: SRG-OS-000342-GPOS-00133, SRG-OS-000479-GPOS-00224

Checks: C-33151r1069270_chk

Verify the operating system authenticates the remote logging server for off-loading audit logs with the following command: $ sudo grep -i '$ActionSendStreamDriverAuthMode' /etc/rsyslog.conf /etc/rsyslog.d/*.conf /etc/rsyslog.conf:$ActionSendStreamDriverAuthMode x509/name If the value of the "$ActionSendStreamDriverAuthMode" option is not set to "x509/name" or the line is commented out, ask the System Administrator to indicate how the audit logs are off-loaded to a different system or media. If the variable name "StreamDriverAuthMode" is present in an omfwd statement block, this is not a finding. However, if the "StreamDriverAuthMode" variable is in a module block, this is a finding. If there is no evidence that the transfer of the audit logs being off-loaded to another system or media is encrypted, this is a finding.

Fix: F-33126r568193_fix

Configure the operating system to authenticate the remote logging server for off-loading audit logs by setting the following option in "/etc/rsyslog.conf" or "/etc/rsyslog.d/[customfile].conf": $ActionSendStreamDriverAuthMode x509/name

b

RHEL 8 must take action when allocated audit record storage volume reaches 75 percent of the repository maximum audit record storage capacity.

AU-5 - Medium - CCI-001855 - V-230483 - SV-230483r971542_rule

RMF Control

AU-5

Severity

M

CCI

CCI-001855

Version

RHEL-08-030730

Vuln IDs

V-230483

Rule IDs

SV-230483r971542_rule

If security personnel are not notified immediately when storage volume reaches 75 percent utilization, they are unable to plan for audit record storage capacity expansion.

Checks: C-33152r744012_chk

Verify RHEL 8 takes action when allocated audit record storage volume reaches 75 percent of the repository maximum audit record storage capacity with the following commands: $ sudo grep -w space_left /etc/audit/auditd.conf space_left = 25% If the value of the "space_left" keyword is not set to "25%" or if the line is commented out, ask the System Administrator to indicate how the system is providing real-time alerts to the SA and ISSO. If there is no evidence that real-time alerts are configured on the system, this is a finding.

Fix: F-33127r744013_fix

Configure the operating system to initiate an action to notify the SA and ISSO (at a minimum) when allocated audit record storage volume reaches 75 percent of the repository maximum audit record storage capacity by adding/modifying the following line in the /etc/audit/auditd.conf file. space_left = 25% Note: Option names and values in the auditd.conf file are case insensitive.

b

RHEL 8 must securely compare internal information system clocks at least every 24 hours with a server synchronized to an authoritative time source, such as the United States Naval Observatory (USNO) time servers, or a time server designated for the appropriate DoD network (NIPRNet/SIPRNet), and/or the Global Positioning System (GPS).

AU-8 - Medium - CCI-001891 - V-230484 - SV-230484r1038944_rule

RMF Control

AU-8

Severity

M

CCI

CCI-001891

Version

RHEL-08-030740

Vuln IDs

V-230484

Rule IDs

SV-230484r1038944_rule

Inaccurate time stamps make it more difficult to correlate events and can lead to an inaccurate analysis. Determining the correct time a particular event occurred on a system is critical when conducting forensic analysis and investigating system events. Sources outside the configured acceptable allowance (drift) may be inaccurate. Synchronizing internal information system clocks provides uniformity of time stamps for information systems with multiple system clocks and systems connected over a network. Organizations should consider endpoints that may not have regular access to the authoritative time server (e.g., mobile, teleworking, and tactical endpoints). If time stamps are not consistently applied and there is no common time reference, it is difficult to perform forensic analysis. Time stamps generated by the operating system include date and time. Time is commonly expressed in Coordinated Universal Time (UTC), a modern continuation of Greenwich Mean Time (GMT), or local time with an offset from UTC. RHEL 8 utilizes the "timedatectl" command to view the status of the "systemd-timesyncd.service". The "timedatectl" status will display the local time, UTC, and the offset from UTC. Note that USNO offers authenticated NTP service to DoD and U.S. Government agencies operating on the NIPR and SIPR networks. Visit https://www.usno.navy.mil/USNO/time/ntp/dod-customers for more information. Satisfies: SRG-OS-000355-GPOS-00143, SRG-OS-000356-GPOS-00144, SRG-OS-000359-GPOS-00146

Checks: C-33153r568198_chk

Verify RHEL 8 is securely comparing internal information system clocks at least every 24 hours with an NTP server with the following commands: $ sudo grep maxpoll /etc/chrony.conf server 0.us.pool.ntp.mil iburst maxpoll 16 If the "maxpoll" option is set to a number greater than 16 or the line is commented out, this is a finding. Verify the "chrony.conf" file is configured to an authoritative DoD time source by running the following command: $ sudo grep -i server /etc/chrony.conf server 0.us.pool.ntp.mil If the parameter "server" is not set or is not set to an authoritative DoD time source, this is a finding.

Fix: F-33128r568199_fix

Configure the operating system to securely compare internal information system clocks at least every 24 hours with an NTP server by adding/modifying the following line in the /etc/chrony.conf file. server [ntp.server.name] iburst maxpoll 16

a

RHEL 8 must disable the chrony daemon from acting as a server.

CM-7 - Low - CCI-000381 - V-230485 - SV-230485r1017269_rule

RMF Control

CM-7

Severity

L

CCI

Version

RHEL-08-030741

Vuln IDs

V-230485

Rule IDs

SV-230485r1017269_rule

Inaccurate time stamps make it more difficult to correlate events and can lead to an inaccurate analysis. Determining the correct time a particular event occurred on a system is critical when conducting forensic analysis and investigating system events. Sources outside the configured acceptable allowance (drift) may be inaccurate. Minimizing the exposure of the server functionality of the chrony daemon diminishes the attack surface. RHEL 8 utilizes the "timedatectl" command to view the status of the "systemd-timesyncd.service". The "timedatectl" status will display the local time, UTC, and the offset from UTC. Note that USNO offers authenticated NTP service to DOD and U.S. Government agencies operating on the NIPR and SIPR networks. Visit https://www.usno.navy.mil/USNO/time/ntp/DOD-customers for more information.

Checks: C-33154r1014804_chk

Note: If the system is approved and documented by the information system security officer (ISSO) to function as an NTP time server, this requirement is Not Applicable. Verify RHEL 8 disables the chrony daemon from acting as a server with the following command: $ sudo grep -w 'port' /etc/chrony.conf port 0 If the "port" option is not set to "0", is commented out or missing, this is a finding.

Fix: F-33129r1014805_fix

Configure the operating system to disable the chrony daemon from acting as a server by adding or modifying the following line in the "/etc/chrony.conf" file: port 0

a

RHEL 8 must disable network management of the chrony daemon.

CM-7 - Low - CCI-000381 - V-230486 - SV-230486r1017270_rule

RMF Control

CM-7

Severity

L

CCI

Version

RHEL-08-030742

Vuln IDs

V-230486

Rule IDs

SV-230486r1017270_rule

Inaccurate time stamps make it more difficult to correlate events and can lead to an inaccurate analysis. Determining the correct time a particular event occurred on a system is critical when conducting forensic analysis and investigating system events. Sources outside the configured acceptable allowance (drift) may be inaccurate. Not exposing the management interface of the chrony daemon on the network diminishes the attack space. RHEL 8 utilizes the "timedatectl" command to view the status of the "systemd-timesyncd.service". The "timedatectl" status will display the local time, UTC, and the offset from UTC. Note that USNO offers authenticated NTP service to DOD and U.S. Government agencies operating on the NIPR and SIPR networks. Visit https://www.usno.navy.mil/USNO/time/ntp/DOD-customers for more information.

Checks: C-33155r1014807_chk

Note: If the system is approved and documented by the information system security officer (ISSO) to function as an NTP time server, this requirement is Not Applicable. Verify RHEL 8 disables network management of the chrony daemon with the following command: $ sudo grep -w 'cmdport' /etc/chrony.conf cmdport 0 If the "cmdport" option is not set to "0", is commented out or missing, this is a finding.

Fix: F-33130r1014808_fix

Configure the operating system disable network management of the chrony daemon by adding or modifying the following line in the "/etc/chrony.conf" file. cmdport 0

c

RHEL 8 must not have the telnet-server package installed.

CM-7 - High - CCI-000381 - V-230487 - SV-230487r1017271_rule

RMF Control

CM-7

Severity

H

CCI

Version

RHEL-08-040000

Vuln IDs

V-230487

Rule IDs

SV-230487r1017271_rule

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions, functions). Examples of non-essential capabilities include, but are not limited to, games, software packages, tools, and demonstration software not related to requirements or providing a wide array of functionality not required for every mission, but which cannot be disabled. Verify the operating system is configured to disable non-essential capabilities. The most secure way of ensuring a non-essential capability is disabled is to not have the capability installed. The telnet service provides an unencrypted remote access service that does not provide for the confidentiality and integrity of user passwords or the remote session. If a privileged user were to log on using this service, the privileged user password could be compromised.

Checks: C-33156r568207_chk

Check to see if the telnet-server package is installed with the following command: $ sudo yum list installed telnet-server If the telnet-server package is installed, this is a finding.

Fix: F-33131r568208_fix

Configure the operating system to disable non-essential capabilities by removing the telnet-server package from the system with the following command: $ sudo yum remove telnet-server

b

RHEL 8 must not have any automated bug reporting tools installed.

CM-7 - Medium - CCI-000381 - V-230488 - SV-230488r1017272_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-08-040001

Vuln IDs

V-230488

Rule IDs

SV-230488r1017272_rule

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions, functions). Examples of non-essential capabilities include, but are not limited to, games, software packages, tools, and demonstration software not related to requirements or providing a wide array of functionality not required for every mission, but which cannot be disabled. Verify the operating system is configured to disable non-essential capabilities. The most secure way of ensuring a non-essential capability is disabled is to not have the capability installed.

Checks: C-33157r568210_chk

Check to see if any automated bug reporting packages are installed with the following command: $ sudo yum list installed abrt* If any automated bug reporting package is installed, this is a finding.

Fix: F-33132r568211_fix

Configure the operating system to disable non-essential capabilities by removing automated bug reporting packages from the system with the following command: $ sudo yum remove abrt*

b

RHEL 8 must not have the sendmail package installed.

CM-7 - Medium - CCI-000381 - V-230489 - SV-230489r1017273_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-08-040002

Vuln IDs

V-230489

Rule IDs

SV-230489r1017273_rule

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions, functions). Examples of non-essential capabilities include, but are not limited to, games, software packages, tools, and demonstration software not related to requirements or providing a wide array of functionality not required for every mission, but which cannot be disabled. Verify the operating system is configured to disable non-essential capabilities. The most secure way of ensuring a non-essential capability is disabled is to not have the capability installed.

Checks: C-33158r568213_chk

Check to see if the sendmail package is installed with the following command: $ sudo yum list installed sendmail If the sendmail package is installed, this is a finding.

Fix: F-33133r568214_fix

Configure the operating system to disable non-essential capabilities by removing the sendmail package from the system with the following command: $ sudo yum remove sendmail

a

RHEL 8 must enable mitigations against processor-based vulnerabilities.

CM-7 - Low - CCI-000381 - V-230491 - SV-230491r1017274_rule

RMF Control

CM-7

Severity

L

CCI

Version

RHEL-08-040004

Vuln IDs

V-230491

Rule IDs

SV-230491r1017274_rule

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions, functions). Examples of non-essential capabilities include, but are not limited to, games, software packages, tools, and demonstration software not related to requirements or providing a wide array of functionality not required for every mission, but which cannot be disabled. Verify the operating system is configured to disable non-essential capabilities. The most secure way of ensuring a non-essential capability is disabled is to not have the capability installed. Kernel page-table isolation is a kernel feature that mitigates the Meltdown security vulnerability and hardens the kernel against attempts to bypass kernel address space layout randomization (KASLR).

Checks: C-33160r818841_chk

Verify RHEL 8 enables kernel page-table isolation with the following commands: $ sudo grub2-editenv list | grep pti kernelopts=root=/dev/mapper/rhel-root ro crashkernel=auto resume=/dev/mapper/rhel-swap rd.lvm.lv=rhel/root rd.lvm.lv=rhel/swap rhgb quiet fips=1 audit=1 audit_backlog_limit=8192 pti=on boot=UUID=8d171156-cd61-421c-ba41-1c021ac29e82 If the "pti" entry does not equal "on", is missing, or the line is commented out, this is a finding. Check that kernel page-table isolation is enabled by default to persist in kernel updates: $ sudo grep pti /etc/default/grub GRUB_CMDLINE_LINUX="pti=on" If "pti" is not set to "on", is missing or commented out, this is a finding.

Fix: F-33135r568220_fix

Configure RHEL 8 to enable kernel page-table isolation with the following command: $ sudo grubby --update-kernel=ALL --args="pti=on" Add or modify the following line in "/etc/default/grub" to ensure the configuration survives kernel updates: GRUB_CMDLINE_LINUX="pti=on"

c

RHEL 8 must not have the rsh-server package installed.

CM-7 - High - CCI-000381 - V-230492 - SV-230492r1017275_rule

RMF Control

CM-7

Severity

H

CCI

Version

RHEL-08-040010

Vuln IDs

V-230492

Rule IDs

SV-230492r1017275_rule

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions, functions). The rsh-server service provides an unencrypted remote access service that does not provide for the confidentiality and integrity of user passwords or the remote session and has very weak authentication. If a privileged user were to log on using this service, the privileged user password could be compromised. Satisfies: SRG-OS-000095-GPOS-00049, SRG-OS-000074-GPOS-00042

Checks: C-33161r568222_chk

Check to see if the rsh-server package is installed with the following command: $ sudo yum list installed rsh-server If the rsh-server package is installed, this is a finding.

Fix: F-33136r568223_fix

Configure the operating system to disable non-essential capabilities by removing the rsh-server package from the system with the following command: $ sudo yum remove rsh-server

b

RHEL 8 must cover or disable the built-in or attached camera when not in use.

CM-7 - Medium - CCI-000381 - V-230493 - SV-230493r1017276_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-08-040020

Vuln IDs

V-230493

Rule IDs

SV-230493r1017276_rule

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Failing to disconnect from collaborative computing devices (i.e., cameras) can result in subsequent compromises of organizational information. Providing easy methods to physically disconnect from such devices after a collaborative computing session helps to ensure participants actually carry out the disconnect activity without having to go through complex and tedious procedures. Satisfies: SRG-OS-000095-GPOS-00049, SRG-OS-000370-GPOS-00155

Checks: C-33162r942913_chk

If the device or operating system does not have a camera installed, this requirement is not applicable. This requirement is not applicable to mobile devices (smartphones and tablets), where the use of the camera is a local AO decision. This requirement is not applicable to dedicated VTC suites located in approved VTC locations that are centrally managed. For an external camera, if there is not a method for the operator to manually disconnect the camera at the end of collaborative computing sessions, this is a finding. For a built-in camera, the camera must be protected by a camera cover (e.g., laptop camera cover slide) when not in use. If the built-in camera is not protected with a camera cover, or is not physically disabled, this is a finding. If the camera is not disconnected, covered, or physically disabled, determine if it is being disabled via software with the following commands: Verify the operating system disables the ability to load the uvcvideo kernel module. $ sudo grep -r uvcvideo /etc/modprobe.d/* | grep "/bin/false" install uvcvideo /bin/false If the command does not return any output, or the line is commented out, and the collaborative computing device has not been authorized for use, this is a finding. Verify the camera is disabled via blacklist with the following command: $ sudo grep -r uvcvideo /etc/modprobe.d/* | grep "blacklist" blacklist uvcvideo If the command does not return any output or the output is not "blacklist uvcvideo", and the collaborative computing device has not been authorized for use, this is a finding.

Fix: F-33137r942914_fix

Configure the operating system to disable the built-in or attached camera when not in use. Build or modify the "/etc/modprobe.d/blacklist.conf" file by using the following example: install uvcvideo /bin/false blacklist uvcvideo Reboot the system for the settings to take effect.

a

RHEL 8 must disable the asynchronous transfer mode (ATM) protocol.

CM-7 - Low - CCI-000381 - V-230494 - SV-230494r1069310_rule

RMF Control

CM-7

Severity

L

CCI

Version

RHEL-08-040021

Vuln IDs

V-230494

Rule IDs

SV-230494r1069310_rule

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Failing to disconnect unused protocols can result in a system compromise. The Asynchronous Transfer Mode (ATM) is a protocol operating on network, data link, and physical layers, based on virtual circuits and virtual paths. Disabling ATM protects the system against exploitation of any laws in its implementation.

Checks: C-33163r1069229_chk

Verify the operating system disables the ability to load the ATM protocol kernel module and ensure that the ATM protocol kernel module is disabled with the following command: $ sudo grep -r atm /etc/modprobe.d/* | grep "blacklist" /etc/modprobe.d/blacklist.conf:install atm /bin/false /etc/modprobe.d/blacklist.conf:blacklist atm If the command does not return any output, or the line is commented out, and use of the ATM protocol is not documented with the Information System Security Officer (ISSO) as an operational requirement, this is a finding.

Fix: F-33138r942917_fix

Configure the operating system to disable the ability to use the ATM protocol kernel module. Add or update the following lines in the file "/etc/modprobe.d/blacklist.conf": install atm /bin/false blacklist atm Reboot the system for the settings to take effect.

a

RHEL 8 must disable the controller area network (CAN) protocol.

CM-7 - Low - CCI-000381 - V-230495 - SV-230495r1069311_rule

RMF Control

CM-7

Severity

L

CCI

Version

RHEL-08-040022

Vuln IDs

V-230495

Rule IDs

SV-230495r1069311_rule

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Failing to disconnect unused protocols can result in a system compromise. The Controller Area Network (CAN) is a serial communications protocol, which was initially developed for automotive and is now also used in marine, industrial, and medical applications. Disabling CAN protects the system against exploitation of any flaws in its implementation.

Checks: C-33164r1069231_chk

Verify the operating system disables the ability to load the CAN protocol kernel module and ensure that the CAN protocol kernel module is disabled with the following command: $ sudo grep -r can /etc/modprobe.d/* | grep "blacklist" /etc/modprobe.d/blacklist.conf:install can /bin/false /etc/modprobe.d/blacklist.conf:blacklist can If the command does not return any output, or the line is commented out, and use of the CAN protocol is not documented with the Information System Security Officer (ISSO) as an operational requirement, this is a finding.

Fix: F-33139r942920_fix

Configure the operating system to disable the ability to use the CAN protocol kernel module. Add or update the following lines in the file "/etc/modprobe.d/blacklist.conf": install can /bin/false blacklist can Reboot the system for the settings to take effect.

a

RHEL 8 must disable the stream control transmission protocol (SCTP).

CM-7 - Low - CCI-000381 - V-230496 - SV-230496r1069312_rule

RMF Control

CM-7

Severity

L

CCI

Version

RHEL-08-040023

Vuln IDs

V-230496

Rule IDs

SV-230496r1069312_rule

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Failing to disconnect unused protocols can result in a system compromise. The Stream Control Transmission Protocol (SCTP) is a transport layer protocol, designed to support the idea of message-oriented communication, with several streams of messages within one connection. Disabling SCTP protects the system against exploitation of any flaws in its implementation.

Checks: C-33165r1069233_chk

Verify the operating system disables the ability to load the SCTP kernel module and ensure that SCTP is disabled with the following command: $ sudo grep -r sctp /etc/modprobe.d/* | grep "blacklist" /etc/modprobe.d/blacklist.conf:install sctp /bin/false /etc/modprobe.d/blacklist.conf:blacklist sctp If the command does not return any output, or the line is commented out, and use of the SCTP is not documented with the Information System Security Officer (ISSO) as an operational requirement, this is a finding.

Fix: F-33140r942923_fix

Configure the operating system to disable the ability to use the SCTP kernel module. Add or update the following lines in the file "/etc/modprobe.d/blacklist.conf": install sctp /bin/false blacklist sctp Reboot the system for the settings to take effect.

a

RHEL 8 must disable the transparent inter-process communication (TIPC) protocol.

CM-7 - Low - CCI-000381 - V-230497 - SV-230497r1069313_rule

RMF Control

CM-7

Severity

L

CCI

Version

RHEL-08-040024

Vuln IDs

V-230497

Rule IDs

SV-230497r1069313_rule

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Failing to disconnect unused protocols can result in a system compromise. The Transparent Inter-Process Communication (TIPC) protocol is designed to provide communications between nodes in a cluster. Disabling TIPC protects the system against exploitation of any flaws in its implementation.

Checks: C-33166r1069235_chk

Verify the operating system disables the ability to load the TIPC protocol kernel module and ensure that TIPC is disabled with the following command: $ sudo grep -r tipc /etc/modprobe.d/* | grep "blacklist" /etc/modprobe.d/blacklist.conf:install tipc /bin/false /etc/modprobe.d/blacklist.conf:blacklist tipc If the command does not return any output, or the line is commented out, and use of the TIPC protocol is not documented with the Information System Security Officer (ISSO) as an operational requirement, this is a finding.

Fix: F-33141r942926_fix

Configure the operating system to disable the ability to use the TIPC protocol kernel module. Add or update the following lines in the file "/etc/modprobe.d/blacklist.conf": install tipc /bin/false blacklist tipc Reboot the system for the settings to take effect.

a

RHEL 8 must disable mounting of cramfs.

CM-7 - Low - CCI-000381 - V-230498 - SV-230498r1069314_rule

RMF Control

CM-7

Severity

L

CCI

Version

RHEL-08-040025

Vuln IDs

V-230498

Rule IDs

SV-230498r1069314_rule

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Removing support for unneeded filesystem types reduces the local attack surface of the server. Compressed ROM/RAM file system (or cramfs) is a read-only file system designed for simplicity and space-efficiency. It is mainly used in embedded and small-footprint systems.

Checks: C-33167r1069237_chk

Verify the operating system disables the ability to load the cramfs kernel module and ensure that the cramfs kernel module is disabled with the following command: $ sudo grep -r cramfs /etc/modprobe.d/* | grep "blacklist" /etc/modprobe.d/blacklist.conf:install cramfs /bin/false /etc/modprobe.d/blacklist.conf:blacklist cramfs If the command does not return any output, or the line is commented out, and use of the cramfs protocol is not documented with the Information System Security Officer (ISSO) as an operational requirement, this is a finding.

Fix: F-33142r942929_fix

Configure the operating system to disable the ability to use the cramfs kernel module. Add or update the following lines in the file "/etc/modprobe.d/blacklist.conf": install cramfs /bin/false blacklist cramfs Reboot the system for the settings to take effect.

a

RHEL 8 must disable IEEE 1394 (FireWire) Support.

CM-7 - Low - CCI-000381 - V-230499 - SV-230499r1069315_rule

RMF Control

CM-7

Severity

L

CCI

Version

RHEL-08-040026

Vuln IDs

V-230499

Rule IDs

SV-230499r1069315_rule

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. The IEEE 1394 (FireWire) is a serial bus standard for high-speed real-time communication. Disabling FireWire protects the system against exploitation of any flaws in its implementation.

Checks: C-33168r1069239_chk

Verify the operating system disables the ability to load the firewire-core kernel module and ensure that the firewire-core kernel module is disabled with the following command: $ sudo grep -r firewire-core /etc/modprobe.d/* | grep "blacklist" /etc/modprobe.d/blacklist.conf:install firewire-core /bin/false /etc/modprobe.d/blacklist.conf:blacklist firewire-core If the command does not return any output, or the line is commented out, and use of the firewire-core protocol is not documented with the Information System Security Officer (ISSO) as an operational requirement, this is a finding.

Fix: F-33143r942932_fix

Configure the operating system to disable the ability to use the firewire-core kernel module. Add or update the following lines in the file "/etc/modprobe.d/blacklist.conf": install firewire-core /bin/false blacklist firewire-core Reboot the system for the settings to take effect.

b

RHEL 8 must be configured to prohibit or restrict the use of functions, ports, protocols, and/or services, as defined in the Ports, Protocols, and Services Management (PPSM) Category Assignments List (CAL) and vulnerability assessments.

CM-7 - Medium - CCI-000382 - V-230500 - SV-230500r1101900_rule

RMF Control

CM-7

Severity

M

CCI

CCI-000382

Version

RHEL-08-040030

Vuln IDs

V-230500

Rule IDs

SV-230500r1101900_rule

To prevent unauthorized connection of devices, unauthorized transfer of information, or unauthorized tunneling (i.e., embedding of data types within data types), organizations must disable or restrict unused or unnecessary physical and logical ports/protocols on information systems. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services provided by default may not be necessary to support essential organizational operations. Additionally, it is sometimes convenient to provide multiple services from a single component (e.g., VPN and IPS); however, doing so increases risk over limiting the services provided by any one component. To support the requirements and principles of least functionality, the operating system must support the organizational requirements, providing only essential capabilities and limiting the use of ports, protocols, and/or services to only those required, authorized, and approved to conduct official business or to address authorized quality-of-life issues.

Checks: C-33169r1101899_chk

Inspect the firewall configuration and running services to verify it is configured to prohibit or restrict the use of functions, ports, protocols, and/or services that are unnecessary or prohibited. Check which services are currently active with the following command: $ firewall-cmd --list-all-zones | grep -e "active" -e "services" custom (active) target: DROP icmp-block-inversion: no interfaces: ens33 sources: services: dhcpv6-client dns http https ldaps rpc-bind ssh ports: masquerade: no forward-ports: icmp-blocks: rich rules: Ask the system administrator (SA) for the site or program Ports, Protocols, and Services Management Component Local Service Assessment (PPSM CLSA). Verify the services allowed by the firewall match the PPSM CLSA. If there are additional ports, protocols, or services that are not in the PPSM CLSA, or there are ports, protocols, or services that are prohibited by the PPSM Category Assurance List (CAL), this is a finding.

Fix: F-33144r568247_fix

Update the host's firewall settings and/or running services to comply with the PPSM Component Local Service Assessment (CLSA) for the site or program and the PPSM CAL.

b

The RHEL 8 file system automounter must be disabled unless required.

IA-3 - Medium - CCI-000778 - V-230502 - SV-230502r1017284_rule

RMF Control

IA-3

Severity

M

CCI

CCI-000778

Version

RHEL-08-040070

Vuln IDs

V-230502

Rule IDs

SV-230502r1017284_rule

Automatically mounting file systems permits easy introduction of unknown devices, thereby facilitating malicious activity.

Checks: C-33171r568252_chk

Verify the operating system disables the ability to automount devices. Check to see if automounter service is active with the following command: Note: If the autofs service is not installed, this requirement is not applicable. $ sudo systemctl status autofs autofs.service - Automounts filesystems on demand Loaded: loaded (/usr/lib/systemd/system/autofs.service; disabled) Active: inactive (dead) If the "autofs" status is set to "active" and is not documented with the Information System Security Officer (ISSO) as an operational requirement, this is a finding.

Fix: F-33146r568253_fix

Configure the operating system to disable the ability to automount devices. Turn off the automount service with the following commands: $ sudo systemctl stop autofs $ sudo systemctl disable autofs If "autofs" is required for Network File System (NFS), it must be documented with the ISSO.

b

RHEL 8 must be configured to disable USB mass storage.

IA-3 - Medium - CCI-000778 - V-230503 - SV-230503r1069316_rule

RMF Control

IA-3

Severity

M

CCI

CCI-000778

Version

RHEL-08-040080

Vuln IDs

V-230503

Rule IDs

SV-230503r1069316_rule

USB mass storage permits easy introduction of unknown devices, thereby facilitating malicious activity. Satisfies: SRG-OS-000114-GPOS-00059, SRG-OS-000378-GPOS-00163

Checks: C-33172r1069241_chk

Verify the operating system disables the ability to load the USB Storage kernel module and ensure that the USB Storage kernel module is disabled with the following command: $ sudo grep usb-storage /etc/modprobe.d/* | grep -i "blacklist" /etc/modprobe.d/blacklist.conf:install usb-storage /bin/false /etc/modprobe.d/blacklist.conf:blacklist usb-storage If the command does not return any output, or the line is commented out, and use of USB Storage is not documented with the Information System Security Officer (ISSO) as an operational requirement, this is a finding.

Fix: F-33147r942935_fix

Configure the operating system to disable the ability to use the USB Storage kernel module and the ability to use USB mass storage devices. Add or update the following lines in the file "/etc/modprobe.d/blacklist.conf": install usb-storage /bin/false blacklist usb-storage Reboot the system for the settings to take effect.

b

A RHEL 8 firewall must employ a deny-all, allow-by-exception policy for allowing connections to other systems.

AC-17 - Medium - CCI-002314 - V-230504 - SV-230504r958672_rule

RMF Control

AC-17

Severity

M

CCI

CCI-002314

Version

RHEL-08-040090

Vuln IDs

V-230504

Rule IDs

SV-230504r958672_rule

Failure to restrict network connectivity only to authorized systems permits inbound connections from malicious systems. It also permits outbound connections that may facilitate exfiltration of DoD data. RHEL 8 incorporates the "firewalld" daemon, which allows for many different configurations. One of these configurations is zones. Zones can be utilized to a deny-all, allow-by-exception approach. The default "drop" zone will drop all incoming network packets unless it is explicitly allowed by the configuration file or is related to an outgoing network connection.

Checks: C-33173r942940_chk

Verify "firewalld" is configured to employ a deny-all, allow-by-exception policy for allowing connections to other systems with the following commands: $ sudo firewall-cmd --state running $ sudo firewall-cmd --get-active-zones [custom] interfaces: ens33 $ sudo firewall-cmd --info-zone=[custom] | grep target target: DROP If no zones are active on the RHEL 8 interfaces or if the target is set to a different option other than "DROP", this is a finding. If the "firewalld" package is not installed, ask the System Administrator if an alternate firewall (such as iptables) is installed and in use, and how is it configured to employ a deny-all, allow-by-exception policy. If the alternate firewall is not configured to employ a deny-all, allow-by-exception policy, this is a finding. If no firewall is installed, this is a finding.

Fix: F-33148r942941_fix

Configure the "firewalld" daemon to employ a deny-all, allow-by-exception with the following commands: $ sudo firewall-cmd --permanent --new-zone=[custom] $ sudo cp /usr/lib/firewalld/zones/drop.xml /etc/firewalld/zones/[custom].xml This will provide a clean configuration file to work with that employs a deny-all approach. Note: Add the exceptions that are required for mission functionality and update the short title in the xml file to match the [custom] zone name. Reload the firewall rules to make the new [custom] zone available to load: $ sudo firewall-cmd --reload Set the default zone to the new [custom] zone: $ sudo firewall-cmd --set-default-zone=[custom] Note: This is a runtime and permanent change. Add any interfaces to the new [custom] zone: $ sudo firewall-cmd --permanent --zone=[custom] --change-interface=ens33 Reload the firewall rules for changes to take effect: $ sudo firewall-cmd --reload

b

A firewall must be installed on RHEL 8.

AC-17 - Medium - CCI-002314 - V-230505 - SV-230505r958672_rule

RMF Control

AC-17

Severity

M

CCI

CCI-002314

Version

RHEL-08-040100

Vuln IDs

V-230505

Rule IDs

SV-230505r958672_rule

"Firewalld" provides an easy and effective way to block/limit remote access to the system via ports, services, and protocols. Remote access services, such as those providing remote access to network devices and information systems, which lack automated control capabilities, increase risk and make remote user access management difficult at best. Remote access is access to DoD nonpublic information systems by an authorized user (or an information system) communicating through an external, non-organization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless. RHEL 8 functionality (e.g., RDP) must be capable of taking enforcement action if the audit reveals unauthorized activity. Automated control of remote access sessions allows organizations to ensure ongoing compliance with remote access policies by enforcing connection rules of remote access applications on a variety of information system components (e.g., servers, workstations, notebook computers, smartphones, and tablets).

Checks: C-33174r744018_chk

Verify that "firewalld" is installed with the following commands: $ sudo yum list installed firewalld firewalld.noarch 0.7.0-5.el8 If the "firewalld" package is not installed, ask the System Administrator if another firewall is installed. If no firewall is installed this is a finding.

Fix: F-33149r744019_fix

Install "firewalld" with the following command: $ sudo yum install firewalld.noarch

b

RHEL 8 wireless network adapters must be disabled.

AC-18 - Medium - CCI-001444 - V-230506 - SV-230506r1017286_rule

RMF Control

AC-18

Severity

M

CCI

CCI-001444

Version

RHEL-08-040110

Vuln IDs

V-230506

Rule IDs

SV-230506r1017286_rule

Without protection of communications with wireless peripherals, confidentiality and integrity may be compromised because unprotected communications can be intercepted and either read, altered, or used to compromise the RHEL 8 operating system. This requirement applies to wireless peripheral technologies (e.g., wireless mice, keyboards, displays, etc.) used with RHEL 8 systems. Wireless peripherals (e.g., Wi-Fi/Bluetooth/IR Keyboards, Mice, and Pointing Devices and Near Field Communications [NFC]) present a unique challenge by creating an open, unsecured port on a computer. Wireless peripherals must meet DoD requirements for wireless data transmission and be approved for use by the Authorizing Official (AO). Even though some wireless peripherals, such as mice and pointing devices, do not ordinarily carry information that need to be protected, modification of communications with these wireless peripherals may be used to compromise the RHEL 8 operating system. Communication paths outside the physical protection of a controlled boundary are exposed to the possibility of interception and modification. Protecting the confidentiality and integrity of communications with wireless peripherals can be accomplished by physical means (e.g., employing physical barriers to wireless radio frequencies) or by logical means (e.g., employing cryptographic techniques). If physical means of protection are employed, then logical means (cryptography) do not have to be employed, and vice versa. If the wireless peripheral is only passing telemetry data, encryption of the data may not be required. Satisfies: SRG-OS-000299-GPOS-00117, SRG-OS-000300-GPOS-00118, SRG-OS-000481-GPOS-000481

Checks: C-33175r568264_chk

Verify there are no wireless interfaces configured on the system with the following command: Note: This requirement is Not Applicable for systems that do not have physical wireless network radios. $ sudo nmcli device status DEVICE TYPE STATE CONNECTION virbr0 bridge connected virbr0 wlp7s0 wifi connected wifiSSID enp6s0 ethernet disconnected -- p2p-dev-wlp7s0 wifi-p2p disconnected -- lo loopback unmanaged -- virbr0-nic tun unmanaged -- If a wireless interface is configured and has not been documented and approved by the Information System Security Officer (ISSO), this is a finding.

Fix: F-33150r568265_fix

Configure the system to disable all wireless network interfaces with the following command: $ sudo nmcli radio all off

b

RHEL 8 Bluetooth must be disabled.

AC-18 - Medium - CCI-001443 - V-230507 - SV-230507r1017287_rule

RMF Control

AC-18

Severity

M

CCI

CCI-001443

Version

RHEL-08-040111

Vuln IDs

V-230507

Rule IDs

SV-230507r1017287_rule

Without protection of communications with wireless peripherals, confidentiality and integrity may be compromised because unprotected communications can be intercepted and either read, altered, or used to compromise the RHEL 8 operating system. This requirement applies to wireless peripheral technologies (e.g., wireless mice, keyboards, displays, etc.) used with RHEL 8 systems. Wireless peripherals (e.g., Wi-Fi/Bluetooth/IR Keyboards, Mice, and Pointing Devices and Near Field Communications [NFC]) present a unique challenge by creating an open, unsecured port on a computer. Wireless peripherals must meet DoD requirements for wireless data transmission and be approved for use by the Authorizing Official (AO). Even though some wireless peripherals, such as mice and pointing devices, do not ordinarily carry information that need to be protected, modification of communications with these wireless peripherals may be used to compromise the RHEL 8 operating system. Communication paths outside the physical protection of a controlled boundary are exposed to the possibility of interception and modification. Protecting the confidentiality and integrity of communications with wireless peripherals can be accomplished by physical means (e.g., employing physical barriers to wireless radio frequencies) or by logical means (e.g., employing cryptographic techniques). If physical means of protection are employed, then logical means (cryptography) do not have to be employed, and vice versa. If the wireless peripheral is only passing telemetry data, encryption of the data may not be required.

Checks: C-33176r942937_chk

If the device or operating system does not have a Bluetooth adapter installed, this requirement is not applicable. This requirement is not applicable to mobile devices (smartphones and tablets), where the use of Bluetooth is a local AO decision. Determine if Bluetooth is disabled with the following command: $ sudo grep bluetooth /etc/modprobe.d/* /etc/modprobe.d/bluetooth.conf:install bluetooth /bin/false If the Bluetooth driver blacklist entry is missing, a Bluetooth driver is determined to be in use, and the collaborative computing device has not been authorized for use, this is a finding. Verify the operating system disables the ability to use Bluetooth with the following command: $ sudo grep -r bluetooth /etc/modprobe.d | grep -i "blacklist" | grep -v "^#" blacklist bluetooth If the command does not return any output or the output is not "blacklist bluetooth", and use of Bluetooth is not documented with the ISSO as an operational requirement, this is a finding.

Fix: F-33151r942938_fix

Configure the operating system to disable the Bluetooth adapter when not in use. Build or modify the "/etc/modprobe.d/bluetooth.conf" file with the following line: install bluetooth /bin/false Disable the ability to use the Bluetooth kernel module. $ sudo vi /etc/modprobe.d/blacklist.conf Add or update the line: blacklist bluetooth Reboot the system for the settings to take effect.

b

RHEL 8 must mount /dev/shm with the nodev option.

CM-7 - Medium - CCI-001764 - V-230508 - SV-230508r958804_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-08-040120

Vuln IDs

V-230508

Rule IDs

SV-230508r958804_rule

The organization must identify authorized software programs and permit execution of authorized software. The process used to identify software programs that are authorized to execute on organizational information systems is commonly referred to as whitelisting. The "noexec" mount option causes the system to not execute binary files. This option must be used for mounting any file system not containing approved binary files, as they may be incompatible. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access. The "nodev" mount option causes the system to not interpret character or block special devices. Executing character or block special devices from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access. The "nosuid" mount option causes the system to not execute "setuid" and "setgid" files with owner privileges. This option must be used for mounting any file system not containing approved "setuid" and "setguid" files. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access.

Checks: C-33177r568270_chk

Verify "/dev/shm" is mounted with the "nodev" option: $ sudo mount | grep /dev/shm tmpfs on /dev/shm type tmpfs (rw,nodev,nosuid,noexec,seclabel) Verify that the "nodev"option is configured for /dev/shm: $ sudo cat /etc/fstab | grep /dev/shm tmpfs /dev/shm tmpfs defaults,nodev,nosuid,noexec 0 0 If results are returned and the "nodev" option is missing, or if /dev/shm is mounted without the "nodev" option, this is a finding.

Fix: F-33152r568271_fix

Configure the system so that /dev/shm is mounted with the "nodev" option by adding /modifying the /etc/fstab with the following line: tmpfs /dev/shm tmpfs defaults,nodev,nosuid,noexec 0 0

b

RHEL 8 must mount /dev/shm with the nosuid option.

CM-7 - Medium - CCI-001764 - V-230509 - SV-230509r958804_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-08-040121

Vuln IDs

V-230509

Rule IDs

SV-230509r958804_rule

The organization must identify authorized software programs and permit execution of authorized software. The process used to identify software programs that are authorized to execute on organizational information systems is commonly referred to as whitelisting. The "noexec" mount option causes the system to not execute binary files. This option must be used for mounting any file system not containing approved binary files, as they may be incompatible. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access. The "nodev" mount option causes the system to not interpret character or block special devices. Executing character or block special devices from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access. The "nosuid" mount option causes the system to not execute "setuid" and "setgid" files with owner privileges. This option must be used for mounting any file system not containing approved "setuid" and "setguid" files. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access.

Checks: C-33178r568273_chk

Verify "/dev/shm" is mounted with the "nosuid" option: $ sudo mount | grep /dev/shm tmpfs on /dev/shm type tmpfs (rw,nodev,nosuid,noexec,seclabel) Verify that the "nosuid" option is configured for /dev/shm: $ sudo cat /etc/fstab | grep /dev/shm tmpfs /dev/shm tmpfs defaults,nodev,nosuid,noexec 0 0 If results are returned and the "nosuid" option is missing, or if /dev/shm is mounted without the "nosuid" option, this is a finding.

Fix: F-33153r568274_fix

Configure the system so that /dev/shm is mounted with the "nosuid" option by adding /modifying the /etc/fstab with the following line: tmpfs /dev/shm tmpfs defaults,nodev,nosuid,noexec 0 0

b

RHEL 8 must mount /dev/shm with the noexec option.

CM-7 - Medium - CCI-001764 - V-230510 - SV-230510r958804_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-08-040122

Vuln IDs

V-230510

Rule IDs

SV-230510r958804_rule

The organization must identify authorized software programs and permit execution of authorized software. The process used to identify software programs that are authorized to execute on organizational information systems is commonly referred to as whitelisting. The "noexec" mount option causes the system to not execute binary files. This option must be used for mounting any file system not containing approved binary files, as they may be incompatible. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access. The "nodev" mount option causes the system to not interpret character or block special devices. Executing character or block special devices from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access. The "nosuid" mount option causes the system to not execute "setuid" and "setgid" files with owner privileges. This option must be used for mounting any file system not containing approved "setuid" and "setguid" files. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access.

Checks: C-33179r568276_chk

Verify "/dev/shm" is mounted with the "noexec" option: $ sudo mount | grep /dev/shm tmpfs on /dev/shm type tmpfs (rw,nodev,nosuid,noexec,seclabel) Verify that the "noexec" options is configured for /dev/shm: $ sudo cat /etc/fstab | grep /dev/shm tmpfs /dev/shm tmpfs defaults,nodev,nosuid,noexec 0 0 If results are returned and the "noexec" option is missing, or if /dev/shm is mounted without the "noexec" option, this is a finding.

Fix: F-33154r568277_fix

Configure the system so that /dev/shm is mounted with the "noexec" option by adding /modifying the /etc/fstab with the following line: tmpfs /dev/shm tmpfs defaults,nodev,nosuid,noexec 0 0

b

RHEL 8 must mount /tmp with the nodev option.

CM-7 - Medium - CCI-001764 - V-230511 - SV-230511r958804_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-08-040123

Vuln IDs

V-230511

Rule IDs

SV-230511r958804_rule

The organization must identify authorized software programs and permit execution of authorized software. The process used to identify software programs that are authorized to execute on organizational information systems is commonly referred to as whitelisting. The "noexec" mount option causes the system to not execute binary files. This option must be used for mounting any file system not containing approved binary files, as they may be incompatible. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access. The "nodev" mount option causes the system to not interpret character or block special devices. Executing character or block special devices from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access. The "nosuid" mount option causes the system to not execute "setuid" and "setgid" files with owner privileges. This option must be used for mounting any file system not containing approved "setuid" and "setguid" files. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access.

Checks: C-33180r568279_chk

Verify "/tmp" is mounted with the "nodev" option: $ sudo mount | grep /tmp /dev/mapper/rhel-tmp on /tmp type xfs (rw,nodev,nosuid,noexec,seclabel) Verify that the "nodev" option is configured for /tmp: $ sudo cat /etc/fstab | grep /tmp /dev/mapper/rhel-tmp /tmp xfs defaults,nodev,nosuid,noexec 0 0 If results are returned and the "nodev" option is missing, or if /tmp is mounted without the "nodev" option, this is a finding.

Fix: F-33155r568280_fix

Configure the system so that /tmp is mounted with the "nodev" option by adding /modifying the /etc/fstab with the following line: /dev/mapper/rhel-tmp /tmp xfs defaults,nodev,nosuid,noexec 0 0

b

RHEL 8 must mount /tmp with the nosuid option.

CM-7 - Medium - CCI-001764 - V-230512 - SV-230512r958804_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-08-040124

Vuln IDs

V-230512

Rule IDs

SV-230512r958804_rule

The organization must identify authorized software programs and permit execution of authorized software. The process used to identify software programs that are authorized to execute on organizational information systems is commonly referred to as whitelisting. The "noexec" mount option causes the system to not execute binary files. This option must be used for mounting any file system not containing approved binary files, as they may be incompatible. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access. The "nodev" mount option causes the system to not interpret character or block special devices. Executing character or block special devices from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access. The "nosuid" mount option causes the system to not execute "setuid" and "setgid" files with owner privileges. This option must be used for mounting any file system not containing approved "setuid" and "setguid" files. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access.

Checks: C-33181r568282_chk

Verify "/tmp" is mounted with the "nosuid" option: $ sudo mount | grep /tmp /dev/mapper/rhel-tmp on /tmp type xfs (rw,nodev,nosuid,noexec,seclabel) Verify that the "nosuid" option is configured for /tmp: $ sudo cat /etc/fstab | grep /tmp /dev/mapper/rhel-tmp /tmp xfs defaults,nodev,nosuid,noexec 0 0 If results are returned and the "nosuid" option is missing, or if /tmp is mounted without the "nosuid" option, this is a finding.

Fix: F-33156r568283_fix

Configure the system so that /tmp is mounted with the "nosuid" option by adding /modifying the /etc/fstab with the following line: /dev/mapper/rhel-tmp /tmp xfs defaults,nodev,nosuid,noexec 0 0

b

RHEL 8 must mount /tmp with the noexec option.

CM-7 - Medium - CCI-001764 - V-230513 - SV-230513r958804_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-08-040125

Vuln IDs

V-230513

Rule IDs

SV-230513r958804_rule

The organization must identify authorized software programs and permit execution of authorized software. The process used to identify software programs that are authorized to execute on organizational information systems is commonly referred to as whitelisting. The "noexec" mount option causes the system to not execute binary files. This option must be used for mounting any file system not containing approved binary files, as they may be incompatible. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access. The "nodev" mount option causes the system to not interpret character or block special devices. Executing character or block special devices from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access. The "nosuid" mount option causes the system to not execute "setuid" and "setgid" files with owner privileges. This option must be used for mounting any file system not containing approved "setuid" and "setguid" files. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access.

Checks: C-33182r568285_chk

Verify "/tmp" is mounted with the "noexec" option: $ sudo mount | grep /tmp /dev/mapper/rhel-tmp on /tmp type xfs (rw,nodev,nosuid,noexec,seclabel) Verify that the "noexec" option is configured for /tmp: $ sudo cat /etc/fstab | grep /tmp /dev/mapper/rhel-tmp /tmp xfs defaults,nodev,nosuid,noexec 0 0 If results are returned and the "noexec" option is missing, or if /tmp is mounted without the "noexec" option, this is a finding.

Fix: F-33157r568286_fix

Configure the system so that /tmp is mounted with the "noexec" option by adding /modifying the /etc/fstab with the following line: /dev/mapper/rhel-tmp /tmp xfs defaults,nodev,nosuid,noexec 0 0

b

RHEL 8 must mount /var/log with the nodev option.

CM-7 - Medium - CCI-001764 - V-230514 - SV-230514r958804_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-08-040126

Vuln IDs

V-230514

Rule IDs

SV-230514r958804_rule

The organization must identify authorized software programs and permit execution of authorized software. The process used to identify software programs that are authorized to execute on organizational information systems is commonly referred to as whitelisting. The "noexec" mount option causes the system to not execute binary files. This option must be used for mounting any file system not containing approved binary files, as they may be incompatible. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access. The "nodev" mount option causes the system to not interpret character or block special devices. Executing character or block special devices from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access. The "nosuid" mount option causes the system to not execute "setuid" and "setgid" files with owner privileges. This option must be used for mounting any file system not containing approved "setuid" and "setguid" files. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access.

Checks: C-33183r568288_chk

Verify "/var/log" is mounted with the "nodev" option: $ sudo mount | grep /var/log /dev/mapper/rhel-var-log on /var/log type xfs (rw,nodev,nosuid,noexec,seclabel) Verify that the "nodev" option is configured for /var/log: $ sudo cat /etc/fstab | grep /var/log /dev/mapper/rhel-var-log /var/log xfs defaults,nodev,nosuid,noexec 0 0 If results are returned and the "nodev" option is missing, or if /var/log is mounted without the "nodev" option, this is a finding.

Fix: F-33158r568289_fix

Configure the system so that /var/log is mounted with the "nodev" option by adding /modifying the /etc/fstab with the following line: /dev/mapper/rhel-var-log /var/log xfs defaults,nodev,nosuid,noexec 0 0

b

RHEL 8 must mount /var/log with the nosuid option.

CM-7 - Medium - CCI-001764 - V-230515 - SV-230515r958804_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-08-040127

Vuln IDs

V-230515

Rule IDs

SV-230515r958804_rule

The organization must identify authorized software programs and permit execution of authorized software. The process used to identify software programs that are authorized to execute on organizational information systems is commonly referred to as whitelisting. The "noexec" mount option causes the system to not execute binary files. This option must be used for mounting any file system not containing approved binary files, as they may be incompatible. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access. The "nodev" mount option causes the system to not interpret character or block special devices. Executing character or block special devices from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access. The "nosuid" mount option causes the system to not execute "setuid" and "setgid" files with owner privileges. This option must be used for mounting any file system not containing approved "setuid" and "setguid" files. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access.

Checks: C-33184r568291_chk

Verify "/var/log" is mounted with the "nosuid" option: $ sudo mount | grep /var/log /dev/mapper/rhel-var-log on /var/log type xfs (rw,nodev,nosuid,noexec,seclabel) Verify that the "nosuid" option is configured for /var/log: $ sudo cat /etc/fstab | grep /var/log /dev/mapper/rhel-var-log /var/log xfs defaults,nodev,nosuid,noexec 0 0 If results are returned and the "nosuid" option is missing, or if /var/log is mounted without the "nosuid" option, this is a finding.

Fix: F-33159r568292_fix

Configure the system so that /var/log is mounted with the "nosuid" option by adding /modifying the /etc/fstab with the following line: /dev/mapper/rhel-var-log /var/log xfs defaults,nodev,nosuid,noexec 0 0

b

RHEL 8 must mount /var/log with the noexec option.

CM-7 - Medium - CCI-001764 - V-230516 - SV-230516r958804_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-08-040128

Vuln IDs

V-230516

Rule IDs

SV-230516r958804_rule

The organization must identify authorized software programs and permit execution of authorized software. The process used to identify software programs that are authorized to execute on organizational information systems is commonly referred to as whitelisting. The "noexec" mount option causes the system to not execute binary files. This option must be used for mounting any file system not containing approved binary files, as they may be incompatible. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access. The "nodev" mount option causes the system to not interpret character or block special devices. Executing character or block special devices from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access. The "nosuid" mount option causes the system to not execute "setuid" and "setgid" files with owner privileges. This option must be used for mounting any file system not containing approved "setuid" and "setguid" files. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access.

Checks: C-33185r568294_chk

Verify "/var/log" is mounted with the "noexec" option: $ sudo mount | grep /var/log /dev/mapper/rhel-var-log on /var/log type xfs (rw,nodev,nosuid,noexec,seclabel) Verify that the "noexec" option is configured for /var/log: $ sudo cat /etc/fstab | grep /var/log /dev/mapper/rhel-var-log /var/log xfs defaults,nodev,nosuid,noexec 0 0 If results are returned and the "noexec" option is missing, or if /var/log is mounted without the "noexec" option, this is a finding.

Fix: F-33160r568295_fix

Configure the system so that /var/log is mounted with the "noexec" option by adding /modifying the /etc/fstab with the following line: /dev/mapper/rhel-var-log /var/log xfs defaults,nodev,nosuid,noexec 0 0

b

RHEL 8 must mount /var/log/audit with the nodev option.

CM-7 - Medium - CCI-001764 - V-230517 - SV-230517r958804_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-08-040129

Vuln IDs

V-230517

Rule IDs

SV-230517r958804_rule

The organization must identify authorized software programs and permit execution of authorized software. The process used to identify software programs that are authorized to execute on organizational information systems is commonly referred to as whitelisting. The "noexec" mount option causes the system to not execute binary files. This option must be used for mounting any file system not containing approved binary files, as they may be incompatible. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access. The "nodev" mount option causes the system to not interpret character or block special devices. Executing character or block special devices from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access. The "nosuid" mount option causes the system to not execute "setuid" and "setgid" files with owner privileges. This option must be used for mounting any file system not containing approved "setuid" and "setguid" files. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access.

Checks: C-33186r568297_chk

Verify "/var/log/audit" is mounted with the "nodev" option: $ sudo mount | grep /var/log/audit /dev/mapper/rhel-var-log-audit on /var/log/audit type xfs (rw,nodev,nosuid,noexec,seclabel) Verify that the "nodev" option is configured for /var/log/audit: $ sudo cat /etc/fstab | grep /var/log/audit /dev/mapper/rhel-var-log-audit /var/log/audit xfs defaults,nodev,nosuid,noexec 0 0 If results are returned and the "nodev" option is missing, or if /var/log/audit is mounted without the "nodev" option, this is a finding.

Fix: F-33161r568298_fix

Configure the system so that /var/log/audit is mounted with the "nodev" option by adding /modifying the /etc/fstab with the following line: /dev/mapper/rhel-var-log-audit /var/log/audit xfs defaults,nodev,nosuid,noexec 0 0

b

RHEL 8 must mount /var/log/audit with the nosuid option.

CM-7 - Medium - CCI-001764 - V-230518 - SV-230518r958804_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-08-040130

Vuln IDs

V-230518

Rule IDs

SV-230518r958804_rule

The organization must identify authorized software programs and permit execution of authorized software. The process used to identify software programs that are authorized to execute on organizational information systems is commonly referred to as whitelisting. The "noexec" mount option causes the system to not execute binary files. This option must be used for mounting any file system not containing approved binary files, as they may be incompatible. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access. The "nodev" mount option causes the system to not interpret character or block special devices. Executing character or block special devices from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access. The "nosuid" mount option causes the system to not execute "setuid" and "setgid" files with owner privileges. This option must be used for mounting any file system not containing approved "setuid" and "setguid" files. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access.

Checks: C-33187r568300_chk

Verify "/var/log/audit" is mounted with the "nosuid" option: $ sudo mount | grep /var/log/audit /dev/mapper/rhel-var-log-audit on /var/log/audit type xfs (rw,nodev,nosuid,noexec,seclabel) Verify that the "nosuid" option is configured for /var/log/audit: $ sudo cat /etc/fstab | grep /var/log/audit /dev/mapper/rhel-var-log-audit /var/log/audit xfs defaults,nodev,nosuid,noexec 0 0 If results are returned and the "nosuid" option is missing, or if /var/log/audit is mounted without the "nosuid" option, this is a finding.

Fix: F-33162r568301_fix

Configure the system so that /var/log/audit is mounted with the "nosuid" option by adding /modifying the /etc/fstab with the following line: /dev/mapper/rhel-var-log-audit /var/log/audit xfs defaults,nodev,nosuid,noexec 0 0

b

RHEL 8 must mount /var/log/audit with the noexec option.

CM-7 - Medium - CCI-001764 - V-230519 - SV-230519r958804_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-08-040131

Vuln IDs

V-230519

Rule IDs

SV-230519r958804_rule

The organization must identify authorized software programs and permit execution of authorized software. The process used to identify software programs that are authorized to execute on organizational information systems is commonly referred to as whitelisting. The "noexec" mount option causes the system to not execute binary files. This option must be used for mounting any file system not containing approved binary files, as they may be incompatible. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access. The "nodev" mount option causes the system to not interpret character or block special devices. Executing character or block special devices from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access. The "nosuid" mount option causes the system to not execute "setuid" and "setgid" files with owner privileges. This option must be used for mounting any file system not containing approved "setuid" and "setguid" files. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access.

Checks: C-33188r568303_chk

Verify "/var/log/audit" is mounted with the "noexec" option: $ sudo mount | grep /var/log/audit /dev/mapper/rhel-var-log-audit on /var/log/audit type xfs (rw,nodev,nosuid,noexec,seclabel) Verify that the "noexec" option is configured for /var/log/audit: $ sudo cat /etc/fstab | grep /var/log/audit /dev/mapper/rhel-var-log-audit /var/log/audit xfs defaults,nodev,nosuid,noexec 0 0 If results are returned and the "noexec" option is missing, or if /var/log/audit is mounted without the "noexec" option, this is a finding.

Fix: F-33163r568304_fix

Configure the system so that /var/log/audit is mounted with the "noexec" option by adding /modifying the /etc/fstab with the following line: /dev/mapper/rhel-var-log-audit /var/log/audit xfs defaults,nodev,nosuid,noexec 0 0

b

RHEL 8 must mount /var/tmp with the nodev option.

CM-7 - Medium - CCI-001764 - V-230520 - SV-230520r958804_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-08-040132

Vuln IDs

V-230520

Rule IDs

SV-230520r958804_rule

The organization must identify authorized software programs and permit execution of authorized software. The process used to identify software programs that are authorized to execute on organizational information systems is commonly referred to as whitelisting. The "noexec" mount option causes the system to not execute binary files. This option must be used for mounting any file system not containing approved binary files, as they may be incompatible. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access. The "nodev" mount option causes the system to not interpret character or block special devices. Executing character or block special devices from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access. The "nosuid" mount option causes the system to not execute "setuid" and "setgid" files with owner privileges. This option must be used for mounting any file system not containing approved "setuid" and "setguid" files. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access.

Checks: C-33189r792925_chk

Verify "/var/tmp" is mounted with the "nodev" option: $ sudo mount | grep /var/tmp /dev/mapper/rhel-var-tmp on /var/tmp type xfs (rw,nodev,nosuid,noexec,seclabel) Verify that the "nodev" option is configured for /var/tmp: $ sudo cat /etc/fstab | grep /var/tmp /dev/mapper/rhel-var-tmp /var/tmp xfs defaults,nodev,nosuid,noexec 0 0 If results are returned and the "nodev" option is missing, or if /var/tmp is mounted without the "nodev" option, this is a finding.

Fix: F-33164r792926_fix

Configure the system so that /var/tmp is mounted with the "nodev" option by adding /modifying the /etc/fstab with the following line: /dev/mapper/rhel-var-tmp /var/tmp xfs defaults,nodev,nosuid,noexec 0 0

b

RHEL 8 must mount /var/tmp with the nosuid option.

CM-7 - Medium - CCI-001764 - V-230521 - SV-230521r958804_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-08-040133

Vuln IDs

V-230521

Rule IDs

SV-230521r958804_rule

The organization must identify authorized software programs and permit execution of authorized software. The process used to identify software programs that are authorized to execute on organizational information systems is commonly referred to as whitelisting. The "noexec" mount option causes the system to not execute binary files. This option must be used for mounting any file system not containing approved binary files, as they may be incompatible. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access. The "nodev" mount option causes the system to not interpret character or block special devices. Executing character or block special devices from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access. The "nosuid" mount option causes the system to not execute "setuid" and "setgid" files with owner privileges. This option must be used for mounting any file system not containing approved "setuid" and "setguid" files. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access.

Checks: C-33190r792928_chk

Verify "/var/tmp" is mounted with the "nosuid" option: $ sudo mount | grep /var/tmp /dev/mapper/rhel-var-tmp on /var/tmp type xfs (rw,nodev,nosuid,noexec,seclabel) Verify that the "nosuid" option is configured for /var/tmp: $ sudo cat /etc/fstab | grep /var/tmp /dev/mapper/rhel-var-tmp /var/tmp xfs defaults,nodev,nosuid,noexec 0 0 If results are returned and the "nosuid" option is missing, or if /var/tmp is mounted without the "nosuid" option, this is a finding.

Fix: F-33165r792929_fix

Configure the system so that /var/tmp is mounted with the "nosuid" option by adding /modifying the /etc/fstab with the following line: /dev/mapper/rhel-var-tmp /var/tmp xfs defaults,nodev,nosuid,noexec 0 0

b

RHEL 8 must mount /var/tmp with the noexec option.

CM-7 - Medium - CCI-001764 - V-230522 - SV-230522r958804_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-08-040134

Vuln IDs

V-230522

Rule IDs

SV-230522r958804_rule

The organization must identify authorized software programs and permit execution of authorized software. The process used to identify software programs that are authorized to execute on organizational information systems is commonly referred to as whitelisting. The "noexec" mount option causes the system to not execute binary files. This option must be used for mounting any file system not containing approved binary files, as they may be incompatible. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access. The "nodev" mount option causes the system to not interpret character or block special devices. Executing character or block special devices from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access. The "nosuid" mount option causes the system to not execute "setuid" and "setgid" files with owner privileges. This option must be used for mounting any file system not containing approved "setuid" and "setguid" files. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access.

Checks: C-33191r792931_chk

Verify "/var/tmp" is mounted with the "noexec" option: $ sudo mount | grep /var/tmp /dev/mapper/rhel-var-tmp on /var/tmp type xfs (rw,nodev,nosuid,noexec,seclabel) Verify that the "noexec" option is configured for /var/tmp: $ sudo cat /etc/fstab | grep /var/tmp /dev/mapper/rhel-var-tmp /var/tmp xfs defaults,nodev,nosuid,noexec 0 0 If results are returned and the "noexec" option is missing, or if /var/tmp is mounted without the "noexec" option, this is a finding.

Fix: F-33166r792932_fix

Configure the system so that /var/tmp is mounted with the "noexec" option by adding /modifying the /etc/fstab with the following line: /dev/mapper/rhel-var-tmp /var/tmp xfs defaults,nodev,nosuid,noexec 0 0

b

The RHEL 8 fapolicy module must be installed.

CM-7 - Medium - CCI-001764 - V-230523 - SV-230523r958804_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-08-040135

Vuln IDs

V-230523

Rule IDs

SV-230523r958804_rule

The organization must identify authorized software programs and permit execution of authorized software. The process used to identify software programs that are authorized to execute on organizational information systems is commonly referred to as whitelisting. Utilizing a whitelist provides a configuration management method for allowing the execution of only authorized software. Using only authorized software decreases risk by limiting the number of potential vulnerabilities. Verification of whitelisted software occurs prior to execution or at system startup. User home directories/folders may contain information of a sensitive nature. Non-privileged users should coordinate any sharing of information with an SA through shared resources. RHEL 8 ships with many optional packages. One such package is a file access policy daemon called "fapolicyd". "fapolicyd" is a userspace daemon that determines access rights to files based on attributes of the process and file. It can be used to either blacklist or whitelist processes or file access. Proceed with caution with enforcing the use of this daemon. Improper configuration may render the system non-functional. The "fapolicyd" API is not namespace aware and can cause issues when launching or running containers. Satisfies: SRG-OS-000368-GPOS-00154, SRG-OS-000370-GPOS-00155, SRG-OS-000480-GPOS-00232

Checks: C-33192r744021_chk

Verify the RHEL 8 "fapolicyd" is installed. Check that "fapolicyd" is installed with the following command: $ sudo yum list installed fapolicyd Installed Packages fapolicyd.x86_64 If fapolicyd is not installed, this is a finding.

Fix: F-33167r744022_fix

Install "fapolicyd" with the following command: $ sudo yum install fapolicyd.x86_64

b

RHEL 8 must block unauthorized peripherals before establishing a connection.

IA-3 - Medium - CCI-001958 - V-230524 - SV-230524r1014813_rule

RMF Control

IA-3

Severity

M

CCI

CCI-001958

Version

RHEL-08-040140

Vuln IDs

V-230524

Rule IDs

SV-230524r1014813_rule

Without authenticating devices, unidentified or unknown devices may be introduced, thereby facilitating malicious activity. Peripherals include, but are not limited to, such devices as flash drives, external storage, and printers. A new feature that RHEL 8 provides is the USBGuard software framework. The USBguard-daemon is the main component of the USBGuard software framework. It runs as a service in the background and enforces the USB device authorization policy for all USB devices. The policy is defined by a set of rules using a rule language described in the usbguard-rules.conf file. The policy and the authorization state of USB devices can be modified during runtime using the usbguard tool. The System Administrator (SA) must work with the site Information System Security Officer (ISSO) to determine a list of authorized peripherals and establish rules within the USBGuard software framework to allow only authorized devices.

Checks: C-33193r1014812_chk

Verify the USBGuard has a policy configured with the following command: $ sudo usbguard list-rules If the command does not return results or an error is returned, ask the SA to indicate how unauthorized peripherals are being blocked. If there is no evidence that unauthorized peripherals are being blocked before establishing a connection, this is a finding. If the USBGuard package is not installed, ask the SA to indicate how unauthorized peripherals are being blocked. If there is no evidence that unauthorized peripherals are being blocked before establishing a connection, this is a finding. If the system is a virtual machine with no virtual or physical USB peripherals attached, this is not a finding.

Fix: F-33168r744025_fix

Configure the operating system to enable the blocking of unauthorized peripherals with the following command: This command must be run from a root shell and will create an allow list for any usb devices currently connect to the system. # usbguard generate-policy > /etc/usbguard/rules.conf Note: Enabling and starting usbguard without properly configuring it for an individual system will immediately prevent any access over a usb device such as a keyboard or mouse

b

A firewall must be able to protect against or limit the effects of Denial of Service (DoS) attacks by ensuring RHEL 8 can implement rate-limiting measures on impacted network interfaces.

SC-5 - Medium - CCI-002385 - V-230525 - SV-230525r958902_rule

RMF Control

SC-5

Severity

M

CCI

CCI-002385

Version

RHEL-08-040150

Vuln IDs

V-230525

Rule IDs

SV-230525r958902_rule

DoS is a condition when a resource is not available for legitimate users. When this occurs, the organization either cannot accomplish its mission or must operate at degraded capacity. This requirement addresses the configuration of RHEL 8 to mitigate the impact of DoS attacks that have occurred or are ongoing on system availability. For each system, known and potential DoS attacks must be identified and solutions for each type implemented. A variety of technologies exists to limit or, in some cases, eliminate the effects of DoS attacks (e.g., limiting processes or establishing memory partitions). Employing increased capacity and bandwidth, combined with service redundancy, may reduce the susceptibility to some DoS attacks. Since version 0.6.0, "firewalld" has incorporated "nftables" as its backend support. Utilizing the limit statement in "nftables" can help to mitigate DoS attacks.

Checks: C-33194r744027_chk

Verify "nftables" is configured to allow rate limits on any connection to the system with the following command: Verify "firewalld" has "nftables" set as the default backend: $ sudo grep -i firewallbackend /etc/firewalld/firewalld.conf # FirewallBackend FirewallBackend=nftables If the "nftables" is not set as the "firewallbackend" default, this is a finding.

Fix: F-33169r902734_fix

Configure "nftables" to be the default "firewallbackend" for "firewalld" by adding or editing the following line in "/etc/firewalld/firewalld.conf": FirewallBackend=nftables Establish rate-limiting rules based on organization-defined types of DoS attacks on impacted network interfaces.

b

All RHEL 8 networked systems must have and implement SSH to protect the confidentiality and integrity of transmitted and received information, as well as information during preparation for transmission.

SC-8 - Medium - CCI-002418 - V-230526 - SV-230526r958908_rule

RMF Control

SC-8

Severity

M

CCI

CCI-002418

Version

RHEL-08-040160

Vuln IDs

V-230526

Rule IDs

SV-230526r958908_rule

Without protection of the transmitted information, confidentiality and integrity may be compromised because unprotected communications can be intercepted and either read or altered. This requirement applies to both internal and external networks and all types of information system components from which information can be transmitted (e.g., servers, mobile devices, notebook computers, printers, copiers, scanners, and facsimile machines). Communication paths outside the physical protection of a controlled boundary are exposed to the possibility of interception and modification. Protecting the confidentiality and integrity of organizational information can be accomplished by physical means (e.g., employing physical distribution systems) or by logical means (e.g., employing cryptographic techniques). If physical means of protection are employed, then logical means (cryptography) do not have to be employed, and vice versa. Satisfies: SRG-OS-000423-GPOS-00187, SRG-OS-000424-GPOS-00188, SRG-OS-000425-GPOS-00189, SRG-OS-000426-GPOS-00190

Checks: C-33195r744030_chk

Verify SSH is loaded and active with the following command: $ sudo systemctl status sshd sshd.service - OpenSSH server daemon Loaded: loaded (/usr/lib/systemd/system/sshd.service; enabled) Active: active (running) since Tue 2015-11-17 15:17:22 EST; 4 weeks 0 days ago Main PID: 1348 (sshd) CGroup: /system.slice/sshd.service 1053 /usr/sbin/sshd -D If "sshd" does not show a status of "active" and "running", this is a finding.

Fix: F-33170r744031_fix

Configure the SSH service to automatically start after reboot with the following command: $ sudo systemctl enable sshd.service

b

RHEL 8 must force a frequent session key renegotiation for SSH connections to the server.

AC-17 - Medium - CCI-000068 - V-230527 - SV-230527r1017288_rule

RMF Control

AC-17

Severity

M

CCI

CCI-000068

Version

RHEL-08-040161

Vuln IDs

V-230527

Rule IDs

SV-230527r1017288_rule

Without protection of the transmitted information, confidentiality and integrity may be compromised because unprotected communications can be intercepted and either read or altered. This requirement applies to both internal and external networks and all types of information system components from which information can be transmitted (e.g., servers, mobile devices, notebook computers, printers, copiers, scanners, and facsimile machines). Communication paths outside the physical protection of a controlled boundary are exposed to the possibility of interception and modification. Protecting the confidentiality and integrity of organizational information can be accomplished by physical means (e.g., employing physical distribution systems) or by logical means (e.g., employing cryptographic techniques). If physical means of protection are employed, then logical means (cryptography) do not have to be employed, and vice versa. Session key regeneration limits the chances of a session key becoming compromised. Satisfies: SRG-OS-000033-GPOS-00014, SRG-OS-000420-GPOS-00186, SRG-OS-000424-GPOS-00188

Checks: C-33196r951615_chk

Verify the SSH server is configured to force frequent session key renegotiation with the following command: $ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH '^\s*rekeylimit' RekeyLimit 1G 1h If "RekeyLimit" does not have a maximum data amount and maximum time defined, is missing, or is commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-33171r568328_fix

Configure the system to force a frequent session key renegotiation for SSH connections to the server by add or modifying the following line in the "/etc/ssh/sshd_config" file: RekeyLimit 1G 1h Restart the SSH daemon for the settings to take effect. $ sudo systemctl restart sshd.service

c

The x86 Ctrl-Alt-Delete key sequence must be disabled on RHEL 8.

CM-6 - High - CCI-000366 - V-230529 - SV-230529r1017289_rule

RMF Control

CM-6

Severity

H

CCI

Version

RHEL-08-040170

Vuln IDs

V-230529

Rule IDs

SV-230529r1017289_rule

A locally logged-on user, who presses Ctrl-Alt-Delete when at the console, can reboot the system. If accidentally pressed, as could happen in the case of a mixed OS environment, this can create the risk of short-term loss of availability of systems due to unintentional reboot. In a graphical user environment, risk of unintentional reboot from the Ctrl-Alt-Delete sequence is reduced because the user will be prompted before any action is taken.

Checks: C-33198r568333_chk

Verify RHEL 8 is not configured to reboot the system when Ctrl-Alt-Delete is pressed with the following command: $ sudo systemctl status ctrl-alt-del.target ctrl-alt-del.target Loaded: masked (Reason: Unit ctrl-alt-del.target is masked.) Active: inactive (dead) If the "ctrl-alt-del.target" is loaded and not masked, this is a finding.

Fix: F-33173r833337_fix

Configure the system to disable the Ctrl-Alt-Delete sequence for the command line with the following commands: $ sudo systemctl disable ctrl-alt-del.target $ sudo systemctl mask ctrl-alt-del.target Created symlink /etc/systemd/system/ctrl-alt-del.target -> /dev/null Reload the daemon for this change to take effect. $ sudo systemctl daemon-reload

c

The x86 Ctrl-Alt-Delete key sequence in RHEL 8 must be disabled if a graphical user interface is installed.

CM-6 - High - CCI-000366 - V-230530 - SV-230530r1069317_rule

RMF Control

CM-6

Severity

H

CCI

Version

RHEL-08-040171

Vuln IDs

V-230530

Rule IDs

SV-230530r1069317_rule

A locally logged-on user, who presses Ctrl-Alt-Delete, when at the console, can reboot the system. If accidentally pressed, as could happen in the case of a mixed OS environment, this can create the risk of short-term loss of availability of systems due to unintentional reboot. In a graphical user environment, risk of unintentional reboot from the Ctrl-Alt-Delete sequence is reduced because the user will be prompted before any action is taken.

Checks: C-33199r1069243_chk

Verify RHEL 8 is not configured to reboot the system when Ctrl-Alt-Delete is pressed when using a graphical user interface with the following command: This requirement assumes the use of the RHEL 8 default graphical user interface, Gnome Shell. If the system does not have any graphical user interface installed, this requirement is Not Applicable. $ sudo grep -r logout /etc/dconf/db/local.d/* /etc/dconf/db/local.d/00-disable-CAD:logout='' If the "logout" key is bound to an action, is commented out, or is missing, this is a finding.

Fix: F-33174r568337_fix

Configure the system to disable the Ctrl-Alt-Delete sequence when using a graphical user interface by creating or editing the /etc/dconf/db/local.d/00-disable-CAD file. Add the setting to disable the Ctrl-Alt-Delete sequence for a graphical user interface: [org/gnome/settings-daemon/plugins/media-keys] logout='' Note: The value above is set to two single quotations. Then update the dconf settings: $ sudo dconf update

c

The systemd Ctrl-Alt-Delete burst key sequence in RHEL 8 must be disabled.

CM-6 - High - CCI-000366 - V-230531 - SV-230531r1017292_rule

RMF Control

CM-6

Severity

H

CCI

Version

RHEL-08-040172

Vuln IDs

V-230531

Rule IDs

SV-230531r1017292_rule

A locally logged-on user who presses Ctrl-Alt-Delete when at the console can reboot the system. If accidentally pressed, as could happen in the case of a mixed OS environment, this can create the risk of short-term loss of availability of systems due to unintentional reboot. In a graphical user environment, risk of unintentional reboot from the Ctrl-Alt-Delete sequence is reduced because the user will be prompted before any action is taken.

Checks: C-33200r568339_chk

Verify RHEL 8 is not configured to reboot the system when Ctrl-Alt-Delete is pressed seven times within two seconds with the following command: $ sudo grep -i ctrl /etc/systemd/system.conf CtrlAltDelBurstAction=none If the "CtrlAltDelBurstAction" is not set to "none", commented out, or is missing, this is a finding.

Fix: F-33175r1017291_fix

Configure the system to disable the CtrlAltDelBurstAction by added or modifying the following line in the "/etc/systemd/system.conf" configuration file: CtrlAltDelBurstAction=none Reload the daemon for this change to take effect. $ sudo systemctl daemon-reload

b

The debug-shell systemd service must be disabled on RHEL 8.

CM-6 - Medium - CCI-000366 - V-230532 - SV-230532r1017294_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-040180

Vuln IDs

V-230532

Rule IDs

SV-230532r1017294_rule

The debug-shell requires no authentication and provides root privileges to anyone who has physical access to the machine. While this feature is disabled by default, masking it adds an additional layer of assurance that it will not be enabled via a dependency in systemd. This also prevents attackers with physical access from trivially bypassing security on the machine through valid troubleshooting configurations and gaining root access when the system is rebooted.

Checks: C-33201r568342_chk

Verify RHEL 8 is configured to mask the debug-shell systemd service with the following command: $ sudo systemctl status debug-shell.service debug-shell.service Loaded: masked (Reason: Unit debug-shell.service is masked.) Active: inactive (dead) If the "debug-shell.service" is loaded and not masked, this is a finding.

Fix: F-33176r1017293_fix

Configure the system to mask the debug-shell systemd service with the following command: $ sudo systemctl mask debug-shell.service Created symlink /etc/systemd/system/debug-shell.service -> /dev/null Reload the daemon to take effect. $ sudo systemctl daemon-reload

c

The Trivial File Transfer Protocol (TFTP) server package must not be installed if not required for RHEL 8 operational support.

CM-6 - High - CCI-000366 - V-230533 - SV-230533r1017295_rule

RMF Control

CM-6

Severity

H

CCI

Version

RHEL-08-040190

Vuln IDs

V-230533

Rule IDs

SV-230533r1017295_rule

If TFTP is required for operational support (such as the transmission of router configurations) its use must be documented with the Information System Security Officer (ISSO), restricted to only authorized personnel, and have access control rules established.

Checks: C-33202r568345_chk

Verify a TFTP server has not been installed on the system with the following command: $ sudo yum list installed tftp-server tftp-server.x86_64 5.2-24.el8 If TFTP is installed and the requirement for TFTP is not documented with the ISSO, this is a finding.

Fix: F-33177r568346_fix

Remove the TFTP package from the system with the following command: $ sudo yum remove tftp-server

c

The root account must be the only account having unrestricted access to the RHEL 8 system.

CM-6 - High - CCI-000366 - V-230534 - SV-230534r1017296_rule

RMF Control

CM-6

Severity

H

CCI

Version

RHEL-08-040200

Vuln IDs

V-230534

Rule IDs

SV-230534r1017296_rule

If an account other than root also has a User Identifier (UID) of "0", it has root authority, giving that account unrestricted access to the entire operating system. Multiple accounts with a UID of "0" afford an opportunity for potential intruders to guess a password for a privileged account.

Checks: C-33203r568348_chk

Check the system for duplicate UID "0" assignments with the following command: $ sudo awk -F: '$3 == 0 {print $1}' /etc/passwd If any accounts other than root have a UID of "0", this is a finding.

Fix: F-33178r568349_fix

Change the UID of any account on the system, other than root, that has a UID of "0". If the account is associated with system commands or applications, the UID should be changed to one greater than "0" but less than "1000". Otherwise, assign a UID of greater than "1000" that has not already been assigned.

b

RHEL 8 must prevent IPv6 Internet Control Message Protocol (ICMP) redirect messages from being accepted.

CM-6 - Medium - CCI-000366 - V-230535 - SV-230535r1017297_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-040210

Vuln IDs

V-230535

Rule IDs

SV-230535r1017297_rule

ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages modify the host's route table and are unauthenticated. An illicit ICMP redirect message could result in a man-in-the-middle attack. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of which of the directories they reside in. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf

Checks: C-33204r833339_chk

Verify RHEL 8 will not accept IPv6 ICMP redirect messages. Note: If IPv6 is disabled on the system, this requirement is Not Applicable. Check the value of the default "accept_redirects" variables with the following command: $ sudo sysctl net.ipv6.conf.default.accept_redirects net.ipv6.conf.default.accept_redirects = 0 If the returned line does not have a value of "0", a line is not returned, or the line is commented out, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r net.ipv6.conf.default.accept_redirects /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: net.ipv6.conf.default.accept_redirects = 0 If "net.ipv6.conf.default.accept_redirects" is not set to "0", is missing or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-33179r858792_fix

Configure RHEL 8 to prevent IPv6 ICMP redirect messages from being accepted. Add or edit the following line in a system configuration file, in the "/etc/sysctl.d/" directory: net.ipv6.conf.default.accept_redirects = 0 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf Load settings from all system configuration files with the following command: $ sudo sysctl --system

b

RHEL 8 must not send Internet Control Message Protocol (ICMP) redirects.

CM-6 - Medium - CCI-000366 - V-230536 - SV-230536r1017298_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-040220

Vuln IDs

V-230536

Rule IDs

SV-230536r1017298_rule

ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages contain information from the system's route table, possibly revealing portions of the network topology. There are notable differences between Internet Protocol version 4 (IPv4) and Internet Protocol version 6 (IPv6). There is only a directive to disable sending of IPv4 redirected packets. Refer to RFC4294 for an explanation of "IPv6 Node Requirements", which resulted in this difference between IPv4 and IPv6. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of which of the directories they reside in. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf

Checks: C-33205r833341_chk

Verify RHEL 8 does not IPv4 ICMP redirect messages. Check the value of the "all send_redirects" variables with the following command: $ sudo sysctl net.ipv4.conf.all.send_redirects net.ipv4.conf.all.send_redirects = 0 If the returned line does not have a value of "0", or a line is not returned, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r net.ipv4.conf.all.send_redirects /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: net.ipv4.conf.all.send_redirects = 0 If "net.ipv4.conf.all.send_redirects" is not set to "0", is missing or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-33180r858794_fix

Configure RHEL 8 to not allow interfaces to perform IPv4 ICMP redirects. Add or edit the following line in a system configuration file, in the "/etc/sysctl.d/" directory: net.ipv4.conf.all.send_redirects=0 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf Load settings from all system configuration files with the following command: $ sudo sysctl --system

b

RHEL 8 must not respond to Internet Control Message Protocol (ICMP) echoes sent to a broadcast address.

CM-6 - Medium - CCI-000366 - V-230537 - SV-230537r1017299_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-040230

Vuln IDs

V-230537

Rule IDs

SV-230537r1017299_rule

Responding to broadcast ICMP echoes facilitates network mapping and provides a vector for amplification attacks. There are notable differences between Internet Protocol version 4 (IPv4) and Internet Protocol version 6 (IPv6). IPv6 does not implement the same method of broadcast as IPv4. Instead, IPv6 uses multicast addressing to the all-hosts multicast group. Refer to RFC4294 for an explanation of "IPv6 Node Requirements", which resulted in this difference between IPv4 and IPv6. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of which of the directories they reside in. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf

Checks: C-33206r833343_chk

Verify RHEL 8 does not respond to ICMP echoes sent to a broadcast address. Check the value of the "icmp_echo_ignore_broadcasts" variable with the following command: $ sudo sysctl net.ipv4.icmp_echo_ignore_broadcasts net.ipv4.icmp_echo_ignore_broadcasts = 1 If the returned line does not have a value of "1", a line is not returned, or the retuned line is commented out, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r net.ipv4.icmp_echo_ignore_broadcasts /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: net.ipv4.icmp_echo_ignore_broadcasts = 1 If "net.ipv4.icmp_echo_ignore_broadcasts" is not set to "1", is missing or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-33181r858796_fix

Configure RHEL 8 to not respond to IPv4 ICMP echoes sent to a broadcast address. Add or edit the following line in a system configuration file, in the "/etc/sysctl.d/" directory: net.ipv4.icmp_echo_ignore_broadcasts=1 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf Load settings from all system configuration files with the following command: $ sudo sysctl --system

b

RHEL 8 must not forward IPv6 source-routed packets.

CM-6 - Medium - CCI-000366 - V-230538 - SV-230538r1017300_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-040240

Vuln IDs

V-230538

Rule IDs

SV-230538r1017300_rule

Source-routed packets allow the source of the packet to suggest that routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures. This requirement applies only to the forwarding of source-routed traffic, such as when forwarding is enabled and the system is functioning as a router. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of which of the directories they reside in. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf

Checks: C-33207r833345_chk

Verify RHEL 8 does not accept IPv6 source-routed packets. Note: If IPv6 is disabled on the system, this requirement is Not Applicable. Check the value of the accept source route variable with the following command: $ sudo sysctl net.ipv6.conf.all.accept_source_route net.ipv6.conf.all.accept_source_route = 0 If the returned line does not have a value of "0", a line is not returned, or the line is commented out, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r net.ipv6.conf.all.accept_source_route /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: net.ipv6.conf.all.accept_source_route = 0 If "net.ipv6.conf.all.accept_source_route" is not set to "0", is missing or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-33182r858800_fix

Configure RHEL 8 to not forward IPv6 source-routed packets. Add or edit the following line in a system configuration file, in the "/etc/sysctl.d/" directory: net.ipv6.conf.all.accept_source_route=0 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf Load settings from all system configuration files with the following command: $ sudo sysctl --system

b

RHEL 8 must not forward IPv6 source-routed packets by default.

CM-6 - Medium - CCI-000366 - V-230539 - SV-230539r1017301_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-040250

Vuln IDs

V-230539

Rule IDs

SV-230539r1017301_rule

Source-routed packets allow the source of the packet to suggest that routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures. This requirement applies only to the forwarding of source-routed traffic, such as when forwarding is enabled and the system is functioning as a router. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of which of the directories they reside in. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf

Checks: C-33208r861084_chk

Verify RHEL 8 does not accept IPv6 source-routed packets by default. Note: If IPv6 is disabled on the system, this requirement is Not Applicable. Check the value of the accept source route variable with the following command: $ sudo sysctl net.ipv6.conf.default.accept_source_route net.ipv6.conf.default.accept_source_route = 0 If the returned line does not have a value of "0", a line is not returned, or the line is commented out, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r net.ipv6.conf.default.accept_source_route /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: net.ipv6.conf.default.accept_source_route = 0 If "net.ipv6.conf.default.accept_source_route" is not set to "0", is missing or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-33183r858805_fix

Configure RHEL 8 to not forward IPv6 source-routed packets by default. Add or edit the following line in a system configuration file, in the "/etc/sysctl.d/" directory: net.ipv6.conf.default.accept_source_route=0 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf Load settings from all system configuration files with the following command: $ sudo sysctl --system

b

RHEL 8 must not enable IPv6 packet forwarding unless the system is a router.

CM-6 - Medium - CCI-000366 - V-230540 - SV-230540r1017302_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-040260

Vuln IDs

V-230540

Rule IDs

SV-230540r1017302_rule

Routing protocol daemons are typically used on routers to exchange network topology information with other routers. If this software is used when not required, system network information may be unnecessarily transmitted across the network. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of which of the directories they reside in. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf

Checks: C-33209r833348_chk

Verify RHEL 8 is not performing IPv6 packet forwarding, unless the system is a router. Note: If IPv6 is disabled on the system, this requirement is Not Applicable. Check that IPv6 forwarding is disabled using the following commands: $ sudo sysctl net.ipv6.conf.all.forwarding net.ipv6.conf.all.forwarding = 0 If the IPv6 forwarding value is not "0" and is not documented with the Information System Security Officer (ISSO) as an operational requirement, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r net.ipv6.conf.all.forwarding /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: net.ipv6.conf.all.forwarding = 0 If "net.ipv6.conf.all.forwarding" is not set to "0", is missing or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-33184r858809_fix

Configure RHEL 8 to not allow IPv6 packet forwarding, unless the system is a router. Add or edit the following line in a system configuration file, in the "/etc/sysctl.d/" directory: net.ipv6.conf.all.forwarding=0 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf Load settings from all system configuration files with the following command: $ sudo sysctl --system

b

RHEL 8 must not accept router advertisements on all IPv6 interfaces.

CM-6 - Medium - CCI-000366 - V-230541 - SV-230541r1017303_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-040261

Vuln IDs

V-230541

Rule IDs

SV-230541r1017303_rule

Routing protocol daemons are typically used on routers to exchange network topology information with other routers. If this software is used when not required, system network information may be unnecessarily transmitted across the network. An illicit router advertisement message could result in a man-in-the-middle attack. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of which of the directories they reside in. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf

Checks: C-33210r833350_chk

Verify RHEL 8 does not accept router advertisements on all IPv6 interfaces, unless the system is a router. Note: If IPv6 is disabled on the system, this requirement is not applicable. Check to see if router advertisements are not accepted by using the following command: $ sudo sysctl net.ipv6.conf.all.accept_ra net.ipv6.conf.all.accept_ra = 0 If the "accept_ra" value is not "0" and is not documented with the Information System Security Officer (ISSO) as an operational requirement, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r net.ipv6.conf.all.accept_ra /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: net.ipv6.conf.all.accept_ra = 0 If "net.ipv6.conf.all.accept_ra" is not set to "0", is missing or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-33185r858811_fix

Configure RHEL 8 to not accept router advertisements on all IPv6 interfaces unless the system is a router. Add or edit the following line in a system configuration file, in the "/etc/sysctl.d/" directory: net.ipv6.conf.all.accept_ra=0 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf Load settings from all system configuration files with the following command: $ sudo sysctl --system

b

RHEL 8 must not accept router advertisements on all IPv6 interfaces by default.

CM-6 - Medium - CCI-000366 - V-230542 - SV-230542r1017304_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-040262

Vuln IDs

V-230542

Rule IDs

SV-230542r1017304_rule

Routing protocol daemons are typically used on routers to exchange network topology information with other routers. If this software is used when not required, system network information may be unnecessarily transmitted across the network. An illicit router advertisement message could result in a man-in-the-middle attack. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of which of the directories they reside in. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf

Checks: C-33211r833352_chk

Verify RHEL 8 does not accept router advertisements on all IPv6 interfaces by default, unless the system is a router. Note: If IPv6 is disabled on the system, this requirement is not applicable. Check to see if router advertisements are not accepted by default by using the following command: $ sudo sysctl net.ipv6.conf.default.accept_ra net.ipv6.conf.default.accept_ra = 0 If the "accept_ra" value is not "0" and is not documented with the Information System Security Officer (ISSO) as an operational requirement, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r net.ipv6.conf.default.accept_ra /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: net.ipv6.conf.default.accept_ra = 0 If "net.ipv6.conf.default.accept_ra" is not set to "0", is missing or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-33186r858813_fix

Configure RHEL 8 to not accept router advertisements on all IPv6 interfaces by default unless the system is a router. Add or edit the following line in a system configuration file, in the "/etc/sysctl.d/" directory: net.ipv6.conf.default.accept_ra=0 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf Load settings from all system configuration files with the following command: $ sudo sysctl --system

b

RHEL 8 must not allow interfaces to perform Internet Control Message Protocol (ICMP) redirects by default.

CM-6 - Medium - CCI-000366 - V-230543 - SV-230543r1017305_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-040270

Vuln IDs

V-230543

Rule IDs

SV-230543r1017305_rule

ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages contain information from the system's route table, possibly revealing portions of the network topology. There are notable differences between Internet Protocol version 4 (IPv4) and Internet Protocol version 6 (IPv6). There is only a directive to disable sending of IPv4 redirected packets. Refer to RFC4294 for an explanation of "IPv6 Node Requirements", which resulted in this difference between IPv4 and IPv6. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of which of the directories they reside in. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf

Checks: C-33212r833354_chk

Verify RHEL 8 does not allow interfaces to perform Internet Protocol version 4 (IPv4) ICMP redirects by default. Check the value of the "default send_redirects" variables with the following command: $ sudo sysctl net.ipv4.conf.default.send_redirects net.ipv4.conf.default.send_redirects=0 If the returned line does not have a value of "0", or a line is not returned, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r net.ipv4.conf.default.send_redirects /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: net.ipv4.conf.default.send_redirects = 0 If "net.ipv4.conf.default.send_redirects" is not set to "0", is missing or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-33187r858815_fix

Configure RHEL 8 to not allow interfaces to perform Internet Protocol version 4 (IPv4) ICMP redirects by default. Add or edit the following line in a system configuration file, in the "/etc/sysctl.d/" directory: net.ipv4.conf.default.send_redirects = 0 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf Load settings from all system configuration files with the following command: $ sudo sysctl --system

b

RHEL 8 must ignore IPv6 Internet Control Message Protocol (ICMP) redirect messages.

CM-6 - Medium - CCI-000366 - V-230544 - SV-230544r1017306_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-040280

Vuln IDs

V-230544

Rule IDs

SV-230544r1017306_rule

ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages modify the host's route table and are unauthenticated. An illicit ICMP redirect message could result in a man-in-the-middle attack. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of which of the directories they reside in. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf

Checks: C-33213r833356_chk

Verify RHEL 8 ignores IPv6 ICMP redirect messages. Note: If IPv6 is disabled on the system, this requirement is Not Applicable. Check the value of the "accept_redirects" variables with the following command: $ sudo sysctl net.ipv6.conf.all.accept_redirects net.ipv6.conf.all.accept_redirects = 0 If the returned line does not have a value of "0", a line is not returned, or the line is commented out, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r net.ipv6.conf.all.accept_redirects /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: net.ipv6.conf.all.accept_redirects = 0 If "net.ipv6.conf.all.accept_redirects" is not set to "0", is missing or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-33188r858819_fix

Configure RHEL 8 to ignore IPv6 ICMP redirect messages. Add or edit the following line in a system configuration file, in the "/etc/sysctl.d/" directory: net.ipv6.conf.all.accept_redirects = 0 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf Load settings from all system configuration files with the following command: $ sudo sysctl --system

b

RHEL 8 must disable access to network bpf syscall from unprivileged processes.

CM-6 - Medium - CCI-000366 - V-230545 - SV-230545r1017307_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-040281

Vuln IDs

V-230545

Rule IDs

SV-230545r1017307_rule

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of which of the directories they reside in. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf

Checks: C-33214r833358_chk

Verify RHEL 8 prevents privilege escalation thru the kernel by disabling access to the bpf syscall with the following commands: $ sudo sysctl kernel.unprivileged_bpf_disabled kernel.unprivileged_bpf_disabled = 1 If the returned line does not have a value of "1", or a line is not returned, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r kernel.unprivileged_bpf_disabled /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: kernel.unprivileged_bpf_disabled = 1 If "kernel.unprivileged_bpf_disabled" is not set to "1", is missing or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-33189r858821_fix

Configure RHEL 8 to prevent privilege escalation thru the kernel by disabling access to the bpf syscall by adding the following line to a file, in the "/etc/sysctl.d" directory: kernel.unprivileged_bpf_disabled = 1 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf The system configuration files need to be reloaded for the changes to take effect. To reload the contents of the files, run the following command: $ sudo sysctl --system

b

RHEL 8 must restrict usage of ptrace to descendant processes.

CM-6 - Medium - CCI-000366 - V-230546 - SV-230546r1017308_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-040282

Vuln IDs

V-230546

Rule IDs

SV-230546r1017308_rule

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of which of the directories they reside in. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf

Checks: C-33215r833360_chk

Verify RHEL 8 restricts usage of ptrace to descendant processes with the following commands: $ sudo sysctl kernel.yama.ptrace_scope kernel.yama.ptrace_scope = 1 If the returned line does not have a value of "1", or a line is not returned, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r kernel.yama.ptrace_scope /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: kernel.yama.ptrace_scope = 1 If "kernel.yama.ptrace_scope" is not set to "1", is missing or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-33190r858823_fix

Configure RHEL 8 to restrict usage of ptrace to descendant processes by adding the following line to a file, in the "/etc/sysctl.d" directory: kernel.yama.ptrace_scope = 1 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf The system configuration files need to be reloaded for the changes to take effect. To reload the contents of the files, run the following command: $ sudo sysctl --system

b

RHEL 8 must restrict exposed kernel pointer addresses access.

CM-6 - Medium - CCI-000366 - V-230547 - SV-230547r1017309_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-040283

Vuln IDs

V-230547

Rule IDs

SV-230547r1017309_rule

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of which of the directories they reside in. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf

Checks: C-33216r833362_chk

Verify RHEL 8 restricts exposed kernel pointer addresses access with the following commands: $ sudo sysctl kernel.kptr_restrict kernel.kptr_restrict = 1 If the returned line does not have a value of "1" or "2", or a line is not returned, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r kernel.kptr_restrict /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: kernel.kptr_restrict = 1 If "kernel.kptr_restrict" is not set to "1" or "2", is missing or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-33191r858825_fix

Configure RHEL 8 to restrict exposed kernel pointer addresses access by adding the following line to a file, in the "/etc/sysctl.d" directory: kernel.kptr_restrict = 1 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf The system configuration files need to be reloaded for the changes to take effect. To reload the contents of the files, run the following command: $ sudo sysctl --system

b

RHEL 8 must disable the use of user namespaces.

CM-6 - Medium - CCI-000366 - V-230548 - SV-230548r1017310_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-040284

Vuln IDs

V-230548

Rule IDs

SV-230548r1017310_rule

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of which of the directories they reside in. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf

Checks: C-33217r1014816_chk

Verify RHEL 8 disables the use of user namespaces with the following commands: $ sudo sysctl user.max_user_namespaces user.max_user_namespaces = 0 If the returned line does not have a value of "0", or a line is not returned, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r user.max_user_namespaces /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: user.max_user_namespaces = 0 If "user.max_user_namespaces" is not set to "0", is missing or commented out, this is a finding. If conflicting results are returned, this is a finding. If the use of namespaces is operationally required and documented with the ISSM, it is not a finding.

Fix: F-33192r1014817_fix

Configure RHEL 8 to disable the use of user namespaces by adding the following line to a file, in the "/etc/sysctl.d" directory: user.max_user_namespaces = 0 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf The system configuration files need to be reloaded for the changes to take effect. To reload the contents of the files, run the following command: $ sudo sysctl --system

b

RHEL 8 must use reverse path filtering on all IPv4 interfaces.

CM-6 - Medium - CCI-000366 - V-230549 - SV-230549r1017311_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-040285

Vuln IDs

V-230549

Rule IDs

SV-230549r1017311_rule

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of which of the directories they reside in. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf

Checks: C-33218r833366_chk

Verify RHEL 8 uses reverse path filtering on all IPv4 interfaces with the following commands: $ sudo sysctl net.ipv4.conf.all.rp_filter net.ipv4.conf.all.rp_filter = 1 If the returned line does not have a value of "1" or "2", or a line is not returned, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r net.ipv4.conf.all.rp_filter /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: net.ipv4.conf.all.rp_filter = 1 If "net.ipv4.conf.all.rp_filter" is not set to "1" or "2", is missing or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-33193r858829_fix

Configure RHEL 8 to use reverse path filtering on all IPv4 interfaces by adding the following line to a file, in the "/etc/sysctl.d" directory: net.ipv4.conf.all.rp_filter = 1 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf The system configuration files need to be reloaded for the changes to take effect. To reload the contents of the files, run the following command: $ sudo sysctl --system

b

RHEL 8 must be configured to prevent unrestricted mail relaying.

CM-6 - Medium - CCI-000366 - V-230550 - SV-230550r1017312_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-040290

Vuln IDs

V-230550

Rule IDs

SV-230550r1017312_rule

If unrestricted mail relaying is permitted, unauthorized senders could use this host as a mail relay for the purpose of sending spam or other unauthorized activity.

Checks: C-33219r568396_chk

Verify the system is configured to prevent unrestricted mail relaying. Determine if "postfix" is installed with the following commands: $ sudo yum list installed postfix postfix.x86_64 2:3.3.1-9.el8 If postfix is not installed, this is Not Applicable. If postfix is installed, determine if it is configured to reject connections from unknown or untrusted networks with the following command: $ sudo postconf -n smtpd_client_restrictions smtpd_client_restrictions = permit_mynetworks, reject If the "smtpd_client_restrictions" parameter contains any entries other than "permit_mynetworks" and "reject", this is a finding.

Fix: F-33194r568397_fix

If "postfix" is installed, modify the "/etc/postfix/main.cf" file to restrict client connections to the local network with the following command: $ sudo postconf -e 'smtpd_client_restrictions = permit_mynetworks,reject'

a

The RHEL 8 file integrity tool must be configured to verify extended attributes.

CM-6 - Low - CCI-000366 - V-230551 - SV-230551r1017313_rule

RMF Control

CM-6

Severity

L

CCI

Version

RHEL-08-040300

Vuln IDs

V-230551

Rule IDs

SV-230551r1017313_rule

Extended attributes in file systems are used to contain arbitrary data and file metadata with security implications. RHEL 8 installation media come with a file integrity tool, Advanced Intrusion Detection Environment (AIDE).

Checks: C-33220r568399_chk

Verify the file integrity tool is configured to verify extended attributes. If AIDE is not installed, ask the System Administrator how file integrity checks are performed on the system. Note: AIDE is highly configurable at install time. This requirement assumes the "aide.conf" file is under the "/etc" directory. Use the following command to determine if the file is in another location: $ sudo find / -name aide.conf Check the "aide.conf" file to determine if the "xattrs" rule has been added to the rule list being applied to the files and directories selection lists. An example rule that includes the "xattrs" rule follows: All= p+i+n+u+g+s+m+S+sha512+acl+xattrs+selinux /bin All # apply the custom rule to the files in bin /sbin All # apply the same custom rule to the files in sbin If the "xattrs" rule is not being used on all uncommented selection lines in the "/etc/aide.conf" file, or extended attributes are not being checked by another file integrity tool, this is a finding.

Fix: F-33195r568400_fix

Configure the file integrity tool to check file and directory extended attributes. If AIDE is installed, ensure the "xattrs" rule is present on all uncommented file and directory selection lists.

a

The RHEL 8 file integrity tool must be configured to verify Access Control Lists (ACLs).

CM-6 - Low - CCI-000366 - V-230552 - SV-230552r1101902_rule

RMF Control

CM-6

Severity

L

CCI

Version

RHEL-08-040310

Vuln IDs

V-230552

Rule IDs

SV-230552r1101902_rule

ACLs can provide permissions beyond those permitted through the file mode and must be verified by file integrity tools. Selection lines in the aide.conf file determine which files and directories AIDE will monitor for changes. They follow this format: The specifies a file, directory or wildcard pattern to monitor. The define which attributes (hashes, permissions, timestamps, etc.) to check. RHEL 8 installation media come with a file integrity tool, Advanced Intrusion Detection Environment (AIDE).

Checks: C-33221r1101901_chk

Verify the file integrity tool is configured to verify ACLs. Note: AIDE is highly configurable at install time. This requirement assumes the "aide.conf" file is under the "/etc" directory. If AIDE is not installed, ask the system administrator (SA) how file integrity checks are performed on the system. Use the following command to determine if the file is in a location other than "/etc/aide/aide.conf": $ sudo find / -name aide.conf Use the following command to review the "aide.conf" file to determine if the "acl" rule has been added to the rule list being applied to the files and directories selection lists: $ sudo cat /etc/aide.conf | more If the "acl" rule is not being used on all selection lines in the "/etc/aide.conf" file, is commented out, or ACLs are not being checked by another file integrity tool, this is a finding.

Fix: F-33196r568403_fix

Configure the file integrity tool to check file and directory ACLs. If AIDE is installed, ensure the "acl" rule is present on all file and directory selection lists.

b

The graphical display manager must not be installed on RHEL 8 unless approved.

CM-6 - Medium - CCI-000366 - V-230553 - SV-230553r1017315_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-040320

Vuln IDs

V-230553

Rule IDs

SV-230553r1017315_rule

Internet services that are not required for system or application processes must not be active to decrease the attack surface of the system. Graphical display managers have a long history of security vulnerabilities and must not be used, unless approved and documented.

Checks: C-33222r809322_chk

Verify that a graphical user interface is not installed: $ rpm -qa | grep xorg | grep server Ask the System Administrator if use of a graphical user interface is an operational requirement. If the use of a graphical user interface on the system is not documented with the ISSO, this is a finding.

Fix: F-33197r809323_fix

Document the requirement for a graphical user interface with the ISSO or reinstall the operating system without the graphical user interface. If reinstallation is not feasible, then continue with the following procedure: Open an SSH session and enter the following commands: $ sudo yum remove xorg-x11-server-Xorg xorg-x11-server-common xorg-x11-server-utils xorg-x11-server-Xwayland A reboot is required for the changes to take effect.

b

RHEL 8 network interfaces must not be in promiscuous mode.

CM-6 - Medium - CCI-000366 - V-230554 - SV-230554r1017316_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-040330

Vuln IDs

V-230554

Rule IDs

SV-230554r1017316_rule

Network interfaces in promiscuous mode allow for the capture of all network traffic visible to the system. If unauthorized individuals can access these applications, it may allow them to collect information such as logon IDs, passwords, and key exchanges between systems. If the system is being used to perform a network troubleshooting function, the use of these tools must be documented with the Information System Security Officer (ISSO) and restricted to only authorized personnel.

Checks: C-33223r568408_chk

Verify network interfaces are not in promiscuous mode unless approved by the ISSO and documented. Check for the status with the following command: $ sudo ip link | grep -i promisc If network interfaces are found on the system in promiscuous mode and their use has not been approved by the ISSO and documented, this is a finding.

Fix: F-33198r568409_fix

Configure network interfaces to turn off promiscuous mode unless approved by the ISSO and documented. Set the promiscuous mode of an interface to off with the following command: $ sudo ip link set dev <devicename> multicast off promisc off

b

RHEL 8 remote X connections for interactive users must be disabled unless to fulfill documented and validated mission requirements.

CM-6 - Medium - CCI-000366 - V-230555 - SV-230555r1017317_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-040340

Vuln IDs

V-230555

Rule IDs

SV-230555r1017317_rule

The security risk of using X11 forwarding is that the client's X11 display server may be exposed to attack when the SSH client requests forwarding. A system administrator may have a stance in which they want to protect clients that may expose themselves to attack by unwittingly requesting X11 forwarding, which can warrant a "no" setting. X11 forwarding should be enabled with caution. Users with the ability to bypass file permissions on the remote host (for the user's X11 authorization database) can access the local X11 display through the forwarded connection. An attacker may then be able to perform activities such as keystroke monitoring if the ForwardX11Trusted option is also enabled. If X11 services are not required for the system's intended function, they should be disabled or restricted as appropriate to the system’s needs.

Checks: C-33224r951617_chk

Verify X11Forwarding is disabled with the following command: $ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH '^\s*x11forwarding' X11Forwarding no If the "X11Forwarding" keyword is set to "yes" and is not documented with the information system security officer (ISSO) as an operational requirement or is missing, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-33199r568412_fix

Edit the "/etc/ssh/sshd_config" file to uncomment or add the line for the "X11Forwarding" keyword and set its value to "no" (this file may be named differently or be in a different location if using a version of SSH that is provided by a third-party vendor): X11Forwarding no The SSH service must be restarted for changes to take effect: $ sudo systemctl restart sshd

b

The RHEL 8 SSH daemon must prevent remote hosts from connecting to the proxy display.

CM-6 - Medium - CCI-000366 - V-230556 - SV-230556r1017318_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-040341

Vuln IDs

V-230556

Rule IDs

SV-230556r1017318_rule

When X11 forwarding is enabled, there may be additional exposure to the server and client displays if the sshd proxy display is configured to listen on the wildcard address. By default, sshd binds the forwarding server to the loopback address and sets the hostname part of the DIPSLAY environment variable to localhost. This prevents remote hosts from connecting to the proxy display.

Checks: C-33225r951619_chk

Verify the SSH daemon prevents remote hosts from connecting to the proxy display. Check the SSH X11UseLocalhost setting with the following command: $ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH '^\s*x11uselocalhost' X11UseLocalhost yes If the "X11UseLocalhost" keyword is set to "no", is missing, or is commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-33200r568415_fix

Configure the SSH daemon to prevent remote hosts from connecting to the proxy display. Edit the "/etc/ssh/sshd_config" file to uncomment or add the line for the "X11UseLocalhost" keyword and set its value to "yes" (this file may be named differently or be in a different location if using a version of SSH that is provided by a third-party vendor): X11UseLocalhost yes

b

If the Trivial File Transfer Protocol (TFTP) server is required, the RHEL 8 TFTP daemon must be configured to operate in secure mode.

CM-6 - Medium - CCI-000366 - V-230557 - SV-230557r1088855_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-040350

Vuln IDs

V-230557

Rule IDs

SV-230557r1088855_rule

Restricting TFTP to a specific directory prevents remote users from copying, transferring, or overwriting system files.

Checks: C-33226r1088854_chk

Note: IAW RHEL-08-040190 if TFTP is not required, it should not be installed. If TFTP is not installed, this rule is not applicable. Check to see if TFTP server is installed with the following command: $ sudo dnf list installed | grep tftp-server tftp-server.x86_64 x.x-x.el8 Verify that the TFTP daemon, if tftp.server is installed, is configured to operate in secure mode with the following command: $ grep -i execstart /usr/lib/systemd/system/tftp.service ExecStart=/usr/sbin/in.tftpd -s /var/lib/tftpboot Note: The "-s" option ensures that the TFTP server only serves files from the specified directory, which is a security measure to prevent unauthorized access to other parts of the file system. If the TFTP server is installed but the TFTP daemon is not configured to operate in secure mode, this is a finding.

Fix: F-33201r1069173_fix

Configure the TFTP daemon to operate in secure mode with the following command: $ sudo systemctl edit tftp.service In the editor enter: [Service] ExecStart=/usr/sbin/in.tftpd -s /var/lib/tftpboot After making changes, reload the systemd daemon and restart the TFTP service as follows: $ sudo systemctl daemon-reload $ sudo systemctl restart tftp.service

c

A File Transfer Protocol (FTP) server package must not be installed unless mission essential on RHEL 8.

CM-6 - High - CCI-000366 - V-230558 - SV-230558r1017320_rule

RMF Control

CM-6

Severity

H

CCI

Version

RHEL-08-040360

Vuln IDs

V-230558

Rule IDs

SV-230558r1017320_rule

The FTP service provides an unencrypted remote access that does not provide for the confidentiality and integrity of user passwords or the remote session. If a privileged user were to log on using this service, the privileged user password could be compromised. SSH or other encrypted file transfer methods must be used in place of this service.

Checks: C-33227r568420_chk

Verify an FTP server has not been installed on the system with the following commands: $ sudo yum list installed *ftpd* vsftpd.x86_64 3.0.3-28.el8 appstream If an FTP server is installed and is not documented with the Information System Security Officer (ISSO) as an operational requirement, this is a finding.

Fix: F-33202r568421_fix

Document the FTP server package with the ISSO as an operational requirement or remove it from the system with the following command: $ sudo yum remove vsftpd

b

The gssproxy package must not be installed unless mission essential on RHEL 8.

CM-7 - Medium - CCI-000381 - V-230559 - SV-230559r1014820_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-08-040370

Vuln IDs

V-230559

Rule IDs

SV-230559r1014820_rule

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions, functions). The gssproxy package is a proxy for GSS API credential handling and could expose secrets on some networks. It is not needed for normal function of the OS.

Checks: C-33228r1014819_chk

Verify the gssproxy package has not been installed on the system with the following commands: $ sudo yum list installed gssproxy gssproxy.x86_64 0.8.0-14.el8 @anaconda If the gssproxy package is installed and is not documented with the information system security officer (ISSO) as an operational requirement, this is a finding. If NFS mounts are being used, this is not a finding.

Fix: F-33203r568424_fix

Document the gssproxy package with the ISSO as an operational requirement or remove it from the system with the following command: $ sudo yum remove gssproxy

b

The iprutils package must not be installed unless mission essential on RHEL 8.

CM-6 - Medium - CCI-000366 - V-230560 - SV-230560r1017321_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-040380

Vuln IDs

V-230560

Rule IDs

SV-230560r1017321_rule

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions, functions). The iprutils package provides a suite of utilities to manage and configure SCSI devices supported by the ipr SCSI storage device driver.

Checks: C-33229r568426_chk

Verify the iprutils package has not been installed on the system with the following commands: $ sudo yum list installed iprutils iprutils.x86_64 2.4.18.1-1.el8 @anaconda If the iprutils package is installed and is not documented with the Information System Security Officer (ISSO) as an operational requirement, this is a finding.

Fix: F-33204r568427_fix

Document the iprutils package with the ISSO as an operational requirement or remove it from the system with the following command: $ sudo yum remove iprutils

b

The tuned package must not be installed unless mission essential on RHEL 8.

CM-6 - Medium - CCI-000366 - V-230561 - SV-230561r1017322_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-040390

Vuln IDs

V-230561

Rule IDs

SV-230561r1017322_rule

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions, functions). The tuned package contains a daemon that tunes the system settings dynamically. It does so by monitoring the usage of several system components periodically. Based on that information, components will then be put into lower or higher power savings modes to adapt to the current usage. The tuned package is not needed for normal OS operations.

Checks: C-33230r568429_chk

Verify the tuned package has not been installed on the system with the following commands: $ sudo yum list installed tuned tuned.noarch 2.12.0-3.el8 @anaconda If the tuned package is installed and is not documented with the Information System Security Officer (ISSO) as an operational requirement, this is a finding.

Fix: F-33205r568430_fix

Document the tuned package with the ISSO as an operational requirement or remove it from the system with the following command: $ sudo yum remove tuned

b

The krb5-server package must not be installed on RHEL 8.

IA-7 - Medium - CCI-000803 - V-237640 - SV-237640r1017323_rule

RMF Control

IA-7

Severity

M

CCI

Version

RHEL-08-010163

Vuln IDs

V-237640

Rule IDs

SV-237640r1017323_rule

Unapproved mechanisms that are used for authentication to the cryptographic module are not verified and therefore cannot be relied upon to provide confidentiality or integrity, and DoD data may be compromised. RHEL 8 systems utilizing encryption are required to use FIPS-compliant mechanisms for authenticating to cryptographic modules. Currently, Kerberos does not utilize FIPS 140-2 cryptography. FIPS 140-2 is the current standard for validating that mechanisms used to access cryptographic modules utilize authentication that meets DoD requirements. This allows for Security Levels 1, 2, 3, or 4 for use on a general-purpose computing system.

Checks: C-40859r646888_chk

Verify the krb5-server package has not been installed on the system with the following commands: If the system is a workstation or is utilizing krb5-server-1.17-18.el8.x86_64 or newer, this is Not Applicable $ sudo yum list installed krb5-server krb5-server.x86_64 1.17-9.el8 repository If the krb5-server package is installed and is not documented with the Information System Security Officer (ISSO) as an operational requirement, this is a finding.

Fix: F-40822r646889_fix

Document the krb5-server package with the ISSO as an operational requirement or remove it from the system with the following command: $ sudo yum remove krb5-server

b

RHEL 8 must restrict privilege elevation to authorized personnel.

CM-6 - Medium - CCI-000366 - V-237641 - SV-237641r1101904_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010382

Vuln IDs

V-237641

Rule IDs

SV-237641r1101904_rule

The sudo command allows a user to execute programs with elevated (administrator) privileges. It prompts the user for their password and confirms your request to execute a command by checking a file, called sudoers. If the "sudoers" file is not configured correctly, any user defined on the system can initiate privileged actions on the target system.

Checks: C-40860r1101903_chk

Verify the "sudoers" file restricts sudo access to authorized personnel. $ sudo grep -iwR 'ALL' /etc/sudoers /etc/sudoers.d/ | grep -v '#' If the either of the following entries are returned, this is a finding: ALL ALL=(ALL) ALL ALL ALL=(ALL:ALL) ALL

Fix: F-40823r646892_fix

Remove the following entries from the sudoers file: ALL ALL=(ALL) ALL ALL ALL=(ALL:ALL) ALL

b

RHEL 8 must use the invoking user's password for privilege escalation when using "sudo".

AC-6 - Medium - CCI-002227 - V-237642 - SV-237642r991589_rule

RMF Control

AC-6

Severity

M

CCI

CCI-002227

Version

RHEL-08-010383

Vuln IDs

V-237642

Rule IDs

SV-237642r991589_rule

The sudoers security policy requires that users authenticate themselves before they can use sudo. When sudoers requires authentication, it validates the invoking user's credentials. If the rootpw, targetpw, or runaspw flags are defined and not disabled, by default the operating system will prompt the invoking user for the "root" user password. For more information on each of the listed configurations, reference the sudoers(5) manual page.

Checks: C-40861r880725_chk

Verify that the sudoers security policy is configured to use the invoking user's password for privilege escalation. $ sudo grep -Eir '(rootpw|targetpw|runaspw)' /etc/sudoers /etc/sudoers.d* | grep -v '#' /etc/sudoers:Defaults !targetpw /etc/sudoers:Defaults !rootpw /etc/sudoers:Defaults !runaspw If conflicting results are returned, this is a finding. If "Defaults !targetpw" is not defined, this is a finding. If "Defaults !rootpw" is not defined, this is a finding. If "Defaults !runaspw" is not defined, this is a finding.

Fix: F-40824r880726_fix

Define the following in the Defaults section of the /etc/sudoers file or a configuration file in the /etc/sudoers.d/ directory: Defaults !targetpw Defaults !rootpw Defaults !runaspw Remove any configurations that conflict with the above from the following locations: /etc/sudoers /etc/sudoers.d/

b

RHEL 8 must require re-authentication when using the "sudo" command.

IA-11 - Medium - CCI-002038 - V-237643 - SV-237643r1050789_rule

RMF Control

IA-11

Severity

M

CCI

Version

RHEL-08-010384

Vuln IDs

V-237643

Rule IDs

SV-237643r1050789_rule

Without re-authentication, users may access resources or perform tasks for which they do not have authorization. When operating systems provide the capability to escalate a functional capability, it is critical the organization requires the user to re-authenticate when using the "sudo" command. If the value is set to an integer less than 0, the user's time stamp will not expire and the user will not have to re-authenticate for privileged actions until the user's session is terminated.

Checks: C-40862r861087_chk

Verify the operating system requires re-authentication when using the "sudo" command to elevate privileges. $ sudo grep -ir 'timestamp_timeout' /etc/sudoers /etc/sudoers.d /etc/sudoers:Defaults timestamp_timeout=0 If conflicting results are returned, this is a finding. If "timestamp_timeout" is set to a negative number, is commented out, or no results are returned, this is a finding.

Fix: F-40825r858763_fix

Configure the "sudo" command to require re-authentication. Edit the /etc/sudoers file: $ sudo visudo Add or modify the following line: Defaults timestamp_timeout=[value] Note: The "[value]" must be a number that is greater than or equal to "0". Remove any duplicate or conflicting lines from /etc/sudoers and /etc/sudoers.d/ files.

b

RHEL 8 must display a banner before granting local or remote access to the system via a graphical user logon.

AC-8 - Medium - CCI-000048 - V-244519 - SV-244519r1017326_rule

RMF Control

AC-8

Severity

M

CCI

Version

RHEL-08-010049

Vuln IDs

V-244519

Rule IDs

SV-244519r1017326_rule

Display of a standardized and approved use notification before granting access to the operating system ensures privacy and security notification verbiage used is consistent with applicable federal laws, Executive Orders, directives, policies, regulations, standards, and guidance. System use notifications are required only for access via logon interfaces with human users and are not required when such human interfaces do not exist. Satisfies: SRG-OS-000023-GPOS-00006, SRG-OS-000228-GPOS-00088

Checks: C-47794r743804_chk

Verify RHEL 8 displays a banner before granting access to the operating system via a graphical user logon. Note: This requirement assumes the use of the RHEL 8 default graphical user interface, Gnome Shell. If the system does not have any graphical user interface installed, this requirement is Not Applicable. Check to see if the operating system displays a banner at the logon screen with the following command: $ sudo grep banner-message-enable /etc/dconf/db/local.d/* banner-message-enable=true If "banner-message-enable" is set to "false" or is missing, this is a finding.

Fix: F-47751r743805_fix

Configure the operating system to display a banner before granting access to the system. Note: If the system does not have a graphical user interface installed, this requirement is Not Applicable. Create a database to contain the system-wide graphical user logon settings (if it does not already exist) with the following command: $ sudo touch /etc/dconf/db/local.d/01-banner-message Add the following lines to the [org/gnome/login-screen] section of the "/etc/dconf/db/local.d/01-banner-message": [org/gnome/login-screen] banner-message-enable=true Run the following command to update the database: $ sudo dconf update

b

RHEL 8 operating systems booted with United Extensible Firmware Interface (UEFI) must require a unique superusers name upon booting into single-user mode and maintenance.

AC-3 - Medium - CCI-000213 - V-244521 - SV-244521r1017327_rule

RMF Control

AC-3

Severity

M

CCI

Version

RHEL-08-010141

Vuln IDs

V-244521

Rule IDs

SV-244521r1017327_rule

If the system does not require valid authentication before it boots into single-user or maintenance mode, anyone who invokes single-user or maintenance mode is granted privileged access to all files on the system. GRUB 2 is the default boot loader for RHEL 8 and is designed to require a password to boot into single-user mode or make modifications to the boot menu. The GRUB 2 superuser account is an account of last resort. Establishing a unique username for this account hardens the boot loader against brute force attacks. Due to the nature of the superuser account database being distinct from the OS account database, this allows the use of a username that is not among those within the OS account database. Examples of non-unique superusers names are root, superuser, unlock, etc.

Checks: C-47796r792981_chk

For systems that use BIOS, this is Not Applicable. Verify that a unique name is set as the "superusers" account: $ sudo grep -iw "superusers" /boot/efi/EFI/redhat/grub.cfg set superusers="[someuniquestringhere]" export superusers If "superusers" is identical to any OS account name or is missing a name, this is a finding.

Fix: F-47753r743811_fix

Configure the system to have a unique name for the grub superusers account. Edit the /etc/grub.d/01_users file and add or modify the following lines: set superusers="[someuniquestringhere]" export superusers password_pbkdf2 [someuniquestringhere] ${GRUB2_PASSWORD} Generate a new grub.cfg file with the following command: $ sudo grub2-mkconfig -o /boot/efi/EFI/redhat/grub.cfg

b

RHEL 8 operating systems booted with a BIOS must require a unique superusers name upon booting into single-user and maintenance modes.

AC-3 - Medium - CCI-000213 - V-244522 - SV-244522r1017328_rule

RMF Control

AC-3

Severity

M

CCI

Version

RHEL-08-010149

Vuln IDs

V-244522

Rule IDs

SV-244522r1017328_rule

If the system does not require valid authentication before it boots into single-user or maintenance mode, anyone who invokes single-user or maintenance mode is granted privileged access to all files on the system. GRUB 2 is the default boot loader for RHEL 8 and is designed to require a password to boot into single-user mode or make modifications to the boot menu. The GRUB 2 superuser account is an account of last resort. Establishing a unique username for this account hardens the boot loader against brute force attacks. Due to the nature of the superuser account database being distinct from the OS account database, this allows the use of a username that is not among those within the OS account database. Examples of non-unique superusers names are root, superuser, unlock, etc.

Checks: C-47797r792983_chk

For systems that use UEFI, this is Not Applicable. Verify that a unique name is set as the "superusers" account: $ sudo grep -iw "superusers" /boot/grub2/grub.cfg set superusers="[someuniquestringhere]" export superusers If "superusers" is identical to any OS account name or is missing a name, this is a finding.

Fix: F-47754r743814_fix

Configure the system to have a unique name for the grub superusers account. Edit the /etc/grub.d/01_users file and add or modify the following lines: set superusers="[someuniquestringhere]" export superusers password_pbkdf2 [someuniquestringhere] ${GRUB2_PASSWORD} Generate a new grub.cfg file with the following command: $ sudo grub2-mkconfig -o /boot/grub2/grub.cfg

b

RHEL 8 operating systems must require authentication upon booting into emergency mode.

AC-3 - Medium - CCI-000213 - V-244523 - SV-244523r1017329_rule

RMF Control

AC-3

Severity

M

CCI

Version

RHEL-08-010152

Vuln IDs

V-244523

Rule IDs

SV-244523r1017329_rule

If the system does not require valid root authentication before it boots into emergency or rescue mode, anyone who invokes emergency or rescue mode is granted privileged access to all files on the system.

Checks: C-47798r743816_chk

Check to see if the system requires authentication for emergency mode with the following command: $ sudo grep sulogin-shell /usr/lib/systemd/system/emergency.service ExecStart=-/usr/lib/systemd/systemd-sulogin-shell emergency If the "ExecStart" line is configured for anything other than "/usr/lib/systemd/systemd-sulogin-shell emergency", commented out, or missing, this is a finding.

Fix: F-47755r743817_fix

Configure the system to require authentication upon booting into emergency mode by adding the following line to the "/usr/lib/systemd/system/emergency.service" file. ExecStart=-/usr/lib/systemd/systemd-sulogin-shell emergency

b

The RHEL 8 pam_unix.so module must be configured in the system-auth file to use a FIPS 140-2 approved cryptographic hashing algorithm for system authentication.

IA-7 - Medium - CCI-000803 - V-244524 - SV-244524r1017330_rule

RMF Control

IA-7

Severity

M

CCI

Version

RHEL-08-010159

Vuln IDs

V-244524

Rule IDs

SV-244524r1017330_rule

Unapproved mechanisms that are used for authentication to the cryptographic module are not verified and therefore cannot be relied upon to provide confidentiality or integrity, and DoD data may be compromised. RHEL 8 systems utilizing encryption are required to use FIPS-compliant mechanisms for authenticating to cryptographic modules. FIPS 140-2 is the current standard for validating that mechanisms used to access cryptographic modules utilize authentication that meets DoD requirements. This allows for Security Levels 1, 2, 3, or 4 for use on a general-purpose computing system.

Checks: C-47799r809329_chk

Verify that pam_unix.so module is configured to use sha512. Check that pam_unix.so module is configured to use sha512 in /etc/pam.d/system-auth with the following command: $ sudo grep password /etc/pam.d/system-auth | grep pam_unix password sufficient pam_unix.so sha512 If "sha512" is missing, or is commented out, this is a finding.

Fix: F-47756r809330_fix

Configure RHEL 8 to use a FIPS 140-2 approved cryptographic hashing algorithm for system authentication. Edit/modify the following line in the "/etc/pam.d/system-auth" file to include the sha512 option for pam_unix.so: password sufficient pam_unix.so sha512

b

RHEL 8 must be configured so that all network connections associated with SSH traffic are terminated after 10 minutes of becoming unresponsive.

SC-10 - Medium - CCI-001133 - V-244525 - SV-244525r1017331_rule

RMF Control

SC-10

Severity

M

CCI

CCI-001133

Version

RHEL-08-010201

Vuln IDs

V-244525

Rule IDs

SV-244525r1017331_rule

Terminating an unresponsive SSH session within a short time period reduces the window of opportunity for unauthorized personnel to take control of a management session enabled on the console or console port that has been left unattended. In addition, quickly terminating an idle SSH session will also free up resources committed by the managed network element. Terminating network connections associated with communications sessions includes, for example, deallocating associated TCP/IP address/port pairs at the operating system level and deallocating networking assignments at the application level if multiple application sessions are using a single operating system-level network connection. This does not mean that the operating system terminates all sessions or network access; it only ends the unresponsive session and releases the resources associated with that session. RHEL 8 uses /etc/ssh/sshd_config for configurations of OpenSSH. Within the sshd_config, the product of the values of "ClientAliveInterval" and "ClientAliveCountMax" is used to establish the inactivity threshold. The "ClientAliveInterval" is a timeout interval in seconds after which if no data has been received from the client, sshd will send a message through the encrypted channel to request a response from the client. The "ClientAliveCountMax" is the number of client alive messages that may be sent without sshd receiving any messages back from the client. If this threshold is met, sshd will disconnect the client. For more information on these settings and others, refer to the sshd_config man pages. Satisfies: SRG-OS-000163-GPOS-00072, SRG-OS-000126-GPOS-00066, SRG-OS-000279-GPOS-00109

Checks: C-47800r951595_chk

Verify the SSH server automatically terminates a user session after the SSH client has been unresponsive for 10 minutes. Check that the "ClientAliveInterval" variable is set to a value of "600" or less by performing the following command: $ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH '^\s*clientaliveinterval' ClientAliveInterval 600 If "ClientAliveInterval" does not exist, does not have a value of "600" or less in "/etc/ssh/sshd_config", or is commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-47757r917885_fix

Note: This setting must be applied in conjunction with RHEL-08-010200 to function correctly. Configure the SSH server to terminate a user session automatically after the SSH client has been unresponsive for 10 minutes. Modify or append the following lines in the "/etc/ssh/sshd_config" file: ClientAliveInterval 600 For the changes to take effect, the SSH daemon must be restarted. $ sudo systemctl restart sshd.service

b

The RHEL 8 SSH daemon must be configured to use system-wide crypto policies.

AC-17 - Medium - CCI-001453 - V-244526 - SV-244526r1017332_rule

RMF Control

AC-17

Severity

M

CCI

Version

RHEL-08-010287

Vuln IDs

V-244526

Rule IDs

SV-244526r1017332_rule

Without cryptographic integrity protections, information can be altered by unauthorized users without detection. Remote access (e.g., RDP) is access to DoD nonpublic information systems by an authorized user (or an information system) communicating through an external, non-organization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless. Cryptographic mechanisms used for protecting the integrity of information include, for example, signed hash functions using asymmetric cryptography enabling distribution of the public key to verify the hash information while maintaining the confidentiality of the secret key used to generate the hash. RHEL 8 incorporates system-wide crypto policies by default. The SSH configuration file has no effect on the ciphers, MACs, or algorithms unless specifically defined in the /etc/sysconfig/sshd file. The employed algorithms can be viewed in the /etc/crypto-policies/back-ends/ directory. Satisfies: SRG-OS-000250-GPOS-00093, SRG-OS-000393-GPOS-00173, SRG-OS-000394-GPOS-00174, SRG-OS-000125-GPOS-00065

Checks: C-47801r809332_chk

Verify that system-wide crypto policies are in effect: $ sudo grep CRYPTO_POLICY /etc/sysconfig/sshd # CRYPTO_POLICY= If the "CRYPTO_POLICY " is uncommented, this is a finding.

Fix: F-47758r809333_fix

Configure the RHEL 8 SSH daemon to use system-wide crypto policies by adding the following line to /etc/sysconfig/sshd: # CRYPTO_POLICY= A reboot is required for the changes to take effect.

a

RHEL 8 must have the packages required to use the hardware random number generator entropy gatherer service.

CM-6 - Low - CCI-000366 - V-244527 - SV-244527r1017333_rule

RMF Control

CM-6

Severity

L

CCI

Version

RHEL-08-010472

Vuln IDs

V-244527

Rule IDs

SV-244527r1017333_rule

The most important characteristic of a random number generator is its randomness, namely its ability to deliver random numbers that are impossible to predict. Entropy in computer security is associated with the unpredictability of a source of randomness. The random source with high entropy tends to achieve a uniform distribution of random values. Random number generators are one of the most important building blocks of cryptosystems. The rngd service feeds random data from hardware device to kernel random device. Quality (non-predictable) random number generation is important for several security functions (i.e., ciphers).

Checks: C-47802r1014789_chk

Note: For RHEL versions 8.4 and above running with kernel FIPS mode enabled as specified by RHEL-08-010020, this requirement is Not Applicable. Check that RHEL 8 has the packages required to enabled the hardware random number generator entropy gatherer service with the following command: $ sudo yum list installed rng-tools rng-tools.x86_64 6.8-3.el8 @anaconda If the "rng-tools" package is not installed, this is a finding.

Fix: F-47759r743829_fix

Install the packages required to enabled the hardware random number generator entropy gatherer service with the following command: $ sudo yum install rng-tools

b

The RHEL 8 SSH daemon must not allow GSSAPI authentication, except to fulfill documented and validated mission requirements.

CM-6 - Medium - CCI-000366 - V-244528 - SV-244528r1017335_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010522

Vuln IDs

V-244528

Rule IDs

SV-244528r1017335_rule

Configuring this setting for the SSH daemon provides additional assurance that remote logon via SSH will require a password, even in the event of misconfiguration elsewhere.

Checks: C-47803r1017334_chk

Verify the SSH daemon does not allow GSSAPI authentication with the following command: $ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH '^\s*gssapiauthentication' GSSAPIAuthentication no If the value is returned as "yes", the returned line is commented out, no output is returned, or has not been documented with the information system security officer (ISSO), this is a finding. If conflicting results are returned, this is a finding.

Fix: F-47760r743832_fix

Configure the SSH daemon to not allow GSSAPI authentication. Add the following line in "/etc/ssh/sshd_config", or uncomment the line and set the value to "no": GSSAPIAuthentication no The SSH daemon must be restarted for the changes to take effect. To restart the SSH daemon, run the following command: $ sudo systemctl restart sshd.service

b

RHEL 8 must use a separate file system for /var/tmp.

CM-6 - Medium - CCI-000366 - V-244529 - SV-244529r1017336_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010544

Vuln IDs

V-244529

Rule IDs

SV-244529r1017336_rule

The use of separate file systems for different paths can protect the system from failures resulting from a file system becoming full or failing.

Checks: C-47804r902736_chk

Verify that a separate file system has been created for "/var/tmp". Check that a file system has been created for "/var/tmp" with the following command: $ sudo grep /var/tmp /etc/fstab /dev/mapper/... /var/tmp xfs defaults,nodev,noexec,nosuid 0 0 If a separate entry for "/var/tmp" is not in use, this is a finding.

Fix: F-47761r743835_fix

Migrate the "/var/tmp" path onto a separate file system.

b

RHEL 8 must prevent files with the setuid and setgid bit set from being executed on the /boot/efi directory.

CM-6 - Medium - CCI-000366 - V-244530 - SV-244530r1017337_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010572

Vuln IDs

V-244530

Rule IDs

SV-244530r1017337_rule

The "nosuid" mount option causes the system not to execute "setuid" and "setgid" files with owner privileges. This option must be used for mounting any file system not containing approved "setuid" and "setguid" files. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access.

Checks: C-47805r809335_chk

For systems that use BIOS, this is Not Applicable. Verify the /boot/efi directory is mounted with the "nosuid" option with the following command: $ sudo mount | grep '\s/boot/efi\s' /dev/sda1 on /boot/efi type vfat (rw,nosuid,relatime,fmask=0077,dmask=0077,codepage=437,iocharset=ascii,shortname=winnt,errors=remount-ro) If the /boot/efi file system does not have the "nosuid" option set, this is a finding.

Fix: F-47762r743838_fix

Configure the "/etc/fstab" to use the "nosuid" option on the /boot/efi directory.

b

All RHEL 8 local interactive user home directory files must have mode 0750 or less permissive.

CM-6 - Medium - CCI-000366 - V-244531 - SV-244531r1017338_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010731

Vuln IDs

V-244531

Rule IDs

SV-244531r1017338_rule

Excessive permissions on local interactive user home directories may allow unauthorized access to user files by other users.

Checks: C-47806r743840_chk

Verify all files and directories contained in a local interactive user home directory, excluding local initialization files, have a mode of "0750". Files that begin with a "." are excluded from this requirement. Note: The example will be for the user "smithj", who has a home directory of "/home/smithj". $ sudo ls -lLR /home/smithj -rwxr-x--- 1 smithj smithj 18 Mar 5 17:06 file1 -rwxr----- 1 smithj smithj 193 Mar 5 17:06 file2 -rw-r-x--- 1 smithj smithj 231 Mar 5 17:06 file3 If any files or directories are found with a mode more permissive than "0750", this is a finding.

Fix: F-47763r743841_fix

Set the mode on files and directories in the local interactive user home directory with the following command: Note: The example will be for the user smithj, who has a home directory of "/home/smithj" and is a member of the users group. $ sudo chmod 0750 /home/smithj/<file or directory>

b

RHEL 8 must be configured so that all files and directories contained in local interactive user home directories are group-owned by a group of which the home directory owner is a member.

CM-6 - Medium - CCI-000366 - V-244532 - SV-244532r1101906_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010741

Vuln IDs

V-244532

Rule IDs

SV-244532r1101906_rule

If a local interactive user's files are group-owned by a group of which the user is not a member, unintended users may be able to access them.

Checks: C-47807r1101905_chk

Verify all files and directories in a local interactive user home directory are group-owned by a group that the user is a member. Check the group owner of all files and directories in a local interactive user's home directory with the following command: Note: The example will be for the user "smithj", who has a home directory of "/home/smithj". $ sudo ls -lLR /<home directory>/<users home directory>/ -rw-r--r-- 1 smithj smithj 18 Mar 5 17:06 file1 -rw-r--r-- 1 smithj smithj 193 Mar 5 17:06 file2 -rw-r--r-- 1 smithj sa 231 Mar 5 17:06 file3 If any files are found with a group owner different from the home directory user private group, check to see if the user is a member of that group with the following command: $ sudo grep smithj /etc/group sa:x:100:juan,shelley,bob,smithj smithj:x:521:smithj If any files or directories are group owned by a group that the directory owner is not a member of verify that it is documented with the information system security officer (ISSO). If it is not, this is a finding.

Fix: F-47764r743844_fix

Change the group of a local interactive user's files and directories to a group that the interactive user is a member. To change the group owner of a local interactive user's files and directories, use the following command: Note: The example will be for the user smithj, who has a home directory of "/home/smithj" and is a member of the users group. $ sudo chgrp smithj /home/smithj/<file or directory>

b

RHEL 8 must configure the use of the pam_faillock.so module in the /etc/pam.d/system-auth file.

AC-7 - Medium - CCI-000044 - V-244533 - SV-244533r1069318_rule

RMF Control

AC-7

Severity

M

CCI

Version

RHEL-08-020025

Vuln IDs

V-244533

Rule IDs

SV-244533r1069318_rule

By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, otherwise known as brute-force attacks, is reduced. Limits are imposed by locking the account. In RHEL 8.2 the "/etc/security/faillock.conf" file was incorporated to centralize the configuration of the pam_faillock.so module. Also introduced is a "local_users_only" option that will only track failed user authentication attempts for local users in /etc/passwd and ignore centralized (AD, IdM, LDAP, etc.) users to allow the centralized platform to solely manage user lockout. From "faillock.conf" man pages: Note that the default directory that "pam_faillock" uses is usually cleared on system boot so the access will be reenabled after system reboot. If that is undesirable a different tally directory must be set with the "dir" option. The preauth argument must be used when the module is called before the modules which ask for the user credentials such as the password. Satisfies: SRG-OS-000021-GPOS-00005, SRG-OS-000329-GPOS-00128

Checks: C-47808r1069245_chk

Verify the pam_faillock.so module is present and is listed before the pam.unix.so line in the "/etc/pam.d/system-auth" file: Note: The first field in the output is the line number of the entry $ sudo grep -E -n 'pam_faillock.so|pam_unix.so' /etc/pam.d/system-auth 7:auth required pam_faillock.so preauth silent 13:auth sufficient pam_unix.so 17:auth required pam_faillock.so authfail 21:account required pam_faillock.so 22:account required pam_unix.so 33:password sufficient pam_unix.so sha512 shadow use_authtok 42:session required pam_unix.so If the pam_faillock.so module is not present in the "/etc/pam.d/system-auth" file with the "preauth" line listed before pam_unix.so, this is a finding.

Fix: F-47765r743847_fix

Configure the operating system to include the use of the pam_faillock.so module in the /etc/pam.d/system-auth file. Add/Modify the appropriate sections of the "/etc/pam.d/system-auth" file to match the following lines: Note: The "preauth" line must be listed before pam_unix.so. auth required pam_faillock.so preauth auth required pam_faillock.so authfail account required pam_faillock.so

b

RHEL 8 must configure the use of the pam_faillock.so module in the /etc/pam.d/password-auth file.

AC-7 - Medium - CCI-000044 - V-244534 - SV-244534r1069319_rule

RMF Control

AC-7

Severity

M

CCI

Version

RHEL-08-020026

Vuln IDs

V-244534

Rule IDs

SV-244534r1069319_rule

By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, otherwise known as brute-force attacks, is reduced. Limits are imposed by locking the account. In RHEL 8.2 the "/etc/security/faillock.conf" file was incorporated to centralize the configuration of the pam_faillock.so module. Also introduced is a "local_users_only" option that will only track failed user authentication attempts for local users in /etc/passwd and ignore centralized (AD, IdM, LDAP, etc.) users to allow the centralized platform to solely manage user lockout. From "faillock.conf" man pages: Note that the default directory that "pam_faillock" uses is usually cleared on system boot so the access will be reenabled after system reboot. If that is undesirable a different tally directory must be set with the "dir" option. The preauth argument must be used when the module is called before the modules which ask for the user credentials such as the password. Satisfies: SRG-OS-000021-GPOS-00005, SRG-OS-000329-GPOS-00128

Checks: C-47809r1069247_chk

Note: This check applies to RHEL versions 8.2 or newer, if the system is RHEL version 8.0 or 8.1, this check is not applicable. Verify the pam_faillock.so module is present and is listed before the pam.unix.so line in the "/etc/pam.d/password-auth" file: Note: The first field in the output is the line number of the entry $ sudo grep -E -n 'pam_faillock.so|pam_unix.so' /etc/pam.d/password-auth 7:auth required pam_faillock.so preauth silent 11:auth sufficient pam_unix.so 15:auth required pam_faillock.so authfail 19:account required pam_faillock.so 20:account required pam_unix.so 31:password sufficient pam_unix.so sha512 shadow use_authtok 40:session required pam_unix.so If the pam_faillock.so module is not present in the "/etc/pam.d/password-auth" file with the "preauth" line listed before pam_unix.so, this is a finding.

Fix: F-47766r743850_fix

Configure the operating system to include the use of the pam_faillock.so module in the /etc/pam.d/password-auth file. Add/Modify the appropriate sections of the "/etc/pam.d/password-auth" file to match the following lines: Note: The "preauth" line must be listed before pam_unix.so. auth required pam_faillock.so preauth auth required pam_faillock.so authfail account required pam_faillock.so

b

RHEL 8 must initiate a session lock for graphical user interfaces when the screensaver is activated.

AC-11 - Medium - CCI-000057 - V-244535 - SV-244535r1017342_rule

RMF Control

AC-11

Severity

M

CCI

Version

RHEL-08-020031

Vuln IDs

V-244535

Rule IDs

SV-244535r1017342_rule

A session time-out lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not log out because of the temporary nature of the absence. Rather than relying on the user to manually lock their operating system session prior to vacating the vicinity, operating systems need to be able to identify when a user's session has idled and take action to initiate the session lock. The session lock is implemented at the point where session activity can be determined and/or controlled. Satisfies: SRG-OS-000029-GPOS-00010, SRG-OS-000031-GPOS-00012, SRG-OS-000480-GPOS-00227

Checks: C-47810r743852_chk

Verify the operating system initiates a session lock a for graphical user interfaces when the screensaver is activated with the following command: Note: This requirement assumes the use of the RHEL 8 default graphical user interface, Gnome Shell. If the system does not have any graphical user interface installed, this requirement is Not Applicable. $ sudo gsettings get org.gnome.desktop.screensaver lock-delay uint32 5 If the "uint32" setting is missing, or is not set to "5" or less, this is a finding.

Fix: F-47767r743853_fix

Configure the operating system to initiate a session lock for graphical user interfaces when a screensaver is activated. Create a database to contain the system-wide screensaver settings (if it does not already exist) with the following command: Note: The example below is using the database "local" for the system, so if the system is using another database in "/etc/dconf/profile/user", the file should be created under the appropriate subdirectory. $ sudo touch /etc/dconf/db/local.d/00-screensaver [org/gnome/desktop/screensaver] lock-delay=uint32 5 The "uint32" must be included along with the integer key values as shown. Update the system databases: $ sudo dconf update

b

RHEL 8 must disable the user list at logon for graphical user interfaces.

CM-6 - Medium - CCI-000366 - V-244536 - SV-244536r1017343_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-020032

Vuln IDs

V-244536

Rule IDs

SV-244536r1017343_rule

Leaving the user list enabled is a security risk since it allows anyone with physical access to the system to enumerate known user accounts without authenticated access to the system.

Checks: C-47811r743855_chk

Verify the operating system disables the user logon list for graphical user interfaces with the following command: Note: This requirement assumes the use of the RHEL 8 default graphical user interface, Gnome Shell. If the system does not have any graphical user interface installed, this requirement is Not Applicable. $ sudo gsettings get org.gnome.login-screen disable-user-list true If the setting is "false", this is a finding.

Fix: F-47768r743856_fix

Configure the operating system to disable the user list at logon for graphical user interfaces. Create a database to contain the system-wide screensaver settings (if it does not already exist) with the following command: Note: The example below is using the database "local" for the system, so if the system is using another database in "/etc/dconf/profile/user", the file should be created under the appropriate subdirectory. $ sudo touch /etc/dconf/db/local.d/02-login-screen [org/gnome/login-screen] disable-user-list=true Update the system databases: $ sudo dconf update

b

RHEL 8 must prevent a user from overriding the session idle-delay setting for the graphical user interface.

AC-11 - Medium - CCI-000057 - V-244538 - SV-244538r1069324_rule

RMF Control

AC-11

Severity

M

CCI

Version

RHEL-08-020081

Vuln IDs

V-244538

Rule IDs

SV-244538r1069324_rule

A session time-out lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not log out because of the temporary nature of the absence. Rather than relying on the user to manually lock their operating system session prior to vacating the vicinity, operating systems need to be able to identify when a user's session has idled and take action to initiate the session lock. The session lock is implemented at the point where session activity can be determined and/or controlled. Implementing session settings will have little value if a user is able to manipulate these settings from the defaults prescribed in the other requirements of this implementation guide. Locking these settings from non-privileged users is crucial to maintaining a protected baseline. Satisfies: SRG-OS-000029-GPOS-00010, SRG-OS-000031-GPOS-00012, SRG-OS-000480-GPOS-00227

Checks: C-47813r743861_chk

Verify the operating system prevents a user from overriding settings for graphical user interfaces. Note: This requirement assumes the use of the RHEL 8 default graphical user interface, Gnome Shell. If the system does not have any graphical user interface installed, this requirement is Not Applicable. Determine which profile the system database is using with the following command: $ sudo grep system-db /etc/dconf/profile/user system-db:local Check that graphical settings are locked from non-privileged user modification with the following command: Note: The example below is using the database "local" for the system, so the path is "/etc/dconf/db/local.d". This path must be modified if a database other than "local" is being used. $ sudo grep -i idle /etc/dconf/db/local.d/locks/* /org/gnome/desktop/session/idle-delay If the command does not return at least the example result, this is a finding.

Fix: F-47770r1069257_fix

Configure the operating system to prevent a user from overriding settings for graphical user interfaces. Create a database to contain the system-wide screensaver settings (if it does not already exist) with the following command: Note: The example below is using the database "local" for the system, so if the system is using another database in "/etc/dconf/profile/user", the file should be created under the appropriate subdirectory. $ sudo touch /etc/dconf/db/local.d/locks/session Add the following setting to prevent non-privileged users from modifying it: /org/gnome/desktop/session/idle-delay Run the following command to update the database: $ sudo dconf update

b

RHEL 8 must prevent a user from overriding the screensaver lock-enabled setting for the graphical user interface.

AC-11 - Medium - CCI-000057 - V-244539 - SV-244539r1069325_rule

RMF Control

AC-11

Severity

M

CCI

Version

RHEL-08-020082

Vuln IDs

V-244539

Rule IDs

SV-244539r1069325_rule

A session time-out lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not log out because of the temporary nature of the absence. Rather than relying on the user to manually lock their operating system session prior to vacating the vicinity, operating systems need to be able to identify when a user's session has idled and take action to initiate the session lock. The session lock is implemented at the point where session activity can be determined and/or controlled. Implementing session settings will have little value if a user is able to manipulate these settings from the defaults prescribed in the other requirements of this implementation guide. Locking these settings from non-privileged users is crucial to maintaining a protected baseline. Satisfies: SRG-OS-000029-GPOS-00010, SRG-OS-000031-GPOS-00012, SRG-OS-000480-GPOS-00227

Checks: C-47814r743864_chk

Verify the operating system prevents a user from overriding settings for graphical user interfaces. Note: This requirement assumes the use of the RHEL 8 default graphical user interface, Gnome Shell. If the system does not have any graphical user interface installed, this requirement is Not Applicable. Determine which profile the system database is using with the following command: $ sudo grep system-db /etc/dconf/profile/user system-db:local Check that graphical settings are locked from non-privileged user modification with the following command: Note: The example below is using the database "local" for the system, so the path is "/etc/dconf/db/local.d". This path must be modified if a database other than "local" is being used. $ sudo grep -i lock-enabled /etc/dconf/db/local.d/locks/* /org/gnome/desktop/screensaver/lock-enabled If the command does not return at least the example result, this is a finding.

Fix: F-47771r1069259_fix

Configure the operating system to prevent a user from overriding settings for graphical user interfaces. Create a database to contain the system-wide screensaver settings (if it does not already exist) with the following command: Note: The example below is using the database "local" for the system, so if the system is using another database in "/etc/dconf/profile/user", the file should be created under the appropriate subdirectory. $ sudo touch /etc/dconf/db/local.d/locks/session Add the following setting to prevent non-privileged users from modifying it: /org/gnome/desktop/screensaver/lock-enabled Run the following command to update the database: $ sudo dconf update

c

RHEL 8 must not allow blank or null passwords in the password-auth file.

CM-6 - High - CCI-000366 - V-244541 - SV-244541r1017347_rule

RMF Control

CM-6

Severity

H

CCI

Version

RHEL-08-020332

Vuln IDs

V-244541

Rule IDs

SV-244541r1017347_rule

If an account has an empty password, anyone could log on and run commands with the privileges of that account. Accounts with empty passwords should never be used in operational environments.

Checks: C-47816r743870_chk

To verify that null passwords cannot be used, run the following command: $ sudo grep -i nullok /etc/pam.d/password-auth If output is produced, this is a finding.

Fix: F-47773r743871_fix

Remove any instances of the "nullok" option in the "/etc/pam.d/password-auth" file to prevent logons with empty passwords. Note: Manual changes to the listed file may be overwritten by the "authselect" program.

b

RHEL 8 audit records must contain information to establish what type of events occurred, the source of events, where events occurred, and the outcome of events.

AU-12 - Medium - CCI-000169 - V-244542 - SV-244542r1017348_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-08-030181

Vuln IDs

V-244542

Rule IDs

SV-244542r1017348_rule

Without establishing what type of events occurred, the source of events, where events occurred, and the outcome of events, it would be difficult to establish, correlate, and investigate the events leading up to an outage or attack. Audit record content that may be necessary to satisfy this requirement includes, for example, time stamps, source and destination addresses, user/process identifiers, event descriptions, success/fail indications, filenames involved, and access control or flow control rules invoked. Associating event types with detected events in RHEL 8 audit logs provides a means of investigating an attack, recognizing resource utilization or capacity thresholds, or identifying an improperly configured RHEL 8 system. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000038-GPOS-00016, SRG-OS-000039-GPOS-00017, SRG-OS-000040-GPOS-00018, SRG-OS-000041-GPOS-00019, SRG-OS-000042-GPOS-00021, SRG-OS-000051-GPOS-00024, SRG-OS-000054-GPOS-00025, SRG-OS-000122-GPOS-00063, SRG-OS-000254-GPOS-00095, SRG-OS-000255-GPOS-00096, SRG-OS-000337-GPOS-00129, SRG-OS-000348-GPOS-00136, SRG-OS-000349-GPOS-00137, SRG-OS-000350-GPOS-00138, SRG-OS-000351-GPOS-00139, SRG-OS-000352-GPOS-00140, SRG-OS-000353-GPOS-00141, SRG-OS-000354-GPOS-00142, SRG-OS-000358-GPOS-00145, SRG-OS-000365-GPOS-00152, SRG-OS-000392-GPOS-00172, SRG-OS-000475-GPOS-00220

Checks: C-47817r818837_chk

Verify the audit service is configured to produce audit records with the following command: $ sudo systemctl status auditd.service auditd.service - Security Auditing Service Loaded:loaded (/usr/lib/systemd/system/auditd.service; enabled; vendor preset: enabled) Active: active (running) since Tues 2020-12-11 12:56:56 EST; 4 weeks 0 days ago If the audit service is not "active" and "running", this is a finding.

Fix: F-47774r743874_fix

Configure the audit service to produce audit records containing the information needed to establish when (date and time) an event occurred with the following commands: $ sudo systemctl enable auditd.service $ sudo systemctl start auditd.service

b

RHEL 8 must notify the System Administrator (SA) and Information System Security Officer (ISSO) (at a minimum) when allocated audit record storage volume 75 percent utilization.

AU-5 - Medium - CCI-001855 - V-244543 - SV-244543r971542_rule

RMF Control

AU-5

Severity

M

CCI

CCI-001855

Version

RHEL-08-030731

Vuln IDs

V-244543

Rule IDs

SV-244543r971542_rule

If security personnel are not notified immediately when storage volume reaches 75 percent utilization, they are unable to plan for audit record storage capacity expansion.

Checks: C-47818r743876_chk

Verify RHEL 8 notifies the SA and ISSO (at a minimum) when allocated audit record storage volume reaches 75 percent of the repository maximum audit record storage capacity with the following command: $ sudo grep -w space_left_action /etc/audit/auditd.conf space_left_action = email If the value of the "space_left_action" is not set to "email", or if the line is commented out, ask the System Administrator to indicate how the system is providing real-time alerts to the SA and ISSO. If there is no evidence that real-time alerts are configured on the system, this is a finding.

Fix: F-47775r743877_fix

Configure the operating system to initiate an action to notify the SA and ISSO (at a minimum) when allocated audit record storage volume reaches 75 percent of the repository maximum audit record storage capacity by adding/modifying the following line in the /etc/audit/auditd.conf file. space_left_action = email Note: Option names and values in the auditd.conf file are case insensitive.

b

A firewall must be active on RHEL 8.

AC-17 - Medium - CCI-002314 - V-244544 - SV-244544r958672_rule

RMF Control

AC-17

Severity

M

CCI

CCI-002314

Version

RHEL-08-040101

Vuln IDs

V-244544

Rule IDs

SV-244544r958672_rule

"Firewalld" provides an easy and effective way to block/limit remote access to the system via ports, services, and protocols. Remote access services, such as those providing remote access to network devices and information systems, which lack automated control capabilities, increase risk and make remote user access management difficult at best. Remote access is access to DoD nonpublic information systems by an authorized user (or an information system) communicating through an external, non-organization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless. RHEL 8 functionality (e.g., RDP) must be capable of taking enforcement action if the audit reveals unauthorized activity. Automated control of remote access sessions allows organizations to ensure ongoing compliance with remote access policies by enforcing connection rules of remote access applications on a variety of information system components (e.g., servers, workstations, notebook computers, smartphones, and tablets).

Checks: C-47819r743879_chk

Verify that "firewalld" is active with the following commands: $ sudo systemctl is-active firewalld active If the "firewalld" package is not "active", ask the System Administrator if another firewall is installed. If no firewall is installed and active this is a finding.

Fix: F-47776r743880_fix

Configure "firewalld" to protect the operating system with the following command: $ sudo systemctl enable firewalld

b

The RHEL 8 fapolicy module must be enabled.

CM-7 - Medium - CCI-001764 - V-244545 - SV-244545r958804_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-08-040136

Vuln IDs

V-244545

Rule IDs

SV-244545r958804_rule

The organization must identify authorized software programs and permit execution of authorized software. The process used to identify software programs that are authorized to execute on organizational information systems is commonly referred to as whitelisting. Utilizing a whitelist provides a configuration management method for allowing the execution of only authorized software. Using only authorized software decreases risk by limiting the number of potential vulnerabilities. Verification of whitelisted software occurs prior to execution or at system startup. User home directories/folders may contain information of a sensitive nature. Non-privileged users should coordinate any sharing of information with an SA through shared resources. RHEL 8 ships with many optional packages. One such package is a file access policy daemon called "fapolicyd". "fapolicyd" is a userspace daemon that determines access rights to files based on attributes of the process and file. It can be used to either blacklist or whitelist processes or file access. Proceed with caution with enforcing the use of this daemon. Improper configuration may render the system non-functional. The "fapolicyd" API is not namespace aware and can cause issues when launching or running containers. Satisfies: SRG-OS-000368-GPOS-00154, SRG-OS-000370-GPOS-00155, SRG-OS-000480-GPOS-00232

Checks: C-47820r743882_chk

Verify the RHEL 8 "fapolicyd" is enabled and running with the following command: $ sudo systemctl status fapolicyd.service fapolicyd.service - File Access Policy Daemon Loaded: loaded (/usr/lib/systemd/system/fapolicyd.service; enabled; vendor preset: disabled) Active: active (running) If fapolicyd is not enabled and running, this is a finding.

Fix: F-47777r743883_fix

Enable "fapolicyd" using the following command: $ sudo systemctl enable --now fapolicyd

b

The RHEL 8 fapolicy module must be configured to employ a deny-all, permit-by-exception policy to allow the execution of authorized software programs.

CM-7 - Medium - CCI-001764 - V-244546 - SV-244546r1017349_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-08-040137

Vuln IDs

V-244546

Rule IDs

SV-244546r1017349_rule

The organization must identify authorized software programs and permit execution of authorized software. The process used to identify software programs that are authorized to execute on organizational information systems is commonly referred to as whitelisting. Utilizing a whitelist provides a configuration management method for allowing the execution of only authorized software. Using only authorized software decreases risk by limiting the number of potential vulnerabilities. Verification of whitelisted software occurs prior to execution or at system startup. User home directories/folders may contain information of a sensitive nature. Non-privileged users should coordinate any sharing of information with an SA through shared resources. RHEL 8 ships with many optional packages. One such package is a file access policy daemon called "fapolicyd". "fapolicyd" is a userspace daemon that determines access rights to files based on attributes of the process and file. It can be used to either blacklist or whitelist processes or file access. Proceed with caution with enforcing the use of this daemon. Improper configuration may render the system non-functional. The "fapolicyd" API is not namespace aware and can cause issues when launching or running containers. Satisfies: SRG-OS-000368-GPOS-00154, SRG-OS-000370-GPOS-00155, SRG-OS-000480-GPOS-00232

Checks: C-47821r858728_chk

Verify the RHEL 8 "fapolicyd" employs a deny-all, permit-by-exception policy. Check that "fapolicyd" is in enforcement mode with the following command: $ sudo grep permissive /etc/fapolicyd/fapolicyd.conf permissive = 0 Check that fapolicyd employs a deny-all policy on system mounts with the following commands: For RHEL 8.4 systems and older: $ sudo tail /etc/fapolicyd/fapolicyd.rules For RHEL 8.5 systems and newer: $ sudo tail /etc/fapolicyd/compiled.rules allow exe=/usr/bin/python3.7 : ftype=text/x-python deny_audit perm=any pattern=ld_so : all deny perm=any all : all If fapolicyd is not running in enforcement mode with a deny-all, permit-by-exception policy, this is a finding.

Fix: F-47778r858729_fix

Configure RHEL 8 to employ a deny-all, permit-by-exception application whitelisting policy with "fapolicyd". With the "fapolicyd" installed and enabled, configure the daemon to function in permissive mode until the whitelist is built correctly to avoid system lockout. Do this by editing the "/etc/fapolicyd/fapolicyd.conf" file with the following line: permissive = 1 For RHEL 8.4 systems and older: Build the whitelist in the "/etc/fapolicyd/fapolicyd.rules" file ensuring the last rule is "deny perm=any all : all". For RHEL 8.5 systems and newer: Build the whitelist in a file within the "/etc/fapolicyd/rules.d" directory ensuring the last rule is "deny perm=any all : all". Once it is determined the whitelist is built correctly, set the fapolicyd to enforcing mode by editing the "permissive" line in the /etc/fapolicyd/fapolicyd.conf file. permissive = 0

b

RHEL 8 must have the USBGuard installed.

IA-3 - Medium - CCI-001958 - V-244547 - SV-244547r1014811_rule

RMF Control

IA-3

Severity

M

CCI

CCI-001958

Version

RHEL-08-040139

Vuln IDs

V-244547

Rule IDs

SV-244547r1014811_rule

Without authenticating devices, unidentified or unknown devices may be introduced, thereby facilitating malicious activity. Peripherals include, but are not limited to, such devices as flash drives, external storage, and printers. A new feature that RHEL 8 provides is the USBGuard software framework. The USBguard-daemon is the main component of the USBGuard software framework. It runs as a service in the background and enforces the USB device authorization policy for all USB devices. The policy is defined by a set of rules using a rule language described in the usbguard-rules.conf file. The policy and the authorization state of USB devices can be modified during runtime using the usbguard tool. The System Administrator (SA) must work with the site Information System Security Officer (ISSO) to determine a list of authorized peripherals and establish rules within the USBGuard software framework to allow only authorized devices.

Checks: C-47822r1014810_chk

Verify USBGuard is installed on the operating system with the following command: $ sudo yum list installed usbguard Installed Packages usbguard.x86_64 0.7.8-7.el8 @ol8_appstream If the USBGuard package is not installed, ask the SA to indicate how unauthorized peripherals are being blocked. If there is no evidence that unauthorized peripherals are being blocked before establishing a connection, this is a finding. If the system is a virtual machine with no virtual or physical USB peripherals attached, this is not a finding.

Fix: F-47779r743889_fix

Install the USBGuard package with the following command: $ sudo yum install usbguard.x86_64

b

RHEL 8 must enable the USBGuard.

IA-3 - Medium - CCI-001958 - V-244548 - SV-244548r1014815_rule

RMF Control

IA-3

Severity

M

CCI

CCI-001958

Version

RHEL-08-040141

Vuln IDs

V-244548

Rule IDs

SV-244548r1014815_rule

Without authenticating devices, unidentified or unknown devices may be introduced, thereby facilitating malicious activity. Peripherals include, but are not limited to, such devices as flash drives, external storage, and printers. A new feature that RHEL 8 provides is the USBGuard software framework. The USBguard-daemon is the main component of the USBGuard software framework. It runs as a service in the background and enforces the USB device authorization policy for all USB devices. The policy is defined by a set of rules using a rule language described in the usbguard-rules.conf file. The policy and the authorization state of USB devices can be modified during runtime using the usbguard tool. The System Administrator (SA) must work with the site Information System Security Officer (ISSO) to determine a list of authorized peripherals and establish rules within the USBGuard software framework to allow only authorized devices.

Checks: C-47823r1014814_chk

Verify the operating system has enabled the use of the USBGuard with the following command: $ sudo systemctl status usbguard.service usbguard.service - USBGuard daemon Loaded: loaded (/usr/lib/systemd/system/usbguard.service; enabled; vendor preset: disabled) Active: active (running) If the usbguard.service is not enabled and active, ask the SA to indicate how unauthorized peripherals are being blocked. If there is no evidence that unauthorized peripherals are being blocked before establishing a connection, this is a finding. If the USBGuard package is not installed, ask the SA to indicate how unauthorized peripherals are being blocked. If there is no evidence that unauthorized peripherals are being blocked before establishing a connection, this is a finding. If the system is a virtual machine with no virtual or physical USB peripherals attached, this is not a finding.

Fix: F-47780r743892_fix

Configure the operating system to enable the blocking of unauthorized peripherals with the following commands: $ sudo systemctl enable usbguard.service $ sudo systemctl start usbguard.service Note: Enabling and starting usbguard without properly configuring it for an individual system will immediately prevent any access over a usb device such as a keyboard or mouse

b

All RHEL 8 networked systems must have SSH installed.

SC-8 - Medium - CCI-002418 - V-244549 - SV-244549r958908_rule

RMF Control

SC-8

Severity

M

CCI

CCI-002418

Version

RHEL-08-040159

Vuln IDs

V-244549

Rule IDs

SV-244549r958908_rule

Without protection of the transmitted information, confidentiality and integrity may be compromised because unprotected communications can be intercepted and either read or altered. This requirement applies to both internal and external networks and all types of information system components from which information can be transmitted (e.g., servers, mobile devices, notebook computers, printers, copiers, scanners, and facsimile machines). Communication paths outside the physical protection of a controlled boundary are exposed to the possibility of interception and modification. Protecting the confidentiality and integrity of organizational information can be accomplished by physical means (e.g., employing physical distribution systems) or by logical means (e.g., employing cryptographic techniques). If physical means of protection are employed, then logical means (cryptography) do not have to be employed, and vice versa. Satisfies: SRG-OS-000423-GPOS-00187, SRG-OS-000424-GPOS-00188, SRG-OS-000425-GPOS-00189, SRG-OS-000426-GPOS-00190

Checks: C-47824r743894_chk

Verify SSH is installed with the following command: $ sudo yum list installed openssh-server openssh-server.x86_64 8.0p1-5.el8 @anaconda If the "SSH server" package is not installed, this is a finding.

Fix: F-47781r743895_fix

Install SSH packages onto the host with the following command: $ sudo yum install openssh-server.x86_64

b

RHEL 8 must prevent IPv4 Internet Control Message Protocol (ICMP) redirect messages from being accepted.

CM-6 - Medium - CCI-000366 - V-244550 - SV-244550r1017350_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-040209

Vuln IDs

V-244550

Rule IDs

SV-244550r1017350_rule

ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages modify the host's route table and are unauthenticated. An illicit ICMP redirect message could result in a man-in-the-middle attack. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of which of the directories they reside in. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf

Checks: C-47825r833372_chk

Verify RHEL 8 will not accept IPv4 ICMP redirect messages. Check the value of the default "accept_redirects" variables with the following command: $ sudo sysctl net.ipv4.conf.default.accept_redirects net.ipv4.conf.default.accept_redirects = 0 If the returned line does not have a value of "0", a line is not returned, or the line is commented out, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r net.ipv4.conf.default.accept_redirects /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: net.ipv4.conf.default.accept_redirects = 0 If "net.ipv4.conf.default.accept_redirects" is not set to "0", is missing or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-47782r858790_fix

Configure RHEL 8 to prevent IPv4 ICMP redirect messages from being accepted. Add or edit the following line in a system configuration file, in the "/etc/sysctl.d/" directory: net.ipv4.conf.default.accept_redirects = 0 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf Load settings from all system configuration files with the following command: $ sudo sysctl --system

b

RHEL 8 must not forward IPv4 source-routed packets.

CM-6 - Medium - CCI-000366 - V-244551 - SV-244551r1017351_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-040239

Vuln IDs

V-244551

Rule IDs

SV-244551r1017351_rule

Source-routed packets allow the source of the packet to suggest that routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures. This requirement applies only to the forwarding of source-routed traffic, such as when forwarding is enabled and the system is functioning as a router. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of which of the directories they reside in. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf

Checks: C-47826r833374_chk

Verify RHEL 8 does not accept IPv4 source-routed packets. Check the value of the accept source route variable with the following command: $ sudo sysctl net.ipv4.conf.all.accept_source_route net.ipv4.conf.all.accept_source_route = 0 If the returned line does not have a value of "0", a line is not returned, or the line is commented out, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r net.ipv4.conf.all.accept_source_route /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: net.ipv4.conf.all.accept_source_route = 0 If "net.ipv4.conf.all.accept_source_route" is not set to "0", is missing or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-47783r858798_fix

Configure RHEL 8 to not forward IPv4 source-routed packets. Add or edit the following line in a system configuration file, in the "/etc/sysctl.d/" directory: net.ipv4.conf.all.accept_source_route=0 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf Load settings from all system configuration files with the following command: $ sudo sysctl --system

b

RHEL 8 must not forward IPv4 source-routed packets by default.

CM-6 - Medium - CCI-000366 - V-244552 - SV-244552r1017352_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-040249

Vuln IDs

V-244552

Rule IDs

SV-244552r1017352_rule

Source-routed packets allow the source of the packet to suggest that routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures. This requirement applies only to the forwarding of source-routed traffic, such as when forwarding is enabled and the system is functioning as a router. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of which of the directories they reside in. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf

Checks: C-47827r833376_chk

Verify RHEL 8 does not accept IPv4 source-routed packets by default. Check the value of the accept source route variable with the following command: $ sudo sysctl net.ipv4.conf.default.accept_source_route net.ipv4.conf.default.accept_source_route = 0 If the returned line does not have a value of "0", a line is not returned, or the line is commented out, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r net.ipv4.conf.default.accept_source_route /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: net.ipv4.conf.default.accept_source_route = 0 If "net.ipv4.conf.default.accept_source_route" is not set to "0", is missing or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-47784r858802_fix

Configure RHEL 8 to not forward IPv4 source-routed packets by default. Add or edit the following line in a system configuration file, in the "/etc/sysctl.d/" directory: net.ipv4.conf.default.accept_source_route=0 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf Load settings from all system configuration files with the following command: $ sudo sysctl --system

b

RHEL 8 must ignore IPv4 Internet Control Message Protocol (ICMP) redirect messages.

CM-6 - Medium - CCI-000366 - V-244553 - SV-244553r1017353_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-040279

Vuln IDs

V-244553

Rule IDs

SV-244553r1017353_rule

ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages modify the host's route table and are unauthenticated. An illicit ICMP redirect message could result in a man-in-the-middle attack. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of which of the directories they reside in. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf

Checks: C-47828r833378_chk

Verify RHEL 8 ignores IPv4 ICMP redirect messages. Check the value of the "accept_redirects" variables with the following command: $ sudo sysctl net.ipv4.conf.all.accept_redirects net.ipv4.conf.all.accept_redirects = 0 If the returned line does not have a value of "0", a line is not returned, or the line is commented out, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r net.ipv4.conf.all.accept_redirects /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: net.ipv4.conf.all.accept_redirects = 0 If "net.ipv4.conf.all.accept_redirects" is not set to "0", is missing or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-47785r858817_fix

Configure RHEL 8 to ignore IPv4 ICMP redirect messages. Add or edit the following line in a system configuration file, in the "/etc/sysctl.d/" directory: net.ipv4.conf.all.accept_redirects = 0 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf Load settings from all system configuration files with the following command: $ sudo sysctl --system

b

RHEL 8 must enable hardening for the Berkeley Packet Filter Just-in-time compiler.

CM-6 - Medium - CCI-000366 - V-244554 - SV-244554r1017354_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-040286

Vuln IDs

V-244554

Rule IDs

SV-244554r1017354_rule

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Enabling hardening for the Berkeley Packet Filter (BPF) Just-in-time (JIT) compiler aids in mitigating JIT spraying attacks. Setting the value to "2" enables JIT hardening for all users. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of which of the directories they reside in. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf

Checks: C-47829r833380_chk

Verify RHEL 8 enables hardening for the BPF JIT with the following commands: $ sudo sysctl net.core.bpf_jit_harden net.core.bpf_jit_harden = 2 If the returned line does not have a value of "2", or a line is not returned, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r net.core.bpf_jit_harden /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: net.core.bpf_jit_harden = 2 If "net.core.bpf_jit_harden" is not set to "2", is missing or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-47786r858831_fix

Configure RHEL 8 to enable hardening for the BPF JIT compiler by adding the following line to a file, in the "/etc/sysctl.d" directory: net.core.bpf_jit_harden = 2 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf The system configuration files need to be reloaded for the changes to take effect. To reload the contents of the files, run the following command: $ sudo sysctl --system

b

RHEL 8 systems, versions 8.2 and above, must configure SELinux context type to allow the use of a non-default faillock tally directory.

AC-7 - Medium - CCI-000044 - V-250315 - SV-250315r1017356_rule

RMF Control

AC-7

Severity

M

CCI

Version

RHEL-08-020027

Vuln IDs

V-250315

Rule IDs

SV-250315r1017356_rule

By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, otherwise known as brute-force attacks, is reduced. Limits are imposed by locking the account. From "faillock.conf" man pages: Note that the default directory that "pam_faillock" uses is usually cleared on system boot so the access will be re-enabled after system reboot. If that is undesirable, a different tally directory must be set with the "dir" option. SELinux, enforcing a targeted policy, will require any non-default tally directory's security context type to match the default directory's security context type. Without updating the security context type, the pam_faillock module will not write failed login attempts to the non-default tally directory.

Checks: C-53749r793000_chk

If the system does not have SELinux enabled and enforcing a targeted policy, or if the pam_faillock module is not configured for use, this requirement is not applicable. Note: This check applies to RHEL versions 8.2 or newer. If the system is RHEL version 8.0 or 8.1, this check is not applicable. Verify the location of the non-default tally directory for the pam_faillock module with the following command: $ sudo grep -w dir /etc/security/faillock.conf dir = /var/log/faillock Check the security context type of the non-default tally directory with the following command: $ sudo ls -Zd /var/log/faillock unconfined_u:object_r:faillog_t:s0 /var/log/faillock If the security context type of the non-default tally directory is not "faillog_t", this is a finding.

Fix: F-53703r793001_fix

Configure RHEL 8 to allow the use of a non-default faillock tally directory while SELinux enforces a targeted policy. Create a non-default faillock tally directory (if it does not already exist) with the following example: $ sudo mkdir /var/log/faillock Update the /etc/selinux/targeted/contexts/files/file_contexts.local with "faillog_t" context type for the non-default faillock tally directory with the following command: $ sudo semanage fcontext -a -t faillog_t "/var/log/faillock(/.*)?" Next, update the context type of the non-default faillock directory/subdirectories and files with the following command: $ sudo restorecon -R -v /var/log/faillock

b

RHEL 8 systems below version 8.2 must configure SELinux context type to allow the use of a non-default faillock tally directory.

AC-7 - Medium - CCI-000044 - V-250316 - SV-250316r1017357_rule

RMF Control

AC-7

Severity

M

CCI

Version

RHEL-08-020028

Vuln IDs

V-250316

Rule IDs

SV-250316r1017357_rule

By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, otherwise known as brute-force attacks, is reduced. Limits are imposed by locking the account. From "Pam_Faillock" man pages: Note that the default directory that "pam_faillock" uses is usually cleared on system boot so the access will be reenabled after system reboot. If that is undesirable, a different tally directory must be set with the "dir" option. SELinux, enforcing a targeted policy, will require any non-default tally directory's security context type to match the default directory's security context type. Without updating the security context type, the pam_faillock module will not write failed login attempts to the non-default tally directory.

Checks: C-53750r793003_chk

If the system does not have SELinux enabled and enforcing a targeted policy, or if the pam_faillock module is not configured for use, this requirement is not applicable. Note: This check applies to RHEL versions 8.0 and 8.1. If the system is RHEL version 8.2 or newer, this check is not applicable. Verify the location of the non-default tally directory for the pam_faillock module with the following command: $ sudo grep -w dir /etc/pam.d/password-auth auth required pam_faillock.so preauth dir=/var/log/faillock auth required pam_faillock.so authfail dir=/var/log/faillock Check the security context type of the non-default tally directory with the following command: $ sudo ls -Zd /var/log/faillock unconfined_u:object_r:faillog_t:s0 /var/log/faillock If the security context type of the non-default tally directory is not "faillog_t", this is a finding.

Fix: F-53704r793004_fix

Configure RHEL 8 to allow the use of a non-default faillock tally directory while SELinux enforces a targeted policy. Update the /etc/selinux/targeted/contexts/files/file_contexts.local with "faillog_t" context type for the non-default faillock tally directory with the following command: $ sudo semanage fcontext -a -t faillog_t "/var/log/faillock(/.*)?" Next, update the context type of the non-default faillock directory/subdirectories and files with the following command: $ sudo restorecon -R -v /var/log/faillock

b

RHEL 8 must not enable IPv4 packet forwarding unless the system is a router.

CM-6 - Medium - CCI-000366 - V-250317 - SV-250317r1017358_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-040259

Vuln IDs

V-250317

Rule IDs

SV-250317r1017358_rule

Routing protocol daemons are typically used on routers to exchange network topology information with other routers. If this software is used when not required, system network information may be unnecessarily transmitted across the network. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of which of the directories they reside in. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf

Checks: C-53751r833382_chk

Verify RHEL 8 is not performing IPv4 packet forwarding, unless the system is a router. Check that IPv4 forwarding is disabled using the following command: $ sudo sysctl net.ipv4.conf.all.forwarding net.ipv4.conf.all.forwarding = 0 If the IPv4 forwarding value is not "0" and is not documented with the Information System Security Officer (ISSO) as an operational requirement, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r net.ipv4.conf.all.forwarding /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: net.ipv4.conf.all.forwarding = 0 If "net.ipv4.conf.all.forwarding" is not set to "0", is missing or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-53705r858807_fix

Configure RHEL 8 to not allow IPv4 packet forwarding, unless the system is a router. Add or edit the following line in a system configuration file, in the "/etc/sysctl.d/" directory: net.ipv4.conf.all.forwarding=0 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf Load settings from all system configuration files with the following command: $ sudo sysctl --system

c

The RHEL 8 operating system must not have accounts configured with blank or null passwords.

CM-6 - High - CCI-000366 - V-251706 - SV-251706r1017359_rule

RMF Control

CM-6

Severity

H

CCI

Version

RHEL-08-010121

Vuln IDs

V-251706

Rule IDs

SV-251706r1017359_rule

If an account has an empty password, anyone could log on and run commands with the privileges of that account. Accounts with empty passwords should never be used in operational environments.

Checks: C-55143r809340_chk

Check the "/etc/shadow" file for blank passwords with the following command: $ sudo awk -F: '!$2 {print $1}' /etc/shadow If the command returns any results, this is a finding.

Fix: F-55097r809341_fix

Configure all accounts on the system to have a password or lock the account with the following commands: Perform a password reset: $ sudo passwd [username] Lock an account: $ sudo passwd -l [username]

b

RHEL 8 library directories must have mode 755 or less permissive.

CM-5 - Medium - CCI-001499 - V-251707 - SV-251707r1017360_rule

RMF Control

CM-5

Severity

M

CCI

Version

RHEL-08-010331

Vuln IDs

V-251707

Rule IDs

SV-251707r1017360_rule

If RHEL 8 were to allow any user to make changes to software libraries, then those changes might be implemented without undergoing the appropriate testing and approvals that are part of a robust change management process. This requirement applies to RHEL 8 with software libraries that are accessible and configurable, as in the case of interpreted languages. Software libraries also include privileged programs that execute with escalated privileges. Only qualified and authorized individuals will be allowed to obtain access to information system components for purposes of initiating changes, including upgrades and modifications.

Checks: C-55144r809343_chk

Verify the system-wide shared library directories within "/lib", "/lib64", "/usr/lib" and "/usr/lib64" have mode "755" or less permissive with the following command: $ sudo find /lib /lib64 /usr/lib /usr/lib64 -perm /022 -type d -exec stat -c "%n %a" '{}' \; If any system-wide shared library directories are found to be group-writable or world-writable, this is a finding.

Fix: F-55098r809344_fix

Configure the library directories to be protected from unauthorized access. Run the following command, replacing "[DIRECTORY]" with any library directory with a mode more permissive than 755. $ sudo chmod 755 [DIRECTORY]

b

RHEL 8 library directories must be owned by root.

CM-5 - Medium - CCI-001499 - V-251708 - SV-251708r1017362_rule

RMF Control

CM-5

Severity

M

CCI

Version

RHEL-08-010341

Vuln IDs

V-251708

Rule IDs

SV-251708r1017362_rule

If RHEL 8 were to allow any user to make changes to software libraries, then those changes might be implemented without undergoing the appropriate testing and approvals that are part of a robust change management process. This requirement applies to RHEL 8 with software libraries that are accessible and configurable, as in the case of interpreted languages. Software libraries also include privileged programs that execute with escalated privileges. Only qualified and authorized individuals will be allowed to obtain access to information system components for purposes of initiating changes, including upgrades and modifications.

Checks: C-55145r1017361_chk

Verify the system-wide shared library directories are owned by "root" with the following command: $ sudo find /lib /lib64 /usr/lib /usr/lib64 ! -user root -type d -exec stat -c "%n %U" '{}' \; If any system-wide shared library directory is returned, this is a finding.

Fix: F-55099r809347_fix

Configure the system-wide shared library directories within (/lib, /lib64, /usr/lib and /usr/lib64) to be protected from unauthorized access. Run the following command, replacing "[DIRECTORY]" with any library directory not owned by "root". $ sudo chown root [DIRECTORY]

b

RHEL 8 library directories must be group-owned by root or a system account.

CM-5 - Medium - CCI-001499 - V-251709 - SV-251709r1017364_rule

RMF Control

CM-5

Severity

M

CCI

Version

RHEL-08-010351

Vuln IDs

V-251709

Rule IDs

SV-251709r1017364_rule

If RHEL 8 were to allow any user to make changes to software libraries, then those changes might be implemented without undergoing the appropriate testing and approvals that are part of a robust change management process. This requirement applies to RHEL 8 with software libraries that are accessible and configurable, as in the case of interpreted languages. Software libraries also include privileged programs that execute with escalated privileges. Only qualified and authorized individuals will be allowed to obtain access to information system components for purposes of initiating changes, including upgrades and modifications.

Checks: C-55146r1017363_chk

Verify the system-wide shared library directories are group-owned by "root" with the following command: $ sudo find /lib /lib64 /usr/lib /usr/lib64 ! -group root -type d -exec stat -c "%n %G" '{}' \; If any system-wide shared library directory is returned and is not group-owned by a required system account, this is a finding.

Fix: F-55100r809350_fix

Configure the system-wide shared library directories (/lib, /lib64, /usr/lib and /usr/lib64) to be protected from unauthorized access. Run the following command, replacing "[DIRECTORY]" with any library directory not group-owned by "root". $ sudo chgrp root [DIRECTORY]

b

The RHEL 8 operating system must use a file integrity tool to verify correct operation of all security functions.

SI-6 - Medium - CCI-002696 - V-251710 - SV-251710r958944_rule

RMF Control

SI-6

Severity

M

CCI

CCI-002696

Version

RHEL-08-010359

Vuln IDs

V-251710

Rule IDs

SV-251710r958944_rule

Without verification of the security functions, security functions may not operate correctly, and the failure may go unnoticed. Security function is defined as the hardware, software, and/or firmware of the information system responsible for enforcing the system security policy and supporting the isolation of code and data on which the protection is based. Security functionality includes, but is not limited to, establishing system accounts, configuring access authorizations (i.e., permissions, privileges), setting events to be audited, and setting intrusion detection parameters. This requirement applies to the RHEL 8 operating system performing security function verification/testing and/or systems and environments that require this functionality.

Checks: C-55147r880728_chk

Verify that Advanced Intrusion Detection Environment (AIDE) is installed and verifies the correct operation of all security functions. Check that the AIDE package is installed with the following command: $ sudo rpm -q aide aide-0.16-14.el8_5.1.x86_64 If AIDE is not installed, ask the System Administrator how file integrity checks are performed on the system. If there is no application installed to perform integrity checks, this is a finding. If AIDE is installed, check if it has been initialized with the following command: $ sudo /usr/sbin/aide --check If the output is "Couldn't open file /var/lib/aide/aide.db.gz for reading", this is a finding.

Fix: F-55101r880729_fix

Install AIDE, initialize it, and perform a manual check. Install AIDE: $ sudo yum install aide Initialize it: $ sudo /usr/sbin/aide --init Example output: Number of entries: 48623 --------------------------------------------------- The attributes of the (uncompressed) database(s): --------------------------------------------------- /var/lib/aide/aide.db.new.gz SHA1 : LTAVQ8tFJthsrf4m9gfRpnf1vyc= SHA256 : NJ9+uzRQKSwmLQ8A6IpKNvYjVKGbhSjt BeJBVcmOVrI= SHA512 : 7d8I/F6A1b07E4ZuGeilZjefRgJJ/F20 eC2xoag1OsOVpctt3Mi7Jjjf3vFW4xoY 5mdS6/ImQpm0xtlTLOPeQQ== End timestamp: 2022-10-20 10:50:52 -0700 (run time: 0m 46s) The new database will need to be renamed to be read by AIDE: $ sudo mv /var/lib/aide/aide.db.new.gz /var/lib/aide/aide.db.gz Perform a manual check: $ sudo /usr/sbin/aide --check Example output: Start timestamp: 2022-10-20 11:03:16 -0700 (AIDE 0.16) AIDE found differences between database and filesystem!! ... Done.

b

RHEL 8 must specify the default "include" directory for the /etc/sudoers file.

CM-6 - Medium - CCI-000366 - V-251711 - SV-251711r1017365_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-010379

Vuln IDs

V-251711

Rule IDs

SV-251711r1017365_rule

The "sudo" command allows authorized users to run programs (including shells) as other users, system users, and root. The "/etc/sudoers" file is used to configure authorized "sudo" users as well as the programs they are allowed to run. Some configuration options in the "/etc/sudoers" file allow configured users to run programs without re-authenticating. Use of these configuration options makes it easier for one compromised account to be used to compromise other accounts. It is possible to include other sudoers files from within the sudoers file currently being parsed using the #include and #includedir directives. When sudo reaches this line it will suspend processing of the current file (/etc/sudoers) and switch to the specified file/directory. Once the end of the included file(s) is reached, the rest of /etc/sudoers will be processed. Files that are included may themselves include other files. A hard limit of 128 nested include files is enforced to prevent include file loops.

Checks: C-55148r833384_chk

Note: If the "include" and "includedir" directives are not present in the /etc/sudoers file, this requirement is not applicable. Verify the operating system specifies only the default "include" directory for the /etc/sudoers file with the following command: $ sudo grep include /etc/sudoers #includedir /etc/sudoers.d If the results are not "/etc/sudoers.d" or additional files or directories are specified, this is a finding. Verify the operating system does not have nested "include" files or directories within the /etc/sudoers.d directory with the following command: $ sudo grep -r include /etc/sudoers.d If results are returned, this is a finding.

Fix: F-55102r809356_fix

Configure the /etc/sudoers file to only include the /etc/sudoers.d directory. Edit the /etc/sudoers file with the following command: $ sudo visudo Add or modify the following line: #includedir /etc/sudoers.d

b

The RHEL 8 operating system must not be configured to bypass password requirements for privilege escalation.

IA-11 - Medium - CCI-002038 - V-251712 - SV-251712r1050789_rule

RMF Control

IA-11

Severity

M

CCI

Version

RHEL-08-010385

Vuln IDs

V-251712

Rule IDs

SV-251712r1050789_rule

Without re-authentication, users may access resources or perform tasks for which they do not have authorization. When operating systems provide the capability to escalate a functional capability, it is critical the user re-authenticate. Satisfies: SRG-OS-000373-GPOS-00156, SRG-OS-000373-GPOS-00157, SRG-OS-000373-GPOS-00158

Checks: C-55149r809358_chk

Verify the operating system is not be configured to bypass password requirements for privilege escalation. Check the configuration of the "/etc/pam.d/sudo" file with the following command: $ sudo grep pam_succeed_if /etc/pam.d/sudo If any occurrences of "pam_succeed_if" is returned from the command, this is a finding.

Fix: F-55103r854082_fix

Configure the operating system to require users to supply a password for privilege escalation. Check the configuration of the "/etc/ pam.d/sudo" file with the following command: $ sudo vi /etc/pam.d/sudo Remove any occurrences of "pam_succeed_if" in the file.

b

RHEL 8 must ensure the password complexity module is enabled in the system-auth file.

CM-6 - Medium - CCI-000366 - V-251713 - SV-251713r1017366_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-020101

Vuln IDs

V-251713

Rule IDs

SV-251713r1017366_rule

Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. "pwquality" enforces complex password construction configuration and has the ability to limit brute-force attacks on the system. RHEL 8 uses "pwquality" as a mechanism to enforce password complexity. This is set in both: /etc/pam.d/password-auth /etc/pam.d/system-auth

Checks: C-55150r902738_chk

Verify the operating system uses "pwquality" to enforce the password complexity rules. Check for the use of "pwquality" in the system-auth file with the following command: $ sudo cat /etc/pam.d/system-auth | grep pam_pwquality password requisite pam_pwquality.so If the command does not return a line containing the value "pam_pwquality.so" as shown, or the line is commented out, this is a finding.

Fix: F-55104r902739_fix

Configure the operating system to use "pwquality" to enforce password complexity rules. Add the following line to the "/etc/pam.d/system-auth" file (or modify the line to have the required value): password requisite pam_pwquality.so

b

RHEL 8 systems, version 8.4 and above, must ensure the password complexity module is configured for three retries or less.

CM-6 - Medium - CCI-000366 - V-251716 - SV-251716r1069329_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-020104

Vuln IDs

V-251716

Rule IDs

SV-251716r1069329_rule

Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. "pwquality" enforces complex password construction configuration and has the ability to limit brute-force attacks on the system. RHEL 8 utilizes "pwquality" as a mechanism to enforce password complexity. This is set in both: /etc/pam.d/password-auth /etc/pam.d/system-auth By limiting the number of attempts to meet the pwquality module complexity requirements before returning with an error, the system will audit abnormal attempts at password changes.

Checks: C-55153r1069267_chk

Note: This requirement applies to RHEL versions 8.4 or newer. If the system is RHEL below version 8.4, this requirement is not applicable. Verify RHEL 8 is configured to limit the "pwquality" retry option to "3". Check for the use of the retry option in the security directory with the following command: $ grep -w retry /etc/security/pwquality.conf /etc/security/pwquality.conf.d/*.conf retry = 3 If the value of "retry" is set to "0" or greater than "3", or is missing, this is a finding.

Fix: F-55107r1069268_fix

Configure RHEL 8 to limit the "pwquality" retry option to "3". Add or update the following line in the "/etc/security/pwquality.conf" file or a file in the "/etc/security/pwquality.conf.d/" directory to contain the "retry" parameter: retry = 3

b

The graphical display manager must not be the default target on RHEL 8 unless approved.

CM-6 - Medium - CCI-000366 - V-251718 - SV-251718r1017371_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-08-040321

Vuln IDs

V-251718

Rule IDs

SV-251718r1017371_rule

Internet services that are not required for system or application processes must not be active to decrease the attack surface of the system. Graphical display managers have a long history of security vulnerabilities and must not be used, unless approved and documented.

Checks: C-55155r809376_chk

Verify that the system is configured to boot to the command line: $ systemctl get-default multi-user.target If the system default target is not set to "multi-user.target" and the Information System Security Officer (ISSO) lacks a documented requirement for a graphical user interface, this is a finding.

Fix: F-55109r809377_fix

Document the requirement for a graphical user interface with the ISSO or reinstall the operating system without the graphical user interface. If reinstallation is not feasible, then continue with the following procedure: Open an SSH session and enter the following commands: $ sudo systemctl set-default multi-user.target A reboot is required for the changes to take effect.

b

RHEL 8 must prevent nonprivileged users from executing privileged functions, including disabling, circumventing, or altering implemented security safeguards/countermeasures.

AC-6 - Medium - CCI-002235 - V-254520 - SV-254520r1069331_rule

RMF Control

AC-6

Severity

M

CCI

CCI-002235

Version

RHEL-08-040400

Vuln IDs

V-254520

Rule IDs

SV-254520r1069331_rule

Preventing nonprivileged users from executing privileged functions mitigates the risk that unauthorized individuals or processes may gain unnecessary access to information or privileges. Privileged functions include, for example, establishing accounts, performing system integrity checks, or administering cryptographic key management activities. Nonprivileged users are individuals who do not possess appropriate authorizations. Circumventing intrusion detection and prevention mechanisms or malicious code protection mechanisms are examples of privileged functions that require protection from nonprivileged users.

Checks: C-58004r928594_chk

Verify the operating system prevents nonprivileged users from executing privileged functions, including disabling, circumventing, or altering implemented security safeguards/countermeasures. Obtain a list of authorized users (other than system administrator and guest accounts) for the system. Check the list against the system by using the following command: $ sudo semanage login -l | more Login Name SELinux User MLS/MCS Range Service __default__ user_u s0-s0:c0.c1023 * root unconfined_u s0-s0:c0.c1023 * system_u system_u s0-s0:c0.c1023 * joe staff_u s0-s0:c0.c1023 * All administrators must be mapped to the "sysadm_u", "staff_u", or an appropriately tailored confined role as defined by the organization. All authorized nonadministrative users must be mapped to the "user_u" role. If they are not mapped in this way, this is a finding.

Fix: F-57953r1069272_fix

Configure RHEL 8 to prevent nonprivileged users from executing privileged functions, including disabling, circumventing, or altering implemented security safeguards/countermeasures. Use the following command to map a new user to the "sysadm_u" role: $ sudo semanage login -a -s sysadm_u <username> Use the following command to map an existing user to the "sysadm_u" role: $ sudo semanage login -m -s sysadm_u <username> Use the following command to map a new user to the "staff_u" role: $ sudo semanage login -a -s staff_u <username> Use the following command to map an existing user to the "staff_u" role: $ sudo semanage login -m -s staff_u <username> Use the following command to map a new user to the "user_u" role: $ sudo semanage login -a -s user_u <username> Use the following command to map an existing user to the "user_u" role: $ sudo semanage login -m -s user_u <username> Note: SELinux confined users mapped to sysadm_u are not allowed to log in to the system over SSH, by default. If this is a required function, it can be configured by setting the ssh_sysadm_login SELinux boolean to "on" with the following command: $ sudo setsebool -P ssh_sysadm_login on This must be documented with the information system security officer (ISSO) as an operational requirement.

b

RHEL 8 SSH server must be configured to use only FIPS-validated key exchange algorithms.

AC-17 - Medium - CCI-001453 - V-255924 - SV-255924r1017372_rule

RMF Control

AC-17

Severity

M

CCI

Version

RHEL-08-040342

Vuln IDs

V-255924

Rule IDs

SV-255924r1017372_rule

Without cryptographic integrity protections provided by FIPS-validated cryptographic algorithms, information can be viewed and altered by unauthorized users without detection. RHEL 8 incorporates system-wide crypto policies by default. The SSH configuration file has no effect on the ciphers, MACs, or algorithms unless specifically defined in the /etc/sysconfig/sshd file. The employed algorithms can be viewed in the /etc/crypto-policies/back-ends/opensshserver.config file. The system will attempt to use the first algorithm presented by the client that matches the server list. Listing the values "strongest to weakest" is a method to ensure the use of the strongest algorithm available to secure the SSH connection.

Checks: C-59601r917887_chk

Verify that the SSH server is configured to use only FIPS-validated key exchange algorithms: $ sudo grep -i kexalgorithms /etc/crypto-policies/back-ends/opensshserver.config CRYPTO_POLICY='-oKexAlgorithms=ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512' If the entries following "KexAlgorithms" have any algorithms defined other than "ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512", appear in different order than shown, or are missing or commented out, this is a finding.

Fix: F-59544r880732_fix

Configure the SSH server to use only FIPS-validated key exchange algorithms by adding or modifying the following line in "/etc/crypto-policies/back-ends/opensshserver.config": -oKexAlgorithms=ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512 A reboot is required for the changes to take effect.

b

RHEL 8 must ensure cryptographic verification of vendor software packages.

CM-5 - Medium - CCI-001749 - V-256973 - SV-256973r1017373_rule

RMF Control

CM-5

Severity

M

CCI

Version

RHEL-08-010019

Vuln IDs

V-256973

Rule IDs

SV-256973r1017373_rule

Cryptographic verification of vendor software packages ensures that all software packages are obtained from a valid source and protects against spoofing that could lead to installation of malware on the system. Red Hat cryptographically signs all software packages, which includes updates, with a GPG key to verify that they are valid.

Checks: C-60651r902750_chk

Confirm Red Hat package-signing keys are installed on the system and verify their fingerprints match vendor values. Note: For RHEL 8 software packages, Red Hat uses GPG keys labeled "release key 2" and "auxiliary key 2". The keys are defined in key file "/etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release" by default. List Red Hat GPG keys installed on the system: $ sudo rpm -q --queryformat "%{SUMMARY}\n" gpg-pubkey | grep -i "red hat" gpg(Red Hat, Inc. (release key 2) <security@redhat.com>) gpg(Red Hat, Inc. (auxiliary key) <security@redhat.com>) If Red Hat GPG keys "release key 2" and "auxiliary key 2" are not installed, this is a finding. Note: The "auxiliary key 2" appears as "auxiliary key" on a RHEL 8 system. List key fingerprints of installed Red Hat GPG keys: $ sudo gpg -q --keyid-format short --with-fingerprint /etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release If key file "/etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release" is missing, this is a finding. Example output: pub rsa4096/FD431D51 2009-10-22 [SC] Key fingerprint = 567E 347A D004 4ADE 55BA 8A5F 199E 2F91 FD43 1D51 uid Red Hat, Inc. (release key 2) <security@redhat.com> pub rsa4096/D4082792 2018-06-27 [SC] Key fingerprint = 6A6A A7C9 7C88 90AE C6AE BFE2 F76F 66C3 D408 2792 uid Red Hat, Inc. (auxiliary key) <security@redhat.com> sub rsa4096/1B5584D3 2018-06-27 [E] Compare key fingerprints of installed Red Hat GPG keys with fingerprints listed for RHEL 8 on Red Hat "Product Signing Keys" webpage at https://access.redhat.com/security/team/key. If key fingerprints do not match, this is a finding.

Fix: F-60593r902751_fix

Install Red Hat package-signing keys on the system and verify their fingerprints match vendor values. Insert RHEL 8 installation disc or attach RHEL 8 installation image to the system. Mount the disc or image to make the contents accessible inside the system. Assuming the mounted location is "/media/cdrom", use the following command to copy Red Hat GPG key file onto the system: $ sudo cp /media/cdrom/RPM-GPG-KEY-redhat-release /etc/pki/rpm-gpg/ Import Red Hat GPG keys from key file into system keyring: $ sudo rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release Using the steps listed in the Check Text, confirm the newly imported keys show as installed on the system and verify their fingerprints match vendor values.

b

RHEL 8 must be configured to allow sending email notifications of unauthorized configuration changes to designated personnel.

CM-3 - Medium - CCI-001744 - V-256974 - SV-256974r1069321_rule

RMF Control

CM-3

Severity

M

CCI

CCI-001744

Version

RHEL-08-010358

Vuln IDs

V-256974

Rule IDs

SV-256974r1069321_rule

Unauthorized changes to the baseline configuration could make the system vulnerable to various attacks or allow unauthorized access to the operating system. Changes to operating system configurations can have unintended side effects, some of which may be relevant to security. Detecting such changes and providing an automated response can help avoid unintended, negative consequences that could ultimately affect the security state of the operating system. The operating system's IMO/ISSO and SAs must be notified via email and/or monitoring system trap when there is an unauthorized modification of a configuration item.

Checks: C-60652r1069251_chk

Verify that the operating system is configured to allow sending email notifications. Note: The "mailx" package provides the "mail" command that is used to send email messages. The s-nail package is also suitable and may be used in place of mailx. Verify that the "mailx" package is installed on the system: $ sudo yum list installed mailx mailx.x86_64 12.5-29.el8 @rhel-8-for-x86_64-baseos-rpm If "mailx" package is not installed, this is a finding.

Fix: F-60594r902754_fix

Install the "mailx" package on the system: $ sudo yum install mailx

b

RHEL 8.7 and higher must terminate idle user sessions.

SC-10 - Medium - CCI-001133 - V-257258 - SV-257258r1069328_rule

RMF Control

SC-10

Severity

M

CCI

CCI-001133

Version

RHEL-08-020035

Vuln IDs

V-257258

Rule IDs

SV-257258r1069328_rule

Terminating an idle session within a short time period reduces the window of opportunity for unauthorized personnel to take control of a management session enabled on the console or console port that has been left unattended.

Checks: C-60942r1069265_chk

Note: This requirement applies to RHEL versions 8.7 and higher. If the system is not RHEL version 8.7 or newer, this requirement is not applicable. Note: For cloud hosted systems where "ClientAliveInterval" (V-244525) is configured, this setting is not applicable. Verify that RHEL 8 logs out sessions that are idle for 10 minutes with the following command: $ sudo grep -i ^StopIdleSessionSec /etc/systemd/logind.conf StopIdleSessionSec=600 If "StopIdleSessionSec" is not configured to "600" seconds, this is a finding.

Fix: F-60884r1014792_fix

Configure RHEL 8 to log out idle sessions after 10 minutes by editing the /etc/systemd/logind.conf file with the following line: StopIdleSessionSec=600 The "logind" service must be restarted for the changes to take effect. To restart the "logind" service, run the following command: $ sudo systemctl restart systemd-logind

c

RHEL 8 must not allow blank or null passwords in the system-auth file.

CM-6 - High - CCI-000366 - V-268322 - SV-268322r1017568_rule

RMF Control

CM-6

Severity

H

CCI

Version

RHEL-08-020331

Vuln IDs

V-268322

Rule IDs

SV-268322r1017568_rule

If an account has an empty password, anyone could log on and run commands with the privileges of that account. Accounts with empty passwords should never be used in operational environments.

Checks: C-72343r1017566_chk

To verify that null passwords cannot be used, run the following command: $ sudo grep -i nullok /etc/pam.d/system-auth If output is produced, this is a finding.

Fix: F-72246r1017567_fix

Remove any instances of the "nullok" option in the "/etc/pam.d/system-auth" file to prevent logons with empty passwords. Note: Manual changes to the listed file may be overwritten by the "authselect" program.

b

RHEL 8 SSH client must be configured to use only Message Authentication Codes (MACs) employing FIPS 140-3 validated cryptographic hash algorithms.

AC-17 - Medium - CCI-001453 - V-272482 - SV-272482r1069414_rule

RMF Control

AC-17

Severity

M

CCI

Version

RHEL-08-010296

Vuln IDs

V-272482

Rule IDs

SV-272482r1069414_rule

Without cryptographic integrity protections, information can be altered by unauthorized users without detection. Remote access (e.g., RDP) is access to DOD nonpublic information systems by an authorized user (or an information system) communicating through an external, non-organizationally controlled network. Remote access methods include, for example, dial-up, broadband, and wireless. Cryptographic mechanisms used for protecting the integrity of information include, for example, signed hash functions using asymmetric cryptography enabling distribution of the public key to verify the hash information while maintaining the confidentiality of the secret key used to generate the hash. RHEL 8.4 and newer releases incorporate system-wide crypto policies by default. The SSH configuration file has no effect on the ciphers, MACs, or algorithms unless specifically defined in the /etc/sysconfig/sshd file. The employed algorithms can be viewed in the /etc/crypto-policies/back-ends/openssh.config file.

Checks: C-76536r1069412_chk

Verify the SSH client is configured to use only MACs employing FIPS 140-3 approved algorithms with the following command: $ grep -i macs /etc/crypto-policies/back-ends/openssh.config -oMACs hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512,hmac-sha2-256 If the MACs entries in the "openssh.config" file have any hashes other than "MACs hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha2-256,hmac-sha2-512", they are missing, or commented out, this is a finding.

Fix: F-76442r1069413_fix

Configure the RHEL 8 SSH client to use only MACs employing FIPS 140-3 approved algorithms. For RHEL 8.4 and newer, update the "/etc/crypto-policies/back-ends/openssh.config" file with the following command: sudo sed -i -E 's/(-oMACs=)[^ ]*/\1hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512,hmac-sha2-256/' "$(readlink -f /etc/crypto-policies/back-ends/openssh.config)" A reboot is required for the changes to take effect.

b

RHEL 8 SSH client must be configured to use only ciphers employing FIPS 140-3 validated cryptographic hash algorithms.

AC-17 - Medium - CCI-001453 - V-272483 - SV-272483r1069415_rule

RMF Control

AC-17

Severity

M

CCI