Oracle Linux 8 Security Technical Implementation Guide

  • Version/Release: V1R10
  • Published: 2024-02-19
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This Security Technical Implementation Guide is published as a tool to improve the security of Department of Defense (DOD) information systems. The requirements are derived from the National Institute of Standards and Technology (NIST) 800-53 and related documents. Comments or proposed revisions to this document should be sent via email to the following address: disa.stig_spt@mail.mil.
b
The OL 8 audit package must be installed.
AU-3 - Medium - CCI-000130 - V-248519 - SV-248519r853745_rule
RMF Control
AU-3
Severity
Medium
CCI
CCI-000130
Version
OL08-00-030180
Vuln IDs
  • V-248519
Rule IDs
  • SV-248519r853745_rule
Without establishing what type of events occurred and their source, location, and outcome, 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 OL 8 audit logs provides a means of investigating an attack, recognizing resource utilization or capacity thresholds, or identifying an improperly configured OL 8 system. Satisfies: 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-000062-GPOS-00031, 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-51953r779121_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 "auditd" package is not installed, this is a finding.

Fix: F-51907r779122_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
OL 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-3 - Medium - CCI-000130 - V-248520 - SV-248520r853746_rule
RMF Control
AU-3
Severity
Medium
CCI
CCI-000130
Version
OL08-00-030181
Vuln IDs
  • V-248520
Rule IDs
  • SV-248520r853746_rule
Without establishing what type of events occurred and their source, location, and outcome, 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 OL 8 audit logs provides a means of investigating an attack, recognizing resource utilization or capacity thresholds, or identifying an improperly configured OL 8 system. Satisfies: 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-000062-GPOS-00031, 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-51954r818593_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-51908r779125_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

c
OL 8 must be a vendor-supported release.
CM-6 - High - CCI-000366 - V-248521 - SV-248521r779129_rule
RMF Control
CM-6
Severity
High
CCI
CCI-000366
Version
OL08-00-010000
Vuln IDs
  • V-248521
Rule IDs
  • SV-248521r779129_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 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-51955r779127_chk

Verify the version of the operating system is vendor supported. Check the version of the operating system with the following command: $ udo cat /etc/oracle-release Oracle Linux Server release 8.2 Current End of Premier Support for Oracle Linux 8 is July 2029, while Extended Support might consider an extended term. If the release is not supported by the vendor, this is a finding.

Fix: F-51909r779128_fix

Upgrade to a supported version of the operating system.

b
The OL 8 operating system must implement the Endpoint Security for Linux Threat Prevention tool.
SI-2 - Medium - CCI-001233 - V-248522 - SV-248522r943103_rule
RMF Control
SI-2
Severity
Medium
CCI
CCI-001233
Version
OL08-00-010001
Vuln IDs
  • V-248522
Rule IDs
  • SV-248522r943103_rule
Adding endpoint security tools can provide the capability to automatically take actions in response to malicious behavior, which can provide additional agility in reacting to network threats. These tools also often include a reporting capability to provide network awareness of the system, which may not otherwise exist in an organization's systems management regime.
Checks: C-51956r943102_chk

Check that the following package has been installed: # rpm -qa | grep -i mcafeetp If the "mcafeetp" package is not installed, this is a finding. Verify that the daemon is running: # ps -ef | grep -i mfetpd If the daemon is not running, this is a finding.

Fix: F-51910r779131_fix

Install and enable the latest McAfee ENSLTP package.

b
OL 8 vendor-packaged system security patches and updates must be installed and up to date.
CM-6 - Medium - CCI-000366 - V-248523 - SV-248523r779135_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010010
Vuln IDs
  • V-248523
Rule IDs
  • SV-248523r779135_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-51957r779133_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 Oracle. The URL for updates is https://linux.oracle.com/errata/. It is important to note that updates provided by Oracle 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 that 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 not in compliance with the Information Assurance Vulnerability Management (IAVM) process, this is a finding.

Fix: F-51911r779134_fix

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

c
OL 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-248524 - SV-248524r928551_rule
RMF Control
AC-17
Severity
High
CCI
CCI-000068
Version
OL08-00-010020
Vuln IDs
  • V-248524
Rule IDs
  • SV-248524r928551_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. OL 8 uses 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-000250-GPOS-00093, SRG-OS-000393-GPOS-00173, SRG-OS-000394-GPOS-00174, SRG-OS-000423-GPOS-00187
Checks: C-51958r928549_chk

Verify the operating system implements DOD-approved encryption to protect the confidentiality of remote access sessions. Check to see if FIPS mode is enabled with the following command: $ fips-mode-setup --check FIPS mode is enabled If FIPS mode is "enabled", check to see if the kernel boot parameter is configured for FIPS mode with the following command: $ sudo grub2-editenv list | grep fips kernelopts=root=/dev/mapper/ol-root ro resume=/dev/mapper/ol-swap rd.lvm.lv=ol/root rd.lvm.lv=ol/swap rhgb quiet fips=1 boot=UUID=25856928-386b-4205-9a0e-a2953ae2712d audit=1 audit_backlog_limit=8192 pti=on random.trust_cpu=on slub_debug=P page_poison=1 If the kernel boot parameter is configured to use FIPS mode, check to see if the system is in FIPS mode with the following command: $ sudo cat /proc/sys/crypto/fips_enabled 1 If FIPS mode is not "enabled", the kernel boot parameter is not configured for FIPS mode, or the system does not have a value of "1" for "fips_enabled" in "/proc/sys/crypto", this is a finding.

Fix: F-51912r928550_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 must 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.

b
All OL 8 local disk partitions must implement cryptographic mechanisms to prevent unauthorized disclosure or modification of all information that requires at-rest protection.
SC-28 - Medium - CCI-001199 - V-248525 - SV-248525r917893_rule
RMF Control
SC-28
Severity
Medium
CCI
CCI-001199
Version
OL08-00-010030
Vuln IDs
  • V-248525
Rule IDs
  • SV-248525r917893_rule
OL 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-51959r917892_chk

Verify OL 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/ol-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 listed, 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-51913r779140_fix

Configure OL 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
OL 8 must display the Standard Mandatory DOD Notice and Consent Banner before granting local or remote access to the system via an SSH logon.
AC-8 - Medium - CCI-000048 - V-248526 - SV-248526r951551_rule
RMF Control
AC-8
Severity
Medium
CCI
CCI-000048
Version
OL08-00-010040
Vuln IDs
  • V-248526
Rule IDs
  • SV-248526r951551_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-51960r951549_chk

Verify that 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' 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-51914r951550_fix

Configure OL 8 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
OL 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-248527 - SV-248527r779147_rule
RMF Control
AC-8
Severity
Medium
CCI
CCI-000048
Version
OL08-00-010049
Vuln IDs
  • V-248527
Rule IDs
  • SV-248527r779147_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-51961r779145_chk

Note: This requirement assumes the use of the OL 8 default graphical user interface, Gnome Shell. If the system does not have any graphical user interface installed, this requirement is Not Applicable. Verify OL 8 displays a banner before granting access to the operating system via a graphical user logon. Determine 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-51915r779146_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
OL 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-248528 - SV-248528r779150_rule
RMF Control
AC-8
Severity
Medium
CCI
CCI-000048
Version
OL08-00-010050
Vuln IDs
  • V-248528
Rule IDs
  • SV-248528r779150_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-51962r779148_chk

Note: This requirement assumes the use of the OL 8 default graphical user interface, Gnome Shell. If the system does not have any graphical user interface installed, this requirement is Not Applicable. Verify OL 8 displays the Standard Mandatory DoD Notice and Consent Banner before granting access to the operating system via a graphical user logon. Check that the operating system displays the exact Standard Mandatory DoD Notice and Consent Banner text with the command: $ sudo grep banner-message-text /etc/dconf/db/local.d/* 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-51916r779149_fix

Configure OL 8 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
OL 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-248529 - SV-248529r779153_rule
RMF Control
AC-8
Severity
Medium
CCI
CCI-000048
Version
OL08-00-010060
Vuln IDs
  • V-248529
Rule IDs
  • SV-248529r779153_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-51963r779151_chk

Verify OL 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 OL 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-51917r779152_fix

Configure OL 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 OL 8 remote access methods must be monitored.
AC-17 - Medium - CCI-000067 - V-248530 - SV-248530r951553_rule
RMF Control
AC-17
Severity
Medium
CCI
CCI-000067
Version
OL08-00-010070
Vuln IDs
  • V-248530
Rule IDs
  • SV-248530r951553_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 cyberattacks 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-51964r951552_chk

Verify that OL 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.conf:auth.*;authpriv.*;daemon.* /var/log/secure If "auth.*", "authpriv.*", or "daemon.*" are not configured to be logged, this is a finding.

Fix: F-51918r779155_fix

Configure OL 8 to monitor all remote access methods by installing rsyslog with the following command: $ sudo yum install rsyslog 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
OL 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-248531 - SV-248531r860907_rule
RMF Control
IA-5
Severity
Medium
CCI
CCI-000185
Version
OL08-00-010090
Vuln IDs
  • V-248531
Rule IDs
  • SV-248531r860907_rule
Without path validation, the relying party cannot make an informed trust decision 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-51965r858601_chk

Verify OL 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 installed in the "/etc/sssd/pki/sssd_auth_ca_db.pem" location, this is a finding.

Fix: F-51919r818597_fix

Configure OL 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 it into the following file: /etc/sssd/pki/sssd_auth_ca_db.pem

b
OL 8, for certificate-based authentication, must enforce authorized access to the corresponding private key.
IA-5 - Medium - CCI-000186 - V-248532 - SV-248532r779162_rule
RMF Control
IA-5
Severity
Medium
CCI
CCI-000186
Version
OL08-00-010100
Vuln IDs
  • V-248532
Rule IDs
  • SV-248532r779162_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-51966r779160_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 If the contents of the key are displayed, this is a finding.

Fix: F-51920r779161_fix

Create a new private and public key pair that uses a passcode with the following command: $ sudo ssh-keygen -n [passphrase]

b
OL 8 must encrypt all stored passwords with a FIPS 140-2 approved cryptographic hashing algorithm.
IA-5 - Medium - CCI-000196 - V-248533 - SV-248533r877397_rule
RMF Control
IA-5
Severity
Medium
CCI
CCI-000196
Version
OL08-00-010110
Vuln IDs
  • V-248533
Rule IDs
  • SV-248533r877397_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 on 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 use authentication that meets DoD requirements.
Checks: C-51967r779163_chk

Verify that the shadow password suite configuration is set to encrypt passwords 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 cat /etc/login.defs | grep -i crypt ENCRYPT_METHOD SHA512 If "ENCRYPT_METHOD" does not equal SHA512 or greater, this is a finding.

Fix: F-51921r779164_fix

Configure OL 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
OL 8 must employ FIPS 140-2 approved cryptographic hashing algorithms for all stored passwords.
IA-5 - Medium - CCI-000196 - V-248534 - SV-248534r877397_rule
RMF Control
IA-5
Severity
Medium
CCI
CCI-000196
Version
OL08-00-010120
Vuln IDs
  • V-248534
Rule IDs
  • SV-248534r877397_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-51968r779166_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-51922r779167_fix

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

b
The OL 8 shadow password suite must be configured to use a sufficient number of hashing rounds.
IA-5 - Medium - CCI-000196 - V-248535 - SV-248535r880546_rule
RMF Control
IA-5
Severity
Medium
CCI
CCI-000196
Version
OL08-00-010130
Vuln IDs
  • V-248535
Rule IDs
  • SV-248535r880546_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-51969r880545_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 "5000", this is a finding. If both "SHA_CRYPT_MIN_ROUNDS" and "SHA_CRYPT_MAX_ROUNDS" are set, and the value for either is below "5000", this is a finding.

Fix: F-51923r818600_fix

Configure OL 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 "5000": SHA_CRYPT_MIN_ROUNDS 5000

c
OL 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-248537 - SV-248537r779177_rule
RMF Control
AC-3
Severity
High
CCI
CCI-000213
Version
OL08-00-010140
Vuln IDs
  • V-248537
Rule IDs
  • SV-248537r779177_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 OL 8 and is designed to require a password to boot into single-user mode or modify the boot menu.
Checks: C-51971r779175_chk

For systems that use BIOS, this is not applicable. Determine if an encrypted password is set for the grub superusers account. 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 account password does not begin with "grub.pbkdf2.sha512", this is a finding.

Fix: F-51925r779176_fix

Configure the system to require an encrypted 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:

b
OL 8 operating systems booted with United Extensible Firmware Interface (UEFI) must have a unique name for the grub superusers account when booting into single-user mode and maintenance.
AC-3 - Medium - CCI-000213 - V-248538 - SV-248538r818603_rule
RMF Control
AC-3
Severity
Medium
CCI
CCI-000213
Version
OL08-00-010141
Vuln IDs
  • V-248538
Rule IDs
  • SV-248538r818603_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 OL 8 and is designed to require a password to boot into single-user mode or modify 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-51972r818602_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="[someuniqueUserNamehere]" export superusers If "superusers" is identical to any OS account name or is missing a name, this is a finding.

Fix: F-51926r779179_fix

Configure the system to replace "root" with 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="[someuniqueUserNamehere]" export superusers password_pbkdf2 [someuniqueUserNamehere] ${GRUB2_PASSWORD} Generate a new grub.cfg file with the following command: $ sudo grub2-mkconfig -o /boot/efi/EFI/redhat/grub.cfg

b
OL 8 operating systems booted with a BIOS must have a unique name for the grub superusers account when booting into single-user and maintenance modes.
AC-3 - Medium - CCI-000213 - V-248539 - SV-248539r818605_rule
RMF Control
AC-3
Severity
Medium
CCI
CCI-000213
Version
OL08-00-010149
Vuln IDs
  • V-248539
Rule IDs
  • SV-248539r818605_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 OL 8 and is designed to require a password to boot into single-user mode or modify 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-51973r818604_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="[someuniqueUserNamehere]" export superusers If "superusers" is identical to any OS account name or is missing a name, this is a finding.

Fix: F-51927r779182_fix

Configure the system to replace "root" with 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="[someuniqueUserNamehere]" export superusers password_pbkdf2 [someuniqueUserNamehere] ${GRUB2_PASSWORD} Generate a new grub.cfg file with the following command: $ sudo grub2-mkconfig -o /boot/grub2/grub.cfg

c
OL 8 operating systems booted with a BIOS must require authentication upon booting into single-user and maintenance modes.
AC-3 - High - CCI-000213 - V-248540 - SV-248540r779186_rule
RMF Control
AC-3
Severity
High
CCI
CCI-000213
Version
OL08-00-010150
Vuln IDs
  • V-248540
Rule IDs
  • SV-248540r779186_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 OL 8 and is designed to require a password to boot into single-user mode or modify the boot menu.
Checks: C-51974r779184_chk

For systems that use UEFI, this is not applicable. Determine if an encrypted password is set for the grub superusers account. 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 account password does not begin with "grub.pbkdf2.sha512", this is a finding.

Fix: F-51928r779185_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
OL 8 operating systems must require authentication upon booting into rescue mode.
AC-3 - Medium - CCI-000213 - V-248541 - SV-248541r779189_rule
RMF Control
AC-3
Severity
Medium
CCI
CCI-000213
Version
OL08-00-010151
Vuln IDs
  • V-248541
Rule IDs
  • SV-248541r779189_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-51975r779187_chk

Determine 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" or is commented out or missing, this is a finding.

Fix: F-51929r779188_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
OL 8 operating systems must require authentication upon booting into emergency mode.
AC-3 - Medium - CCI-000213 - V-248542 - SV-248542r779192_rule
RMF Control
AC-3
Severity
Medium
CCI
CCI-000213
Version
OL08-00-010152
Vuln IDs
  • V-248542
Rule IDs
  • SV-248542r779192_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-51976r779190_chk

Determine 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" or is commented out or missing, this is a finding.

Fix: F-51930r779191_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 OL 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-248543 - SV-248543r818608_rule
RMF Control
IA-7
Severity
Medium
CCI
CCI-000803
Version
OL08-00-010159
Vuln IDs
  • V-248543
Rule IDs
  • SV-248543r818608_rule
Unapproved mechanisms that are used for authentication to the cryptographic module are not verified and therefore cannot be relied on to provide confidentiality or integrity, and DoD data may be compromised. OL 8 systems using 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 use 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-51977r818606_chk

Verify that the "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-51931r818607_fix

Configure OL 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
The OL 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-248544 - SV-248544r818611_rule
RMF Control
IA-7
Severity
Medium
CCI
CCI-000803
Version
OL08-00-010160
Vuln IDs
  • V-248544
Rule IDs
  • SV-248544r818611_rule
Unapproved mechanisms that are used for authentication to the cryptographic module are not verified and therefore cannot be relied on to provide confidentiality or integrity, and DoD data may be compromised. OL 8 systems using 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 use 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-51978r818609_chk

Verify 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-51932r818610_fix

Configure OL 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
OL 8 must prevent system daemons from using Kerberos for authentication.
IA-7 - Medium - CCI-000803 - V-248545 - SV-248545r779201_rule
RMF Control
IA-7
Severity
Medium
CCI
CCI-000803
Version
OL08-00-010161
Vuln IDs
  • V-248545
Rule IDs
  • SV-248545r779201_rule
Unapproved mechanisms that are used for authentication to the cryptographic module are not verified and therefore cannot be relied on to provide confidentiality or integrity, and DoD data may be compromised. OL 8 systems using 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 use 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-51979r779199_chk

Verify that OL 8 prevents system daemons from using Kerberos for authentication. If the system is a server using krb5-server-1.17-18.el8.x86_64 or newer, this requirement is not applicable. If the system is a workstation using 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-51933r779200_fix

Configure OL 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 OL 8.
IA-7 - Medium - CCI-000803 - V-248546 - SV-248546r779204_rule
RMF Control
IA-7
Severity
Medium
CCI
CCI-000803
Version
OL08-00-010162
Vuln IDs
  • V-248546
Rule IDs
  • SV-248546r779204_rule
Unapproved mechanisms that are used for authentication to the cryptographic module are not verified and therefore cannot be relied on to provide confidentiality or integrity, and DoD data may be compromised. OL 8 systems using encryption are required to use FIPS-compliant mechanisms for authenticating to cryptographic modules. Currently, Kerberos does not use FIPS 140-2 cryptography. FIPS 140-2 is the current standard for validating that mechanisms used to access cryptographic modules use 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-51980r779202_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 using 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-51934r779203_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
The krb5-server package must not be installed on OL 8.
IA-7 - Medium - CCI-000803 - V-248547 - SV-248547r779207_rule
RMF Control
IA-7
Severity
Medium
CCI
CCI-000803
Version
OL08-00-010163
Vuln IDs
  • V-248547
Rule IDs
  • SV-248547r779207_rule
Unapproved mechanisms that are used for authentication to the cryptographic module are not verified and therefore cannot be relied on to provide confidentiality or integrity, and DoD data may be compromised. OL 8 systems using encryption are required to use FIPS-compliant mechanisms for authenticating to cryptographic modules. Currently, Kerberos does not use FIPS 140-2 cryptography. FIPS 140-2 is the current standard for validating that mechanisms used to access cryptographic modules use 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-51981r779205_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 using 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-51935r779206_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
OL 8 must use a Linux Security Module configured to enforce limits on system services.
SC-3 - Medium - CCI-001084 - V-248548 - SV-248548r779210_rule
RMF Control
SC-3
Severity
Medium
CCI
CCI-001084
Version
OL08-00-010170
Vuln IDs
  • V-248548
Rule IDs
  • SV-248548r779210_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-51982r779208_chk

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

Fix: F-51936r779209_fix

Configure OL 8 to verify correct operation of all security functions. Set "SELinux" to "Enforcing" mode by modifying the "/etc/selinux/config" file with the following line: SELINUX=enforcing A reboot is required for the changes to take effect.

a
OL 8 must have the "policycoreutils" package installed.
SC-3 - Low - CCI-001084 - V-248549 - SV-248549r779213_rule
RMF Control
SC-3
Severity
Low
CCI
CCI-001084
Version
OL08-00-010171
Vuln IDs
  • V-248549
Rule IDs
  • SV-248549r779213_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.
Checks: C-51983r779211_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-51937r779212_fix

Install the "policycoreutil" package, if it is not already installed, by running the following command: $ sudo yum install policycoreutils

b
A sticky bit must be set on all OL 8 public directories to prevent unauthorized and unintended information transferred via shared system resources.
SC-4 - Medium - CCI-001090 - V-248551 - SV-248551r779219_rule
RMF Control
SC-4
Severity
Medium
CCI
CCI-001090
Version
OL08-00-010190
Vuln IDs
  • V-248551
Rule IDs
  • SV-248551r779219_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-51985r779217_chk

Verify that all world-writable directories have the sticky bit set. Verify that all world-writable directories have the sticky bit set by running the following command: $ sudo find / -type d \( -perm -0002 -a ! -perm -1000 \) -print 2>/dev/null If any of the returned directories are world-writable and do not have the sticky bit set, this is a finding.

Fix: F-51939r779218_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
OL 8 must be configured so that all network connections associated with SSH traffic terminate after becoming unresponsive.
MA-4 - Medium - CCI-000879 - V-248552 - SV-248552r951555_rule
RMF Control
MA-4
Severity
Medium
CCI
CCI-000879
Version
OL08-00-010200
Vuln IDs
  • V-248552
Rule IDs
  • SV-248552r951555_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, de-allocating associated TCP/IP address/port pairs at the operating system level and de-allocating 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. OL 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-000126-GPOS-00066, SRG-OS-000163-GPOS-00072, SRG-OS-000279-GPOS-00109
Checks: C-51986r951554_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 running 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' ClientAliveCountMax 1 If "ClientAliveCountMax" does not exist, does not have a product 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-51940r917895_fix

Note: This setting must be applied in conjunction with OL08-00-010201 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 line 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
OL 8 must be configured so that all network connections associated with SSH traffic are terminated after 10 minutes of becoming unresponsive.
MA-4 - Medium - CCI-000879 - V-248553 - SV-248553r951557_rule
RMF Control
MA-4
Severity
Medium
CCI
CCI-000879
Version
OL08-00-010201
Vuln IDs
  • V-248553
Rule IDs
  • SV-248553r951557_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, de-allocating associated TCP/IP address/port pairs at the operating system level and de-allocating 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. OL 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-000126-GPOS-00066, SRG-OS-000163-GPOS-00072, SRG-OS-000279-GPOS-00109
Checks: C-51987r951556_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 running 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 product 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-51941r917898_fix

Note: This setting must be applied in conjunction with OL08-00-010200 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 to have a product value of "600" or less: ClientAliveInterval 600 The SSH daemon must be restarted for changes to take effect. $ sudo systemctl restart sshd.service

b
The OL 8 "/var/log/messages" file must have mode 0640 or less permissive.
SI-11 - Medium - CCI-001314 - V-248554 - SV-248554r779228_rule
RMF Control
SI-11
Severity
Medium
CCI
CCI-001314
Version
OL08-00-010210
Vuln IDs
  • V-248554
Rule IDs
  • SV-248554r779228_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 OL 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-51988r779226_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-51942r779227_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 OL 8 "/var/log/messages" file must be owned by root.
SI-11 - Medium - CCI-001314 - V-248555 - SV-248555r779231_rule
RMF Control
SI-11
Severity
Medium
CCI
CCI-001314
Version
OL08-00-010220
Vuln IDs
  • V-248555
Rule IDs
  • SV-248555r779231_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 OL 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-51989r779229_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-51943r779230_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 OL 8 "/var/log/messages" file must be group-owned by root.
SI-11 - Medium - CCI-001314 - V-248556 - SV-248556r779234_rule
RMF Control
SI-11
Severity
Medium
CCI
CCI-001314
Version
OL08-00-010230
Vuln IDs
  • V-248556
Rule IDs
  • SV-248556r779234_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 OL 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-51990r779232_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-51944r779233_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 OL 8 "/var/log" directory must have mode 0755 or less permissive.
SI-11 - Medium - CCI-001314 - V-248557 - SV-248557r779237_rule
RMF Control
SI-11
Severity
Medium
CCI
CCI-001314
Version
OL08-00-010240
Vuln IDs
  • V-248557
Rule IDs
  • SV-248557r779237_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 OL 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-51991r779235_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-51945r779236_fix

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

b
The OL 8 "/var/log" directory must be owned by root.
SI-11 - Medium - CCI-001314 - V-248558 - SV-248558r779240_rule
RMF Control
SI-11
Severity
Medium
CCI
CCI-001314
Version
OL08-00-010250
Vuln IDs
  • V-248558
Rule IDs
  • SV-248558r779240_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 OL 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-51992r779238_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-51946r779239_fix

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

b
The OL 8 "/var/log" directory must be group-owned by root.
SI-11 - Medium - CCI-001314 - V-248559 - SV-248559r779243_rule
RMF Control
SI-11
Severity
Medium
CCI
CCI-001314
Version
OL08-00-010260
Vuln IDs
  • V-248559
Rule IDs
  • SV-248559r779243_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 OL 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-51993r779241_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-51947r779242_fix

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

b
The OL 8 SSH daemon must be configured to use system-wide crypto policies.
AC-17 - Medium - CCI-001453 - V-248560 - SV-248560r877394_rule
RMF Control
AC-17
Severity
Medium
CCI
CCI-001453
Version
OL08-00-010287
Vuln IDs
  • V-248560
Rule IDs
  • SV-248560r877394_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. OL 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.
Checks: C-51994r818612_chk

Verify that system-wide crypto policies are in effect: $ sudo grep -i CRYPTO_POLICY /etc/sysconfig/sshd # CRYPTO_POLICY= If the "CRYPTO_POLICY" is uncommented, this is a finding.

Fix: F-51948r818613_fix

Configure the OL 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.

b
The OL 8 SSH server must be configured to use only Message Authentication Codes (MACs) employing FIPS 140-2 validated cryptographic hash algorithms.
MA-4 - Medium - CCI-000877 - V-248561 - SV-248561r917902_rule
RMF Control
MA-4
Severity
Medium
CCI
CCI-000877
Version
OL08-00-010290
Vuln IDs
  • V-248561
Rule IDs
  • SV-248561r917902_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. OL 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 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.
Checks: C-51995r917900_chk

Verify the SSH server is configured to use only MACs employing FIPS 140-2-approved algorithms with the following command: $ sudo grep -i macs /etc/crypto-policies/back-ends/opensshserver.config -oMACS=hmac-sha2-512,hmac-sha2-256,hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com If the MACs entries in the "opensshserver.config" file have any hashes other than shown here, the order differs from the example above, or they are missing or commented out, this is a finding.

Fix: F-51949r917901_fix

Configure the OL 8 SSH server to use only MACs employing FIPS 140-2 approved algorithms: Update the "/etc/crypto-policies/back-ends/opensshserver.config" file to include these MACs employing FIPS 140-2 approved algorithms: -oMACS=hmac-sha2-512,hmac-sha2-256,hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com A reboot is required for the changes to take effect.

b
The OL 8 SSH server must be configured to use only ciphers employing FIPS 140-2 validated cryptographic algorithms.
MA-4 - Medium - CCI-000877 - V-248562 - SV-248562r917905_rule
RMF Control
MA-4
Severity
Medium
CCI
CCI-000877
Version
OL08-00-010291
Vuln IDs
  • V-248562
Rule IDs
  • SV-248562r917905_rule
Unapproved mechanisms that are used for authentication to the cryptographic module are not verified and therefore cannot be relied on to provide confidentiality or integrity, and DoD data may be compromised. Operating systems using 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 use authentication that meets DoD requirements. This allows for Security Levels 1, 2, 3, or 4 for use on a general-purpose computing system. 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 cipher available to secure the SSH connection.
Checks: C-51996r917903_chk

Verify the OL 8 SSH server is configured to use only ciphers employing FIPS 140-2 approved algorithms with the following command: $ sudo grep -i ciphers /etc/crypto-policies/back-ends/opensshserver.config CRYPTO_POLICY='-oCiphers=aes256-ctr,aes192-ctr,aes128-ctr,aes256-gcm@openssh.com,aes128-gcm@openssh.com' If the cipher entries in the "opensshserver.config" file have any ciphers other than shown here, the order differs from the example above, or they are missing or commented out, this is a finding.

Fix: F-51950r917904_fix

Configure the OL 8 SSH server to use only ciphers employing FIPS 140-2 approved algorithms: Update the "/etc/crypto-policies/back-ends/opensshserver.config" file to include these ciphers employing FIPS 140-2-approved algorithms: CRYPTO_POLICY='-oCiphers=aes256-ctr,aes192-ctr,aes128-ctr,aes256-gcm@openssh.com,aes128-gcm@openssh.com' A reboot is required for the changes to take effect.

a
The OL 8 SSH server must be configured to use strong entropy.
CM-6 - Low - CCI-000366 - V-248563 - SV-248563r779255_rule
RMF Control
CM-6
Severity
Low
CCI
CCI-000366
Version
OL08-00-010292
Vuln IDs
  • V-248563
Rule IDs
  • SV-248563r779255_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 OL 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-51997r779253_chk

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" or is commented out or missing, this is a finding.

Fix: F-51951r779254_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.

b
The OL 8 operating system must implement DoD-approved encryption in the OpenSSL package.
AC-17 - Medium - CCI-001453 - V-248564 - SV-248564r877394_rule
RMF Control
AC-17
Severity
Medium
CCI
CCI-001453
Version
OL08-00-010293
Vuln IDs
  • V-248564
Rule IDs
  • SV-248564r877394_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. OL 8 incorporates system-wide crypto policies by default. The employed algorithms can be viewed in the "/etc/crypto-policies/back-ends/openssl.config" file.
Checks: C-51998r779256_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-51952r779257_fix

Configure the OL 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 OL 8 operating system must implement DoD-approved TLS encryption in the OpenSSL package.
AC-17 - Medium - CCI-001453 - V-248565 - SV-248565r877394_rule
RMF Control
AC-17
Severity
Medium
CCI
CCI-001453
Version
OL08-00-010294
Vuln IDs
  • V-248565
Rule IDs
  • SV-248565r877394_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. OL 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-51999r818615_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-51953r818616_fix

Configure the OL 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 OL 8 operating system must implement DoD-approved TLS encryption in the GnuTLS package.
AC-17 - Medium - CCI-001453 - V-248566 - SV-248566r877394_rule
RMF Control
AC-17
Severity
Medium
CCI
CCI-001453
Version
OL08-00-010295
Vuln IDs
  • V-248566
Rule IDs
  • SV-248566r877394_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 OL 8 system-wide crypto policy defines employed algorithms in the "/etc/crypto-policies/back-ends/gnutls.config" file.
Checks: C-52000r818618_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-51954r779263_fix

Configure the OL 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
OL 8 system commands must have mode 755 or less permissive.
CM-5 - Medium - CCI-001499 - V-248567 - SV-248567r818622_rule
RMF Control
CM-5
Severity
Medium
CCI
CCI-001499
Version
OL08-00-010300
Vuln IDs
  • V-248567
Rule IDs
  • SV-248567r818622_rule
If OL 8 were to allow any user to make changes to software libraries, 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 OL 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 must be allowed to obtain access to information system components for purposes of initiating changes, including upgrades and modifications.
Checks: C-52001r818620_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-51955r818621_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
OL 8 system commands must be owned by root.
CM-5 - Medium - CCI-001499 - V-248568 - SV-248568r779270_rule
RMF Control
CM-5
Severity
Medium
CCI
CCI-001499
Version
OL08-00-010310
Vuln IDs
  • V-248568
Rule IDs
  • SV-248568r779270_rule
If OL 8 were to allow any user to make changes to software libraries, 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 OL 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 must be allowed to obtain access to information system components for purposes of initiating changes, including upgrades and modifications.
Checks: C-52002r779268_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-51956r779269_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
OL 8 system commands must be group-owned by root or a system account.
CM-5 - Medium - CCI-001499 - V-248569 - SV-248569r818625_rule
RMF Control
CM-5
Severity
Medium
CCI
CCI-001499
Version
OL08-00-010320
Vuln IDs
  • V-248569
Rule IDs
  • SV-248569r818625_rule
If OL 8 were to allow any user to make changes to software libraries, 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 OL 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 must be allowed to obtain access to information system components for purposes of initiating changes, including upgrades and modifications.
Checks: C-52003r818623_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-51957r818624_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
OL 8 library files must have mode 755 or less permissive.
CM-5 - Medium - CCI-001499 - V-248570 - SV-248570r818628_rule
RMF Control
CM-5
Severity
Medium
CCI
CCI-001499
Version
OL08-00-010330
Vuln IDs
  • V-248570
Rule IDs
  • SV-248570r818628_rule
If OL 8 were to allow any user to make changes to software libraries, 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 OL 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 must be allowed to obtain access to information system components for purposes of initiating changes, including upgrades and modifications.
Checks: C-52004r818626_chk

Verify the system-wide shared library files contained in the following directories have mode "755" or less permissive with the following command: $ sudo find -L /lib /lib64 /usr/lib /usr/lib64 -perm /022 -type f -exec ls -l {} \; If any system-wide shared library file is found to be group-writable or world-writable, this is a finding.

Fix: F-51958r818627_fix

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

b
OL 8 library files must be owned by root.
CM-5 - Medium - CCI-001499 - V-248571 - SV-248571r779279_rule
RMF Control
CM-5
Severity
Medium
CCI
CCI-001499
Version
OL08-00-010340
Vuln IDs
  • V-248571
Rule IDs
  • SV-248571r779279_rule
If OL 8 were to allow any user to make changes to software libraries, 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 OL 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 must be allowed to obtain access to information system components for purposes of initiating changes, including upgrades and modifications.
Checks: C-52005r779277_chk

Verify the system-wide shared library files are owned by "root" with the following command: $ sudo find -L /lib /lib64 /usr/lib /usr/lib64 ! -user root -exec ls -l {} \; If any system-wide shared library file is returned, this is a finding.

Fix: F-51959r779278_fix

Configure the system-wide shared library files (/lib, /lib64, /usr/lib, and /usr/lib64) to be protected from unauthorized access. Run the following command, replacing "[FILE]" with any library file not owned by "root". $ sudo chown root [FILE]

b
OL 8 library files must be group-owned by root.
CM-5 - Medium - CCI-001499 - V-248572 - SV-248572r779282_rule
RMF Control
CM-5
Severity
Medium
CCI
CCI-001499
Version
OL08-00-010350
Vuln IDs
  • V-248572
Rule IDs
  • SV-248572r779282_rule
If OL 8 were to allow any user to make changes to software libraries, 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 OL 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 must be allowed to obtain access to information system components for purposes of initiating changes, including upgrades and modifications.
Checks: C-52006r779280_chk

Verify the system-wide shared library files are group-owned by "root" with the following command: $ sudo find -L /lib /lib64 /usr/lib /usr/lib64 ! -group root -exec ls -l {} \; If any system-wide shared library file is returned, this is a finding.

Fix: F-51960r779281_fix

Configure the system-wide shared library files (/lib, /lib64, /usr/lib, and /usr/lib64) to be protected from unauthorized access. Run the following command, replacing "[FILE]" with any library file not group-owned by "root". $ sudo chgrp root [FILE]

b
The OL 8 file integrity tool must notify the System Administrator (SA) 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-248573 - SV-248573r902806_rule
RMF Control
CM-3
Severity
Medium
CCI
CCI-001744
Version
OL08-00-010360
Vuln IDs
  • V-248573
Rule IDs
  • SV-248573r902806_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 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. OL 8 comes with many optional software packages, including the file integrity tool Advanced Intrusion Detection Environment (AIDE). 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-52007r902804_chk

Verify the operating system routinely checks the baseline configuration for unauthorized changes and notifies the SA when anomalies in the operation of any security functions are discovered. Check that OL 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/aide /var/spool/cron/root: 30 04 * * * /root/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, 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-51961r902805_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 an 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 OL08-00-010358, the "mailx" package must be installed on the system to enable email functionality.

c
YUM must be configured to prevent the installation of patches, service packs, device drivers, or OL 8 system components that have not been digitally signed using a certificate that is recognized and approved by the organization.
CM-5 - High - CCI-001749 - V-248574 - SV-248574r877463_rule
RMF Control
CM-5
Severity
High
CCI
CCI-001749
Version
OL08-00-010370
Vuln IDs
  • V-248574
Rule IDs
  • SV-248574r877463_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 Certificate Authority (CA).
Checks: C-52008r779286_chk

Check that YUM verifies the signature of packages from a repository prior to install with the following command: $ sudo grep gpgcheck /etc/yum.repos.d/*.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-51962r779287_fix

Configure OL 8 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
OL 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-248575 - SV-248575r877463_rule
RMF Control
CM-5
Severity
High
CCI
CCI-001749
Version
OL08-00-010371
Vuln IDs
  • V-248575
Rule IDs
  • SV-248575r877463_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 Certificate Authority (CA).
Checks: C-52009r779289_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-51963r779290_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
OL 8 must prevent the loading of a new kernel for later execution.
CM-5 - Medium - CCI-001749 - V-248576 - SV-248576r917907_rule
RMF Control
CM-5
Severity
Medium
CCI
CCI-001749
Version
OL08-00-010372
Vuln IDs
  • V-248576
Rule IDs
  • SV-248576r917907_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 to 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-52010r917906_chk

Note: For OL 8 systems using the Oracle Unbreakable Enterprise Kernel (UEK) Release 6 or above and with secureboot enabled, this requirement is not applicable. 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" or is missing or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-51964r858608_fix

Configure OL 8 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
OL 8 must enable kernel parameters to enforce Discretionary Access Control (DAC) on symlinks.
AC-3 - Medium - CCI-002165 - V-248577 - SV-248577r860911_rule
RMF Control
AC-3
Severity
Medium
CCI
CCI-002165
Version
OL08-00-010373
Vuln IDs
  • V-248577
Rule IDs
  • SV-248577r860911_rule
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 DAC policies are implemented, subjects are not constrained as 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 (MAC) policies is still able to operate under the less rigorous constraints of this requirement. Therefore, while MAC 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 DAC require identity-based access control, that limitation is not required for this use of DAC. 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
Checks: C-52011r858610_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" or is missing or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-51965r858611_fix

Configure OL 8 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
OL 8 must enable kernel parameters to enforce Discretionary Access Control (DAC) on hardlinks.
AC-3 - Medium - CCI-002165 - V-248578 - SV-248578r860912_rule
RMF Control
AC-3
Severity
Medium
CCI
CCI-002165
Version
OL08-00-010374
Vuln IDs
  • V-248578
Rule IDs
  • SV-248578r860912_rule
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 DAC policies are implemented, subjects are not constrained as 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 (MAC) policies is still able to operate under the less rigorous constraints of this requirement. Therefore, while MAC 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 DAC require identity-based access control, that limitation is not required for this use of DAC. 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
Checks: C-52012r858613_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" or is missing or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-51966r858614_fix

Configure OL 8 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
OL 8 must restrict access to the kernel message buffer.
SC-4 - Low - CCI-001090 - V-248579 - SV-248579r858617_rule
RMF Control
SC-4
Severity
Low
CCI
CCI-001090
Version
OL08-00-010375
Vuln IDs
  • V-248579
Rule IDs
  • SV-248579r858617_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-52013r833200_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" or is missing or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-51967r858616_fix

Configure OL 8 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
OL 8 must prevent kernel profiling by unprivileged users.
SC-4 - Low - CCI-001090 - V-248580 - SV-248580r858619_rule
RMF Control
SC-4
Severity
Low
CCI
CCI-001090
Version
OL08-00-010376
Vuln IDs
  • V-248580
Rule IDs
  • SV-248580r858619_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-52014r833202_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" or is missing or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-51968r858618_fix

Configure OL 8 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
OL 8 must require users to provide a password for privilege escalation.
IA-11 - Medium - CCI-002038 - V-248581 - SV-248581r860915_rule
RMF Control
IA-11
Severity
Medium
CCI
CCI-002038
Version
OL08-00-010380
Vuln IDs
  • V-248581
Rule IDs
  • SV-248581r860915_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-52015r860913_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 ISSO as an organizationally defined administrative group using MFA, this is a finding.

Fix: F-51969r860914_fix

Configure the operating system to require users to supply a password for privilege escalation. Check the configuration of the "/etc/sudoers" file with the following command: $ sudo visudo Remove any occurrences of "NOPASSWD" tags in the file. Check the configuration of the /etc/sudoers.d/* files with the following command: $ sudo grep -ir nopasswd /etc/sudoers.d Remove any occurrences of "NOPASSWD" tags in the file.

b
OL 8 must require users to reauthenticate for privilege escalation and changing roles.
IA-11 - Medium - CCI-002038 - V-248582 - SV-248582r880551_rule
RMF Control
IA-11
Severity
Medium
CCI
CCI-002038
Version
OL08-00-010381
Vuln IDs
  • V-248582
Rule IDs
  • SV-248582r880551_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-52016r880550_chk

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

Fix: F-51970r779311_fix

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

b
OL 8 must restrict privilege elevation to authorized personnel.
CM-6 - Medium - CCI-000366 - V-248583 - SV-248583r779315_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010382
Vuln IDs
  • V-248583
Rule IDs
  • SV-248583r779315_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-52017r779313_chk

Verify the "sudoers" file restricts sudo access to authorized personnel. $ sudo grep -iw 'ALL' /etc/sudoers /etc/sudoers.d/* If the either of the following entries are returned, this is a finding: ALL ALL=(ALL) ALL ALL ALL=(ALL:ALL) ALL

Fix: F-51971r779314_fix

Remove the following entries from the sudoers file: ALL ALL=(ALL) ALL ALL ALL=(ALL:ALL) ALL

b
OL 8 must use the invoking user's password for privilege escalation when using "sudo".
CM-6 - Medium - CCI-000366 - V-248584 - SV-248584r880554_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010383
Vuln IDs
  • V-248584
Rule IDs
  • SV-248584r880554_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-52018r880552_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-51972r880553_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
OL 8 must require re-authentication when using the "sudo" command.
IA-11 - Medium - CCI-002038 - V-248585 - SV-248585r880557_rule
RMF Control
IA-11
Severity
Medium
CCI
CCI-002038
Version
OL08-00-010384
Vuln IDs
  • V-248585
Rule IDs
  • SV-248585r880557_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. Satisfies: SRG-OS-000373-GPOS-00156, SRG-OS-000373-GPOS-00157, SRG-OS-000373-GPOS-00158
Checks: C-52019r880555_chk

Verify the operating system requires re-authentication when using the "sudo" command to elevate privileges. $ sudo grep -Eir '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-51973r880556_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.

a
OL 8 must have the package required for multifactor authentication installed.
IA-2 - Low - CCI-001948 - V-248586 - SV-248586r853767_rule
RMF Control
IA-2
Severity
Low
CCI
CCI-001948
Version
OL08-00-010390
Vuln IDs
  • V-248586
Rule IDs
  • SV-248586r853767_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-52020r779322_chk

Verify the operating system has the package required for multifactor authentication installed with the following command: $ 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 used and what packages are installed to support it. If there is no evidence of multifactor authentication being used, this is a finding.

Fix: F-51974r779323_fix

Configure OL 8 to implement multifactor authentication by installing the required package with the following command: $ sudo yum install openssl-pkcs11

b
OL 8 must implement certificate status checking for multifactor authentication.
IA-2 - Medium - CCI-001948 - V-248587 - SV-248587r860917_rule
RMF Control
IA-2
Severity
Medium
CCI
CCI-001948
Version
OL08-00-010400
Vuln IDs
  • V-248587
Rule IDs
  • SV-248587r860917_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. OL 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-52021r858603_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. Determine 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 used 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-51975r818643_fix

Configure OL 8 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
OL 8 must accept Personal Identity Verification (PIV) credentials.
IA-2 - Medium - CCI-001953 - V-248588 - SV-248588r853769_rule
RMF Control
IA-2
Severity
Medium
CCI
CCI-001953
Version
OL08-00-010410
Vuln IDs
  • V-248588
Rule IDs
  • SV-248588r853769_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-52022r779328_chk

Verify OL 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-51976r779329_fix

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

b
OL 8 must implement non-executable data to protect its memory from unauthorized code execution.
SI-16 - Medium - CCI-002824 - V-248589 - SV-248589r853770_rule
RMF Control
SI-16
Severity
Medium
CCI
CCI-002824
Version
OL08-00-010420
Vuln IDs
  • V-248589
Rule IDs
  • SV-248589r853770_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-52023r779331_chk

Verify the NX (no-execution) bit flag is set on the system 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-51977r779332_fix

Enable the NX bit execute protection in the system BIOS.

b
OL 8 must clear the page allocator to prevent use-after-free attacks.
SC-3 - Medium - CCI-001084 - V-248590 - SV-248590r779336_rule
RMF Control
SC-3
Severity
Medium
CCI
CCI-001084
Version
OL08-00-010421
Vuln IDs
  • V-248590
Rule IDs
  • SV-248590r779336_rule
Adversaries may 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.
Checks: C-52024r779334_chk

Verify that GRUB 2 is configured to enable page poisoning to mitigate use-after-free vulnerabilities with the following commands: $ sudo grub2-editenv list | grep page_poison kernelopts=root=/dev/mapper/ol-root ro crashkernel=auto resume=/dev/mapper/ol-swap rd.lvm.lv=ol/root rd.lvm.lv=ol/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" or is missing or commented out, this is a finding.

Fix: F-51978r779335_fix

Configure OL 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
OL 8 must disable virtual syscalls.
SC-3 - Medium - CCI-001084 - V-248591 - SV-248591r779339_rule
RMF Control
SC-3
Severity
Medium
CCI
CCI-001084
Version
OL08-00-010422
Vuln IDs
  • V-248591
Rule IDs
  • SV-248591r779339_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 OL 6 components, then virtual syscalls will need enabled so the components function properly.
Checks: C-52025r779337_chk

Verify that GRUB 2 is configured to disable vsyscalls with the following commands: $ sudo grub2-editenv list | grep vsyscall kernelopts=root=/dev/mapper/ol-root ro crashkernel=auto resume=/dev/mapper/ol-swap rd.lvm.lv=ol/root rd.lvm.lv=ol/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-51979r779338_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
OL 8 must clear SLUB/SLAB objects to prevent use-after-free attacks.
SC-3 - Medium - CCI-001084 - V-248592 - SV-248592r952103_rule
RMF Control
SC-3
Severity
Medium
CCI
CCI-001084
Version
OL08-00-010423
Vuln IDs
  • V-248592
Rule IDs
  • SV-248592r952103_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. SLAB objects are blocks of physically contiguous memory. SLUB is the unqueued SLAB allocator.
Checks: C-52026r952103_chk

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

Fix: F-51980r779341_fix

Configure OL 8 to enable poisoning of SLUB/SLAB objects with the following commands: $ sudo grubby --update-kernel=ALL --args="slub_debug=P" Add or modify the following line in "/etc/default/grub" to ensure the configuration survives kernel updates: GRUB_CMDLINE_LINUX="slub_debug=P"

b
OL 8 must not let Meltdown and Spectre exploit critical vulnerabilities in modern processors.
CM-6 - Medium - CCI-000366 - V-248593 - SV-248593r951562_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010424
Vuln IDs
  • V-248593
Rule IDs
  • SV-248593r951562_rule
Hardware vulnerabilities allow programs to steal data that is currently processed on the computer. While programs are typically not permitted to read data from other programs, a malicious program can exploit Meltdown and Spectre to obtain secrets stored in the memory of other running programs. This might include passwords stored in a password manager or browser; personal photos, emails, and instant messages; and business-critical documents.
Checks: C-52027r951560_chk

Determine the default kernel: $ sudo grubby --default-kernel /boot/vmlinuz-5.4.17-2011.1.2.el8uek.x86_64 Using the default kernel, verify that Meltdown mitigations are not disabled: $ sudo grubby --info=<path-to-default-kernel> | grep mitigations If the "mitigations" parameter is set to "off", this is a finding.

Fix: F-51981r951561_fix

Determine the default kernel: $ sudo grubby --default-kernel /boot/vmlinuz-5.4.17-2011.1.2.el8uek.x86_64 Using the default kernel, remove the argument that sets the Meltdown mitigations to "off": $ sudo grubby --update-kernel=<path-to-default-kernel> --remove-args=mitigations=off Reboot the system for the change to take effect.

b
OL 8 must implement address space layout randomization (ASLR) to protect its memory from unauthorized code execution.
SI-16 - Medium - CCI-002824 - V-248594 - SV-248594r860918_rule
RMF Control
SI-16
Severity
Medium
CCI
CCI-002824
Version
OL08-00-010430
Vuln IDs
  • V-248594
Rule IDs
  • SV-248594r860918_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-52028r858625_chk

Verify that OL 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-51982r858626_fix

Configure OL 8 to implement virtual address space randomization. Set the system to the required kernel parameter by adding the following line to "/etc/sysctl.d/*.conf" (or modify the line to have the required value): 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 OL 8.
SI-2 - Low - CCI-002617 - V-248595 - SV-248595r853773_rule
RMF Control
SI-2
Severity
Low
CCI
CCI-002617
Version
OL08-00-010440
Vuln IDs
  • V-248595
Rule IDs
  • SV-248595r853773_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-52029r779349_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/yum.conf clean_requirements_on_remove=True If "clean_requirements_on_remove" is not set to "True", commented out, or missing from "/etc/yum.conf", this is a finding.

Fix: F-51983r779350_fix

Configure OL 8 to remove all software components after updated versions have been installed. Set the "clean_requirements_on_remove" option to "True" in the "/etc/yum.conf" file: clean_requirements_on_remove=True

b
OL 8 must enable the SELinux targeted policy.
SI-6 - Medium - CCI-002696 - V-248596 - SV-248596r853774_rule
RMF Control
SI-6
Severity
Medium
CCI
CCI-002696
Version
OL08-00-010450
Vuln IDs
  • V-248596
Rule IDs
  • SV-248596r853774_rule
Without verification of the security functions, they 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-52030r779352_chk

Ensure the operating system verifies correct operation of all security functions. Verify that "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" as "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-51984r779353_fix

Configure OL 8 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 OL 8 operating system.
CM-6 - High - CCI-000366 - V-248597 - SV-248597r779357_rule
RMF Control
CM-6
Severity
High
CCI
CCI-000366
Version
OL08-00-010460
Vuln IDs
  • V-248597
Rule IDs
  • SV-248597r779357_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-52031r779355_chk

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

Fix: F-51985r779356_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 OL 8 operating system.
CM-6 - High - CCI-000366 - V-248598 - SV-248598r779360_rule
RMF Control
CM-6
Severity
High
CCI
CCI-000366
Version
OL08-00-010470
Vuln IDs
  • V-248598
Rule IDs
  • SV-248598r779360_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-52032r779358_chk

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

Fix: F-51986r779359_fix

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

a
OL 8 must enable the hardware random number generator entropy gatherer service.
CM-6 - Low - CCI-000366 - V-248599 - SV-248599r943105_rule
RMF Control
CM-6
Severity
Low
CCI
CCI-000366
Version
OL08-00-010473
Vuln IDs
  • V-248599
Rule IDs
  • SV-248599r943105_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-52033r928552_chk

Note: For OL versions 8.4 and above running with kernel FIPS mode enabled as specified by OL08-00-010020, this requirement is Not Applicable. Check that OL 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-51987r917909_fix

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

a
OL 8 must have the packages required to use the hardware random number generator entropy gatherer service.
CM-6 - Low - CCI-000366 - V-248600 - SV-248600r779366_rule
RMF Control
CM-6
Severity
Low
CCI
CCI-000366
Version
OL08-00-010472
Vuln IDs
  • V-248600
Rule IDs
  • SV-248600r779366_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-52034r779364_chk

Check that OL 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-51988r779365_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 OL 8 SSH public host key files must have mode "0644" or less permissive.
CM-6 - Medium - CCI-000366 - V-248601 - SV-248601r779369_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010480
Vuln IDs
  • V-248601
Rule IDs
  • SV-248601r779369_rule
If a public host key file is modified by an unauthorized user, the SSH service may be compromised.
Checks: C-52035r779367_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 wheel 618 Nov 28 06:43 ssh_host_dsa_key.pub -rw-r--r-- 1 root wheel 347 Nov 28 06:43 ssh_host_key.pub -rw-r--r-- 1 root wheel 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-51989r779368_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 OL 8 SSH private host key files must have mode "0640" or less permissive.
CM-6 - Medium - CCI-000366 - V-248602 - SV-248602r880541_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010490
Vuln IDs
  • V-248602
Rule IDs
  • SV-248602r880541_rule
If an unauthorized user obtains the private SSH host key file, the host could be impersonated.
Checks: C-52036r880539_chk

Verify the SSH private host key files have mode "0640" or less permissive with the following command: $ sudo ls -alL /etc/ssh/ssh_host*key -rw-r----- 1 root wheel 668 Nov 28 06:43 ssh_host_dsa_key -rw-r----- 1 root wheel 582 Nov 28 06:43 ssh_host_key -rw-r----- 1 root wheel 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-51990r880540_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 OL 8 SSH daemon must perform strict mode checking of home directory configuration files.
CM-6 - Medium - CCI-000366 - V-248603 - SV-248603r951564_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010500
Vuln IDs
  • V-248603
Rule IDs
  • SV-248603r951564_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-52037r951563_chk

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

Fix: F-51991r779374_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 OL 8 SSH daemon must not allow authentication using known host's authentication.
CM-6 - Medium - CCI-000366 - V-248605 - SV-248605r951566_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010520
Vuln IDs
  • V-248605
Rule IDs
  • SV-248605r951566_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-52039r951565_chk

Verify the SSH daemon does not allow authentication using known host’s authentication with the following command: $ sudo /usr/sbin/sshd -dd 2&gt;&amp;1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH '^\s*ignoreuserknownhosts' 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-51993r779380_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 OL 8 SSH daemon must not allow Kerberos authentication, except to fulfill documented and validated mission requirements.
CM-6 - Medium - CCI-000366 - V-248606 - SV-248606r951568_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010521
Vuln IDs
  • V-248606
Rule IDs
  • SV-248606r951568_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-52040r951567_chk

Verify the SSH daemon does not allow Kerberos authentication with the following command: $ sudo /usr/sbin/sshd -dd 2&gt;&amp;1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH '^\s*kerberosauthentication' KerberosAuthentication no If the value is returned as "yes", the returned line is commented out, or 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-51994r779383_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

b
The OL 8 SSH daemon must not allow GSSAPI authentication, except to fulfill documented and validated mission requirements.
CM-6 - Medium - CCI-000366 - V-248607 - SV-248607r951570_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010522
Vuln IDs
  • V-248607
Rule IDs
  • SV-248607r951570_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-52041r951569_chk

Verify the SSH daemon does not allow GSSAPI authentication with the following command: $ sudo /usr/sbin/sshd -dd 2&gt;&amp;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, or 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-51995r779386_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

a
OL 8 must use a separate file system for "/var".
CM-6 - Low - CCI-000366 - V-248608 - SV-248608r902793_rule
RMF Control
CM-6
Severity
Low
CCI
CCI-000366
Version
OL08-00-010540
Vuln IDs
  • V-248608
Rule IDs
  • SV-248608r902793_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-52042r902792_chk

Verify that a separate 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-51996r779389_fix

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

a
OL 8 must use a separate file system for "/var/log".
CM-6 - Low - CCI-000366 - V-248609 - SV-248609r902795_rule
RMF Control
CM-6
Severity
Low
CCI
CCI-000366
Version
OL08-00-010541
Vuln IDs
  • V-248609
Rule IDs
  • SV-248609r902795_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-52043r902794_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-51997r779392_fix

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

a
OL 8 must use a separate file system for the system audit data path.
CM-6 - Low - CCI-000366 - V-248610 - SV-248610r779396_rule
RMF Control
CM-6
Severity
Low
CCI
CCI-000366
Version
OL08-00-010542
Vuln IDs
  • V-248610
Rule IDs
  • SV-248610r779396_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-52044r779394_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 ext4 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 and 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-51998r779395_fix

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

b
OL 8 must use a separate file system for "/tmp".
CM-6 - Medium - CCI-000366 - V-248611 - SV-248611r779399_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010543
Vuln IDs
  • V-248611
Rule IDs
  • SV-248611r779399_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-52045r779397_chk

The use of separate file systems for different paths can protect the system from failures resulting from a file system becoming full or failing. Check Text: 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/ol-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-51999r779398_fix

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

b
OL 8 must use a separate file system for /var/tmp.
CM-6 - Medium - CCI-000366 - V-248612 - SV-248612r902797_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010544
Vuln IDs
  • V-248612
Rule IDs
  • SV-248612r902797_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-52046r902796_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-52000r779401_fix

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

b
OL 8 must not permit direct logons to the root account using remote access via SSH.
IA-2 - Medium - CCI-000770 - V-248613 - SV-248613r951572_rule
RMF Control
IA-2
Severity
Medium
CCI
CCI-000770
Version
OL08-00-010550
Vuln IDs
  • V-248613
Rule IDs
  • SV-248613r951572_rule
Although 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-52047r951571_chk

Verify remote access using SSH prevents users from logging on directly as "root" with the following command: $ sudo /usr/sbin/sshd -dd 2&gt;&amp;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 "yes", is missing, or is commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-52001r779404_fix

Configure OL 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
OL 8 must have the rsyslog service enabled and active.
CM-6 - Medium - CCI-000366 - V-248615 - SV-248615r779411_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010561
Vuln IDs
  • V-248615
Rule IDs
  • SV-248615r779411_rule
Configuring OL 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 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-52049r779409_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-52003r779410_fix

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

b
OL 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-248616 - SV-248616r779414_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010570
Vuln IDs
  • V-248616
Rule IDs
  • SV-248616r779414_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-52050r779412_chk

Verify that file systems containing user home directories are mounted with the "nosuid" option. Find the file system(s) that contain the user home directories with the following command: $ sudo awk -F: '($3&gt;=1000)&amp;&amp;($1!="nobody"){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 "nosuid" option set, this is a finding.

Fix: F-52004r779413_fix

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

b
OL 8 must prevent files with the setuid and setgid bit set from being executed on the /boot directory.
CM-6 - Medium - CCI-000366 - V-248617 - SV-248617r779417_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010571
Vuln IDs
  • V-248617
Rule IDs
  • SV-248617r779417_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-52051r779415_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-52005r779416_fix

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

b
OL 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-248618 - SV-248618r818648_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010572
Vuln IDs
  • V-248618
Rule IDs
  • SV-248618r818648_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-52052r818647_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-52006r779419_fix

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

b
OL 8 must prevent special devices on non-root local partitions.
CM-6 - Medium - CCI-000366 - V-248619 - SV-248619r779423_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010580
Vuln IDs
  • V-248619
Rule IDs
  • SV-248619r779423_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-52053r779421_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-52007r779422_fix

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

b
OL 8 file systems that contain user home directories must not execute binary files.
CM-6 - Medium - CCI-000366 - V-248620 - SV-248620r779426_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010590
Vuln IDs
  • V-248620
Rule IDs
  • SV-248620r779426_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-52054r779424_chk

Verify that file systems containing user home directories are mounted with the "noexec" option. Find the file system(s) that contain the user home directories with the following command: $ sudo awk -F: '($3&gt;=1000)&amp;&amp;($1!="nobody"){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-52008r779425_fix

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

b
OL 8 file systems must not interpret character or block special devices from untrusted file systems.
CM-6 - Medium - CCI-000366 - V-248621 - SV-248621r779429_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010600
Vuln IDs
  • V-248621
Rule IDs
  • SV-248621r779429_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-52055r779427_chk

Verify that file systems 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-52009r779428_fix

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

b
OL 8 file systems must not execute binary files on removable media.
CM-6 - Medium - CCI-000366 - V-248622 - SV-248622r779432_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010610
Vuln IDs
  • V-248622
Rule IDs
  • SV-248622r779432_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-52056r779430_chk

Verify that file systems 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-52010r779431_fix

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

b
OL 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-248623 - SV-248623r779435_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010620
Vuln IDs
  • V-248623
Rule IDs
  • SV-248623r779435_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-52057r779433_chk

Verify that file systems 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-52011r779434_fix

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

b
OL 8 file systems must not execute binary files that are imported via Network File System (NFS).
CM-6 - Medium - CCI-000366 - V-248624 - SV-248624r779438_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010630
Vuln IDs
  • V-248624
Rule IDs
  • SV-248624r779438_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-52058r779436_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-52012r779437_fix

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

b
OL 8 file systems must not interpret character or block special devices that are imported via NFS.
CM-6 - Medium - CCI-000366 - V-248625 - SV-248625r779441_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010640
Vuln IDs
  • V-248625
Rule IDs
  • SV-248625r779441_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-52059r779439_chk

Verify that file systems being imported via NFS 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-52013r779440_fix

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

b
OL 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-248626 - SV-248626r779444_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010650
Vuln IDs
  • V-248626
Rule IDs
  • SV-248626r779444_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-52060r779442_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-52014r779443_fix

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

b
Local OL 8 initialization files must not execute world-writable programs.
CM-6 - Medium - CCI-000366 - V-248627 - SV-248627r779447_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010660
Vuln IDs
  • V-248627
Rule IDs
  • SV-248627r779447_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-52061r779445_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 users' home directories in the "/home" directory. $ sudo grep &lt;file&gt; /home/*/.* If any local initialization files are found to reference world-writable files, this is a finding.

Fix: F-52015r779446_fix

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

b
OL 8 must disable kernel dumps unless needed.
SC-24 - Medium - CCI-001665 - V-248628 - SV-248628r779450_rule
RMF Control
SC-24
Severity
Medium
CCI
CCI-001665
Version
OL08-00-010670
Vuln IDs
  • V-248628
Rule IDs
  • SV-248628r779450_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. OL 8 installation media presents the option to enable or disable the kdump service at the time of system installation.
Checks: C-52062r779448_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; disabled; vendor preset: enabled) Active: failed (Result: exit-code)since Mon 2020-05-04 16:08:09 EDT; 3min ago Main PID: 1130 (code=exited, status=0/FAILURE) 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-52016r779449_fix

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

b
OL 8 must disable the "kernel.core_pattern".
CM-6 - Medium - CCI-000366 - V-248629 - SV-248629r858629_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010671
Vuln IDs
  • V-248629
Rule IDs
  • SV-248629r858629_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-52063r833215_chk

Verify that OL 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-52017r858628_fix

Configure OL 8 to disable storing core dumps by adding the following line to a 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 must be reloaded for the changes to take effect. To reload the contents of the files, run the following command: $ sudo sysctl --system

b
OL 8 must disable acquiring, saving, and processing core dumps.
CM-6 - Medium - CCI-000366 - V-248630 - SV-248630r779456_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010672
Vuln IDs
  • V-248630
Rule IDs
  • SV-248630r779456_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-coredump" 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-52064r779454_chk

Verify OL 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-52018r779455_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

b
OL 8 must disable core dumps for all users.
CM-6 - Medium - CCI-000366 - V-248631 - SV-248631r779459_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010673
Vuln IDs
  • V-248631
Rule IDs
  • SV-248631r779459_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-52065r779457_chk

Verify the operating system disables core dumps for all users with the following command: $ sudo grep -r -s '^[^#].*core' /etc/security/limits.conf /etc/security/limits.d/*.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 or 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-52019r779458_fix

Configure OL 8 to disable core dumps for all users. Add the following line to the top of "/etc/security/limits.conf" or in a ".conf" file defined in "/etc/security/limits.d/": * hard core 0

b
OL 8 must disable storing core dumps.
CM-6 - Medium - CCI-000366 - V-248632 - SV-248632r779462_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010674
Vuln IDs
  • V-248632
Rule IDs
  • SV-248632r779462_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-52066r779460_chk

Verify the operating system disables storing core dumps for all users with the following command: $ sudo grep -i storage /etc/systemd/coredump.conf Storage=none If the "Storage" item is missing or 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-52020r779461_fix

Configure OL 8 to disable storing core dumps for all users. Add or modify the following line in "/etc/systemd/coredump.conf": Storage=none

b
OL 8 must disable core dump backtraces.
CM-6 - Medium - CCI-000366 - V-248633 - SV-248633r779465_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010675
Vuln IDs
  • V-248633
Rule IDs
  • SV-248633r779465_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-52067r779463_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 or 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-52021r779464_fix

Configure OL 8 to disable core dump backtraces. Add or modify the following line in "/etc/systemd/coredump.conf": ProcessSizeMax=0

b
For OL 8 systems using Domain Name Servers (DNS) resolution, at least two name servers must be configured.
CM-6 - Medium - CCI-000366 - V-248634 - SV-248634r779468_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010680
Vuln IDs
  • V-248634
Rule IDs
  • SV-248634r779468_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-52068r779466_chk

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-52022r779467_fix

Configure OL 8 to use two or more name servers for DNS resolution. By default, "NetworkManager" on OL 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 OL 8 users must only contain paths that resolve to the system default or the user's home directory.
CM-6 - Medium - CCI-000366 - V-248635 - SV-248635r779471_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010690
Vuln IDs
  • V-248635
Rule IDs
  • SV-248635r779471_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-52069r779469_chk

Verify that all local interactive user initialization files' executable search path statements do not contain statements that will reference a working directory other than the users' home directory with the following commands: Note: The example will be for the "smithj" user, which has a home directory of "/home/smithj". $ sudo grep -i path /home/smithj/.* /home/smithj/.bash_profile:PATH=$PATH:$HOME/.local/bin:$HOME/bin /home/smithj/.bash_profile:export PATH If any local interactive user initialization files have executable search path statements that include directories outside of their home directory, this is a finding.

Fix: F-52023r779470_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 OL 8 world-writable directories must be owned by root, sys, bin, or an application user.
CM-6 - Medium - CCI-000366 - V-248636 - SV-248636r779474_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010700
Vuln IDs
  • V-248636
Rule IDs
  • SV-248636r779474_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 the 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-52070r779472_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-52024r779473_fix

Investigate any world-writable directories that are not owned by a system account and then delete the files or assign them to an appropriate group.

b
All OL 8 world-writable directories must be group-owned by root, sys, bin, or an application group.
CM-6 - Medium - CCI-000366 - V-248637 - SV-248637r779477_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010710
Vuln IDs
  • V-248637
Rule IDs
  • SV-248637r779477_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 the 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-52071r779475_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-52025r779476_fix

Investigate any world-writable directories that are not group-owned by a system account and then delete the files or assign them to an appropriate group.

b
All OL 8 local interactive users must have a home directory assigned in the "/etc/passwd" file.
CM-6 - Medium - CCI-000366 - V-248638 - SV-248638r779480_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010720
Vuln IDs
  • V-248638
Rule IDs
  • SV-248638r779480_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-52072r779478_chk

Verify local interactive users on OL 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&gt;=1000)&amp;&amp;($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-52026r779479_fix

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

b
All OL 8 local interactive user home directories must have mode "0750" or less permissive.
CM-6 - Medium - CCI-000366 - V-248639 - SV-248639r779483_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010730
Vuln IDs
  • V-248639
Rule IDs
  • SV-248639r779483_rule
Excessive permissions on local interactive user home directories may allow unauthorized access to user files by other users.
Checks: C-52073r779481_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&gt;=1000)&amp;&amp;($1!="nobody"){print $6}' /etc/passwd) drwxr-x--- 2 smithj admin 4096 Jun 5 12:41 smithj If home directories of interactive users referenced in "/etc/passwd" do not have a mode of "0750" or less permissive, this is a finding.

Fix: F-52027r779482_fix

Change the mode of interactive users' home directories to "0750" using the following command. Note: The example will be for the user "smithj". $ sudo chmod 0750 /home/smithj

b
All OL 8 local interactive user home directory files must have mode "0750" or less permissive.
CM-6 - Medium - CCI-000366 - V-248640 - SV-248640r779486_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010731
Vuln IDs
  • V-248640
Rule IDs
  • SV-248640r779486_rule
Excessive permissions on local interactive user home directories may allow unauthorized access to user files by other users.
Checks: C-52074r779484_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-52028r779485_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
All OL 8 local interactive user home directories must be group-owned by the home directory owner's primary group.
CM-6 - Medium - CCI-000366 - V-248641 - SV-248641r880567_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010740
Vuln IDs
  • V-248641
Rule IDs
  • SV-248641r880567_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. Users that share the same group may not be able to access files to which they legitimately should have access.
Checks: C-52075r880565_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 User Identifier (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&gt;=1000)&amp;&amp;($1!="nobody"){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-52029r880566_fix

Change the group owner of a local interactive user’s home directory to the group found in "/etc/passwd" using 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
OL 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-248642 - SV-248642r779492_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010741
Vuln IDs
  • V-248642
Rule IDs
  • SV-248642r779492_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-52076r779490_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 /&lt;home directory&gt;/&lt;users home directory&gt;/ -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 found with a group-owner different from the home directory user private group, determine 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, this is a finding.

Fix: F-52030r779491_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
All OL 8 local interactive user home directories defined in the "/etc/passwd" file must exist.
CM-6 - Medium - CCI-000366 - V-248643 - SV-248643r779495_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010750
Vuln IDs
  • V-248643
Rule IDs
  • SV-248643r779495_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-52077r779493_chk

Verify that the assigned home directory of all local interactive users on OL 8 exists with the following command: $ sudo ls -ld $(awk -F: '($3&gt;=1000)&amp;&amp;($1!="nobody"){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-52031r779494_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 OL 8 local interactive user accounts must be assigned a home directory upon creation.
CM-6 - Medium - CCI-000366 - V-248644 - SV-248644r779498_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010760
Vuln IDs
  • V-248644
Rule IDs
  • SV-248644r779498_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-52078r779496_chk

Verify all local interactive users on OL 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-52032r779497_fix

Configure OL 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 OL 8 local initialization files must have mode "0740" or less permissive.
CM-6 - Medium - CCI-000366 - V-248645 - SV-248645r779501_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010770
Vuln IDs
  • V-248645
Rule IDs
  • SV-248645r779501_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-52079r779499_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 -rwxr----- 1 smithj users 896 Mar 10 2011 .profile -rwxr----- 1 smithj users 497 Jan 6 2007 .login -rwxr----- 1 smithj users 886 Jan 6 2007 .something If any local initialization files have a mode more permissive than "0740", this is a finding.

Fix: F-52033r779500_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 OL 8 files and directories must have a valid owner.
CM-6 - Medium - CCI-000366 - V-248646 - SV-248646r779504_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010780
Vuln IDs
  • V-248646
Rule IDs
  • SV-248646r779504_rule
Unowned files and directories may be unintentionally inherited if a user is assigned the same User Identifier "UID" as the UID of the unowned files.
Checks: C-52080r779502_chk

Verify all files and directories on OL 8 have a valid owner with the following command: $ sudo find / -nouser If any files on the system do not have an assigned owner, this is a finding.

Fix: F-52034r779503_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 OL 8 with the "chown" command: $ sudo chown <user> <file>

b
All OL 8 files and directories must have a valid group owner.
CM-6 - Medium - CCI-000366 - V-248647 - SV-248647r779507_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010790
Vuln IDs
  • V-248647
Rule IDs
  • SV-248647r779507_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-52081r779505_chk

Verify all files and directories on OL 8 have a valid group with the following command: $ sudo find / -nogroup If any files on the system do not have an assigned group, this is a finding.

Fix: F-52035r779506_fix

Either remove all files and directories from OL 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 OL 8 filesystem must be used for user home directories (such as "/home" or an equivalent).
CM-6 - Medium - CCI-000366 - V-248648 - SV-248648r902800_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-010800
Vuln IDs
  • V-248648
Rule IDs
  • SV-248648r902800_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-52082r902798_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&gt;=1000)&amp;&amp;($1!="nobody"){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 that contains the home directories for the nonprivileged 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 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 that contains the nonprivileged interactive users' home directories does not exist, this is a finding.

Fix: F-52036r902799_fix

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

c
Unattended or automatic logon via the OL 8 graphical user interface must not be allowed.
CM-6 - High - CCI-000366 - V-248649 - SV-248649r877377_rule
RMF Control
CM-6
Severity
High
CCI
CCI-000366
Version
OL08-00-010820
Vuln IDs
  • V-248649
Rule IDs
  • SV-248649r877377_rule
Failure to restrict system access to authenticated users negatively impacts operating system security.
Checks: C-52083r779511_chk

Note: This requirement assumes the use of the OL 8 default graphical user interface, Gnome Shell. If the system does not have any graphical user interface installed, this requirement is Not Applicable. Verify the operating system does not allow an unattended or automatic logon to the system via a graphical user interface. Check for the value of "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-52037r779512_fix

Configure OL 8 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

c
OL 8 must not allow users to override SSH environment variables.
CM-6 - High - CCI-000366 - V-248650 - SV-248650r951574_rule
RMF Control
CM-6
Severity
High
CCI
CCI-000366
Version
OL08-00-010830
Vuln IDs
  • V-248650
Rule IDs
  • SV-248650r951574_rule
SSH environment options potentially allow users to bypass access restriction in some configurations.
Checks: C-52084r951573_chk

Verify that unattended or automatic login via SSH is disabled with the following command: $ sudo /usr/sbin/sshd -dd 2&gt;&amp;1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH '^\s*permituserenvironment' 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-52038r779515_fix

Configure OL 8 to allow the SSH daemon to not allow unattended or automatic login 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
OL 8 temporary user accounts must be provisioned with an expiration time of 72 hours or less.
AC-2 - Medium - CCI-000016 - V-248651 - SV-248651r779519_rule
RMF Control
AC-2
Severity
Medium
CCI
CCI-000016
Version
OL08-00-020000
Vuln IDs
  • V-248651
Rule IDs
  • SV-248651r779519_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, OL 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 OL 8 operating systems may be integrated with enterprise-level authentication/access mechanisms that meet or exceed access control policy requirements.
Checks: C-52085r779517_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-52039r779518_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
OL 8 systems below version 8.2 must automatically lock an account when three unsuccessful logon attempts occur.
AC-7 - Medium - CCI-000044 - V-248652 - SV-248652r853775_rule
RMF Control
AC-7
Severity
Medium
CCI
CCI-000044
Version
OL08-00-020010
Vuln IDs
  • V-248652
Rule IDs
  • SV-248652r853775_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. OL 8 can use 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-52086r779520_chk

Verify 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 OL versions 8.0 and 8.1. If the system is OL 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-52040r779521_fix

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
OL 8 systems, versions 8.2 and above, must automatically lock an account when three unsuccessful logon attempts occur.
AC-7 - Medium - CCI-000044 - V-248653 - SV-248653r853776_rule
RMF Control
AC-7
Severity
Medium
CCI
CCI-000044
Version
OL08-00-020011
Vuln IDs
  • V-248653
Rule IDs
  • SV-248653r853776_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 OL 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-52087r779523_chk

Note: This check applies to OL versions 8.2 or newer. If the system is OL 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") or is missing or commented out, this is a finding.

Fix: F-52041r779524_fix

Configure OL 8 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
OL 8 systems below version 8.2 must automatically lock an account when three unsuccessful logon attempts occur during a 15-minute time period.
AC-7 - Medium - CCI-000044 - V-248654 - SV-248654r853777_rule
RMF Control
AC-7
Severity
Medium
CCI
CCI-000044
Version
OL08-00-020012
Vuln IDs
  • V-248654
Rule IDs
  • SV-248654r853777_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. OL 8 can use 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-52088r779526_chk

Verify 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 OL versions 8.0 and 8.1. If the system is OL 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 more 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 more on the "preauth" lines with the "pam_faillock.so" module or is missing from this line, this is a finding.

Fix: F-52042r779527_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
OL 8 systems, versions 8.2 and above, must automatically lock an account when three unsuccessful logon attempts occur during a 15-minute time period.
AC-7 - Medium - CCI-000044 - V-248655 - SV-248655r853778_rule
RMF Control
AC-7
Severity
Medium
CCI
CCI-000044
Version
OL08-00-020013
Vuln IDs
  • V-248655
Rule IDs
  • SV-248655r853778_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 OL 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-52089r779529_chk

Note: This check applies to OL versions 8.2 or newer. If the system is OL 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 or is missing or commented out, this is a finding.

Fix: F-52043r779530_fix

Configure OL 8 to lock an account when three unsuccessful logon attempts occur. Add/modify the "/etc/security/faillock.conf" file to match the following line: fail_interval = 900

b
OL 8 systems below version 8.2 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-248656 - SV-248656r853779_rule
RMF Control
AC-7
Severity
Medium
CCI
CCI-000044
Version
OL08-00-020014
Vuln IDs
  • V-248656
Rule IDs
  • SV-248656r853779_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. OL 8 can use 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-52090r779532_chk

Verify 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 OL versions 8.0 and 8.1. If the system is OL 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-52044r779533_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
OL 8 systems, versions 8.2 and above, 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-248657 - SV-248657r853780_rule
RMF Control
AC-7
Severity
Medium
CCI
CCI-000044
Version
OL08-00-020015
Vuln IDs
  • V-248657
Rule IDs
  • SV-248657r853780_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 OL 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-52091r779535_chk

Note: This check applies to OL versions 8.2 or newer. If the system is OL 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" or is missing or commented out, this is a finding.

Fix: F-52045r779536_fix

Configure OL 8 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
OL 8 systems below version 8.2 must ensure account lockouts persist.
AC-7 - Medium - CCI-000044 - V-248658 - SV-248658r853781_rule
RMF Control
AC-7
Severity
Medium
CCI
CCI-000044
Version
OL08-00-020016
Vuln IDs
  • V-248658
Rule IDs
  • SV-248658r853781_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. OL 8 can use 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-52092r779538_chk

Verify the faillock directory contents persist 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 OL versions 8.0 and 8.1. If the system is OL 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-52046r779539_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
OL 8 systems, versions 8.2 and above, must ensure account lockouts persist.
AC-7 - Medium - CCI-000044 - V-248659 - SV-248659r853782_rule
RMF Control
AC-7
Severity
Medium
CCI
CCI-000044
Version
OL08-00-020017
Vuln IDs
  • V-248659
Rule IDs
  • SV-248659r853782_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 OL 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-52093r779541_chk

Note: This check applies to OL versions 8.2 or newer. If the system is OL 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 or is missing or commented out, this is a finding.

Fix: F-52047r779542_fix

Configure OL 8 to 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
OL 8 systems below version 8.2 must prevent system messages from being presented when three unsuccessful logon attempts occur.
AC-7 - Medium - CCI-000044 - V-248660 - SV-248660r853783_rule
RMF Control
AC-7
Severity
Medium
CCI
CCI-000044
Version
OL08-00-020018
Vuln IDs
  • V-248660
Rule IDs
  • SV-248660r853783_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. OL 8 can use 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-52094r779544_chk

Verify 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 OL versions 8.0 and 8.1. If the system is OL 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-52048r779545_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
OL 8 systems, versions 8.2 and above, must prevent system messages from being presented when three unsuccessful logon attempts occur.
AC-7 - Medium - CCI-000044 - V-248661 - SV-248661r853784_rule
RMF Control
AC-7
Severity
Medium
CCI
CCI-000044
Version
OL08-00-020019
Vuln IDs
  • V-248661
Rule IDs
  • SV-248661r853784_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 OL 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-52095r779547_chk

Note: This check applies to OL versions 8.2 or newer. If the system is OL 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 or is missing or commented out, this is a finding.

Fix: F-52049r779548_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
OL 8 systems below version 8.2 must log user name information when unsuccessful logon attempts occur.
AC-7 - Medium - CCI-000044 - V-248662 - SV-248662r853785_rule
RMF Control
AC-7
Severity
Medium
CCI
CCI-000044
Version
OL08-00-020020
Vuln IDs
  • V-248662
Rule IDs
  • SV-248662r853785_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. OL 8 can use 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-52096r779550_chk

Verify the system logs user name information when unsuccessful logon attempts occur 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 OL versions 8.0 and 8.1. If the system is OL 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 "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-52050r779551_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
OL 8 systems, versions 8.2 and above, must log user name information when unsuccessful logon attempts occur.
AC-7 - Medium - CCI-000044 - V-248663 - SV-248663r853786_rule
RMF Control
AC-7
Severity
Medium
CCI
CCI-000044
Version
OL08-00-020021
Vuln IDs
  • V-248663
Rule IDs
  • SV-248663r853786_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 OL 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-52097r779553_chk

Note: This check applies to OL versions 8.2 or newer. If the system is OL 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-52051r779554_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
OL 8 systems below version 8.2 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-248664 - SV-248664r853787_rule
RMF Control
AC-7
Severity
Medium
CCI
CCI-000044
Version
OL08-00-020022
Vuln IDs
  • V-248664
Rule IDs
  • SV-248664r853787_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. OL 8 can use 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-52098r779556_chk

Verify 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. 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 OL versions 8.0 and 8.1. If the system is OL 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 "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-52052r779557_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
OL 8 systems, versions 8.2 and above, 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-248665 - SV-248665r853788_rule
RMF Control
AC-7
Severity
Medium
CCI
CCI-000044
Version
OL08-00-020023
Vuln IDs
  • V-248665
Rule IDs
  • SV-248665r853788_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 OL 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-52099r779559_chk

Note: This check applies to OL versions 8.2 or newer. If the system is OL 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 or is missing or commented out, this is a finding.

Fix: F-52053r779560_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
OL 8 must limit the number of concurrent sessions to 10 for all accounts and/or account types.
AC-10 - Low - CCI-000054 - V-248666 - SV-248666r877399_rule
RMF Control
AC-10
Severity
Low
CCI
CCI-000054
Version
OL08-00-020024
Vuln IDs
  • V-248666
Rule IDs
  • SV-248666r877399_rule
Operating system management includes the ability to control the number of users and user sessions that use an operating system. Limiting the number of allowed users and sessions per user is helpful in reducing the risks related to denial-of-service 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-52100r779562_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 "maxlogins" /etc/security/limits.conf /etc/security/limits.d/*.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 or commented out, or the value is not set to "10" or less for all domains that have the "maxlogins" item assigned, this is a finding.

Fix: F-52054r779563_fix

Configure OL 8 to limit the number of concurrent sessions to 10 for all accounts and/or account types. Add the following line to the top of "/etc/security/limits.conf" or in a ".conf" file defined in "/etc/security/limits.d/": * hard maxlogins 10

b
OL 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-248667 - SV-248667r853789_rule
RMF Control
AC-7
Severity
Medium
CCI
CCI-000044
Version
OL08-00-020025
Vuln IDs
  • V-248667
Rule IDs
  • SV-248667r853789_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 OL 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 that ask for user credentials, such as the password. Satisfies: SRG-OS-000021-GPOS-00005, SRG-OS-000329-GPOS-00128
Checks: C-52101r779565_chk

Note: This check applies to OL versions 8.2 or newer, if the system is OL version 8.0 or 8.1, this check is not applicable. Verify the pam_faillock.so module is present in the "/etc/pam.d/system-auth" file: $ sudo grep pam_faillock.so /etc/pam.d/system-auth auth required pam_faillock.so preauth auth required pam_faillock.so authfail account required pam_faillock.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-52055r779566_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
OL 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-248668 - SV-248668r853790_rule
RMF Control
AC-7
Severity
Medium
CCI
CCI-000044
Version
OL08-00-020026
Vuln IDs
  • V-248668
Rule IDs
  • SV-248668r853790_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 OL 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 that ask for user credentials, such as the password. Satisfies: SRG-OS-000021-GPOS-00005, SRG-OS-000329-GPOS-00128
Checks: C-52102r779568_chk

Note: This check applies to OL versions 8.2 or newer, if the system is OL version 8.0 or 8.1, this check is not applicable. Verify the pam_faillock.so module is present in the "/etc/pam.d/password-auth" file: $ sudo grep pam_faillock.so /etc/pam.d/password-auth auth required pam_faillock.so preauth auth required pam_faillock.so authfail account required pam_faillock.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-52056r779569_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
OL 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-248669 - SV-248669r853791_rule
RMF Control
AC-7
Severity
Medium
CCI
CCI-000044
Version
OL08-00-020027
Vuln IDs
  • V-248669
Rule IDs
  • SV-248669r853791_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. Satisfies: SRG-OS-000021-GPOS-00005, SRG-OS-000329-GPOS-00128
Checks: C-52103r779571_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 OL versions 8.2 or newer. If the system is OL 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-52057r779572_fix

Configure OL 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
OL 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-248670 - SV-248670r853792_rule
RMF Control
AC-7
Severity
Medium
CCI
CCI-000044
Version
OL08-00-020028
Vuln IDs
  • V-248670
Rule IDs
  • SV-248670r853792_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. Satisfies: SRG-OS-000021-GPOS-00005, SRG-OS-000329-GPOS-00128
Checks: C-52104r779574_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 OL versions 8.0 and 8.1. If the system is OL 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-52058r779575_fix

Configure OL 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
OL 8 must enable a user session lock until that user reestablishes access using established identification and authentication procedures for graphical user sessions.
AC-11 - Medium - CCI-000056 - V-248671 - SV-248671r779579_rule
RMF Control
AC-11
Severity
Medium
CCI
CCI-000056
Version
OL08-00-020030
Vuln IDs
  • V-248671
Rule IDs
  • SV-248671r779579_rule
To establish acceptance of the application usage policy, a click-through banner at system logon is required. The system must prevent further activity until the user executes a positive action to manifest agreement by clicking on a box indicating "OK". Satisfies: SRG-OS-000028-GPOS-00009, SRG-OS-000030-GPOS-00011
Checks: C-52105r779577_chk

Note: This requirement assumes the use of the OL 8 default graphical user interface, Gnome Shell. If the system does not have any graphical user interface installed, this requirement is Not Applicable. Verify the operating system enables a user's session lock until that user reestablishes 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.

Fix: F-52059r779578_fix

Configure OL 8 to enable a user's session lock until that user reestablishes 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
OL 8 must initiate a session lock for graphical user interfaces when the screensaver is activated.
AC-11 - Medium - CCI-000057 - V-248672 - SV-248672r779582_rule
RMF Control
AC-11
Severity
Medium
CCI
CCI-000057
Version
OL08-00-020031
Vuln IDs
  • V-248672
Rule IDs
  • SV-248672r779582_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
Checks: C-52106r779580_chk

Note: This requirement assumes the use of the OL 8 default graphical user interface, Gnome Shell. If the system does not have any graphical user interface installed, this requirement is Not Applicable. Verify the operating system initiates a session lock a for graphical user interfaces when the screensaver is activated with the following command: $ 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-52060r779581_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
OL 8 must disable the user list at logon for graphical user interfaces.
CM-6 - Medium - CCI-000366 - V-248673 - SV-248673r779585_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-020032
Vuln IDs
  • V-248673
Rule IDs
  • SV-248673r779585_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-52107r779583_chk

Note: This requirement assumes the use of the OL 8 default graphical user interface, Gnome Shell. If the system does not have any graphical user interface installed, this requirement is Not Applicable. Verify the operating system disables the user logon list for graphical user interfaces with the following command: $ sudo gsettings get org.gnome.login-screen disable-user-list true If the setting is "false", this is a finding.

Fix: F-52061r779584_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
OL 8 must have the tmux package installed.
AC-11 - Medium - CCI-000056 - V-248674 - SV-248674r779588_rule
RMF Control
AC-11
Severity
Medium
CCI
CCI-000056
Version
OL08-00-020039
Vuln IDs
  • V-248674
Rule IDs
  • SV-248674r779588_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, OL 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. Tmux is a terminal multiplexer that enables a number of terminals to be created, accessed, and controlled from a single screen. Satisfies: SRG-OS-000028-GPOS-00009, SRG-OS-000030-GPOS-00011
Checks: C-52108r779586_chk

Verify OL 8 has the "tmux" package installed, by running the following command: $ sudo yum list installed tmux tmux.x86.64 2.7-1.el8 @repository If "tmux" is not installed, this is a finding.

Fix: F-52062r779587_fix

Configure the operating system to enable a user to initiate a session lock via tmux. Install the "tmux" package, if it is not already installed, by running the following command: $ sudo yum install tmux

b
OL 8 must enable a user session lock until that user re-establishes access using established identification and authentication procedures for command line sessions.
AC-11 - Medium - CCI-000056 - V-248675 - SV-248675r902786_rule
RMF Control
AC-11
Severity
Medium
CCI
CCI-000056
Version
OL08-00-020040
Vuln IDs
  • V-248675
Rule IDs
  • SV-248675r902786_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, OL 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. Tmux is a terminal multiplexer that enables a number of terminals to be created, accessed, and controlled from a single screen. Satisfies: SRG-OS-000028-GPOS-00009, SRG-OS-000030-GPOS-00011
Checks: C-52109r902785_chk

Verify the operating system enables the user to manually initiate a session lock with the following command: $ sudo grep -Ei 'lock-command|lock-session' /etc/tmux.conf set -g lock-command vlock bind X lock-session If the "lock-command" is not set and "lock-session" is not bound to a specific keyboard key in the global settings, this is a finding.

Fix: F-52063r880563_fix

Configure the operating system to enable a user to manually initiate a session lock via tmux. This configuration binds the uppercase letter "X" to manually initiate a session lock after the prefix key "Ctrl + b" has been sent. The complete key sequence is thus "Ctrl + b" then "Shift + x" to lock tmux. Create a global configuration file "/etc/tmux.conf" and add the following lines: set -g lock-command vlock bind X lock-session Reload tmux configuration to take effect. This can be performed in tmux while it is running: $ tmux source-file /etc/tmux.conf

b
OL 8 must ensure session control is automatically started at shell initialization.
AC-11 - Medium - CCI-000056 - V-248676 - SV-248676r917911_rule
RMF Control
AC-11
Severity
Medium
CCI
CCI-000056
Version
OL08-00-020041
Vuln IDs
  • V-248676
Rule IDs
  • SV-248676r917911_rule
Tmux is a terminal multiplexer that enables a number of terminals to be created, accessed, and controlled from a single screen. Satisfies: SRG-OS-000028-GPOS-00009, SRG-OS-000030-GPOS-00011
Checks: C-52110r880536_chk

Verify the operating system shell initialization file is configured to start each shell with the tmux terminal multiplexer with the following commands: Determine if tmux is currently running: $ sudo ps all | grep tmux | grep -v grep If the command does not produce output, this is a finding. Determine the location of the tmux script: $ sudo grep tmux /etc/profile.d/* /etc/profile.d/tmux.sh: case "$name" in (sshd|login) tmux ;; esac Review the tmux script by using the following example: $ sudo cat /etc/profile.d/tmux.sh if [ "$PS1" ]; then parent=$(ps -o ppid= -p $$) name=$(ps -o comm= -p $parent) case "$name" in (sshd|login) tmux ;; esac fi If "tmux" is not configured as the example above, is commented out or missing, this is a finding.

Fix: F-52064r880537_fix

Configure the operating system to initialize the tmux terminal multiplexer as each shell is called by adding the following lines to a custom.sh shell script in the /etc/profile.d/ directory: if [ "$PS1" ]; then parent=$(ps -o ppid= -p $$) name=$(ps -o comm= -p $parent) case "$name" in (sshd|login) tmux ;; esac fi This setting will take effect at next logon.

a
OL 8 must prevent users from disabling session control mechanisms.
AC-11 - Low - CCI-000056 - V-248677 - SV-248677r779597_rule
RMF Control
AC-11
Severity
Low
CCI
CCI-000056
Version
OL08-00-020042
Vuln IDs
  • V-248677
Rule IDs
  • SV-248677r779597_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, OL 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. Tmux is a terminal multiplexer that enables a number of terminals to be created, accessed, and controlled from a single screen. Satisfies: SRG-OS-000028-GPOS-00009, SRG-OS-000030-GPOS-00011
Checks: C-52111r779595_chk

Verify the operating system prevents users from disabling the tmux terminal multiplexer with the following command: $ sudo grep -i tmux /etc/shells If any output is produced, this is a finding.

Fix: F-52065r779596_fix

Configure the operating system to prevent users from disabling the tmux terminal multiplexer by editing the "/etc/shells" configuration file to remove any instances of tmux.

b
OL 8 must enable a user session lock until that user reestablishes access using established identification and authentication procedures for command line sessions.
AC-11 - Medium - CCI-000056 - V-248678 - SV-248678r779600_rule
RMF Control
AC-11
Severity
Medium
CCI
CCI-000056
Version
OL08-00-020043
Vuln IDs
  • V-248678
Rule IDs
  • SV-248678r779600_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, OL 8 needs to provide users with the ability to manually invoke a session lock so users may secure their session should the need arise for them to temporarily vacate the immediate physical vicinity. Systemd, a core component of OL 8, has a variety of dependencies needed to function. One of those packages is the Keytable files and keyboard utilities (kbd.x86_64). This package provides the "vlock" binary, a utility used to lock one or several user virtual console sessions. Satisfies: SRG-OS-000028-GPOS-00009, SRG-OS-000030-GPOS-00011
Checks: C-52112r779598_chk

Verify OL 8 has the "vlock" package installed by running the following command: $ sudo grep vlock /usr/bin/* Binary file /usr/bin/vlock matches If "vlock" is not installed, this is a finding.

Fix: F-52066r779599_fix

Install the "vlock" package, if it is not already installed, by running the following command: $ sudo yum install kbd.x86_64

b
OL 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-248679 - SV-248679r818655_rule
RMF Control
AC-11
Severity
Medium
CCI
CCI-000056
Version
OL08-00-020050
Vuln IDs
  • V-248679
Rule IDs
  • SV-248679r818655_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. OL 8 includes "authselect" as a tool to configure system identity, authentication sources, and providers by selecting a specific profile. A profile is a set of files that describes the resulting system configuration. When a profile is selected, "authselect" will create the "nsswitch.conf" and "PAM" stack to use identity and authentication sources defined by the profile. Satisfies: SRG-OS-000028-GPOS-00009, SRG-OS-000030-GPOS-00011
Checks: C-52113r818654_chk

Verify the operating system enables a user's session lock until that user reestablishes access using established identification and authentication procedures with the following command: This requirement assumes the use of the OL 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-52067r779602_fix

Configure OL 8 to enable a user's session lock until that user reestablishes access using established identification and authentication procedures. Select/create an "authselect" profile and incorporate the "with-smartcard-lock-on-removal" feature as in 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 line: removal-action='lock-screen' Update the system databases: $ sudo dconf update

b
OL 8 must automatically lock graphical user sessions after 15 minutes of inactivity.
AC-11 - Medium - CCI-000057 - V-248680 - SV-248680r779606_rule
RMF Control
AC-11
Severity
Medium
CCI
CCI-000057
Version
OL08-00-020060
Vuln IDs
  • V-248680
Rule IDs
  • SV-248680r779606_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 must 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
Checks: C-52114r779604_chk

Note: This requirement assumes the use of the OL 8 default graphical user interface, Gnome Shell. If the system does not have any graphical user interface installed, this requirement is Not Applicable. Verify the operating system initiates a session lock after a 15-minute period of inactivity for graphical user interfaces with the following commands: $ 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-52068r779605_fix

Configure OL 8 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
OL 8 must automatically lock command line user sessions after 15 minutes of inactivity.
AC-11 - Medium - CCI-000057 - V-248681 - SV-248681r779609_rule
RMF Control
AC-11
Severity
Medium
CCI
CCI-000057
Version
OL08-00-020070
Vuln IDs
  • V-248681
Rule IDs
  • SV-248681r779609_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. In addition, quickly terminating an idle session will also free up resources committed by the managed network element. Terminating network connections associated with communications sessions includes, for example, de-allocating associated TCP/IP address/port pairs at the operating system level and de-allocating 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 inactive session and releases the resources associated with that session. Satisfies: SRG-OS-000029-GPOS-00010, SRG-OS-000031-GPOS-00012
Checks: C-52115r779607_chk

Verify the operating system initiates a session lock after 15 minutes of inactivity. Check the value of the system inactivity timeout with the following command: $ sudo grep -i lock-after-time /etc/tmux.conf set -g lock-after-time 900 If "lock-after-time" is not set to "900" or less in the global tmux configuration file to enforce session lock after inactivity, this is a finding.

Fix: F-52069r779608_fix

Configure the operating system to enforce session lock after a period of 15 minutes of inactivity by adding the following line to the "/etc/tmux.conf" global configuration file: set -g lock-after-time 900

b
OL 8 must prevent a user from overriding the session lock-delay setting for the graphical user interface.
AC-11 - Medium - CCI-000057 - V-248682 - SV-248682r779612_rule
RMF Control
AC-11
Severity
Medium
CCI
CCI-000057
Version
OL08-00-020080
Vuln IDs
  • V-248682
Rule IDs
  • SV-248682r779612_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
Checks: C-52116r779610_chk

Note: This requirement assumes the use of the OL 8 default graphical user interface, Gnome Shell. If the system does not have any graphical user interface installed, this requirement is Not Applicable. Verify the operating system prevents a user from overriding settings for graphical user interfaces. 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-52070r779611_fix

Configure OL 8 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

b
OL 8 must prevent a user from overriding the session idle-delay setting for the graphical user interface.
AC-11 - Medium - CCI-000057 - V-248683 - SV-248683r779615_rule
RMF Control
AC-11
Severity
Medium
CCI
CCI-000057
Version
OL08-00-020081
Vuln IDs
  • V-248683
Rule IDs
  • SV-248683r779615_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
Checks: C-52117r779613_chk

Note: This requirement assumes the use of the OL 8 default graphical user interface, Gnome Shell. If the system does not have any graphical user interface installed, this requirement is Not Applicable. Verify the operating system prevents a user from overriding settings for graphical user interfaces. 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/screensaver/idle-delay If the command does not return at least the example result, this is a finding.

Fix: F-52071r779614_fix

Configure OL 8 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/idle-delay

b
OL 8 must prevent a user from overriding the session lock-enabled setting for the graphical user interface.
AC-11 - Medium - CCI-000057 - V-248684 - SV-248684r779618_rule
RMF Control
AC-11
Severity
Medium
CCI
CCI-000057
Version
OL08-00-020082
Vuln IDs
  • V-248684
Rule IDs
  • SV-248684r779618_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
Checks: C-52118r779616_chk

Note: This requirement assumes the use of the OL 8 default graphical user interface, Gnome Shell. If the system does not have any graphical user interface installed, this requirement is Not Applicable. Verify the operating system prevents a user from overriding settings for graphical user interfaces. 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-52072r779617_fix

Configure OL 8 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

b
OL 8 must map the authenticated identity to the user or group account for PKI-based authentication.
IA-5 - Medium - CCI-000187 - V-248685 - SV-248685r858606_rule
RMF Control
IA-5
Severity
Medium
CCI
CCI-000187
Version
OL08-00-020090
Vuln IDs
  • V-248685
Rule IDs
  • SV-248685r858606_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 OL 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 using an idM server, or a local system mapping, where the system is not part of a domain.
Checks: C-52119r858605_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 =&lt;SAN&gt;.*EDIPI@mil maprule = (userCertificate;binary={cert!bin}) domains = testing.test If the "certmap" section does not exist, this is a finding.

Fix: F-52073r779620_fix

Configure OL 8 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
OL 8 must ensure the password complexity module is enabled in the password-auth file.
CM-6 - Medium - CCI-000366 - V-248686 - SV-248686r902809_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-020100
Vuln IDs
  • V-248686
Rule IDs
  • SV-248686r902809_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. Use of "pwquality" enforces complex password construction configuration and has the ability to limit brute-force attacks on the system. OL 8 uses "pwquality" as a mechanism to enforce password complexity. This is set in both of the following: /etc/pam.d/password-auth /etc/pam.d/system-auth Satisfies: SRG-OS-000069-GPOS-00037, SRG-OS-000070-GPOS-00038
Checks: C-52120r902807_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-52074r902808_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

a
OL 8 must enforce password complexity by requiring that at least one uppercase character be used.
IA-5 - Low - CCI-000192 - V-248687 - SV-248687r858631_rule
RMF Control
IA-5
Severity
Low
CCI
CCI-000192
Version
OL08-00-020110
Vuln IDs
  • V-248687
Rule IDs
  • SV-248687r858631_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. OL 8 uses 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". Satisfies: SRG-OS-000069-GPOS-00037, SRG-OS-000070-GPOS-00038
Checks: C-52121r833219_chk

Verify the value for "ucredit" in "/etc/security/pwquality.conf" or "/etc/security/pwquality.conf.d/*.conf" files 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-52075r858630_fix

Configure OL 8 to enforce password complexity by requiring that at least one uppercase character be used by setting the "ucredit" option. Add or update the following line in the "/etc/security/pwquality.conf" file or a configuration file in the "/etc/security/pwquality.conf.d/" directory: ucredit = -1 Remove any configurations that conflict with the above value.

a
OL 8 must enforce password complexity by requiring that at least one lowercase character be used.
IA-5 - Low - CCI-000193 - V-248688 - SV-248688r858633_rule
RMF Control
IA-5
Severity
Low
CCI
CCI-000193
Version
OL08-00-020120
Vuln IDs
  • V-248688
Rule IDs
  • SV-248688r858633_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. OL 8 uses pwquality as a mechanism to enforce password complexity. Note that in order to require lowercase characters without degrading the "minlen" value, the credit value must be expressed as a negative number in "/etc/security/pwquality.conf".
Checks: C-52122r833221_chk

Verify the value for "lcredit" in "/etc/security/pwquality.conf" or "/etc/security/pwquality.conf.d/*.conf" files 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-52076r858632_fix

Configure OL 8 to enforce password complexity by requiring that at least one lowercase character be used by setting the "lcredit" option. Add or update the following line in the "/etc/security/pwquality.conf" file or a configuration file in the "/etc/security/pwquality.conf.d/" directory: lcredit = -1 Remove any configurations that conflict with the above value.

a
OL 8 must enforce password complexity by requiring that at least one numeric character be used.
IA-5 - Low - CCI-000194 - V-248689 - SV-248689r858635_rule
RMF Control
IA-5
Severity
Low
CCI
CCI-000194
Version
OL08-00-020130
Vuln IDs
  • V-248689
Rule IDs
  • SV-248689r858635_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. OL 8 uses "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-52123r833223_chk

Verify the value for "dcredit" in "/etc/security/pwquality.conf" or "/etc/security/pwquality.conf.d/*.conf" files 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-52077r858634_fix

Configure OL 8 to enforce password complexity by requiring that at least one numeric character be used by setting the "dcredit" option. Add or update the following line in the "/etc/security/pwquality.conf" file or a configuration file in the "/etc/security/pwquality.conf.d/" directory: dcredit = -1 Remove any configurations that conflict with the above value.

b
OL 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-248690 - SV-248690r858637_rule
RMF Control
IA-5
Severity
Medium
CCI
CCI-000195
Version
OL08-00-020140
Vuln IDs
  • V-248690
Rule IDs
  • SV-248690r858637_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. OL 8 uses "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-52124r833225_chk

Check for the value of the "maxclassrepeat" option in "/etc/security/pwquality.conf" or "/etc/security/pwquality.conf.d/*.conf" files 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-52078r858636_fix

Configure OL 8 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 or update the following line in the "/etc/security/pwquality.conf" file or a configuration file in the "/etc/security/pwquality.conf.d/" directory: maxclassrepeat = 4 Remove any configurations that conflict with the above value.

b
OL 8 must require the maximum number of repeating characters be limited to three when passwords are changed.
IA-5 - Medium - CCI-000195 - V-248691 - SV-248691r858639_rule
RMF Control
IA-5
Severity
Medium
CCI
CCI-000195
Version
OL08-00-020150
Vuln IDs
  • V-248691
Rule IDs
  • SV-248691r858639_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. OL 8 uses "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-52125r833227_chk

Check for the value of the "maxrepeat" option in "/etc/security/pwquality.conf" or "/etc/security/pwquality.conf.d/*.conf" files 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-52079r858638_fix

Configure OL 8 to require the change of the number of repeating consecutive characters when passwords are changed by setting the "maxrepeat" option. Add or update the following line in the "/etc/security/pwquality.conf" file or a configuration file in the "/etc/security/pwquality.conf.d/" directory: maxrepeat = 3 Remove any configurations that conflict with the above value.

b
OL 8 must require the change of at least four character classes when passwords are changed.
IA-5 - Medium - CCI-000195 - V-248692 - SV-248692r858641_rule
RMF Control
IA-5
Severity
Medium
CCI
CCI-000195
Version
OL08-00-020160
Vuln IDs
  • V-248692
Rule IDs
  • SV-248692r858641_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. OL 8 uses "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, upper-case, lower-case, others).
Checks: C-52126r833229_chk

Verify the value of the "minclass" option in "/etc/security/pwquality.conf" or "/etc/security/pwquality.conf.d/*.conf" files 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-52080r858640_fix

Configure OL 8 to require the change of at least four character classes when passwords are changed by setting the "minclass" option. Add or update the following line in the "/etc/security/pwquality.conf" file or a configuration file in the "/etc/security/pwquality.conf.d/" directory: minclass = 4 Remove any configurations that conflict with the above value.

a
OL 8 must require the change of at least 8 characters when passwords are changed.
IA-5 - Low - CCI-000195 - V-248693 - SV-248693r858643_rule
RMF Control
IA-5
Severity
Low
CCI
CCI-000195
Version
OL08-00-020170
Vuln IDs
  • V-248693
Rule IDs
  • SV-248693r858643_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. OL 8 uses "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-52127r833231_chk

Verify the value of the "difok" option in "/etc/security/pwquality.conf" or "/etc/security/pwquality.conf.d/*.conf" files 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-52081r858642_fix

Configure OL 8 to require the change of at least eight of the total number of characters when passwords are changed by setting the "difok" option. Add or update the following line in the "/etc/security/pwquality.conf" file or a configuration file in the "/etc/security/pwquality.conf.d/" directory: difok = 8 Remove any configurations that conflict with the above value.

b
OL 8 passwords for new users or password changes must have a 24 hours/1 day minimum password lifetime restriction in "/etc/shadow".
IA-5 - Medium - CCI-000198 - V-248694 - SV-248694r779648_rule
RMF Control
IA-5
Severity
Medium
CCI
CCI-000198
Version
OL08-00-020180
Vuln IDs
  • V-248694
Rule IDs
  • SV-248694r779648_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-52128r779646_chk

Verify the minimum time period between password changes for each user account is one day or greater. $ sudo awk -F: '$4 &lt; 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-52082r779647_fix

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

b
OL 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-248695 - SV-248695r858592_rule
RMF Control
IA-5
Severity
Medium
CCI
CCI-000198
Version
OL08-00-020190
Vuln IDs
  • V-248695
Rule IDs
  • SV-248695r858592_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-52129r779649_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-52083r779650_fix

Configure OL 8 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
OL 8 user account passwords must have a 60-day maximum password lifetime restriction.
IA-5 - Medium - CCI-000199 - V-248696 - SV-248696r779654_rule
RMF Control
IA-5
Severity
Medium
CCI
CCI-000199
Version
OL08-00-020200
Vuln IDs
  • V-248696
Rule IDs
  • SV-248696r779654_rule
Any password, no matter how complex, can eventually be cracked. Therefore, passwords need to be changed periodically. If OL 8 does not limit the lifetime of passwords and force users to change their passwords, there is the risk that OL 8 passwords could be compromised.
Checks: C-52130r779652_chk

Verify that OL 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-52084r779653_fix

Configure OL 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
OL 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-248697 - SV-248697r779657_rule
RMF Control
IA-5
Severity
Medium
CCI
CCI-000199
Version
OL08-00-020210
Vuln IDs
  • V-248697
Rule IDs
  • SV-248697r779657_rule
Any password, no matter how complex, can eventually be cracked. Therefore, passwords need to be changed periodically. If OL 8 does not limit the lifetime of passwords and force users to change their passwords, there is the risk that OL 8 passwords could be compromised.
Checks: C-52131r779655_chk

Verify the maximum time period for existing passwords is restricted to 60 days with the following commands: $ sudo awk -F: '$5 &gt; 60 {print $1 " " $5}' /etc/shadow $ sudo awk -F: '$5 &lt;= 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-52085r779656_fix

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

a
OL 8 must be configured in the password-auth file to prohibit password reuse for a minimum of five generations.
IA-5 - Low - CCI-000200 - V-248698 - SV-248698r902821_rule
RMF Control
IA-5
Severity
Low
CCI
CCI-000200
Version
OL08-00-020220
Vuln IDs
  • V-248698
Rule IDs
  • SV-248698r902821_rule
Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. If the information system or application allows the user to reuse their password consecutively when that password has exceeded its defined lifetime, the end result is a password that is not changed per policy requirements. OL 8 uses "pwhistory" consecutively as a mechanism to prohibit password reuse. This is set in both of the following: /etc/pam.d/password-auth /etc/pam.d/system-auth Note that manual changes to the listed files may be overwritten by the "authselect" program.
Checks: C-52132r902819_chk

Verify the operating system is configured in the password-auth file to prohibit password reuse for a minimum of five generations. Check for the value of the "remember" argument in "/etc/pam.d/password-auth" with the following command: $ sudo grep -i remember /etc/pam.d/password-auth password requisite pam_pwhistory.so use_authtok remember=5 retry=3 If the line containing "pam_pwhistory.so" does not have the "remember" module argument set, is commented out, or the value of the "remember" module argument is set to less than "5", this is a finding.

Fix: F-52086r902820_fix

Configure the operating system in the password-auth file to prohibit password reuse for a minimum of five generations. Add the following line in "/etc/pam.d/password-auth" (or modify the line to have the required value): password requisite pam_pwhistory.so use_authtok remember=5 retry=3

b
OL 8 passwords must have a minimum of 15 characters.
IA-5 - Medium - CCI-000205 - V-248699 - SV-248699r858645_rule
RMF Control
IA-5
Severity
Medium
CCI
CCI-000205
Version
OL08-00-020230
Vuln IDs
  • V-248699
Rule IDs
  • SV-248699r858645_rule
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. OL 8 uses "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, but they will not count toward the total "score" of "minlen". This will enable "minlen" to require a 15-character minimum.
Checks: C-52133r833233_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 in "/etc/security/pwquality.conf" or "/etc/security/pwquality.conf.d/*.conf" files 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 or is commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-52087r858644_fix

Configure OL 8 to enforce a minimum 15-character password length. Add or update the following line in the "/etc/security/pwquality.conf" file or a configuration file in the "/etc/security/pwquality.conf.d/" directory: minlen = 15 Remove any configurations that conflict with the above value.

b
OL 8 passwords for new users must have a minimum of 15 characters.
IA-5 - Medium - CCI-000205 - V-248700 - SV-248700r779666_rule
RMF Control
IA-5
Severity
Medium
CCI
CCI-000205
Version
OL08-00-020231
Vuln IDs
  • V-248700
Rule IDs
  • SV-248700r779666_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-52134r779664_chk

Verify that OL 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 is commented out, this is a finding.

Fix: F-52088r779665_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
OL 8 duplicate User IDs (UIDs) must not exist for interactive users.
AU-3 - Medium - CCI-000135 - V-248701 - SV-248701r779669_rule
RMF Control
AU-3
Severity
Medium
CCI
CCI-000135
Version
OL08-00-020240
Vuln IDs
  • V-248701
Rule IDs
  • SV-248701r779669_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-000042-GPOS-00020, SRG-OS-000104-GPOS-00051, SRG-OS-000121-GPOS-00062
Checks: C-52135r779667_chk

Verify that OL 8 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-52089r779668_fix

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

b
OL 8 must implement multifactor authentication for access to interactive accounts.
IA-2 - Medium - CCI-000765 - V-248702 - SV-248702r943098_rule
RMF Control
IA-2
Severity
Medium
CCI
CCI-000765
Version
OL08-00-020250
Vuln IDs
  • V-248702
Rule IDs
  • SV-248702r943098_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 OL 8. Some methods include a local system multifactor account mapping or joining the system to a domain and using an 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-52136r943096_chk

Verify OL 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-52090r943097_fix

Configure OL 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
The OL 8 system-auth file must disable access to the system for account identifiers (individuals, groups, roles, and devices) with 35 days of inactivity.
IA-4 - Medium - CCI-000795 - V-248703 - SV-248703r779675_rule
RMF Control
IA-4
Severity
Medium
CCI
CCI-000795
Version
OL08-00-020260
Vuln IDs
  • V-248703
Rule IDs
  • SV-248703r779675_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. OL 8 needs to track periods of inactivity and disable application identifiers after 35 days of inactivity.
Checks: C-52137r779673_chk

Verify the account identifiers (individuals, groups, roles, and devices) are disabled after 35 days of inactivity by checking the account inactivity value with the following command: $ sudo grep 'inactive\|pam_unix' /etc/pam.d/system-auth | grep -w auth auth required pam_lastlog.so inactive=35 auth sufficient pam_unix.so If the pam_lastlog.so module is listed below the pam_unix.so module in the "system-auth" file, this is a finding. If the value of "inactive" is set to zero, a negative number, or is greater than 35, this is a finding. If the line is commented out or missing, ask the administrator to indicate how the system disables access for account identifiers. If there is no evidence that the system is disabling access for account identifiers after 35 days of inactivity, this is a finding.

Fix: F-52091r779674_fix

Configure OL 8 to disable access to the system for account identifiers with 35 days of inactivity. Add/Modify the following line to "/etc/pam.d/system-auth" above the "pam_unix.so" statement: auth required pam_lastlog.so inactive=35 Note: The DoD recommendation is 35 days, but a lower value is acceptable.

b
The OL 8 password-auth file must disable access to the system for account identifiers (individuals, groups, roles, and devices) with 35 days of inactivity.
IA-4 - Medium - CCI-000795 - V-248704 - SV-248704r779678_rule
RMF Control
IA-4
Severity
Medium
CCI
CCI-000795
Version
OL08-00-020261
Vuln IDs
  • V-248704
Rule IDs
  • SV-248704r779678_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. OL 8 needs to track periods of inactivity and disable application identifiers after 35 days of inactivity.
Checks: C-52138r779676_chk

Verify the account identifiers (individuals, groups, roles, and devices) are disabled after 35 days of inactivity by checking the account inactivity value with the following command: $ sudo grep 'inactive\|pam_unix' /etc/pam.d/password-auth | grep -w auth auth required pam_lastlog.so inactive=35 auth sufficient pam_unix.so If the pam_lastlog.so module is listed below the pam_unix.so module in the "password-auth" file, this is a finding. If the value of "inactive" is set to zero, a negative number, or is greater than 35, this is a finding. If the line is commented out or missing, ask the administrator to indicate how the system disables access for account identifiers. If there is no evidence that the system is disabling access for account identifiers after 35 days of inactivity, this is a finding.

Fix: F-52092r779677_fix

Configure OL 8 to disable access to the system for account identifiers with 35 days of inactivity. Add/Modify the following line to "/etc/pam.d/password-auth" above the "pam_unix.so" statement: auth required pam_lastlog.so inactive=35 Note: The DoD recommendation is 35 days, but a lower value is acceptable.

b
The OL 8 lastlog command must have a mode of "0750" or less permissive.
SI-11 - Medium - CCI-001314 - V-248705 - SV-248705r779681_rule
RMF Control
SI-11
Severity
Medium
CCI
CCI-001314
Version
OL08-00-020262
Vuln IDs
  • V-248705
Rule IDs
  • SV-248705r779681_rule
Unauthorized disclosure of the contents of the /var/log/lastlog file can reveal system data to attackers, thus compromising its confidentiality.
Checks: C-52139r779679_chk

Verify the "lastlog" command has a mode of "0750" or less permissive with the following command: $ sudo stat -c "%a %n" /usr/bin/lastlog 750 /usr/bin/lastlog If the "lastlog" command has a mode more permissive than "0750", this is a finding.

Fix: F-52093r779680_fix

Configure the mode of the "lastlog" command for OL 8 to "0750" with the following command: $ sudo chmod 0750 /usr/bin/lastlog

b
The OL 8 lastlog command must be owned by root.
SI-11 - Medium - CCI-001314 - V-248706 - SV-248706r779684_rule
RMF Control
SI-11
Severity
Medium
CCI
CCI-001314
Version
OL08-00-020263
Vuln IDs
  • V-248706
Rule IDs
  • SV-248706r779684_rule
Unauthorized disclosure of the contents of the /var/log/lastlog file can reveal system data to attackers, thus compromising its confidentiality.
Checks: C-52140r779682_chk

Verify the "lastlog" command is owned by root with the following command: $ sudo ls -l /usr/bin/lastlog -rwxr-x---. 1 root root 21200 Nov 4 22:51 /usr/bin/lastlog If the "lastlog" command is not owned by root, this is a finding.

Fix: F-52094r779683_fix

Configure the "lastlog" command for OL 8 to be owned by root with the following command: $ sudo chown root /usr/bin/lastlog

b
The OL 8 lastlog command must be group-owned by root.
SI-11 - Medium - CCI-001314 - V-248707 - SV-248707r779687_rule
RMF Control
SI-11
Severity
Medium
CCI
CCI-001314
Version
OL08-00-020264
Vuln IDs
  • V-248707
Rule IDs
  • SV-248707r779687_rule
Unauthorized disclosure of the contents of the /var/log/lastlog file can reveal system data to attackers, thus compromising its confidentiality.
Checks: C-52141r779685_chk

Verify the "lastlog" command is group-owned by root with the following command: $ sudo ls -l /usr/bin/lastlog -rwxr-x---. 1 root root 21200 Nov 4 22:51 /usr/bin/lastlog If the "lastlog" command is not group-owned by root, this is a finding.

Fix: F-52095r779686_fix

Configure the "lastlog" command for OL 8 to be group-owned by root with the following command: $ sudo chgrp root /usr/bin/lastlog

b
OL 8 must automatically expire temporary accounts within 72 hours.
AC-2 - Medium - CCI-001682 - V-248708 - SV-248708r902791_rule
RMF Control
AC-2
Severity
Medium
CCI
CCI-001682
Version
OL08-00-020270
Vuln IDs
  • V-248708
Rule IDs
  • SV-248708r902791_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 expoitation 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-52142r902789_chk

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 &lt;temporary_account_name&gt; | 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-52096r902790_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>

a
All OL 8 passwords must contain at least one special character.
IA-5 - Low - CCI-001619 - V-248709 - SV-248709r858647_rule
RMF Control
IA-5
Severity
Low
CCI
CCI-001619
Version
OL08-00-020280
Vuln IDs
  • V-248709
Rule IDs
  • SV-248709r858647_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. OL 8 uses "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-52143r833235_chk

Verify the value for "ocredit" in "/etc/security/pwquality.conf" or "/etc/security/pwquality.conf.d/*.conf" files 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-52097r858646_fix

Configure OL 8 to enforce password complexity by requiring that at least one special character be used by setting the "ocredit" option. Add or update the following line in the "/etc/security/pwquality.conf" file or a configuration file in the "/etc/security/pwquality.conf.d/" directory: ocredit = -1 Remove any configurations that conflict with the above value.

b
OL 8 must prohibit the use of cached authentications after one day.
IA-5 - Medium - CCI-002007 - V-248710 - SV-248710r943101_rule
RMF Control
IA-5
Severity
Medium
CCI
CCI-002007
Version
OL08-00-020290
Vuln IDs
  • V-248710
Rule IDs
  • SV-248710r943101_rule
If cached authentication information is out of date, the validity of the authentication information may be questionable. OL 8 includes multiple options for configuring authentication, but this requirement will focus on the System Security Services Daemon (SSSD). By default, SSSD does not cache credentials.
Checks: C-52144r943099_chk

Verify that the SSSD prohibits the use of cached authentications after one day. Note: If smart card authentication is not being used on the system, this item is not applicable. Check that SSSD allows cached authentications with the following command: $ sudo grep -ir cache_credentials /etc/sssd/sssd.conf /etc/sssd/conf.d/*.conf cache_credentials = true If "cache_credentials" is set to "false" or is 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 -ir offline_credentials_expiration /etc/sssd/sssd.conf /etc/sssd/conf.d/*.conf offline_credentials_expiration = 1 If "offline_credentials_expiration" is not set to a value of "1", this is a finding.

Fix: F-52098r943100_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
OL 8 must prevent the use of dictionary words for passwords.
CM-6 - Medium - CCI-000366 - V-248711 - SV-248711r858649_rule
RMF Control
CM-6
Severity
Medium
CCI
CCI-000366
Version
OL08-00-020300
Vuln IDs
  • V-248711
Rule IDs
  • SV-248711r858649_rule
If OL 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-52145r833237_chk

Verify OL 8 prevents the use of dictionary words for passwords. Determine if the field "dictcheck" is set in the "/etc/security/pwquality.conf" or "/etc/security/pwquality.conf.d/*.conf" files 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-52099r858648_fix

Configure OL 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/security/pwquality.conf.d/" directory: dictcheck=1 Remove any configurations that conflict with the above value.

b
OL 8 must enforce a delay of at least four seconds between logon prompts following a failed logon attempt.
CM-6 - Medium - CCI-000366 - V-248712 - SV-248712r779702_rule
RMF Control
CM-6
Severity