Red Hat Enterprise Linux 9 Security Technical Implementation Guide

Version

RHEL-09-211010

Vuln IDs

V-257777

Rule IDs

SV-257777r991589_rule

An operating system release is considered "supported" if the vendor continues to provide security patches for the product. With an unsupported release, it will not be possible to resolve security issues discovered in the system software. Red Hat offers the Extended Update Support (EUS) add-on to a Red Hat Enterprise Linux subscription, for a fee, for those customers who wish to standardize on a specific minor release for an extended period.

Checks: C-61518r925316_chk

Verify that the version or RHEL 9 is vendor supported with the following command: $ cat /etc/redhat-release Red Hat Enterprise Linux release 9.2 (Plow) If the installed version of RHEL 9 is not supported, this is a finding.

Fix: F-61442r925317_fix

Upgrade to a supported version of RHEL 9.

b

RHEL 9 vendor packaged system security patches and updates must be installed and up to date.

CM-6 - Medium - CCI-000366 - V-257778 - SV-257778r1134892_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-211015

Vuln IDs

V-257778

Rule IDs

SV-257778r1134892_rule

Installing software updates is a fundamental mitigation against the exploitation of publicly known vulnerabilities. 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-61519r1134891_chk

Verify RHEL 9 security patches and updates are installed and up to date. Updates are required to be applied with a frequency determined by organizational policy. Obtain the list of available package security updates from Red Hat. The URL for updates is https://access.redhat.com/errata-search/. It is important to note that updates provided by Red Hat may not be present on the system if the underlying packages are not installed. Check that the available package security updates have been installed on the system with the following command: $ sudo dnf history list | more ID | Command line | Date and time | Action(s) | Altered ------------------------------------------------------------------------------- 70 | install aide | 2023-03-05 10:58 | Install | 1 69 | update -y | 2023-03-04 14:34 | Update | 18 EE 68 | install vlc | 2023-02-21 17:12 | Install | 21 67 | update -y | 2023-02-21 17:04 | Update | 7 EE Typical update frequency may be overridden by Information Assurance Vulnerability Alert (IAVA) notifications from CYBERCOM. If the system is in noncompliance with the organizational patching policy, this is a finding.

Fix: F-61443r925320_fix

Install RHEL 9 security patches and updates at the organizationally defined frequency. If system updates are installed via a centralized repository that is configured on the system, all updates can be installed with the following command: $ sudo dnf update

b

RHEL 9 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-257779 - SV-257779r958390_rule

RMF Control

AC-8

Severity

M

CCI

Version

RHEL-09-211020

Vuln IDs

V-257779

Rule IDs

SV-257779r958390_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 login 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-61520r925322_chk

Verify RHEL 9 displays the Standard Mandatory DOD Notice and Consent Banner before granting access to the operating system via a command line user logon. Check that a banner is displayed 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, or the line is commented out, this is a finding.

Fix: F-61444r925323_fix

Configure RHEL 9 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

The graphical display manager must not be the default target on RHEL 9 unless approved.

CM-6 - Medium - CCI-000366 - V-257781 - SV-257781r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-211030

Vuln IDs

V-257781

Rule IDs

SV-257781r991589_rule

Unnecessary service packages must not be installed to decrease the attack surface of the system. Graphical display managers have a long history of security vulnerabilities and must not be used, unless approved and documented.

Checks: C-61522r925328_chk

Verify that RHEL 9 is configured to boot to the command line: $ systemctl get-default multi-user.target If the system default target is not set to "multi-user.target" and the information system security officer (ISSO) lacks a documented requirement for a graphical user interface, this is a finding.

Fix: F-61446r925329_fix

Document the requirement for a graphical user interface with the ISSO or set the default target to multi-user with the following command: $ sudo systemctl set-default multi-user.target

a

RHEL 9 must enable the hardware random number generator entropy gatherer service.

CM-6 - Low - CCI-000366 - V-257782 - SV-257782r991589_rule

RMF Control

CM-6

Severity

L

CCI

Version

RHEL-09-211035

Vuln IDs

V-257782

Rule IDs

SV-257782r991589_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-61523r942960_chk

Note: For RHEL 9 systems running with kernel FIPS mode enabled as specified by RHEL-09-671010, this requirement is Not Applicable. Verify that RHEL 9 has enabled the hardware random number generator entropy gatherer service with the following command: $ systemctl is-active rngd active If the "rngd" service is not active, this is a finding.

Fix: F-61447r925332_fix

Install the rng-tools package with the following command: $ sudo dnf install rng-tools Then enable the rngd service run the following command: $ sudo systemctl enable --now rngd

b

RHEL 9 systemd-journald service must be enabled.

SC-24 - Medium - CCI-001665 - V-257783 - SV-257783r991562_rule

RMF Control

SC-24

Severity

M

CCI

CCI-001665

Version

RHEL-09-211040

Vuln IDs

V-257783

Rule IDs

SV-257783r991562_rule

In the event of a system failure, RHEL 9 must preserve any information necessary to determine cause of failure and any information necessary to return to operations with least disruption to system processes.

Checks: C-61524r925334_chk

Verify that "systemd-journald" is active with the following command: $ systemctl is-active systemd-journald active If the systemd-journald service is not active, this is a finding.

Fix: F-61448r925335_fix

To enable the systemd-journald service, run the following command: $ sudo systemctl enable --now systemd-journald

c

The systemd Ctrl-Alt-Delete burst key sequence in RHEL 9 must be disabled.

AC-6 - High - CCI-002235 - V-257784 - SV-257784r1044832_rule

RMF Control

AC-6

Severity

H

CCI

Version

RHEL-09-211045

Vuln IDs

V-257784

Rule IDs

SV-257784r1044832_rule

A locally logged-on user who presses Ctrl-Alt-Delete when at the console can reboot the system. If accidentally pressed, as could happen in the case of a mixed OS environment, this can create the risk of short-term loss of availability of systems due to unintentional reboot. In a graphical user environment, risk of unintentional reboot from the Ctrl-Alt-Delete sequence is reduced because the user will be prompted before any action is taken. Satisfies: SRG-OS-000324-GPOS-00125, SRG-OS-000480-GPOS-00227

Checks: C-61525r925337_chk

Verify RHEL 9 is configured to not reboot the system when Ctrl-Alt-Delete is pressed seven times within two seconds with the following command: $ grep -i ctrl /etc/systemd/system.conf CtrlAltDelBurstAction=none If the "CtrlAltDelBurstAction" is not set to "none", commented out, or is missing, this is a finding.

Fix: F-61449r925338_fix

Configure the system to disable the CtrlAltDelBurstAction by added or modifying the following line in the "/etc/systemd/system.conf" configuration file: CtrlAltDelBurstAction=none Reload the daemon for this change to take effect. $ sudo systemctl daemon-reload

c

The x86 Ctrl-Alt-Delete key sequence must be disabled on RHEL 9.

AC-6 - High - CCI-002235 - V-257785 - SV-257785r1044833_rule

RMF Control

AC-6

Severity

H

CCI

Version

RHEL-09-211050

Vuln IDs

V-257785

Rule IDs

SV-257785r1044833_rule

A locally logged-on user who presses Ctrl-Alt-Delete when at the console can reboot the system. If accidentally pressed, as could happen in the case of a mixed OS environment, this can create the risk of short-term loss of availability of systems due to unintentional reboot. In a graphical user environment, risk of unintentional reboot from the Ctrl-Alt-Delete sequence is reduced because the user will be prompted before any action is taken. Satisfies: SRG-OS-000324-GPOS-00125, SRG-OS-000480-GPOS-00227

Checks: C-61526r925340_chk

Verify RHEL 9 is not configured to reboot the system when Ctrl-Alt-Delete is pressed with the following command: $ sudo systemctl status ctrl-alt-del.target ctrl-alt-del.target Loaded: masked (Reason: Unit ctrl-alt-del.target is masked.) Active: inactive (dead) If the "ctrl-alt-del.target" is loaded and not masked, this is a finding.

Fix: F-61450r925341_fix

Configure RHEL 9 to disable the ctrl-alt-del.target with the following command: $ sudo systemctl disable --now ctrl-alt-del.target $ sudo systemctl mask --now ctrl-alt-del.target

b

RHEL 9 debug-shell systemd service must be disabled.

AC-6 - Medium - CCI-002235 - V-257786 - SV-257786r1044834_rule

RMF Control

AC-6

Severity

M

CCI

Version

RHEL-09-211055

Vuln IDs

V-257786

Rule IDs

SV-257786r1044834_rule

The debug-shell requires no authentication and provides root privileges to anyone who has physical access to the machine. While this feature is disabled by default, masking it adds an additional layer of assurance that it will not be enabled via a dependency in systemd. This also prevents attackers with physical access from trivially bypassing security on the machine through valid troubleshooting configurations and gaining root access when the system is rebooted. Satisfies: SRG-OS-000324-GPOS-00125, SRG-OS-000480-GPOS-00227

Checks: C-61527r925343_chk

Verify RHEL 9 is configured to mask the debug-shell systemd service with the following command: $ sudo systemctl status debug-shell.service debug-shell.service Loaded: masked (Reason: Unit debug-shell.service is masked.) Active: inactive (dead) If the "debug-shell.service" is loaded and not masked, this is a finding.

Fix: F-61451r943025_fix

Configure RHEL 9 to mask the debug-shell systemd service with the following command: $ sudo systemctl disable --now debug-shell.service $ sudo systemctl mask --now debug-shell.service

b

RHEL 9 must require a boot loader superuser password.

AC-3 - Medium - CCI-000213 - V-257787 - SV-257787r1117265_rule

RMF Control

AC-3

Severity

M

CCI

Version

RHEL-09-212010

Vuln IDs

V-257787

Rule IDs

SV-257787r1117265_rule

To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DOD-approved PKIs, all DOD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Password protection on the boot loader configuration ensures users with physical access cannot trivially alter important bootloader settings. These include which kernel to use, and whether to enter single-user mode.

Checks: C-61528r1044835_chk

Verify the boot loader superuser password has been set with the following command: $ sudo grep password_pbkdf2 /etc/grub2.cfg password_pbkdf2 <superusers-accountname> ${GRUB2_PASSWORD} To verify the boot loader superuser account password has been set and the password encrypted, run the following command: $ sudo cat /boot/grub2/user.cfg GRUB2_PASSWORD=grub.pbkdf2.sha512.10000.C4E08AC72FBFF7E837FD267BFAD7AEB3D42DDC 2C99F2A94DD5E2E75C2DC331B719FE55D9411745F82D1B6CFD9E927D61925F9BBDD1CFAA0080E0 916F7AB46E0D.1302284FCCC52CD73BA3671C6C12C26FF50BA873293B24EE2A96EE3B57963E6D7 0C83964B473EC8F93B07FE749AA6710269E904A9B08A6BBACB00A2D242AD828 If a "GRUB2_PASSWORD" is not set, this is a finding.

Fix: F-61452r925347_fix

Configure RHEL 9 to require a grub bootloader password for the grub superuser account. Generate an encrypted grub2 password for the grub superuser account with the following command: $ sudo grub2-setpassword Enter password: Confirm password:

b

RHEL 9 must disable the ability of systemd to spawn an interactive boot process.

CM-6 - Medium - CCI-000366 - V-257788 - SV-257788r1044838_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-212015

Vuln IDs

V-257788

Rule IDs

SV-257788r1044838_rule

Using interactive or recovery boot, the console user could disable auditing, firewalls, or other services, weakening system security.

Checks: C-61529r925349_chk

Verify that GRUB 2 is configured to disable interactive boot. Check that the current GRUB 2 configuration disables the ability of systemd to spawn an interactive boot process with the following command: $ sudo grubby --info=ALL | grep args | grep 'systemd.confirm_spawn' If any output is returned, this is a finding.

Fix: F-61453r1044837_fix

Configure the current GRUB 2 configuration to disable the ability of systemd to spawn an interactive boot process with the following command: $ sudo grubby --update-kernel=ALL --remove-args="systemd.confirm_spawn"

c

RHEL 9 must require a unique superusers name upon booting into single-user and maintenance modes.

AC-3 - High - CCI-000213 - V-257789 - SV-257789r1134895_rule

RMF Control

AC-3

Severity

H

CCI

Version

RHEL-09-212020

Vuln IDs

V-257789

Rule IDs

SV-257789r1134895_rule

Having a nondefault grub superuser username makes password-guessing attacks less effective.

Checks: C-61530r1134893_chk

Verify the RHEL 9 boot loader superuser account has been set with the following command: $ sudo grep -A1 "superusers" /etc/grub2.cfg set superusers="<accountname>" export superusers password_pbkdf2 <accountname> ${GRUB2_PASSWORD} Verify <accountname> is not a common name such as root, admin, or administrator. If superusers contains easily guessable usernames, this is a finding.

Fix: F-61454r1134894_fix

Configure RHEL 9 to have a unique username for the grub superuser account. Edit the "/etc/grub.d/01_users" file and add or modify the following lines with a nondefault username for the superuser account: set superusers="<accountname>" export superusers Once the superuser account has been added, update the grub.cfg file by running: In RHEL 9.0, 9.1 and 9.2: sudo grub2-mkconfig -o /boot/grub2/grub.cfg In RHEL 9.3 and later: sudo grub2-mkconfig -o /boot/grub2/grub.cfg --update-bls-cmdline

b

RHEL 9 /boot/grub2/grub.cfg file must be group-owned by root.

CM-6 - Medium - CCI-000366 - V-257790 - SV-257790r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-212025

Vuln IDs

V-257790

Rule IDs

SV-257790r991589_rule

The "root" group is a highly privileged group. Furthermore, the group-owner of this file should not have any access privileges anyway.

Checks: C-61531r925355_chk

Verify the group ownership of the "/boot/grub2/grub.cfg" file with the following command: $ sudo stat -c "%G %n" /boot/grub2/grub.cfg root /boot/grub2/grub.cfg If "/boot/grub2/grub.cfg" file does not have a group owner of "root", this is a finding.

Fix: F-61455r925356_fix

Change the group of the file /boot/grub2/grub.cfg to root by running the following command: $ sudo chgrp root /boot/grub2/grub.cfg

b

RHEL 9 /boot/grub2/grub.cfg file must be owned by root.

CM-6 - Medium - CCI-000366 - V-257791 - SV-257791r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-212030

Vuln IDs

V-257791

Rule IDs

SV-257791r991589_rule

The " /boot/grub2/grub.cfg" file stores sensitive system configuration. Protection of this file is critical for system security.

Checks: C-61532r925358_chk

Verify the ownership of the "/boot/grub2/grub.cfg" file with the following command: $ sudo stat -c "%U %n" /boot/grub2/grub.cfg root /boot/grub2/grub.cfg If "/boot/grub2/grub.cfg" file does not have an owner of "root", this is a finding.

Fix: F-61456r925359_fix

Change the owner of the file /boot/grub2/grub.cfg to root by running the following command: $ sudo chown root /boot/grub2/grub.cfg

b

RHEL 9 must disable virtual system calls.

SC-3 - Medium - CCI-001084 - V-257792 - SV-257792r1044842_rule

RMF Control

SC-3

Severity

M

CCI

Version

RHEL-09-212035

Vuln IDs

V-257792

Rule IDs

SV-257792r1044842_rule

System calls 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 system calls 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 system calls provide an opportunity of attack for a user who has control of the return instruction pointer. Disabling virtual system calls help to prevent return oriented programming (ROP) attacks via buffer overflows and overruns. If the system intends to run containers based on RHEL 6 components, then virtual system calls will need enabled so the components function properly. Satisfies: SRG-OS-000480-GPOS-00227, SRG-OS-000134-GPOS-00068

Checks: C-61533r925361_chk

Verify the current GRUB 2 configuration disables virtual system calls with the following command: $ sudo grubby --info=ALL | grep args | grep -v 'vsyscall=none' If any output is returned, this is a finding. Check that virtual system calls are disabled by default to persist in kernel updates with the following command: $ 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-61457r925362_fix

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

b

RHEL 9 must clear the page allocator to prevent use-after-free attacks.

SC-3 - Medium - CCI-001084 - V-257793 - SV-257793r1044843_rule

RMF Control

SC-3

Severity

M

CCI

Version

RHEL-09-212040

Vuln IDs

V-257793

Rule IDs

SV-257793r1044843_rule

Poisoning writes an arbitrary value to freed pages, so any modification or reference to that page after being freed or before being initialized will be detected and prevented. This prevents many types of use-after-free vulnerabilities at little performance cost. Also prevents leak of data and detection of corrupted memory. Satisfies: SRG-OS-000480-GPOS-00227, SRG-OS-000134-GPOS-00068

Checks: C-61534r925364_chk

Verify that GRUB 2 is configured to enable page poisoning to mitigate use-after-free vulnerabilities. Check that the current GRUB 2 configuration has page poisoning enabled with the following command: $ sudo grubby --info=ALL | grep args | grep -v 'page_poison=1' If any output is returned, this is a finding. Check that page poisoning is enabled by default to persist in kernel updates with the following command: $ sudo grep page_poison /etc/default/grub GRUB_CMDLINE_LINUX="page_poison=1" If "page_poison" is not set to "1", is missing or commented out, this is a finding.

Fix: F-61458r925365_fix

Configure RHEL 9 to enable page poisoning with the following commands: $ sudo grubby --update-kernel=ALL --args="page_poison=1" Add or modify the following line in "/etc/default/grub" to ensure the configuration survives kernel updates: GRUB_CMDLINE_LINUX="page_poison=1"

b

RHEL 9 must clear memory when it is freed to prevent use-after-free attacks.

SC-3 - Medium - CCI-001084 - V-257794 - SV-257794r1069362_rule

RMF Control

SC-3

Severity

M

CCI

Version

RHEL-09-212045

Vuln IDs

V-257794

Rule IDs

SV-257794r1069362_rule

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

Checks: C-61535r1069360_chk

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

Fix: F-61459r1069361_fix

Configure RHEL 9 to enable init_on_free with the following command: $ sudo grubby --update-kernel=ALL --args="init_on_free=1" Regenerate the GRUB configuration: $ sudo grub2-mkconfig -o /boot/grub2/grub.cfg Reboot the system: $ sudo reboot

a

RHEL 9 must enable mitigations against processor-based vulnerabilities.

CM-7 - Low - CCI-000381 - V-257795 - SV-257795r1044845_rule

RMF Control

CM-7

Severity

L

CCI

Version

RHEL-09-212050

Vuln IDs

V-257795

Rule IDs

SV-257795r1044845_rule

Kernel page-table isolation is a kernel feature that mitigates the Meltdown security vulnerability and hardens the kernel against attempts to bypass kernel address space layout randomization (KASLR). Satisfies: SRG-OS-000433-GPOS-00193, SRG-OS-000095-GPOS-00049

Checks: C-61536r1044844_chk

Verify RHEL 9 enables kernel page-table isolation with the following command: $ sudo grubby --info=ALL | grep args | grep -v 'pti=on' If any output is returned, this is a finding. Check that kernel page-table isolation is enabled by default to persist in kernel updates: $ grep pti /etc/default/grub GRUB_CMDLINE_LINUX="pti=on" If "pti" is not set to "on", is missing or commented out, this is a finding.

Fix: F-61460r925371_fix

Configure RHEL 9 to enable kernel page-table isolation with the following command: $ sudo grubby --update-kernel=ALL --args="pti=on" Add or modify the following line in "/etc/default/grub" to ensure the configuration survives kernel updates: GRUB_CMDLINE_LINUX="pti=on"

a

RHEL 9 must enable auditing of processes that start prior to the audit daemon.

AU-3 - Low - CCI-000130 - V-257796 - SV-257796r1044847_rule

RMF Control

AU-3

Severity

L

CCI

Version

RHEL-09-212055

Vuln IDs

V-257796

Rule IDs

SV-257796r1044847_rule

Without the capability to generate audit records, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. If auditing is enabled late in the startup process, the actions of some startup processes may not be audited. Some audit systems also maintain state information only available if auditing is enabled before a given process is created. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000473-GPOS-00218, SRG-OS-000254-GPOS-00095

Checks: C-61537r1044846_chk

Verify that GRUB 2 is configured to enable auditing of processes that start prior to the audit daemon with the following commands: Check that the current GRUB 2 configuration enables auditing: $ sudo grubby --info=ALL | grep args | grep -v 'audit=1' If any output is returned, this is a finding. Check that auditing is enabled by default to persist in kernel updates: $ grep audit /etc/default/grub GRUB_CMDLINE_LINUX="audit=1" If "audit" is not set to "1", is missing, or is commented out, this is a finding.

Fix: F-61461r925374_fix

Enable auditing of processes that start prior to the audit daemon with the following command: $ sudo grubby --update-kernel=ALL --args="audit=1" Add or modify the following line in "/etc/default/grub" to ensure the configuration survives kernel updates: GRUB_CMDLINE_LINUX="audit=1"

b

RHEL 9 must restrict access to the kernel message buffer.

SC-2 - Medium - CCI-001082 - V-257797 - SV-257797r1117266_rule

RMF Control

SC-2

Severity

M

CCI

Version

RHEL-09-213010

Vuln IDs

V-257797

Rule IDs

SV-257797r1117266_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 nonprivileged 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 the directories in which they reside. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf Satisfies: SRG-OS-000132-GPOS-00067, SRG-OS-000138-GPOS-00069

Checks: C-61538r1106424_chk

Verify RHEL 9 is configured to restrict access to the kernel message buffer with the following commands: Check the status of the kernel.dmesg_restrict kernel parameter. $ sudo sysctl kernel.dmesg_restrict kernel.dmesg_restrict = 1 If "kernel.dmesg_restrict" is not set to "1" or is missing, this is a finding. Check that the configuration files are present to enable this kernel parameter. $ sudo grep -r kernel.dmesg_restrict /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf:kernel.dmesg_restrict = 1 If "kernel.dmesg_restrict" is not set to "1", is missing, or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-61462r1102065_fix

Configure RHEL 9 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

b

RHEL 9 must prevent kernel profiling by nonprivileged users.

SC-2 - Medium - CCI-001082 - V-257798 - SV-257798r1117266_rule

RMF Control

SC-2

Severity

M

CCI

Version

RHEL-09-213015

Vuln IDs

V-257798

Rule IDs

SV-257798r1117266_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 nonprivileged 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 the directories in which they reside. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf Satisfies: SRG-OS-000132-GPOS-00067, SRG-OS-000138-GPOS-00069

Checks: C-61539r1106426_chk

Verify RHEL 9 is configured to prevent kernel profiling by nonprivileged users with the following commands: Check the status of the kernel.perf_event_paranoid kernel parameter. $ sudo sysctl kernel.perf_event_paranoid kernel.perf_event_paranoid = 2 If "kernel.perf_event_paranoid" is not set to "2" or is missing, this is a finding. Check that the configuration files are present to enable this kernel parameter. $ sudo grep -r kernel.perf_event_paranoid /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf:kernel.perf_event_paranoid = 2 If "kernel.perf_event_paranoid" is not set to "2", is missing, or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-61463r1102051_fix

Configure RHEL 9 to prevent kernel profiling by nonprivileged users. Add or edit the following line in a system configuration file, in the "/etc/sysctl.d/" directory: kernel.perf_event_paranoid = 2 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf Load settings from all system configuration files with the following command: $ sudo sysctl --system

b

RHEL 9 must prevent the loading of a new kernel for later execution.

Medium - CCI-003992 - V-257799 - SV-257799r1106273_rule

RMF Control

Severity

M

CCI

Version

RHEL-09-213020

Vuln IDs

V-257799

Rule IDs

SV-257799r1106273_rule

Changes to any software components can have significant effects on the overall security of the operating system. This requirement ensures the software has not been tampered with and that it has been provided by a trusted vendor. Disabling kexec_load prevents an unsigned kernel image (that could be a windows kernel or modified vulnerable kernel) from being loaded. Kexec can be used subvert the entire secureboot process and should be avoided at all costs especially since it can load unsigned kernel images. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of the directories in which they reside. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf Satisfies: SRG-OS-000480-GPOS-00227, SRG-OS-000366-GPOS-00153

Checks: C-61540r1106271_chk

Verify RHEL 9 is configured to disable kernel image loading. Check the status of the kernel.kexec_load_disabled kernel parameter. $ sudo sysctl kernel.kexec_load_disabled kernel.kexec_load_disabled = 1 If "kernel.kexec_load_disabled" is not set to "1" or is missing, this is a finding. Check that the configuration files are present to enable this kernel parameter. $ sudo grep -r kernel.kexec_load_disabled /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf:kernel.kexec_load_disabled = 1 If "kernel.kexec_load_disabled" is not set to "1", is missing, or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-61464r1106272_fix

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

b

RHEL 9 must restrict exposed kernel pointer addresses access.

SC-2 - Medium - CCI-001082 - V-257800 - SV-257800r1117266_rule

RMF Control

SC-2

Severity

M

CCI

Version

RHEL-09-213025

Vuln IDs

V-257800

Rule IDs

SV-257800r1117266_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 the directories in which they reside. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf Satisfies: SRG-OS-000132-GPOS-00067, SRG-OS-000433-GPOS-00192, SRG-OS-000480-GPOS-00227

Checks: C-61541r1106274_chk

Verify RHEL 9 restricts exposed kernel pointer addresses access with the following commands: $ sudo sysctl kernel.kptr_restrict kernel.kptr_restrict = 1 If the returned line does not have a value of "1" or "2", or a line is not returned, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r kernel.kptr_restrict /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: kernel.kptr_restrict = 1 If "kernel.kptr_restrict" is not set to "1" or "2", is missing, or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-61465r1106275_fix

Configure RHEL 9 to restrict exposed kernel pointer addresses access by adding the following line to a file in the "/etc/sysctl.d" directory: kernel.kptr_restrict = 1 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf The system configuration files need to be reloaded for the changes to take effect. To reload the contents of the files, run the following command: $ sudo sysctl --system

b

RHEL 9 must enable kernel parameters to enforce discretionary access control on hardlinks.

AC-3 - Medium - CCI-002165 - V-257801 - SV-257801r1106279_rule

RMF Control

AC-3

Severity

M

CCI

CCI-002165

Version

RHEL-09-213030

Vuln IDs

V-257801

Rule IDs

SV-257801r1106279_rule

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

Checks: C-61542r1106277_chk

Verify RHEL 9 is configured to enable DAC on hardlinks. Check the status of the fs.protected_hardlinks kernel parameter. $ sudo sysctl fs.protected_hardlinks fs.protected_hardlinks = 1 If "fs.protected_hardlinks" is not set to "1" or is missing, this is a finding. Check that the configuration files are present to enable this kernel parameter. $ sudo grep -r fs.protected_hardlinks /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf:fs.protected_hardlinks = 1 If "fs.protected_hardlinks" is not set to "1", is missing, or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-61466r1106278_fix

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

b

RHEL 9 must enable kernel parameters to enforce discretionary access control on symlinks.

AC-3 - Medium - CCI-002165 - V-257802 - SV-257802r1106282_rule

RMF Control

AC-3

Severity

M

CCI

CCI-002165

Version

RHEL-09-213035

Vuln IDs

V-257802

Rule IDs

SV-257802r1106282_rule

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

Checks: C-61543r1106280_chk

Verify RHEL 9 is configured to enable DAC on symlinks. Check the status of the fs.protected_symlinks kernel parameter. $ sudo sysctl fs.protected_symlinks fs.protected_symlinks = 1 If "fs.protected_symlinks" is not set to "1" or is missing, this is a finding. Check that the configuration files are present to enable this kernel parameter. $ sudo grep -r fs.protected_symlinks /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf:fs.protected_symlinks = 1 If "fs.protected_symlinks" is not set to "1", is missing, or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-61467r1106281_fix

Configure RHEL 9 to enable DAC on symlinks. Add or edit the following line in a system configuration file in the "/etc/sysctl.d/" directory: fs.protected_symlinks = 1 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf Load settings from all system configuration files with the following command: $ sudo sysctl --system

b

RHEL 9 must disable the kernel.core_pattern.

CM-6 - Medium - CCI-000366 - V-257803 - SV-257803r1106429_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-213040

Vuln IDs

V-257803

Rule IDs

SV-257803r1106429_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 the directories in which they reside. 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-61544r1106283_chk

Verify RHEL 9 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-61468r1106428_fix

Configure RHEL 9 to disable storing core dumps. Add or edit the following line in a system configuration file in the "/etc/sysctl.d/" directory: kernel.core_pattern = |/bin/false Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf The system configuration files must reloaded for the changes to take effect. To reload the contents of the files, run the following command: $ sudo sysctl --system

b

RHEL 9 must be configured to disable the Asynchronous Transfer Mode kernel module.

CM-7 - Medium - CCI-000381 - V-257804 - SV-257804r1044853_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-09-213045

Vuln IDs

V-257804

Rule IDs

SV-257804r1044853_rule

Disabling Asynchronous Transfer Mode (ATM) protects the system against exploitation of any flaws in its implementation.

Checks: C-61545r1044852_chk

Verify that RHEL 9 disables the ability to load the ATM kernel module with the following command: $ grep -r atm /etc/modprobe.conf /etc/modprobe.d/* install atm /bin/false blacklist atm If the command does not return any output, or the line is commented out, and use of ATM is not documented with the information system security officer (ISSO) as an operational requirement, this is a finding.

Fix: F-61469r925398_fix

To configure the system to prevent the atm kernel module from being loaded, add the following line to the file /etc/modprobe.d/atm.conf (or create atm.conf if it does not exist): install atm /bin/false blacklist atm

b

RHEL 9 must be configured to disable the Controller Area Network kernel module.

CM-7 - Medium - CCI-000381 - V-257805 - SV-257805r1044856_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-09-213050

Vuln IDs

V-257805

Rule IDs

SV-257805r1044856_rule

Disabling Controller Area Network (CAN) protects the system against exploitation of any flaws in its implementation.

Checks: C-61546r1044854_chk

Verify that RHEL 9 disables the ability to load the CAN kernel module with the following command: $ grep -r can /etc/modprobe.conf /etc/modprobe.d/* install can /bin/false blacklist can If the command does not return any output, or the lines are commented out, and use of CAN is not documented with the information system security officer (ISSO) as an operational requirement, this is a finding.

Fix: F-61470r1044855_fix

To configure the system to prevent the can kernel module from being loaded, add the following lines to the file /etc/modprobe.d/can.conf (or create can.conf if it does not exist): install can /bin/false blacklist can

b

RHEL 9 must be configured to disable the FireWire kernel module.

CM-7 - Medium - CCI-000381 - V-257806 - SV-257806r1044859_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-09-213055

Vuln IDs

V-257806

Rule IDs

SV-257806r1044859_rule

Disabling firewire protects the system against exploitation of any flaws in its implementation.

Checks: C-61547r1044857_chk

Verify that RHEL 9 disables the ability to load the firewire-core kernel module with the following command: $ grep -r firewire-core /etc/modprobe.conf /etc/modprobe.d/* install firewire-core /bin/false blacklist firewire-core If the command does not return any output, or the lines are commented out, and use of firewire-core is not documented with the information system security officer (ISSO) as an operational requirement, this is a finding.

Fix: F-61471r1044858_fix

To configure the system to prevent the firewire-core kernel module from being loaded, add the following lines to the file /etc/modprobe.d/firewire-core.conf (or create firewire-core.conf if it does not exist): install firewire-core /bin/false blacklist firewire-core

b

RHEL 9 must disable the Stream Control Transmission Protocol (SCTP) kernel module.

CM-7 - Medium - CCI-000381 - V-257807 - SV-257807r1044862_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-09-213060

Vuln IDs

V-257807

Rule IDs

SV-257807r1044862_rule

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Failing to disconnect unused protocols can result in a system compromise. The Stream Control Transmission Protocol (SCTP) is a transport layer protocol, designed to support the idea of message-oriented communication, with several streams of messages within one connection. Disabling SCTP protects the system against exploitation of any flaws in its implementation.

Checks: C-61548r1044860_chk

Verify that RHEL 9 disables the ability to load the sctp kernel module with the following command: $ grep -r sctp /etc/modprobe.conf /etc/modprobe.d/* install sctp /bin/false blacklist sctp If the command does not return any output, or the lines are commented out, and use of sctp is not documented with the information system security officer (ISSO) as an operational requirement, this is a finding.

Fix: F-61472r1044861_fix

To configure the system to prevent the sctp kernel module from being loaded, add the following lines to the file /etc/modprobe.d/sctp.conf (or create sctp.conf if it does not exist): install sctp /bin/false blacklist sctp

b

RHEL 9 must disable the Transparent Inter Process Communication (TIPC) kernel module.

CM-7 - Medium - CCI-000381 - V-257808 - SV-257808r1044865_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-09-213065

Vuln IDs

V-257808

Rule IDs

SV-257808r1044865_rule

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Failing to disconnect unused protocols can result in a system compromise. The Transparent Inter Process Communication (TIPC) is a protocol that is specially designed for intra-cluster communication. It can be configured to transmit messages either on UDP or directly across Ethernet. Message delivery is sequence guaranteed, loss free and flow controlled. Disabling TIPC protects the system against exploitation of any flaws in its implementation.

Checks: C-61549r1044863_chk

Verify that RHEL 9 disables the ability to load the tipc kernel module with the following command: $ grep -r tipc /etc/modprobe.conf /etc/modprobe.d/* install tipc /bin/false blacklist tipc If the command does not return any output, or the lines are commented out, and use of tipc is not documented with the information system security officer (ISSO) as an operational requirement, this is a finding.

Fix: F-61473r1044864_fix

To configure the system to prevent the tipc kernel module from being loaded, add the following lines to the file /etc/modprobe.d/tipc.conf (or create tipc.conf if it does not exist): install tipc /bin/false blacklist tipc

b

RHEL 9 must implement address space layout randomization (ASLR) to protect its memory from unauthorized code execution.

SI-16 - Medium - CCI-002824 - V-257809 - SV-257809r1106288_rule

RMF Control

SI-16

Severity

M

CCI

CCI-002824

Version

RHEL-09-213070

Vuln IDs

V-257809

Rule IDs

SV-257809r1106288_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. 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 the directories in which they reside. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf Satisfies: SRG-OS-000433-GPOS-00193, SRG-OS-000480-GPOS-00227

Checks: C-61550r1106286_chk

Verify RHEL 9 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-61474r1106287_fix

Configure RHEL 9 to implement virtual address space randomization. Add or edit the following line in a system configuration file in the "/etc/sysctl.d/" directory: kernel.randomize_va_space=2 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf Issue the following command to make the changes take effect: $ sudo sysctl --system

b

RHEL 9 must disable access to network bpf system call from nonprivileged processes.

SC-2 - Medium - CCI-001082 - V-257810 - SV-257810r1117266_rule

RMF Control

SC-2

Severity

M

CCI

Version

RHEL-09-213075

Vuln IDs

V-257810

Rule IDs

SV-257810r1117266_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 the directories in which they reside. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf Satisfies: SRG-OS-000132-GPOS-00067, SRG-OS-000480-GPOS-00227

Checks: C-61551r1106289_chk

Verify RHEL 9 prevents privilege escalation through the kernel by disabling access to the bpf syscall with the following commands: $ sudo sysctl kernel.unprivileged_bpf_disabled kernel.unprivileged_bpf_disabled = 1 If the returned line does not have a value of "1", or a line is not returned, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r kernel.unprivileged_bpf_disabled /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: kernel.unprivileged_bpf_disabled = 1 If "kernel.unprivileged_bpf_disabled" is not set to "1", is missing, or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-61475r1106430_fix

Configure RHEL 9 to prevent privilege escalation through the kernel by disabling access to the bpf syscall by adding the following line to a file in the "/etc/sysctl.d" directory: kernel.unprivileged_bpf_disabled = 1 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf The system configuration files must be reloaded for the changes to take effect. To reload the contents of the files, run the following command: $ sudo sysctl --system

b

RHEL 9 must restrict usage of ptrace to descendant processes.

SC-2 - Medium - CCI-001082 - V-257811 - SV-257811r1117266_rule

RMF Control

SC-2

Severity

M

CCI

Version

RHEL-09-213080

Vuln IDs

V-257811

Rule IDs

SV-257811r1117266_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 the directories in which they reside. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf Satisfies: SRG-OS-000132-GPOS-00067, SRG-OS-000480-GPOS-00227

Checks: C-61552r1106292_chk

Verify RHEL 9 restricts usage of ptrace to descendant processes with the following commands: $ sudo sysctl kernel.yama.ptrace_scope kernel.yama.ptrace_scope = 1 If the returned line does not have a value of "1", or a line is not returned, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r kernel.yama.ptrace_scope /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: kernel.yama.ptrace_scope = 1 If "kernel.yama.ptrace_scope" is not set to "1", is missing, or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-61476r1106432_fix

Configure RHEL 9 to restrict usage of ptrace to descendant processes by adding the following line to a file in the "/etc/sysctl.d" directory: kernel.yama.ptrace_scope = 1 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf The system configuration files must be reloaded for the changes to take effect. To reload the contents of the files, run the following command: $ sudo sysctl --system

b

RHEL 9 must disable core dump backtraces.

CM-6 - Medium - CCI-000366 - V-257812 - SV-257812r1134897_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-213085

Vuln IDs

V-257812

Rule IDs

SV-257812r1134897_rule

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 or system operators trying to debug problems. Enabling core dumps on production systems is not recommended; however, there may be overriding operational requirements to enable advanced debugging. Permitting temporary enablement of core dumps during such situations must be reviewed through local needs and policy.

Checks: C-61553r1134896_chk

Note: If kernel dumps are disabled in accordance with RHEL-09-213040, this requirement is not applicable. Verify RHEL 9 disables core dump backtraces by issuing the following command: $ 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-61477r925422_fix

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

b

RHEL 9 must disable storing core dumps.

CM-6 - Medium - CCI-000366 - V-257813 - SV-257813r1134899_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-213090

Vuln IDs

V-257813

Rule IDs

SV-257813r1134899_rule

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 or system operators trying to debug problems. Enabling core dumps on production systems is not recommended; however, there may be overriding operational requirements to enable advanced debugging. Permitting temporary enablement of core dumps during such situations must be reviewed through local needs and policy.

Checks: C-61554r1134898_chk

Note: If kernel dumps are disabled in accordance with RHEL-09-213040, this requirement is not applicable. Verify RHEL 9 disables storing core dumps for all users by issuing the following command: $ 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-61478r925425_fix

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

b

RHEL 9 must disable core dumps for all users.

CM-6 - Medium - CCI-000366 - V-257814 - SV-257814r1134901_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-213095

Vuln IDs

V-257814

Rule IDs

SV-257814r1134901_rule

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-61555r1134900_chk

Note: If kernel dumps are disabled in accordance with RHEL-09-213040, this requirement is not applicable. Verify RHEL 9 disables core dumps for all users by issuing the following command: $ grep -r -s core /etc/security/limits.conf /etc/security/limits.d/*.conf /etc/security/limits.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-61479r925428_fix

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

b

RHEL 9 must disable acquiring, saving, and processing core dumps.

CM-6 - Medium - CCI-000366 - V-257815 - SV-257815r1134903_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-213100

Vuln IDs

V-257815

Rule IDs

SV-257815r1134903_rule

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-61556r1134902_chk

Note: If kernel dumps are disabled in accordance with RHEL-09-213040, this requirement is not applicable. Verify RHEL 9 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-61480r925431_fix

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

b

RHEL 9 must disable the use of user namespaces.

CM-6 - Medium - CCI-000366 - V-257816 - SV-257816r1106435_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-213105

Vuln IDs

V-257816

Rule IDs

SV-257816r1106435_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 the directories in which they reside. 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-61557r1106295_chk

Verify RHEL 9 disables the use of user namespaces with the following commands: $ sudo sysctl user.max_user_namespaces user.max_user_namespaces = 0 If the returned line does not have a value of "0", or a line is not returned, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r user.max_user_namespaces /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: user.max_user_namespaces = 0 If "user.max_user_namespaces" is not set to "0", is missing, or commented out, this is a finding. If conflicting results are returned, this is a finding. If the use of namespaces is operationally required and documented with the information system security manager (ISSM), it is not a finding.

Fix: F-61481r1106434_fix

Configure RHEL 9 to disable the use of user namespaces by adding the following line to a file in the "/etc/sysctl.d" directory: user.max_user_namespaces = 0 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf The system configuration files must be reloaded for the changes to take effect. To reload the contents of the files, run the following command: $ sudo sysctl --system

b

RHEL 9 must implement nonexecutable data to protect its memory from unauthorized code execution.

SI-16 - Medium - CCI-002824 - V-257817 - SV-257817r1069383_rule

RMF Control

SI-16

Severity

M

CCI

CCI-002824

Version

RHEL-09-213110

Vuln IDs

V-257817

Rule IDs

SV-257817r1069383_rule

ExecShield uses the segmentation feature on all x86 systems to prevent execution in memory higher than a certain address. It writes an address as a limit in the code segment descriptor, to control where code can be executed, on a per-process basis. When the kernel places a process's memory regions such as the stack and heap higher than this address, the hardware prevents execution in that address range. This is enabled by default on the latest Red Hat and Fedora systems if supported by the hardware. Checking dmesg will return a false-positive if the system has generated enough kernel messages that the "(Execute Disable) protection: active" line is no longer present in the output from dmesg(1). A better way to ensure that ExecShield is enabled is to first ensure all processors support the NX feature, and then to check that noexec was not passed to the kernel command line.

Checks: C-61558r1069381_chk

Verify ExecShield is enabled on 64-bit RHEL 9 systems. Run the following command: $ grep ^flags /proc/cpuinfo | grep -Ev '([^[:alnum:]])(nx)([^[:alnum:]]|$)' If any output is returned, this is a finding. Next, run the following command: $ sudo grubby --info=ALL | grep args | grep -E '([^[:alnum:]])(noexec)([^[:alnum:]])' If any output is returned, this is a finding.

Fix: F-61482r1069382_fix

If /proc/cpuinfo shows that one or more processors do not enable ExecShield (lack the "nx" feature flag), verify that the NX/XD feature is not disabled in the BIOS or UEFI. If it is disabled, enable it. If the noexec option is present on the kernel command line, update the GRUB 2 bootloader configuration to remove it by running the following command: $ sudo grubby --update-kernel=ALL --remove-args=noexec

b

The kdump service on RHEL 9 must be disabled.

CM-6 - Medium - CCI-000366 - V-257818 - SV-257818r1044876_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-213115

Vuln IDs

V-257818

Rule IDs

SV-257818r1044876_rule

Kernel core dumps may contain the full contents of system memory at the time of the crash. Kernel core dumps 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. Unless the system is used for kernel development or testing, there is little need to run the kdump service.

Checks: C-61559r1044875_chk

Verify that the kdump service is disabled in system boot configuration with the following command: $ sudo systemctl is-enabled kdump disabled Verify that the kdump service is not active (i.e., not running) through current runtime configuration with the following command: $ sudo systemctl is-active kdump masked Verify that the kdump service is masked with the following command: $ sudo systemctl show kdump | grep "LoadState\|UnitFileState" LoadState=masked UnitFileState=masked If the "kdump" service is loaded or active, and is not masked, this is a finding.

Fix: F-61483r925440_fix

Disable and mask the kdump service on RHEL 9. To disable the kdump service run the following command: $ sudo systemctl disable --now kdump To mask the kdump service run the following command: $ sudo systemctl mask --now kdump

b

RHEL 9 must ensure cryptographic verification of vendor software packages.

Medium - CCI-003992 - V-257819 - SV-257819r1015075_rule

RMF Control

Severity

M

CCI

Version

RHEL-09-214010

Vuln IDs

V-257819

Rule IDs

SV-257819r1015075_rule

Cryptographic verification of vendor software packages ensures that all software packages are obtained from a valid source and protects against spoofing that could lead to installation of malware on the system. Red Hat cryptographically signs all software packages, which includes updates, with a GPG key to verify that they are valid.

Checks: C-61560r925442_chk

Confirm Red Hat package-signing keys are installed on the system and verify their fingerprints match vendor values. Note: For RHEL 9 software packages, Red Hat uses GPG keys labeled "release key 2" and "auxiliary key 3". The keys are defined in key file "/etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release" by default. List Red Hat GPG keys installed on the system: $ sudo rpm -q --queryformat "%{SUMMARY}\n" gpg-pubkey | grep -i "red hat" Red Hat, Inc. (release key 2) <security@redhat.com> public key Red Hat, Inc. (auxiliary key 3) <security@redhat.com> public key If Red Hat GPG keys "release key 2" and "auxiliary key 3" are not installed, this is a finding. List key fingerprints of installed Red Hat GPG keys: $ sudo gpg -q --keyid-format short --with-fingerprint /etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release If key file "/etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release" is missing, this is a finding. Example output: pub rsa4096/FD431D51 2009-10-22 [SC] Key fingerprint = 567E 347A D004 4ADE 55BA 8A5F 199E 2F91 FD43 1D51 uid Red Hat, Inc. (release key 2) <security@redhat.com> pub rsa4096/5A6340B3 2022-03-09 [SC] Key fingerprint = 7E46 2425 8C40 6535 D56D 6F13 5054 E4A4 5A63 40B3 uid Red Hat, Inc. (auxiliary key 3) <security@redhat.com> Compare key fingerprints of installed Red Hat GPG keys with fingerprints listed for RHEL 9 on Red Hat "Product Signing Keys" webpage at https://access.redhat.com/security/team/key. If key fingerprints do not match, this is a finding.

Fix: F-61484r925443_fix

Install Red Hat package-signing keys on the system and verify their fingerprints match vendor values. Insert RHEL 9 installation disc or attach RHEL 9 installation image to the system. Mount the disc or image to make the contents accessible inside the system. Assuming the mounted location is "/media/cdrom", use the following command to copy Red Hat GPG key file onto the system: $ sudo cp /media/cdrom/RPM-GPG-KEY-redhat-release /etc/pki/rpm-gpg/ Import Red Hat GPG keys from key file into system keyring: $ sudo rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release Using the steps listed in the Check Text, confirm the newly imported keys show as installed on the system and verify their fingerprints match vendor values.

c

RHEL 9 must check the GPG signature of software packages originating from external software repositories before installation.

High - CCI-003992 - V-257820 - SV-257820r1044878_rule

RMF Control

Severity

H

CCI

Version

RHEL-09-214015

Vuln IDs

V-257820

Rule IDs

SV-257820r1044878_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. All software packages must be signed with a cryptographic key recognized and approved by the organization. Verifying the authenticity of software prior to installation validates the integrity of the software package received from a vendor. This verifies the software has not been tampered with and that it has been provided by a trusted vendor.

Checks: C-61561r1044877_chk

Verify that dnf always checks the GPG signature of software packages originating from external software repositories before installation: $ grep -w gpgcheck /etc/dnf/dnf.conf gpgcheck=1 If "gpgcheck" is not set to "1", or if the option is missing or commented out, ask the system administrator how the GPG signatures of software packages are being verified. If there is no process to verify GPG signatures that is approved by the organization, this is a finding.

Fix: F-61485r925446_fix

Configure dnf to always check the GPG signature of software packages originating from external software repositories before installation. Add or update the following line in the [main] section of the /etc/dnf/dnf.conf file: gpgcheck=1

c

RHEL 9 must check the GPG signature of locally installed software packages before installation.

High - CCI-003992 - V-257821 - SV-257821r1015077_rule

RMF Control

Severity

H

CCI

Version

RHEL-09-214020

Vuln IDs

V-257821

Rule IDs

SV-257821r1015077_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. All software packages must be signed with a cryptographic key recognized and approved by the organization. Verifying the authenticity of software prior to installation validates the integrity of the software package received from a vendor. This verifies the software has not been tampered with and that it has been provided by a trusted vendor.

Checks: C-61562r925448_chk

Verify that dnf always checks the GPG signature of locally installed software packages before installation: $ grep localpkg_gpgcheck /etc/dnf/dnf.conf localpkg_gpgcheck=1 If "localpkg_gpgcheck" is not set to "1", or if the option is missing or commented out, ask the system administrator how the GPG signatures of local software packages are being verified. If there is no process to verify GPG signatures that is approved by the organization, this is a finding.

Fix: F-61486r925449_fix

Configure dnf to always check the GPG signature of local software packages before installation. Add or update the following line in the [main] section of the /etc/dnf/dnf.conf file: localpkg_gpgcheck=1

c

RHEL 9 must have GPG signature verification enabled for all software repositories.

High - CCI-003992 - V-257822 - SV-257822r1044880_rule

RMF Control

Severity

H

CCI

Version

RHEL-09-214025

Vuln IDs

V-257822

Rule IDs

SV-257822r1044880_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. All software packages must be signed with a cryptographic key recognized and approved by the organization. Verifying the authenticity of software prior to installation validates the integrity of the software package received from a vendor. This verifies the software has not been tampered with and that it has been provided by a trusted vendor.

Checks: C-61563r1044879_chk

Verify that all software repositories defined in "/etc/yum.repos.d/" have been configured with "gpgcheck" enabled: $ grep -w gpgcheck /etc/yum.repos.d/*.repo | more gpgcheck = 1 If "gpgcheck" is not set to "1" for all returned lines, this is a finding.

Fix: F-61487r925452_fix

Configure all software repositories defined in "/etc/yum.repos.d/" to have "gpgcheck" enabled: $ sudo sed -i 's/gpgcheck\s*=.*/gpgcheck=1/g' /etc/yum.repos.d/*

b

RHEL 9 must be configured so that the cryptographic hashes of system files match vendor values.

CM-6 - Medium - CCI-000366 - V-257823 - SV-257823r1051231_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-214030

Vuln IDs

V-257823

Rule IDs

SV-257823r1051231_rule

The hashes of important files such as system executables should match the information given by the RPM database. Executables with erroneous hashes could be a sign of nefarious activity on the system.

Checks: C-61564r1051229_chk

Verify that RHEL 9 is configured so that the cryptographic hashes of system files match vendor values. List files on the system that have file hashes different from what is expected by the RPM database with the following command: $ sudo rpm -Va --noconfig | awk '$1 ~ /..5/ && $2 != "c"' If there is output, this is a finding.

Fix: F-61488r1051230_fix

Configure RHEL 9 so that the cryptographic hashes of system files match vendor values. Given output from the check command, identify the package that provides the output and reinstall it. The following trimmed example output shows a package that has failed verification, been identified, and been reinstalled: $ sudo rpm -Va --noconfig | awk '$1 ~ /..5/ && $2 != "c"' S.5....T. /usr/bin/znew $ sudo dnf provides /usr/bin/znew [...] gzip-1.10-8.el9.x86_64 : The GNU data compression program [...] $ sudo dnf -y reinstall gzip [...] $ sudo rpm -Va --noconfig | awk '$1 ~ /..5/ && $2 != "c"' [no output]

a

RHEL 9 must remove all software components after updated versions have been installed.

SI-2 - Low - CCI-002617 - V-257824 - SV-257824r1044886_rule

RMF Control

SI-2

Severity

L

CCI

CCI-002617

Version

RHEL-09-214035

Vuln IDs

V-257824

Rule IDs

SV-257824r1044886_rule

Previous versions of software components that are not removed from the information system after updates have been installed may be exploited by some adversaries.

Checks: C-61565r1044884_chk

Verify RHEL 9 removes all software components after updated versions have been installed with the following command: $ grep -i clean_requirements_on_remove /etc/dnf/dnf.conf clean_requirements_on_remove=True If "clean_requirements_on_remove" is not set to "True", this is a finding.

Fix: F-61489r1044885_fix

Configure RHEL 9 to remove all software components after updated versions have been installed. Edit the file /etc/dnf/dnf.conf by adding or editing the following line: clean_requirements_on_remove=True

b

RHEL 9 subscription-manager package must be installed.

Medium - CCI-003992 - V-257825 - SV-257825r1044888_rule

RMF Control

Severity

M

CCI

Version

RHEL-09-215010

Vuln IDs

V-257825

Rule IDs

SV-257825r1044888_rule

The Red Hat Subscription Manager application manages software subscriptions and software repositories for installed software products on the local system. It communicates with backend servers, such as the Red Hat Customer Portal or an on-premise instance of Subscription Asset Manager, to register the local system and grant access to software resources determined by the subscription entitlement.

Checks: C-61566r1044887_chk

Verify that RHEL 9 subscription-manager package is installed with the following command: $ dnf list --installed subscription-manager Example output: subscription-manager.x86_64 1.29.26-3.el9_0 If the "subscription-manager" package is not installed, this is a finding.

Fix: F-61490r925461_fix

The subscription-manager package can be installed with the following command: $ sudo dnf install subscription-manager

c

RHEL 9 must not have a File Transfer Protocol (FTP) server package installed.

IA-5 - High - CCI-000197 - V-257826 - SV-257826r1106299_rule

RMF Control

IA-5

Severity

H

CCI

CCI-000197

Version

RHEL-09-215015

Vuln IDs

V-257826

Rule IDs

SV-257826r1106299_rule

The FTP service provides an unencrypted remote access that does not provide for the confidentiality and integrity of user passwords or the remote session. If a privileged user were to log on using this service, the privileged user password could be compromised. SSH or other encrypted file transfer methods must be used in place of this service. Removing the "vsftpd" package decreases the risk of accidental activation. If FTP is required for operational support (such as transmission of router configurations), its use must be documented with the information systems security manager (ISSM), restricted to only authorized personnel, and have access control rules established. Satisfies: SRG-OS-000074-GPOS-00042, SRG-OS-000095-GPOS-00049, SRG-OS-000480-GPOS-00227

Checks: C-61567r1106298_chk

Verify RHEL 9 does not have an FTP server package installed with the following command: $ sudo dnf list --installed vsftpd Error: No matching Packages to list If the "ftp" package is installed, this is a finding.

Fix: F-61491r925464_fix

The ftp package can be removed with the following command (using vsftpd as an example): $ sudo dnf remove vsftpd

b

RHEL 9 must not have the sendmail package installed.

CM-7 - Medium - CCI-000381 - V-257827 - SV-257827r1044892_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-09-215020

Vuln IDs

V-257827

Rule IDs

SV-257827r1044892_rule

The sendmail software was not developed with security in mind, and its design prevents it from being effectively contained by SELinux. Postfix must be used instead. Satisfies: SRG-OS-000480-GPOS-00227, SRG-OS-000095-GPOS-00049

Checks: C-61568r1044891_chk

Verify that the sendmail package is not installed with the following command: $ dnf list --installed sendmail Error: No matching Packages to list If the "sendmail" package is installed, this is a finding.

Fix: F-61492r925467_fix

Remove the sendmail package with the following command: $ sudo dnf remove sendmail

b

RHEL 9 must not have the nfs-utils package installed.

CM-7 - Medium - CCI-000381 - V-257828 - SV-257828r1044894_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-09-215025

Vuln IDs

V-257828

Rule IDs

SV-257828r1044894_rule

"nfs-utils" provides a daemon for the kernel NFS server and related tools. This package also contains the "showmount" program. "showmount" queries the mount daemon on a remote host for information about the Network File System (NFS) server on the remote host. For example, "showmount" can display the clients that are mounted on that host.

Checks: C-61569r1044893_chk

Verify that the nfs-utils package is not installed with the following command: $ dnf list --installed nfs-utils Error: No matching Packages to list If the "nfs-utils" package is installed, this is a finding.

Fix: F-61493r925470_fix

Remove the nfs-utils package with the following command: $ sudo dnf remove nfs-utils

b

RHEL 9 must not have the ypserv package installed.

CM-7 - Medium - CCI-000381 - V-257829 - SV-257829r1044896_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-09-215030

Vuln IDs

V-257829

Rule IDs

SV-257829r1044896_rule

The NIS service provides an unencrypted authentication service, which does not provide for the confidentiality and integrity of user passwords or the remote session. Removing the "ypserv" package decreases the risk of the accidental (or intentional) activation of NIS or NIS+ services.

Checks: C-61570r1044895_chk

Verify that the ypserv package is not installed with the following command: $ dnf list --installed ypserv Error: No matching Packages to list If the "ypserv" package is installed, this is a finding.

Fix: F-61494r925473_fix

Remove the ypserv package with the following command: $ sudo dnf remove ypserv

b

RHEL 9 must not install packages from the Extra Packages for Enterprise Linux (EPEL) repository.

CM-7 - Medium - CCI-000381 - V-257830 - SV-257830r1134906_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-09-215035

Vuln IDs

V-257830

Rule IDs

SV-257830r1134906_rule

The EPEL is a repository of high-quality open-source packages for enterprise-class Linux distributions such as RHEL, CentOS, AlmaLinux, Rocky Linux, and Oracle Linux. These packages are not part of the official distribution but are built using the same Fedora build system to ensure compatibility and maintain quality standards.

Checks: C-61571r1134904_chk

Verify that RHEL 9 is not able to install packages from the EPEL with the following command: $ dnf repolist rhel-9-for-x86_64-appstream-rpms Red Hat Enterprise Linux 9 for x86_64 - AppStream (RPMs) rhel-9-for-x86_64-baseos-rpms Red Hat Enterprise Linux 9 for x86_64 - BaseOS (RPMs) If any repositories containing the word "epel" in the name exist, this is a finding.

Fix: F-61495r1134905_fix

The repo package can be manually removed with the following command: $ sudo dnf remove epel-release Configure the operating system to disable use of the EPEL repository with the following command: $ sudo dnf config-manager --set-disabled epel

b

RHEL 9 must not have the telnet-server package installed.

CM-7 - Medium - CCI-000381 - V-257831 - SV-257831r1044898_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-09-215040

Vuln IDs

V-257831

Rule IDs

SV-257831r1044898_rule

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities are often overlooked and therefore, may remain unsecure. They increase the risk to the platform by providing additional attack vectors. The telnet service provides an unencrypted remote access service, which does not provide for the confidentiality and integrity of user passwords or the remote session. If a privileged user were to login using this service, the privileged user password could be compromised. Removing the "telnet-server" package decreases the risk of accidental (or intentional) activation of the telnet service.

Checks: C-61572r1044897_chk

Verify that the telnet-server package is not installed with the following command: $ dnf list --installed telnet-server Error: No matching Packages to list If the "telnet-server" package is installed, this is a finding.

Fix: F-61496r925479_fix

Remove the telnet-server package with the following command: $ sudo dnf remove telnet-server

b

RHEL 9 must not have the gssproxy package installed.

CM-7 - Medium - CCI-000381 - V-257832 - SV-257832r1044900_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-09-215045

Vuln IDs

V-257832

Rule IDs

SV-257832r1044900_rule

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore, may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services provided by default may not be necessary to support essential organizational operations (e.g., key missions, functions). The gssproxy package is a proxy for GSS API credential handling and could expose secrets on some networks. It is not needed for normal function of the OS. Satisfies: SRG-OS-000095-GPOS-00049, SRG-OS-000480-GPOS-00227

Checks: C-61573r1044899_chk

Verify that the gssproxy package is not installed with the following command: $ dnf list --installed gssproxy Error: No matching Packages to list If the "gssproxy" package is installed and is not documented with the information system security officer (ISSO) as an operational requirement, this is a finding.

Fix: F-61497r925482_fix

Remove the gssproxy package with the following command: $ sudo dnf remove gssproxy

b

RHEL 9 must not have the iprutils package installed.

CM-7 - Medium - CCI-000381 - V-257833 - SV-257833r1044902_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-09-215050

Vuln IDs

V-257833

Rule IDs

SV-257833r1044902_rule

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions, functions). The iprutils package provides a suite of utilities to manage and configure SCSI devices supported by the ipr SCSI storage device driver. Satisfies: SRG-OS-000095-GPOS-00049, SRG-OS-000480-GPOS-00227

Checks: C-61574r1044901_chk

Verify that the iprutils package is not installed with the following command: $ dnf list --installed iprutils Error: No matching Packages to list If the "iprutils" package is installed and is not documented with the information system security officer (ISSO) as an operational requirement, this is a finding.

Fix: F-61498r925485_fix

Remove the iprutils package with the following command: $ sudo dnf remove iprutils

b

RHEL 9 must not have the tuned package installed.

CM-7 - Medium - CCI-000381 - V-257834 - SV-257834r1044904_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-09-215055

Vuln IDs

V-257834

Rule IDs

SV-257834r1044904_rule

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions, functions). The tuned package contains a daemon that tunes the system settings dynamically. It does so by monitoring the usage of several system components periodically. Based on that information, components will then be put into lower or higher power savings modes to adapt to the current usage. The tuned package is not needed for normal OS operations. Satisfies: SRG-OS-000095-GPOS-00049, SRG-OS-000480-GPOS-00227

Checks: C-61575r1044903_chk

Verify that the tuned package is not installed with the following command: $ dnf list --installed tuned Error: No matching Packages to list If the "tuned" package is installed and is not documented with the information system security officer (ISSO) as an operational requirement, this is a finding.

Fix: F-61499r925488_fix

Remove the tuned package with the following command: $ sudo dnf remove tuned

c

RHEL 9 must not have a Trivial File Transfer Protocol (TFTP) server package installed.

CM-6 - High - CCI-000366 - V-257835 - SV-257835r1102037_rule

RMF Control

CM-6

Severity

H

CCI

Version

RHEL-09-215060

Vuln IDs

V-257835

Rule IDs

SV-257835r1102037_rule

Removing the "tftp-server" package decreases the risk of the accidental (or intentional) activation of tftp services. If TFTP is required for operational support (such as transmission of router configurations), its use must be documented with the information systems security manager (ISSM), restricted to only authorized personnel, and have access control rules established.

Checks: C-61576r1102036_chk

Verify that RHEL 9 does not have a "tftp-server" package installed with the following command: $ sudo dnf list --installed tftp-server Error: No matching Packages to list If the "tftp-server" package is installed, this is a finding.

Fix: F-61500r952170_fix

The "tftp-server" package can be removed with the following command: $ sudo dnf remove tftp-server

b

RHEL 9 must not have the quagga package installed.

CM-6 - Medium - CCI-000366 - V-257836 - SV-257836r1044908_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-215065

Vuln IDs

V-257836

Rule IDs

SV-257836r1044908_rule

Quagga is a network routing software suite providing implementations of Open Shortest Path First (OSPF), Routing Information Protocol (RIP), Border Gateway Protocol (BGP) for Unix and Linux platforms. If there is no need to make the router software available, removing it provides a safeguard against its activation.

Checks: C-61577r1044907_chk

Verify that the quagga package is not installed with the following command: $ dnf list --installed quagga Error: No matching Packages to list If the "quagga" package is installed and is not documented with the information system security officer (ISSO) as an operational requirement, this is a finding.

Fix: F-61501r925494_fix

Remove the quagga package with the following command: $ sudo dnf remove quagga

b

A graphical display manager must not be installed on RHEL 9 unless approved.

CM-6 - Medium - CCI-000366 - V-257837 - SV-257837r1044910_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-215070

Vuln IDs

V-257837

Rule IDs

SV-257837r1044910_rule

Unnecessary service packages must not be installed to decrease the attack surface of the system. Graphical display managers have a long history of security vulnerabilities and must not be used, unless approved and documented.

Checks: C-61578r1044909_chk

Verify that a graphical user interface is not installed with the following command: $ dnf list --installed "xorg-x11-server-common" Error: No matching Packages to list If the "xorg-x11-server-common" package is installed, and the use of a graphical user interface has not been documented with the information system security officer (ISSO) as an operational requirement, this is a finding.

Fix: F-61502r925497_fix

Document the requirement for a graphical user interface with the ISSO or remove all xorg packages with the following command: Warning: If you are accessing the system through the graphical user interface, change to the multi-user.target with the following command: $ sudo systemctl isolate multi-user.target Warning: Removal of the graphical user interface will immediately render it useless. The following commands must not be run from a virtual terminal emulator in the graphical interface. $ sudo dnf remove "xorg*" $ sudo systemctl set-default multi-user.target

b

RHEL 9 must have the openssl-pkcs11 package installed.

IA-2 - Medium - CCI-000765 - V-257838 - SV-257838r1044912_rule

RMF Control

IA-2

Severity

M

CCI

CCI-000765

Version

RHEL-09-215075

Vuln IDs

V-257838

Rule IDs

SV-257838r1044912_rule

Without the use of multifactor authentication, the ease of access to privileged functions is greatly increased. Multifactor authentication requires using two or more factors to achieve authentication. A privileged account is defined as an information system account with authorizations of a privileged user. The DOD common access card (CAC) with DOD-approved PKI is an example of multifactor authentication. Satisfies: SRG-OS-000105-GPOS-00052, SRG-OS-000375-GPOS-00160, SRG-OS-000376-GPOS-00161, SRG-OS-000377-GPOS-00162

Checks: C-61579r1044911_chk

Note: If the system administrator demonstrates the use of an approved alternate multifactor authentication method, this requirement is Not Applicable. Verify that RHEL 9 has the openssl-pkcs11 package installed with the following command: $ dnf list --installed openssl-pkcs11 Example output: openssl-pkcs.i686 0.4.11-7.el9 openssl-pkcs.x86_64 0.4.11-7.el9 If the "openssl-pkcs11" package is not installed, this is a finding.

Fix: F-61503r925500_fix

The openssl-pkcs11 package can be installed with the following command: $ sudo dnf install openssl-pkcs11

b

RHEL 9 must have the gnutls-utils package installed.

CM-6 - Medium - CCI-000366 - V-257839 - SV-257839r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-215080

Vuln IDs

V-257839

Rule IDs

SV-257839r991589_rule

GnuTLS is a secure communications library implementing the SSL, TLS and DTLS protocols and technologies around them. It provides a simple C language application programming interface (API) to access the secure communications protocols as well as APIs to parse and write X.509, PKCS #12, OpenPGP and other required structures. This package contains command line TLS client and server and certificate manipulation tools.

Checks: C-61580r925502_chk

Verify that RHEL 9 has the gnutls-utils package installed with the following command: $ dnf list --installed gnutls-utils Example output: gnutls-utils.x86_64 3.7.3-9.el9 If the "gnutls-utils" package is not installed, this is a finding.

Fix: F-61504r925503_fix

The gnutls-utils package can be installed with the following command: $ sudo dnf install gnutls-utils

b

RHEL 9 must have the nss-tools package installed.

CM-6 - Medium - CCI-000366 - V-257840 - SV-257840r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-215085

Vuln IDs

V-257840

Rule IDs

SV-257840r991589_rule

Network Security Services (NSS) is a set of libraries designed to support cross-platform development of security-enabled client and server applications. Install the "nss-tools" package to install command-line tools to manipulate the NSS certificate and key database.

Checks: C-61581r925505_chk

Verify that RHEL 9 has the nss-tools package installed with the following command: $ dnf list --installed nss-tools Example output: nss-tools.x86_64 3.71.0-7.el9 If the "nss-tools" package is not installed, this is a finding.

Fix: F-61505r925506_fix

The nss-tools package can be installed with the following command: $ sudo dnf install nss-tools

b

RHEL 9 must have the rng-tools package installed.

CM-6 - Medium - CCI-000366 - V-257841 - SV-257841r1044914_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-215090

Vuln IDs

V-257841

Rule IDs

SV-257841r1044914_rule

"rng-tools" provides hardware random number generator tools, such as those used in the formation of x509/PKI certificates.

Checks: C-61582r1044913_chk

Verify that RHEL 9 has the rng-tools package installed with the following command: $ dnf list --installed rng-tools Example output: rng-tools.x86_64 6.14-2.git.b2b7934e.el9 If the "rng-tools" package is not installed, this is a finding.

Fix: F-61506r925509_fix

The rng-tools package can be installed with the following command: $ sudo dnf install rng-tools

b

RHEL 9 must have the s-nail package installed.

CM-3 - Medium - CCI-001744 - V-257842 - SV-257842r1044916_rule

RMF Control

CM-3

Severity

M

CCI

CCI-001744

Version

RHEL-09-215095

Vuln IDs

V-257842

Rule IDs

SV-257842r1044916_rule

The "s-nail" package provides the mail command required to allow sending email notifications of unauthorized configuration changes to designated personnel.

Checks: C-61583r1044915_chk

Verify that RHEL 9 is configured to allow sending email notifications. Note: The "s-nail" package provides the "mail" command that is used to send email messages. Verify that the "s-nail" package is installed on the system: $ dnf list --installed s-nail s-nail.x86_64 14.9.22-6.el9 If "s-nail" package is not installed, this is a finding.

Fix: F-61507r925512_fix

The s-nail package can be installed with the following command: $ sudo dnf install s-nail

b

A separate RHEL 9 file system must be used for user home directories (such as /home or an equivalent).

CM-6 - Medium - CCI-000366 - V-257843 - SV-257843r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-231010

Vuln IDs

V-257843

Rule IDs

SV-257843r991589_rule

Ensuring that "/home" is mounted on its own partition enables the setting of more restrictive mount options, and also helps ensure that users cannot trivially fill partitions used for log or audit data storage.

Checks: C-61584r925514_chk

Verify that a separate file system/partition has been created for "/home" with the following command: $ mount | grep /home UUID=fba5000f-2ffa-4417-90eb-8c54ae74a32f on /home type ext4 (rw,nodev,nosuid,noexec,seclabel) If a separate entry for "/home" is not in use, this is a finding.

Fix: F-61508r925515_fix

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

b

RHEL 9 must use a separate file system for /tmp.

CM-6 - Medium - CCI-000366 - V-257844 - SV-257844r1044918_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-231015

Vuln IDs

V-257844

Rule IDs

SV-257844r1044918_rule

The "/tmp" partition is used as temporary storage by many programs. Placing "/tmp" in its own partition enables the setting of more restrictive mount options, which can help protect programs that use it.

Checks: C-61585r1044917_chk

Verify that a separate file system/partition has been created for "/tmp" with the following command: $ mount | grep /tmp /dev/mapper/rhel-tmp on /tmp type xfs (rw,nodev,nosuid,noexec,seclabel) If a separate entry for "/tmp" is not in use, this is a finding.

Fix: F-61509r925518_fix

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

a

RHEL 9 must use a separate file system for /var.

CM-6 - Low - CCI-000366 - V-257845 - SV-257845r1044920_rule

RMF Control

CM-6

Severity

L

CCI

Version

RHEL-09-231020

Vuln IDs

V-257845

Rule IDs

SV-257845r1044920_rule

Ensuring that "/var" is mounted on its own partition enables the setting of more restrictive mount options. This helps protect system services such as daemons or other programs which use it. It is not uncommon for the "/var" directory to contain world-writable directories installed by other software packages.

Checks: C-61586r1044919_chk

Verify that a separate file system/partition has been created for "/var" with the following command: $ mount | grep /var /dev/mapper/rootvg-varlv on /var type xfs (rw,relatime,seclabel,attr2,inode64,logbufs=8,logbsize=32k,noquota) Note: Options displayed for mount may differ. If a separate entry for "/var" is not in use, this is a finding.

Fix: F-61510r925521_fix

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

a

RHEL 9 must use a separate file system for /var/log.

CM-6 - Low - CCI-000366 - V-257846 - SV-257846r1044922_rule

RMF Control

CM-6

Severity

L

CCI

Version

RHEL-09-231025

Vuln IDs

V-257846

Rule IDs

SV-257846r1044922_rule

Placing "/var/log" in its own partition enables better separation between log files and other files in "/var/".

Checks: C-61587r1044921_chk

Verify that a separate file system/partition has been created for "/var/log" with the following command: $ mount | grep /var/log /dev/mapper/rhel-var_log on /var/log type xfs (rw,nosuid,nodev,noexec,relatime,seclabel,attr2,inode64,logbufs=8,logbsize=32k) Note: Options displayed for mount may differ. If a separate entry for "/var/log" is not in use, this is a finding.

Fix: F-61511r925524_fix

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

a

RHEL 9 must use a separate file system for the system audit data path.

AU-4 - Low - CCI-001849 - V-257847 - SV-257847r1044924_rule

RMF Control

AU-4

Severity

L

CCI

CCI-001849

Version

RHEL-09-231030

Vuln IDs

V-257847

Rule IDs

SV-257847r1044924_rule

Placing "/var/log/audit" in its own partition enables better separation between audit files and other system files, and helps ensure that auditing cannot be halted due to the partition running out of space. Satisfies: SRG-OS-000341-GPOS-00132, SRG-OS-000480-GPOS-00227

Checks: C-61588r1044923_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. $ mount | grep /var/log/audit /dev/mapper/rootvg-varlogaudit on /var/log/audit type xfs (rw,relatime,seclabel,attr2,inode64,logbufs=8,logbsize=32k,noquota) Note: Options displayed for mount may differ. If no line is returned, this is a finding.

Fix: F-61512r925527_fix

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

b

RHEL 9 must use a separate file system for /var/tmp.

CM-6 - Medium - CCI-000366 - V-257848 - SV-257848r1044926_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-231035

Vuln IDs

V-257848

Rule IDs

SV-257848r1044926_rule

The "/var/tmp" partition is used as temporary storage by many programs. Placing "/var/tmp" in its own partition enables the setting of more restrictive mount options, which can help protect programs that use it.

Checks: C-61589r1044925_chk

Verify that a separate file system/partition has been created for "/var/tmp" with the following command: $ mount | grep /var/tmp /dev/mapper/rhel-tmp on /var/tmp type xfs (rw,nosuid,nodev,noexec,relatime,seclabel,attr2,inode64,logbufs=8,logbsize=32k) Note: Options displayed for mount may differ. If a separate entry for "/var/tmp" is not in use, this is a finding.

Fix: F-61513r925530_fix

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

b

RHEL 9 file system automount function must be disabled unless required.

IA-3 - Medium - CCI-000778 - V-257849 - SV-257849r1044928_rule

RMF Control

IA-3

Severity

M

CCI

Version

RHEL-09-231040

Vuln IDs

V-257849

Rule IDs

SV-257849r1044928_rule

An authentication process resists replay attacks if it is impractical to achieve a successful authentication by recording and replaying a previous authentication message. Satisfies: SRG-OS-000114-GPOS-00059, SRG-OS-000378-GPOS-00163, SRG-OS-000480-GPOS-00227

Checks: C-61590r1044927_chk

Note: If the autofs service is not installed, this requirement is Not Applicable. Verify that the RHEL 9 file system automount function has been disabled with the following command: $ systemctl is-enabled autofs masked If the returned value is not "masked", "disabled", or "Failed to get unit file state for autofs.service for autofs" and is not documented as an operational requirement with the information system security officer (ISSO), this is a finding.

Fix: F-61514r925533_fix

Configure RHEL 9 to disable the ability to automount devices. The autofs service can be disabled with the following command: $ sudo systemctl mask --now autofs.service

b

RHEL 9 must prevent device files from being interpreted on file systems that contain user home directories.

CM-7 - Medium - CCI-001764 - V-257850 - SV-257850r1044930_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-09-231045

Vuln IDs

V-257850

Rule IDs

SV-257850r1044930_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 nonprivileged users to attain unauthorized administrative access. The only legitimate location for device files is the "/dev" directory located on the root partition, with the exception of chroot jails if implemented.

Checks: C-61591r1044929_chk

Verify "/home" is mounted with the "nodev" option with the following command: Note: If a separate file system has not been created for the user home directories (user home directories are mounted under "/"), this is automatically a finding, as the "nodev" option cannot be used on the "/" system. $ mount | grep /home tmpfs on /home type xfs (rw,nodev,nosuid,noexec,seclabel) If the "/home" file system is mounted without the "nodev" option, this is a finding.

Fix: F-61515r925536_fix

Modify "/etc/fstab" to use the "nodev" option on the "/home" directory.

b

RHEL 9 must prevent files with the setuid and setgid bit set from being executed on file systems that contain user home directories.

CM-7 - Medium - CCI-001764 - V-257851 - SV-257851r1044932_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-09-231050

Vuln IDs

V-257851

Rule IDs

SV-257851r1044932_rule

The "nosuid" mount option causes the system to not execute "setuid" and "setgid" files with owner privileges. This option must be used for mounting any file system not containing approved "setuid" and "setguid" files. Executing files from untrusted file systems increases the opportunity for nonprivileged users to attain unauthorized administrative access. Satisfies: SRG-OS-000368-GPOS-00154, SRG-OS-000480-GPOS-00227

Checks: C-61592r1044931_chk

Verify "/home" is mounted with the "nosuid" option with the following command: Note: If a separate file system has not been created for the user home directories (user home directories are mounted under "/"), this is automatically a finding, as the "nosuid" option cannot be used on the "/" system. $ mount | grep /home tmpfs on /home type xfs (rw,nodev,nosuid,noexec,seclabel) If the "/home" file system is mounted without the "nosuid" option, this is a finding.

Fix: F-61516r925539_fix

Modify "/etc/fstab" to use the "nosuid" option on the "/home" directory.

b

RHEL 9 must prevent code from being executed on file systems that contain user home directories.

CM-6 - Medium - CCI-000366 - V-257852 - SV-257852r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-231055

Vuln IDs

V-257852

Rule IDs

SV-257852r991589_rule

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

Checks: C-61593r925541_chk

Verify "/home" is mounted with the "noexec" option with the following command: Note: If a separate file system has not been created for the user home directories (user home directories are mounted under "/"), this is automatically a finding, as the "noexec" option cannot be used on the "/" system. $ mount | grep /home tmpfs on /home type xfs (rw,nodev,nosuid,noexec,seclabel) If the "/home" file system is mounted without the "noexec" option, this is a finding.

Fix: F-61517r925542_fix

Modify "/etc/fstab" to use the "noexec" option on the "/home" directory.

b

RHEL 9 must prevent special devices on file systems that are imported via Network File System (NFS).

CM-6 - Medium - CCI-000366 - V-257854 - SV-257854r1044934_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-231065

Vuln IDs

V-257854

Rule IDs

SV-257854r1044934_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 nonprivileged users to attain unauthorized administrative access.

Checks: C-61595r1044933_chk

Note: If no NFS mounts are configured, this requirement is Not Applicable. Verify RHEL 9 has the "nodev" option configured for all NFS mounts with the following command: $ grep nfs /etc/fstab 192.168.22.2:/mnt/export /data nfs4 rw,nosuid,nodev,noexec,sync,soft,sec=krb5:krb5i:krb5p If the system is mounting file systems via NFS and the "nodev" option is missing, this is a finding.

Fix: F-61519r925548_fix

Update each NFS mounted file system to use the "nodev" option on file systems that are being imported via NFS.

b

RHEL 9 must prevent code from being executed on file systems that are imported via Network File System (NFS).

CM-6 - Medium - CCI-000366 - V-257855 - SV-257855r1044936_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-231070

Vuln IDs

V-257855

Rule IDs

SV-257855r1044936_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 nonprivileged users to attain unauthorized administrative access.

Checks: C-61596r1044935_chk

Note: If no NFS mounts are configured, this requirement is Not Applicable. Verify RHEL 9 has the "noexec" option configured for all NFS mounts with the following command: $ grep nfs /etc/fstab 192.168.22.2:/mnt/export /data nfs4 rw,nosuid,nodev,noexec,sync,soft,sec=krb5:krb5i:krb5p If the system is mounting file systems via NFS and the "noexec" option is missing, this is a finding.

Fix: F-61520r925551_fix

Update each NFS mounted file system to use the "noexec" option on file systems that are being imported via NFS.

b

RHEL 9 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-257856 - SV-257856r1044938_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-231075

Vuln IDs

V-257856

Rule IDs

SV-257856r1044938_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 nonprivileged users to attain unauthorized administrative access.

Checks: C-61597r1044937_chk

Note: If no NFS mounts are configured, this requirement is Not Applicable. Verify RHEL 9 has the "nosuid" option configured for all NFS mounts with the following command: $ grep nfs /etc/fstab 192.168.22.2:/mnt/export /data nfs4 rw,nosuid,nodev,noexec,sync,soft,sec=krb5:krb5i:krb5p If the system is mounting file systems via NFS and the "nosuid" option is missing, this is a finding.

Fix: F-61521r925554_fix

Update each NFS mounted file system to use the "nosuid" option on file systems that are being imported via NFS.

b

RHEL 9 must prevent code from being executed on file systems that are used with removable media.

CM-6 - Medium - CCI-000366 - V-257857 - SV-257857r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-231080

Vuln IDs

V-257857

Rule IDs

SV-257857r991589_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 nonprivileged users to attain unauthorized administrative access.

Checks: C-61598r925556_chk

Verify file systems that are used for removable media are mounted with the "noexec" option with the following command: $ 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-61522r925557_fix

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

b

RHEL 9 must prevent special devices on file systems that are used with removable media.

CM-6 - Medium - CCI-000366 - V-257858 - SV-257858r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-231085

Vuln IDs

V-257858

Rule IDs

SV-257858r991589_rule

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

Checks: C-61599r925559_chk

Verify file systems that are used for removable media are mounted with the "nodev" option with the following command: $ 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-61523r925560_fix

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

b

RHEL 9 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-257859 - SV-257859r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-231090

Vuln IDs

V-257859

Rule IDs

SV-257859r991589_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 nonprivileged users to attain unauthorized administrative access.

Checks: C-61600r925562_chk

Verify file systems that are used for removable media are mounted with the "nosuid" option with the following command: $ 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-61524r925563_fix

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

b

RHEL 9 must mount /boot with the nodev option.

CM-7 - Medium - CCI-001764 - V-257860 - SV-257860r1044940_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-09-231095

Vuln IDs

V-257860

Rule IDs

SV-257860r1044940_rule

The only legitimate location for device files is the "/dev" directory located on the root partition. The only exception to this is chroot jails.

Checks: C-61601r1044939_chk

Verify that the "/boot" mount point has the "nodev" option with the following command: $ mount | grep '\s/boot\s' /dev/sda1 on /boot type xfs (rw,nodev,relatime,seclabel,attr2) If the "/boot" file system does not have the "nodev" option set, this is a finding.

Fix: F-61525r925566_fix

Modify "/etc/fstab" to use the "nodev" option on the "/boot" directory.

b

RHEL 9 must prevent files with the setuid and setgid bit set from being executed on the /boot directory.

CM-7 - Medium - CCI-001764 - V-257861 - SV-257861r1044941_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-09-231100

Vuln IDs

V-257861

Rule IDs

SV-257861r1044941_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 nonprivileged users to attain unauthorized administrative access. Satisfies: SRG-OS-000368-GPOS-00154, SRG-OS-000480-GPOS-00227

Checks: C-61602r1014833_chk

Verify the /boot directory is mounted with the "nosuid" option with the following command: $ 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-61526r925569_fix

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

b

RHEL 9 must prevent files with the setuid and setgid bit set from being executed on the /boot/efi directory.

CM-7 - Medium - CCI-001764 - V-257862 - SV-257862r1134908_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-09-231105

Vuln IDs

V-257862

Rule IDs

SV-257862r1134908_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 nonprivileged users to attain unauthorized administrative access. Satisfies: SRG-OS-000368-GPOS-00154, SRG-OS-000480-GPOS-00227

Checks: C-61603r1134907_chk

Note: For systems that use BIOS, this requirement is not applicable. Verify the /boot/efi directory is mounted with the "nosuid" option with the following command: $ 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. Note: This control is not applicable to vfat file systems.

Fix: F-61527r1051264_fix

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

b

RHEL 9 must mount /dev/shm with the nodev option.

CM-7 - Medium - CCI-001764 - V-257863 - SV-257863r958804_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-09-231110

Vuln IDs

V-257863

Rule IDs

SV-257863r958804_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 nonprivileged users to attain unauthorized administrative access. The only legitimate location for device files is the "/dev" directory located on the root partition, with the exception of chroot jails if implemented.

Checks: C-61604r925574_chk

Verify "/dev/shm" is mounted with the "nodev" option with the following command: $ mount | grep /dev/shm tmpfs on /dev/shm type tmpfs (rw,nodev,nosuid,noexec,seclabel) If the /dev/shm file system is mounted without the "nodev" option, this is a finding.

Fix: F-61528r925575_fix

Modify "/etc/fstab" to use the "nodev" option on the "/dev/shm" file system.

b

RHEL 9 must mount /dev/shm with the noexec option.

CM-7 - Medium - CCI-001764 - V-257864 - SV-257864r1106304_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-09-231115

Vuln IDs

V-257864

Rule IDs

SV-257864r1106304_rule

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

Checks: C-61605r1102006_chk

Verify "/dev/shm" is mounted with the "noexec" option with the following command: $ findmnt /dev/shm TARGET SOURCE FSTYPE OPTIONS /dev/shm tmpfs tmpfs rw,nodev,nosuid,noexec,seclabel 0 0 If the /dev/shm file system is mounted without the "noexec" option, this is a finding.

Fix: F-61529r1106303_fix

Configure "/dev/shm" to mount with the "noexec" option. Determine how /dev/shm is managed. $ systemctl status systemd-tmpfiles-setup If "active", systemd is managing temporary files (including /dev/shm). Otherwise, /etc/fstab is managing temporary files. If systemd is managing /dev/shm, use the following commands to add the noexec option to the mount: If /etc/tmpfiles.d does not exist, create it: $ sudo mkdir -p /etc/tmpfiles.d Add a configuration file with the appropriate options for /dev/shm as follows: $ echo 'd /dev/shm 1777 root root 10d' | sudo tee /etc/tmpfiles.d/dev-shm.conf $ echo 'x /dev/shm' | sudo tee -a /etc/tmpfiles.d/dev-shm.conf Apply new mount options with the following commands: $ sudo systemctl mask tmp.mount Created symlink /etc/systemd/system/tmp.mount ? /dev/null. $ echo 'tmpfs /dev/shm tmpfs rw,nodev,nosuid,noexec,seclabel 0 0' | sudo tee -a /etc/fstab $ sudo mount -o remount /dev/shm $ sudo systemctl daemon-reload If /dev/shm is managed by /etc/fstab, use the following commands to add the noexec option to the mount: $ sudo vi /etc/fstab Add or modify the following line: tmpfs /dev/shm tmpfs rw,nodev,nosuid,noexec,seclabel 0 0 Remount /dev/shm: $ sudo mount -o remount /dev/shm Note: Although systemd manages tmpfs mounts by default, administrators can override settings by adding entries to /etc/fstab. Either approach is acceptable.

b

RHEL 9 must mount /dev/shm with the nosuid option.

CM-7 - Medium - CCI-001764 - V-257865 - SV-257865r1044946_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-09-231120

Vuln IDs

V-257865

Rule IDs

SV-257865r1044946_rule

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

Checks: C-61606r1044945_chk

Verify "/dev/shm" is mounted with the "nosuid" option with the following command: $ mount | grep /dev/shm tmpfs on /dev/shm type tmpfs (rw,nodev,nosuid,noexec,seclabel) If the /dev/shm file system is mounted without the "nosuid" option, this is a finding.

Fix: F-61530r925581_fix

Modify "/etc/fstab" to use the "nosuid" option on the "/dev/shm" file system.

b

RHEL 9 must mount /tmp with the nodev option.

CM-7 - Medium - CCI-001764 - V-257866 - SV-257866r958804_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-09-231125

Vuln IDs

V-257866

Rule IDs

SV-257866r958804_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 nonprivileged users to attain unauthorized administrative access. The only legitimate location for device files is the "/dev" directory located on the root partition, with the exception of chroot jails if implemented.

Checks: C-61607r925583_chk

Verify "/tmp" is mounted with the "nodev" option: $ mount | grep /tmp /dev/mapper/rhel-tmp on /tmp type xfs (rw,nodev,nosuid,noexec,seclabel) If the "/tmp" file system is mounted without the "nodev" option, this is a finding.

Fix: F-61531r925584_fix

Modify "/etc/fstab" to use the "nodev" option on the "/tmp" directory.

b

RHEL 9 must mount /tmp with the noexec option.

CM-7 - Medium - CCI-001764 - V-257867 - SV-257867r958804_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-09-231130

Vuln IDs

V-257867

Rule IDs

SV-257867r958804_rule

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

Checks: C-61608r925586_chk

Verify "/tmp" is mounted with the "noexec" option: $ mount | grep /tmp /dev/mapper/rhel-tmp on /tmp type xfs (rw,nodev,nosuid,noexec,seclabel) If the "/tmp" file system is mounted without the "noexec" option, this is a finding.

Fix: F-61532r925587_fix

Modify "/etc/fstab" to use the "noexec" option on the "/tmp" directory.

b

RHEL 9 must mount /tmp with the nosuid option.

CM-7 - Medium - CCI-001764 - V-257868 - SV-257868r958804_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-09-231135

Vuln IDs

V-257868

Rule IDs

SV-257868r958804_rule

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

Checks: C-61609r925589_chk

Verify "/tmp" is mounted with the "nosuid" option: $ mount | grep /tmp /dev/mapper/rhel-tmp on /tmp type xfs (rw,nodev,nosuid,noexec,seclabel) If the "/tmp" file system is mounted without the "nosuid" option, this is a finding.

Fix: F-61533r925590_fix

Modify "/etc/fstab" to use the "nosuid" option on the "/tmp" directory.

b

RHEL 9 must mount /var with the nodev option.

CM-7 - Medium - CCI-001764 - V-257869 - SV-257869r1102009_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-09-231140

Vuln IDs

V-257869

Rule IDs

SV-257869r1102009_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 nonprivileged users to attain unauthorized administrative access. The only legitimate location for device files is the "/dev" directory located on the root partition, with the exception of chroot jails if implemented.

Checks: C-61610r925592_chk

Verify "/var" is mounted with the "nodev" option: $ mount | grep /var /dev/mapper/rhel-var on /var type xfs (rw,nodev,nosuid,noexec,seclabel) If the "/var" file system is mounted without the "nodev" option, this is a finding.

Fix: F-61534r925593_fix

Modify "/etc/fstab" to use the "nodev" option on the "/var" directory.

b

RHEL 9 must mount /var/log with the nodev option.

CM-7 - Medium - CCI-001764 - V-257870 - SV-257870r958804_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-09-231145

Vuln IDs

V-257870

Rule IDs

SV-257870r958804_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 nonprivileged users to attain unauthorized administrative access. The only legitimate location for device files is the "/dev" directory located on the root partition, with the exception of chroot jails if implemented.

Checks: C-61611r925595_chk

Verify "/var/log" is mounted with the "nodev" option: $ mount | grep /var/log /dev/mapper/rhel-var-log on /var/log type xfs (rw,nodev,nosuid,noexec,seclabel) If the "/var/log" file system is mounted without the "nodev" option, this is a finding.

Fix: F-61535r925596_fix

Modify "/etc/fstab" to use the "nodev" option on the "/var/log" directory.

b

RHEL 9 must mount /var/log with the noexec option.

CM-7 - Medium - CCI-001764 - V-257871 - SV-257871r958804_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-09-231150

Vuln IDs

V-257871

Rule IDs

SV-257871r958804_rule

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

Checks: C-61612r925598_chk

Verify "/var/log" is mounted with the "noexec" option: $ mount | grep /var/log /dev/mapper/rhel-var-log on /var/log type xfs (rw,nodev,nosuid,noexec,seclabel) If the "/var/log" file system is mounted without the "noexec" option, this is a finding.

Fix: F-61536r925599_fix

Modify "/etc/fstab" to use the "noexec" option on the "/var/log" directory.

b

RHEL 9 must mount /var/log with the nosuid option.

CM-7 - Medium - CCI-001764 - V-257872 - SV-257872r958804_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-09-231155

Vuln IDs

V-257872

Rule IDs

SV-257872r958804_rule

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

Checks: C-61613r925601_chk

Verify "/var/log" is mounted with the "nosuid" option: $ mount | grep /var/log /dev/mapper/rhel-var-log on /var/log type xfs (rw,nodev,nosuid,noexec,seclabel) If the "/var/log" file system is mounted without the "nosuid" option, this is a finding.

Fix: F-61537r925602_fix

Modify "/etc/fstab" to use the "nosuid" option on the "/var/log" directory.

b

RHEL 9 must mount /var/log/audit with the nodev option.

CM-7 - Medium - CCI-001764 - V-257873 - SV-257873r958804_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-09-231160

Vuln IDs

V-257873

Rule IDs

SV-257873r958804_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 nonprivileged users to attain unauthorized administrative access. The only legitimate location for device files is the "/dev" directory located on the root partition, with the exception of chroot jails if implemented.

Checks: C-61614r925604_chk

Verify "/var/log/audit" is mounted with the "nodev" option: $ mount | grep /var/log/audit /dev/mapper/rhel-var-log-audit on /var/log/audit type xfs (rw,nodev,nosuid,noexec,seclabel) If the "/var/log/audit" file system is mounted without the "nodev" option, this is a finding.

Fix: F-61538r925605_fix

Modify "/etc/fstab" to use the "nodev" option on the "/var/log/audit" directory.

b

RHEL 9 must mount /var/log/audit with the noexec option.

CM-7 - Medium - CCI-001764 - V-257874 - SV-257874r958804_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-09-231165

Vuln IDs

V-257874

Rule IDs

SV-257874r958804_rule

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

Checks: C-61615r925607_chk

Verify "/var/log/audit" is mounted with the "noexec" option: $ mount | grep /var/log/audit /dev/mapper/rhel-var-log-audit on /var/log/audit type xfs (rw,nodev,nosuid,noexec,seclabel) If the "/var/log/audit" file system is mounted without the "noexec" option, this is a finding.

Fix: F-61539r925608_fix

Modify "/etc/fstab" to use the "noexec" option on the "/var/log/audit" directory.

b

RHEL 9 must mount /var/log/audit with the nosuid option.

CM-7 - Medium - CCI-001764 - V-257875 - SV-257875r958804_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-09-231170

Vuln IDs

V-257875

Rule IDs

SV-257875r958804_rule

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

Checks: C-61616r925610_chk

Verify "/var/log/audit" is mounted with the "nosuid" option: $ mount | grep /var/log/audit /dev/mapper/rhel-var-log-audit on /var/log/audit type xfs (rw,nodev,nosuid,noexec,seclabel) If the "/var/log/audit" file system is mounted without the "nosuid" option, this is a finding.

Fix: F-61540r925611_fix

Modify "/etc/fstab" to use the "nosuid" option on the "/var/log/audit" directory.

b

RHEL 9 must mount /var/tmp with the nodev option.

CM-7 - Medium - CCI-001764 - V-257876 - SV-257876r958804_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-09-231175

Vuln IDs

V-257876

Rule IDs

SV-257876r958804_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 nonprivileged users to attain unauthorized administrative access. The only legitimate location for device files is the "/dev" directory located on the root partition, with the exception of chroot jails if implemented.

Checks: C-61617r925613_chk

Verify "/var/tmp" is mounted with the "nodev" option: $ mount | grep /var/tmp /dev/mapper/rhel-var-tmp on /var/tmp type xfs (rw,nodev,nosuid,noexec,seclabel) If the "/var/tmp" file system is mounted without the "nodev" option, this is a finding.

Fix: F-61541r925614_fix

Modify "/etc/fstab" to use the "nodev" option on the "/var/tmp" directory.

b

RHEL 9 must mount /var/tmp with the noexec option.

CM-7 - Medium - CCI-001764 - V-257877 - SV-257877r958804_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-09-231180

Vuln IDs

V-257877

Rule IDs

SV-257877r958804_rule

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

Checks: C-61618r925616_chk

Verify "/var/tmp" is mounted with the "noexec" option: $ mount | grep /var/tmp /dev/mapper/rhel-var-tmp on /var/tmp type xfs (rw,nodev,nosuid,noexec,seclabel) If the "/var/tmp" file system is mounted without the "noexec" option, this is a finding.

Fix: F-61542r925617_fix

Modify "/etc/fstab" to use the "noexec" option on the "/var/tmp" directory.

b

RHEL 9 must mount /var/tmp with the nosuid option.

CM-7 - Medium - CCI-001764 - V-257878 - SV-257878r958804_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-09-231185

Vuln IDs

V-257878

Rule IDs

SV-257878r958804_rule

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

Checks: C-61619r925619_chk

Verify "/var/tmp" is mounted with the "nosuid" option: $ mount | grep /var/tmp /dev/mapper/rhel-var-tmp on /var/tmp type xfs (rw,nodev,nosuid,noexec,seclabel) If the "/var/tmp" file system is mounted without the "nosuid" option, this is a finding.

Fix: F-61543r925620_fix

Modify "/etc/fstab" to use the "nosuid" option on the "/var/tmp" directory.

c

RHEL 9 local disk partitions must implement cryptographic mechanisms to prevent unauthorized disclosure or modification of all information that requires at rest protection.

SC-28 - High - CCI-001199 - V-257879 - SV-257879r1045454_rule

RMF Control

SC-28

Severity

H

CCI

CCI-001199

Version

RHEL-09-231190

Vuln IDs

V-257879

Rule IDs

SV-257879r1045454_rule

RHEL 9 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-000405-GPOS-00184, SRG-OS-000185-GPOS-00079, SRG-OS-000404-GPOS-00183

Checks: C-61620r1045453_chk

Note: 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 RHEL 9 prevents unauthorized disclosure or modification of all information requiring at-rest protection by using disk encryption. Note: If there is a documented and approved reason for not having data-at-rest encryption, this requirement is Not Applicable. List all block devices in tree-like format: $ sudo lsblk --tree NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS zram0 252:0 0 8G 0 disk [SWAP] nvme0n1 259:0 0 476.9G 0 disk |-nvme0n1p1 259:1 0 1G 0 part /boot/efi |-nvme0n1p2 259:2 0 1G 0 part /boot |-nvme0n1p3 259:3 0 474.9G 0 part |-luks-<encrypted_id> 253:0 0 474.9G 0 crypt |-rhel-root 253:1 0 16G 0 lvm / |-rhel-varcache 253:2 0 8G 0 lvm /var/cache |-rhel-vartmp 253:3 0 4G 0 lvm /var/tmp |-rhel-varlog 253:4 0 4G 0 lvm /var/log |-rhel-home 253:5 0 64G 0 lvm /home |-rhel-varlogaudit 253:6 0 4G 0 lvm /var/log/audit Verify that the block device tree for each persistent filesystem, excluding the /boot and /boot/efi filesystems, has at least one parent block device of type "crypt", and that the encryption type is LUKS: $ sudo cryptsetup status luks-b74f6910-2547-4399-86b2-8b0252d926d7 /dev/mapper/luks-b74f6910-2547-4399-86b2-8b0252d926d7 is active and is in use. type: LUKS2 cipher: aes-xts-plain64 keysize: 512 bits key location: keyring device: /dev/nvme0n1p3 sector size: 512 offset: 32768 sectors size: 995986063 sectors mode: read/write If there are persistent filesystems (other than /boot or /boot/efi) whose block device trees do not have a crypt block device of type LUKS, ask the administrator to indicate how persistent filesystems are encrypted. If there is no evidence that persistent filesystems are encrypted, this is a finding.

Fix: F-61544r925623_fix

Configure RHEL 9 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.

a

RHEL 9 must disable mounting of cramfs.

CM-7 - Low - CCI-000381 - V-257880 - SV-257880r1044951_rule

RMF Control

CM-7

Severity

L

CCI

Version

RHEL-09-231195

Vuln IDs

V-257880

Rule IDs

SV-257880r1044951_rule

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Removing support for unneeded filesystem types reduces the local attack surface of the server. Compressed ROM/RAM file system (or cramfs) is a read-only file system designed for simplicity and space-efficiency. It is mainly used in embedded and small-footprint systems.

Checks: C-61621r1044949_chk

Verify that RHEL 9 disables the ability to load the cramfs kernel module with the following command: $ grep -r cramfs /etc/modprobe.conf /etc/modprobe.d/* install cramfs /bin/false blacklist cramfs If the command does not return any output or the lines are commented out, and use of cramfs is not documented with the information system security officer (ISSO) as an operational requirement, this is a finding.

Fix: F-61545r1044950_fix

To configure the system to prevent the cramfs kernel module from being loaded, add the following lines to the file /etc/modprobe.d/blacklist.conf (or create blacklist.conf if it does not exist): install cramfs /bin/false blacklist cramfs

b

RHEL 9 must prevent special devices on non-root local partitions.

CM-6 - Medium - CCI-000366 - V-257881 - SV-257881r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-231200

Vuln IDs

V-257881

Rule IDs

SV-257881r991589_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 nonprivileged users to attain unauthorized administrative access. The only legitimate location for device files is the "/dev" directory located on the root partition, with the exception of chroot jails if implemented.

Checks: C-61622r925628_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-61546r925629_fix

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

b

RHEL 9 system commands must have mode 755 or less permissive.

CM-5 - Medium - CCI-001499 - V-257882 - SV-257882r991560_rule

RMF Control

CM-5

Severity

M

CCI

Version

RHEL-09-232010

Vuln IDs

V-257882

Rule IDs

SV-257882r991560_rule

If RHEL 9 allowed any user to make changes to software libraries, then those changes might be implemented without undergoing the appropriate testing and approvals that are part of a robust change management process. This requirement applies to RHEL 9 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.

Checks: C-61623r925631_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/libexec /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-61547r925632_fix

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

b

RHEL 9 library directories must have mode 755 or less permissive.

CM-5 - Medium - CCI-001499 - V-257883 - SV-257883r991560_rule

RMF Control

CM-5

Severity

M

CCI

Version

RHEL-09-232015

Vuln IDs

V-257883

Rule IDs

SV-257883r991560_rule

If RHEL 9 allowed any user to make changes to software libraries, then those changes might be implemented without undergoing the appropriate testing and approvals that are part of a robust change management process. This requirement applies to RHEL 9 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.

Checks: C-61624r925634_chk

Verify the system-wide shared library directories have mode "755" or less permissive with the following command: $ sudo find -L /lib /lib64 /usr/lib /usr/lib64 -perm /022 -type d -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-61548r925635_fix

Configure the system-wide shared library directories (/lib, /lib64, /usr/lib and /usr/lib64) to be protected from unauthorized access. Run the following command, replacing "[DIRECTORY]" with any library directory with a mode more permissive than 755. $ sudo chmod 755 [DIRECTORY]

b

RHEL 9 library files must have mode 755 or less permissive.

CM-5 - Medium - CCI-001499 - V-257884 - SV-257884r1106306_rule

RMF Control

CM-5

Severity

M

CCI

Version

RHEL-09-232020

Vuln IDs

V-257884

Rule IDs

SV-257884r1106306_rule

If RHEL 9 allowed any user to make changes to software libraries, then those changes might be implemented without undergoing the appropriate testing and approvals that are part of a robust change management process. This requirement applies to RHEL 9 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.

Checks: C-61625r1101927_chk

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

Fix: F-61549r1106305_fix

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

b

RHEL 9 /var/log directory must have mode 0755 or less permissive.

SI-11 - Medium - CCI-001314 - V-257885 - SV-257885r1044953_rule

RMF Control

SI-11

Severity

M

CCI

Version

RHEL-09-232025

Vuln IDs

V-257885

Rule IDs

SV-257885r1044953_rule

Only authorized personnel should be aware of errors and the details of the errors. Error messages are an indicator of an organization's operational state or can identify the RHEL 9 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-61626r1044952_chk

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

Fix: F-61550r925641_fix

Configure the "/var/log" directory to a mode of "0755" by running the following command: $ sudo chmod 0755 /var/log

b

RHEL 9 /var/log/messages file must have mode 0640 or less permissive.

SI-11 - Medium - CCI-001314 - V-257886 - SV-257886r1044955_rule

RMF Control

SI-11

Severity

M

CCI

Version

RHEL-09-232030

Vuln IDs

V-257886

Rule IDs

SV-257886r1044955_rule

Only authorized personnel should be aware of errors and the details of the errors. Error messages are an indicator of an organization's operational state or can identify the RHEL 9 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-61627r1044954_chk

Verify the "/var/log/messages" file has a mode of "0640" or less permissive with the following command: $ stat -c '%a %n' /var/log/messages 600 /var/log/messages If "/var/log/messages" does not have a mode of "0640" or less permissive, this is a finding.

Fix: F-61551r925644_fix

Configure the "/var/log/messages" file to have a mode of "0640" by running the following command: $ sudo chmod 0640 /var/log/messages

b

RHEL 9 audit tools must have a mode of 0755 or less permissive.

AU-9 - Medium - CCI-001493 - V-257887 - SV-257887r991557_rule

RMF Control

AU-9

Severity

M

CCI

Version

RHEL-09-232035

Vuln IDs

V-257887

Rule IDs

SV-257887r991557_rule

Protecting audit information also includes identifying and protecting the tools used to view and manipulate log data. Therefore, protecting audit tools is necessary to prevent unauthorized operation on audit information. RHEL 9 systems providing tools to interface with audit information will leverage user permissions and roles identifying the user accessing the tools, and the corresponding rights the user enjoys, to make access decisions regarding the access to audit tools. Audit tools include, but are not limited to, vendor-provided and open source audit tools needed to successfully view and manipulate audit information system activity and records. Audit tools include custom queries and report generators.

Checks: C-61628r925646_chk

Verify the audit tools have a mode of "0755" or less with the following command: $ stat -c "%a %n" /sbin/auditctl /sbin/aureport /sbin/ausearch /sbin/autrace /sbin/auditd /sbin/rsyslogd /sbin/augenrules 755 /sbin/auditctl 755 /sbin/aureport 755 /sbin/ausearch 750 /sbin/autrace 755 /sbin/auditd 755 /sbin/rsyslogd 755 /sbin/augenrules If any of the audit tool files have a mode more permissive than "0755", this is a finding.

Fix: F-61552r925647_fix

Configure the audit tools to have a mode of "0755" by running the following command: $ sudo chmod 0755 [audit_tool] Replace "[audit_tool]" with each audit tool that has a more permissive mode than 0755.

b

RHEL 9 permissions of cron configuration files and directories must not be modified from the operating system defaults.

CM-6 - Medium - CCI-000366 - V-257888 - SV-257888r1134910_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-232040

Vuln IDs

V-257888

Rule IDs

SV-257888r1134910_rule

If the permissions of cron configuration files or directories are modified from the operating system defaults, it may be possible for individuals to insert unauthorized cron jobs that perform unauthorized actions, including potentially escalating privileges.

Checks: C-61629r1134909_chk

Run the following command to verify that the owner, group, and mode of cron configuration files and directories match the operating system defaults: $ rpm --verify cronie crontabs | awk '! ($2 == "c" && $1 ~ /^.\..\.\.\.\..\./) {print $0}' If the command returns any output, this is a finding. If there are findings, run the following command to determine what the permissions are: $ ls -ld /etc/cron* drwxr-xr-x. 2 root root 21 Oct 3 2024 /etc/cron.d drwxr-xr-x. 2 root root 6 May 1 09:03 /etc/cron.daily -rw-r--r--. 1 root root 0 Oct 3 2024 /etc/cron.deny drwxr-xr-x. 2 root root 22 Mar 5 12:49 /etc/cron.hourly drwxr-xr-x. 2 root root 6 Mar 23 2022 /etc/cron.monthly -rw-r--r--. 1 root root 451 Mar 23 2022 /etc/crontab drwxr-xr-x. 2 root root 6 Mar 23 2022 /etc/cron.weekly

Fix: F-61553r1069377_fix

Run the following commands to restore the permissions of cron configuration files and directories to the operating system defaults: $ sudo dnf reinstall cronie crontabs $ rpm --setugids cronie crontabs $ rpm --setperms cronie crontabs

b

All RHEL 9 local initialization files must have mode 0740 or less permissive.

CM-6 - Medium - CCI-000366 - V-257889 - SV-257889r1044959_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-232045

Vuln IDs

V-257889

Rule IDs

SV-257889r1044959_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-61630r1044958_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 "bingwa" user, who has a home directory of "/home/bingwa". $ find /home/bingwa/.[^.]* -maxdepth 0 -perm -740 -exec stat -c "%a %n" {} \; | more 755 /home/bingwa/.somepermissivefile If any local initialization files are returned, this indicates a mode more permissive than "0740", and this is a finding.

Fix: F-61554r925653_fix

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

b

All RHEL 9 local interactive user home directories must have mode 0750 or less permissive.

CM-6 - Medium - CCI-000366 - V-257890 - SV-257890r1044961_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-232050

Vuln IDs

V-257890

Rule IDs

SV-257890r1044961_rule

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

Checks: C-61631r1044960_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. $ stat -L -c '%a %n' $(awk -F: '($3>=1000)&&($7 !~ /nologin/){print $6}' /etc/passwd) 2>/dev/null 700 /home/bingwa If home directories referenced in "/etc/passwd" do not have a mode of "0750" or less permissive, this is a finding.

Fix: F-61555r925656_fix

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

b

RHEL 9 /etc/group file must have mode 0644 or less permissive to prevent unauthorized access.

CM-6 - Medium - CCI-000366 - V-257891 - SV-257891r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-232055

Vuln IDs

V-257891

Rule IDs

SV-257891r991589_rule

The "/etc/group" file contains information regarding groups that are configured on the system. Protection of this file is important for system security.

Checks: C-61632r925658_chk

Verify that the "/etc/group" file has mode "0644" or less permissive with the following command: $ sudo stat -c "%a %n" /etc/group 644 /etc/group If a value of "0644" or less permissive is not returned, this is a finding.

Fix: F-61556r925659_fix

Change the mode of the file "/etc/group" to "0644" by running the following command: $ sudo chmod 0644 /etc/group

b

RHEL 9 /etc/group- file must have mode 0644 or less permissive to prevent unauthorized access.

CM-6 - Medium - CCI-000366 - V-257892 - SV-257892r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-232060

Vuln IDs

V-257892

Rule IDs

SV-257892r991589_rule

The "/etc/group-" file is a backup file of "/etc/group", and as such, contains information regarding groups that are configured on the system. Protection of this file is important for system security.

Checks: C-61633r925661_chk

Verify that the "/etc/group-" file has mode "0644" or less permissive with the following command: $ sudo stat -c "%a %n" /etc/group- 644 /etc/group- If a value of "0644" or less permissive is not returned, this is a finding.

Fix: F-61557r925662_fix

Change the mode of the file "/etc/group-" to "0644" by running the following command: $ sudo chmod 0644 /etc/group-

b

RHEL 9 /etc/gshadow file must have mode 0000 or less permissive to prevent unauthorized access.

CM-6 - Medium - CCI-000366 - V-257893 - SV-257893r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-232065

Vuln IDs

V-257893

Rule IDs

SV-257893r991589_rule

The "/etc/gshadow" file contains group password hashes. Protection of this file is critical for system security.

Checks: C-61634r925664_chk

Verify that the "/etc/gshadow" file has mode "0000" with the following command: $ sudo stat -c "%a %n" /etc/gshadow 0 /etc/gshadow If a value of "0" is not returned, this is a finding.

Fix: F-61558r925665_fix

Change the mode of the file "/etc/gshadow" to "0000" by running the following command: $ sudo chmod 0000 /etc/gshadow

b

RHEL 9 /etc/gshadow- file must have mode 0000 or less permissive to prevent unauthorized access.

CM-6 - Medium - CCI-000366 - V-257894 - SV-257894r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-232070

Vuln IDs

V-257894

Rule IDs

SV-257894r991589_rule

The "/etc/gshadow-" file is a backup of "/etc/gshadow", and as such, contains group password hashes. Protection of this file is critical for system security.

Checks: C-61635r925667_chk

Verify that the "/etc/gshadow-" file has mode "0000" with the following command: $ sudo stat -c "%a %n" /etc/gshadow- 0 /etc/gshadow- If a value of "0" is not returned, this is a finding.

Fix: F-61559r925668_fix

Change the mode of the file "/etc/gshadow-" to "0000" by running the following command: $ sudo chmod 0000 /etc/gshadow-

b

RHEL 9 /etc/passwd file must have mode 0644 or less permissive to prevent unauthorized access.

CM-6 - Medium - CCI-000366 - V-257895 - SV-257895r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-232075

Vuln IDs

V-257895

Rule IDs

SV-257895r991589_rule

If the "/etc/passwd" file is writable by a group-owner or the world the risk of its compromise is increased. The file contains the list of accounts on the system and associated information, and protection of this file is critical for system security.

Checks: C-61636r925670_chk

Verify that the "/etc/passwd" file has mode "0644" or less permissive with the following command: $ sudo stat -c "%a %n" /etc/passwd 644 /etc/passwd If a value of "0644" or less permissive is not returned, this is a finding.

Fix: F-61560r925671_fix

Change the mode of the file "/etc/passwd" to "0644" by running the following command: $ sudo chmod 0644 /etc/passwd

b

RHEL 9 /etc/passwd- file must have mode 0644 or less permissive to prevent unauthorized access.

CM-6 - Medium - CCI-000366 - V-257896 - SV-257896r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-232080

Vuln IDs

V-257896

Rule IDs

SV-257896r991589_rule

The "/etc/passwd-" file is a backup file of "/etc/passwd", and as such, contains information about the users that are configured on the system. Protection of this file is critical for system security.

Checks: C-61637r925673_chk

Verify that the "/etc/passwd-" file has mode "0644" or less permissive with the following command: $ sudo stat -c "%a %n" /etc/passwd- 644 /etc/passwd- If a value of "0644" or less permissive is not returned, this is a finding.

Fix: F-61561r925674_fix

Change the mode of the file "/etc/passwd-" to "0644" by running the following command: $ sudo chmod 0644 /etc/passwd-

b

RHEL 9 /etc/shadow- file must have mode 0000 or less permissive to prevent unauthorized access.

CM-6 - Medium - CCI-000366 - V-257897 - SV-257897r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-232085

Vuln IDs

V-257897

Rule IDs

SV-257897r991589_rule

The "/etc/shadow-" file is a backup file of "/etc/shadow", and as such, contains the list of local system accounts and password hashes. Protection of this file is critical for system security.

Checks: C-61638r925676_chk

Verify that the "/etc/shadow-" file has mode "0000" with the following command: $ sudo stat -c "%a %n" /etc/shadow- 0 /etc/shadow- If a value of "0" is not returned, this is a finding.

Fix: F-61562r925677_fix

Change the mode of the file "/etc/shadow-" to "0000" by running the following command: $ sudo chmod 0000 /etc/shadow-

b

RHEL 9 /etc/group file must be owned by root.

CM-6 - Medium - CCI-000366 - V-257898 - SV-257898r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-232090

Vuln IDs

V-257898

Rule IDs

SV-257898r991589_rule

The "/etc/group" file contains information regarding groups that are configured on the system. Protection of this file is important for system security.

Checks: C-61639r925679_chk

Verify the ownership of the "/etc/group" file with the following command: $ sudo stat -c "%U %n" /etc/group root /etc/group If "/etc/group" file does not have an owner of "root", this is a finding.

Fix: F-61563r925680_fix

Change the owner of the file /etc/group to root by running the following command: $ sudo chown root /etc/group

b

RHEL 9 /etc/group file must be group-owned by root.

CM-6 - Medium - CCI-000366 - V-257899 - SV-257899r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-232095

Vuln IDs

V-257899

Rule IDs

SV-257899r991589_rule

The "/etc/group" file contains information regarding groups that are configured on the system. Protection of this file is important for system security.

Checks: C-61640r925682_chk

Verify the group ownership of the "/etc/group" file with the following command: $ sudo stat -c "%G %n" /etc/group root /etc/group If "/etc/group" file does not have a group owner of "root", this is a finding.

Fix: F-61564r925683_fix

Change the group of the file /etc/group to root by running the following command: $ sudo chgrp root /etc/group

b

RHEL 9 /etc/group- file must be owned by root.

CM-6 - Medium - CCI-000366 - V-257900 - SV-257900r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-232100

Vuln IDs

V-257900

Rule IDs

SV-257900r991589_rule

The "/etc/group-" file is a backup file of "/etc/group", and as such, contains information regarding groups that are configured on the system. Protection of this file is important for system security.

Checks: C-61641r925685_chk

Verify the ownership of the "/etc/group-" file with the following command: $ sudo stat -c "%U %n" /etc/group- root /etc/group- If "/etc/group-" file does not have an owner of "root", this is a finding.

Fix: F-61565r925686_fix

Change the owner of the file /etc/group- to root by running the following command: $ sudo chown root /etc/group-

b

RHEL 9 /etc/group- file must be group-owned by root.

CM-6 - Medium - CCI-000366 - V-257901 - SV-257901r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-232105

Vuln IDs

V-257901

Rule IDs

SV-257901r991589_rule

The "/etc/group-" file is a backup file of "/etc/group", and as such, contains information regarding groups that are configured on the system. Protection of this file is important for system security.

Checks: C-61642r925688_chk

Verify the group ownership of the "/etc/group-" file with the following command: $ sudo stat -c "%G %n" /etc/group- root /etc/group- If "/etc/group-" file does not have a group owner of "root", this is a finding.

Fix: F-61566r925689_fix

Change the group of the file /etc/group- to root by running the following command: $ sudo chgrp root /etc/group-

b

RHEL 9 /etc/gshadow file must be owned by root.

CM-6 - Medium - CCI-000366 - V-257902 - SV-257902r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-232110

Vuln IDs

V-257902

Rule IDs

SV-257902r991589_rule

The "/etc/gshadow" file contains group password hashes. Protection of this file is critical for system security.

Checks: C-61643r925691_chk

Verify the ownership of the "/etc/gshadow" file with the following command: $ sudo stat -c "%U %n" /etc/gshadow root /etc/gshadow If "/etc/gshadow" file does not have an owner of "root", this is a finding.

Fix: F-61567r925692_fix

Change the owner of the file /etc/gshadow to root by running the following command: $ sudo chown root /etc/gshadow

b

RHEL 9 /etc/gshadow file must be group-owned by root.

CM-6 - Medium - CCI-000366 - V-257903 - SV-257903r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-232115

Vuln IDs

V-257903

Rule IDs

SV-257903r991589_rule

The "/etc/gshadow" file contains group password hashes. Protection of this file is critical for system security.

Checks: C-61644r925694_chk

Verify the group ownership of the "/etc/gshadow" file with the following command: $ sudo stat -c "%G %n" /etc/gshadow root /etc/gshadow If "/etc/gshadow" file does not have a group owner of "root", this is a finding.

Fix: F-61568r925695_fix

Change the group of the file /etc/gshadow to root by running the following command: $ sudo chgrp root /etc/gshadow

b

RHEL 9 /etc/gshadow- file must be owned by root.

CM-6 - Medium - CCI-000366 - V-257904 - SV-257904r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-232120

Vuln IDs

V-257904

Rule IDs

SV-257904r991589_rule

The "/etc/gshadow-" file is a backup of "/etc/gshadow", and as such, contains group password hashes. Protection of this file is critical for system security.

Checks: C-61645r925697_chk

Verify the ownership of the "/etc/gshadow-" file with the following command: $ sudo stat -c "%U %n" /etc/gshadow- root /etc/gshadow- If "/etc/gshadow-" file does not have an owner of "root", this is a finding.

Fix: F-61569r925698_fix

Change the owner of the file /etc/gshadow- to root by running the following command: $ sudo chown root /etc/gshadow-

b

RHEL 9 /etc/gshadow- file must be group-owned by root.

CM-6 - Medium - CCI-000366 - V-257905 - SV-257905r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-232125

Vuln IDs

V-257905

Rule IDs

SV-257905r991589_rule

The "/etc/gshadow-" file is a backup of "/etc/gshadow", and as such, contains group password hashes. Protection of this file is critical for system security.

Checks: C-61646r925700_chk

Verify the group ownership of the "/etc/gshadow-" file with the following command: $ sudo stat -c "%G %n" /etc/gshadow- root /etc/gshadow- If "/etc/gshadow-" file does not have a group owner of "root", this is a finding.

Fix: F-61570r925701_fix

Change the group of the file /etc/gshadow- to root by running the following command: $ sudo chgrp root /etc/gshadow-

b

RHEL 9 /etc/passwd file must be owned by root.

CM-6 - Medium - CCI-000366 - V-257906 - SV-257906r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-232130

Vuln IDs

V-257906

Rule IDs

SV-257906r991589_rule

The "/etc/passwd" file contains information about the users that are configured on the system. Protection of this file is critical for system security.

Checks: C-61647r925703_chk

Verify the ownership of the "/etc/passwd" file with the following command: $ sudo stat -c "%U %n" /etc/passwd root /etc/passwd If "/etc/passwd" file does not have an owner of "root", this is a finding.

Fix: F-61571r925704_fix

Change the owner of the file /etc/passwd to root by running the following command: $ sudo chown root /etc/passwd

b

RHEL 9 /etc/passwd file must be group-owned by root.

CM-6 - Medium - CCI-000366 - V-257907 - SV-257907r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-232135

Vuln IDs

V-257907

Rule IDs

SV-257907r991589_rule

The "/etc/passwd" file contains information about the users that are configured on the system. Protection of this file is critical for system security.

Checks: C-61648r925706_chk

Verify the group ownership of the "/etc/passwd" file with the following command: $ sudo stat -c "%G %n" /etc/passwd root /etc/passwd If "/etc/passwd" file does not have a group owner of "root", this is a finding.

Fix: F-61572r925707_fix

Change the group of the file /etc/passwd to root by running the following command: $ sudo chgrp root /etc/passwd

b

RHEL 9 /etc/passwd- file must be owned by root.

CM-6 - Medium - CCI-000366 - V-257908 - SV-257908r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-232140

Vuln IDs

V-257908

Rule IDs

SV-257908r991589_rule

The "/etc/passwd-" file is a backup file of "/etc/passwd", and as such, contains information about the users that are configured on the system. Protection of this file is critical for system security.

Checks: C-61649r925709_chk

Verify the ownership of the "/etc/passwd-" file with the following command: $ sudo stat -c "%U %n" /etc/passwd- root /etc/passwd- If "/etc/passwd-" file does not have an owner of "root", this is a finding.

Fix: F-61573r925710_fix

Change the owner of the file /etc/passwd- to root by running the following command: $ sudo chown root /etc/passwd-

b

RHEL 9 /etc/passwd- file must be group-owned by root.

CM-6 - Medium - CCI-000366 - V-257909 - SV-257909r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-232145

Vuln IDs

V-257909

Rule IDs

SV-257909r991589_rule

The "/etc/passwd-" file is a backup file of "/etc/passwd", and as such, contains information about the users that are configured on the system. Protection of this file is critical for system security.

Checks: C-61650r925712_chk

Verify the group ownership of the "/etc/passwd-" file with the following command: $ sudo stat -c "%G %n" /etc/passwd- root /etc/passwd- If "/etc/passwd-" file does not have a group owner of "root", this is a finding.

Fix: F-61574r925713_fix

Change the group of the file /etc/passwd- to root by running the following command: $ sudo chgrp root /etc/passwd-

b

RHEL 9 /etc/shadow file must be owned by root.

CM-6 - Medium - CCI-000366 - V-257910 - SV-257910r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-232150

Vuln IDs

V-257910

Rule IDs

SV-257910r991589_rule

The "/etc/shadow" file contains the list of local system accounts and stores password hashes. Protection of this file is critical for system security. Failure to give ownership of this file to root provides the designated owner with access to sensitive information, which could weaken the system security posture.

Checks: C-61651r925715_chk

Verify the ownership of the "/etc/shadow" file with the following command: $ sudo stat -c "%U %n" /etc/shadow root /etc/shadow If "/etc/shadow" file does not have an owner of "root", this is a finding.

Fix: F-61575r925716_fix

Change the owner of the file /etc/shadow to root by running the following command: $ sudo chown root /etc/shadow

b

RHEL 9 /etc/shadow file must be group-owned by root.

CM-6 - Medium - CCI-000366 - V-257911 - SV-257911r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-232155

Vuln IDs

V-257911

Rule IDs

SV-257911r991589_rule

The "/etc/shadow" file stores password hashes. Protection of this file is critical for system security.

Checks: C-61652r925718_chk

Verify the group ownership of the "/etc/shadow" file with the following command: $ sudo stat -c "%G %n" /etc/shadow root /etc/shadow If "/etc/shadow" file does not have a group owner of "root", this is a finding.

Fix: F-61576r925719_fix

Change the group of the file /etc/shadow to root by running the following command: $ sudo chgrp root /etc/shadow

b

RHEL 9 /etc/shadow- file must be owned by root.

CM-6 - Medium - CCI-000366 - V-257912 - SV-257912r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-232160

Vuln IDs

V-257912

Rule IDs

SV-257912r991589_rule

The "/etc/shadow-" file is a backup file of "/etc/shadow", and as such, contains the list of local system accounts and password hashes. Protection of this file is critical for system security.

Checks: C-61653r925721_chk

Verify the ownership of the "/etc/shadow-" file with the following command: $ sudo stat -c "%U %n" /etc/shadow- root /etc/shadow- If "/etc/shadow-" file does not have an owner of "root", this is a finding.

Fix: F-61577r925722_fix

Change the owner of the file /etc/shadow- to root by running the following command: $ sudo chown root /etc/shadow-

b

RHEL 9 /etc/shadow- file must be group-owned by root.

CM-6 - Medium - CCI-000366 - V-257913 - SV-257913r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-232165

Vuln IDs

V-257913

Rule IDs

SV-257913r991589_rule

The "/etc/shadow-" file is a backup file of "/etc/shadow", and as such, contains the list of local system accounts and password hashes. Protection of this file is critical for system security.

Checks: C-61654r925724_chk

Verify the group ownership of the "/etc/shadow-" file with the following command: $ sudo stat -c "%G %n" /etc/shadow- root /etc/shadow- If "/etc/shadow-" file does not have a group owner of "root", this is a finding.

Fix: F-61578r925725_fix

Change the group of the file /etc/shadow- to root by running the following command: $ sudo chgrp root /etc/shadow-

b

RHEL 9 /var/log directory must be owned by root.

SI-11 - Medium - CCI-001314 - V-257914 - SV-257914r1044969_rule

RMF Control

SI-11

Severity

M

CCI

Version

RHEL-09-232170

Vuln IDs

V-257914

Rule IDs

SV-257914r1044969_rule

Only authorized personnel should be aware of errors and the details of the errors. Error messages are an indicator of an organization's operational state or can identify the RHEL 9 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-61655r1044968_chk

Verify the "/var/log" directory is owned by root with the following command: $ stat -c "%U %n" /var/log root /var/log If "/var/log" does not have an owner of "root", this is a finding.

Fix: F-61579r925728_fix

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

b

RHEL 9 /var/log directory must be group-owned by root.

SI-11 - Medium - CCI-001314 - V-257915 - SV-257915r1044971_rule

RMF Control

SI-11

Severity

M

CCI

Version

RHEL-09-232175

Vuln IDs

V-257915

Rule IDs

SV-257915r1044971_rule

Only authorized personnel should be aware of errors and the details of the errors. Error messages are an indicator of an organization's operational state or can identify the RHEL 9 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-61656r1044970_chk

Verify the "/var/log" directory is group-owned by root with the following command: $ stat -c "%G %n" /var/log root /var/log If "/var/log" does not have a group owner of "root", this is a finding.

Fix: F-61580r925731_fix

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

b

RHEL 9 /var/log/messages file must be owned by root.

SI-11 - Medium - CCI-001314 - V-257916 - SV-257916r1101916_rule

RMF Control

SI-11

Severity

M

CCI

Version

RHEL-09-232180

Vuln IDs

V-257916

Rule IDs

SV-257916r1101916_rule

Only authorized personnel should be aware of errors and the details of the errors. Error messages are an indicator of an organization's operational state or can identify the RHEL 9 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-61657r1101915_chk

Verify the "/var/log/messages" file is owned by root with the following command: $ stat -c "%U %n" /var/log/messages root /var/log/messages If "/var/log/messages" does not have an owner of "root", this is a finding.

Fix: F-61581r925734_fix

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

b

RHEL 9 /var/log/messages file must be group-owned by root.

SI-11 - Medium - CCI-001314 - V-257917 - SV-257917r1101914_rule

RMF Control

SI-11

Severity

M

CCI

Version

RHEL-09-232185

Vuln IDs

V-257917

Rule IDs

SV-257917r1101914_rule

Only authorized personnel should be aware of errors and the details of the errors. Error messages are an indicator of an organization's operational state or can identify the RHEL 9 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-61658r1101913_chk

Verify the "/var/log/messages" file is group-owned by root with the following command: $ stat -c "%G %n" /var/log/messages root /var/log/messages If "/var/log/messages" does not have a group owner of "root", this is a finding.

Fix: F-61582r925737_fix

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

b

RHEL 9 system commands must be owned by root.

CM-5 - Medium - CCI-001499 - V-257918 - SV-257918r1044977_rule

RMF Control

CM-5

Severity

M

CCI

Version

RHEL-09-232190

Vuln IDs

V-257918

Rule IDs

SV-257918r1044977_rule

If RHEL 9 allowed any user to make changes to software libraries, then those changes might be implemented without undergoing the appropriate testing and approvals that are part of a robust change management process. This requirement applies to RHEL 9 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.

Checks: C-61659r1044976_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/libexec /usr/local/bin /usr/local/sbin ! -user root -exec stat -L -c "%U %n" {} \; If any system commands are found to not be owned by root, this is a finding.

Fix: F-61583r925740_fix

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

b

RHEL 9 system commands must be group-owned by root or a system account.

CM-5 - Medium - CCI-001499 - V-257919 - SV-257919r1044979_rule

RMF Control

CM-5

Severity

M

CCI

Version

RHEL-09-232195

Vuln IDs

V-257919

Rule IDs

SV-257919r1044979_rule

If RHEL 9 allowed any user to make changes to software libraries, then those changes might be implemented without undergoing the appropriate testing and approvals that are part of a robust change management process. This requirement applies to RHEL 9 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.

Checks: C-61660r1044978_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/libexec /usr/local/bin /usr/local/sbin ! -group root -exec stat -L -c "%G %n" {} \; If any system commands are returned and are not group-owned by a required system account, this is a finding.

Fix: F-61584r925743_fix

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

b

RHEL 9 library files must be owned by root.

CM-5 - Medium - CCI-001499 - V-257920 - SV-257920r1101926_rule

RMF Control

CM-5

Severity

M

CCI

Version

RHEL-09-232200

Vuln IDs

V-257920

Rule IDs

SV-257920r1101926_rule

If RHEL 9 allowed any user to make changes to software libraries, then those changes might be implemented without undergoing the appropriate testing and approvals that are part of a robust change management process. This requirement applies to RHEL 9 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.

Checks: C-61661r1101924_chk

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

Fix: F-61585r1101925_fix

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

b

RHEL 9 library files must be group-owned by root or a system account.

CM-5 - Medium - CCI-001499 - V-257921 - SV-257921r1106308_rule

RMF Control

CM-5

Severity

M

CCI

Version

RHEL-09-232205

Vuln IDs

V-257921

Rule IDs

SV-257921r1106308_rule

If RHEL 9 allowed any user to make changes to software libraries, then those changes might be implemented without undergoing the appropriate testing and approvals that are part of a robust change management process. This requirement applies to RHEL 9 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.

Checks: C-61662r1101921_chk

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

Fix: F-61586r1106307_fix

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

b

RHEL 9 library directories must be owned by root.

CM-5 - Medium - CCI-001499 - V-257922 - SV-257922r1044988_rule

RMF Control

CM-5

Severity

M

CCI

Version

RHEL-09-232210

Vuln IDs

V-257922

Rule IDs

SV-257922r1044988_rule

If RHEL 9 allowed any user to make changes to software libraries, then those changes might be implemented without undergoing the appropriate testing and approvals that are part of a robust change management process. This requirement applies to RHEL 9 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.

Checks: C-61663r1044986_chk

Verify the systemwide shared library directories are owned by "root" with the following command: $ sudo find /lib /lib64 /usr/lib /usr/lib64 ! -user root -type d -exec stat -c "%U %n" {} \; If any systemwide shared library directory is not owned by "root", this is a finding.

Fix: F-61587r1044987_fix

Configure the systemwide shared library directories within (/lib, /lib64, /usr/lib and /usr/lib64) to be protected from unauthorized access. Run the following command, replacing "[DIRECTORY]" with any library directory not owned by "root". $ sudo chown root [DIRECTORY]

b

RHEL 9 library directories must be group-owned by root or a system account.

CM-5 - Medium - CCI-001499 - V-257923 - SV-257923r1044991_rule

RMF Control

CM-5

Severity

M

CCI

Version

RHEL-09-232215

Vuln IDs

V-257923

Rule IDs

SV-257923r1044991_rule

If RHEL 9 allowed any user to make changes to software libraries, then those changes might be implemented without undergoing the appropriate testing and approvals that are part of a robust change management process. This requirement applies to RHEL 9 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.

Checks: C-61664r1044989_chk

Verify the systemwide shared library directories are group-owned by "root" with the following command: $ sudo find /lib /lib64 /usr/lib /usr/lib64 ! -group root -type d -exec stat -c "%G %n" {} \; If any systemwide shared library directory is returned and is not group-owned by a required system account, this is a finding.

Fix: F-61588r1044990_fix

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

b

RHEL 9 audit tools must be owned by root.

AU-9 - Medium - CCI-001493 - V-257924 - SV-257924r991557_rule

RMF Control

AU-9

Severity

M

CCI

Version

RHEL-09-232220

Vuln IDs

V-257924

Rule IDs

SV-257924r991557_rule

Protecting audit information also includes identifying and protecting the tools used to view and manipulate log data. Therefore, protecting audit tools is necessary to prevent unauthorized operation on audit information. RHEL 9 systems providing tools to interface with audit information will leverage user permissions and roles identifying the user accessing the tools, and the corresponding rights the user enjoys, to make access decisions regarding the access to audit tools. Audit tools include, but are not limited to, vendor-provided and open source audit tools needed to successfully view and manipulate audit information system activity and records. Audit tools include custom queries and report generators.

Checks: C-61665r925757_chk

Verify the audit tools are owned by "root" with the following command: $ sudo stat -c "%U %n" /sbin/auditctl /sbin/aureport /sbin/ausearch /sbin/autrace /sbin/auditd /sbin/rsyslogd /sbin/augenrules root /sbin/auditctl root /sbin/aureport root /sbin/ausearch root /sbin/autrace root /sbin/auditd root /sbin/rsyslogd root /sbin/augenrules If any audit tools do not have an owner of "root", this is a finding.

Fix: F-61589r925758_fix

Configure the audit tools to be owned by "root" by running the following command: $ sudo chown root [audit_tool] Replace "[audit_tool]" with each audit tool not owned by "root".

b

RHEL 9 audit tools must be group-owned by root.

AU-9 - Medium - CCI-001493 - V-257925 - SV-257925r991557_rule

RMF Control

AU-9

Severity

M

CCI

Version

RHEL-09-232225

Vuln IDs

V-257925

Rule IDs

SV-257925r991557_rule

Protecting audit information also includes identifying and protecting the tools used to view and manipulate log data; therefore, protecting audit tools is necessary to prevent unauthorized operation on audit information. RHEL 9 systems providing tools to interface with audit information will leverage user permissions and roles identifying the user accessing the tools, and the corresponding rights the user enjoys, to make access decisions regarding the access to audit tools. Audit tools include, but are not limited to, vendor-provided and open source audit tools needed to successfully view and manipulate audit information system activity and records. Audit tools include custom queries and report generators.

Checks: C-61666r925760_chk

Verify the audit tools are group owned by "root" with the following command: $ sudo stat -c "%G %n" /sbin/auditctl /sbin/aureport /sbin/ausearch /sbin/autrace /sbin/auditd /sbin/rsyslogd /sbin/augenrules root /sbin/auditctl root /sbin/aureport root /sbin/ausearch root /sbin/autrace root /sbin/auditd root /sbin/rsyslogd root /sbin/augenrules If any audit tools do not have a group owner of "root", this is a finding.

Fix: F-61590r925761_fix

Configure the audit tools to be group-owned by "root" by running the following command: $ sudo chgrp root [audit_tool] Replace "[audit_tool]" with each audit tool not group-owned by "root".

b

RHEL 9 cron configuration files directory must be owned by root.

CM-6 - Medium - CCI-000366 - V-257926 - SV-257926r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-232230

Vuln IDs

V-257926

Rule IDs

SV-257926r991589_rule

Service configuration files enable or disable features of their respective services that if configured incorrectly can lead to insecure and vulnerable configurations; therefore, service configuration files must be owned by the correct group to prevent unauthorized changes.

Checks: C-61667r925763_chk

Verify the ownership of all cron configuration files with the command: $ stat -c "%U %n" /etc/cron* root /etc/cron.d root /etc/cron.daily root /etc/cron.deny root /etc/cron.hourly root /etc/cron.monthly root /etc/crontab root /etc/cron.weekly If any crontab is not owned by root, this is a finding.

Fix: F-61591r925764_fix

Configure any cron configuration not owned by root with the following command: $ sudo chown root [cron config file]

b

RHEL 9 cron configuration files directory must be group-owned by root.

CM-6 - Medium - CCI-000366 - V-257927 - SV-257927r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-232235

Vuln IDs

V-257927

Rule IDs

SV-257927r991589_rule

Service configuration files enable or disable features of their respective services that if configured incorrectly can lead to insecure and vulnerable configurations; therefore, service configuration files should be owned by the correct group to prevent unauthorized changes.

Checks: C-61668r925766_chk

Verify the group ownership of all cron configuration files with the following command: $ stat -c "%G %n" /etc/cron* root /etc/cron.d root /etc/cron.daily root /etc/cron.deny root /etc/cron.hourly root /etc/cron.monthly root /etc/crontab root /etc/cron.weekly If any crontab is not group owned by root, this is a finding.

Fix: F-61592r925767_fix

Configure any cron configuration not group-owned by root with the following command: $ sudo chgrp root [cron config file]

b

All RHEL 9 world-writable directories must be owned by root, sys, bin, or an application user.

SC-4 - Medium - CCI-001090 - V-257928 - SV-257928r1044992_rule

RMF Control

SC-4

Severity

M

CCI

CCI-001090

Version

RHEL-09-232240

Vuln IDs

V-257928

Rule IDs

SV-257928r1044992_rule

If a world-writable directory is not owned by root, sys, bin, or an application user identifier (UID), unauthorized users may be able to modify files created by others. The only authorized public directories are those temporary directories supplied with the system or those designed to be temporary file repositories. The setting is normally reserved for directories used by the system and by users for temporary file storage, (e.g., /tmp), and for directories requiring global read/write access. Satisfies: SRG-OS-000480-GPOS-00227, SRG-OS-000138-GPOS-00069

Checks: C-61669r925769_chk

Verify that world writable directories are owned by root, a system account, or an application account with the following command. It will discover and print world-writable directories that are not owned by root. Run it once for each local partition [PART]: $ sudo find PART -xdev -type d -perm -0002 -uid +0 -print If there is output, this is a finding.

Fix: F-61593r925770_fix

Configure all public directories to be owned by root or a system account to prevent unauthorized and unintended information transferred via shared system resources. Set the owner of all public directories as root or a system account using the command, replace "[Public Directory]" with any directory path not owned by root or a system account: $ sudo chown root [Public Directory]

b

A sticky bit must be set on all RHEL 9 public directories.

SC-4 - Medium - CCI-001090 - V-257929 - SV-257929r1117267_rule

RMF Control

SC-4

Severity

M

CCI

CCI-001090

Version

RHEL-09-232245

Vuln IDs

V-257929

Rule IDs

SV-257929r1117267_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.

Checks: C-61670r925772_chk

Verify that all world-writable directories have the sticky bit set. Determine if 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 drwxrwxrwt 7 root root 4096 Jul 26 11:19 /tmp If any of the returned directories are world-writable and do not have the sticky bit set, this is a finding.

Fix: F-61594r925773_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: $ chmod a+t [World-Writable Directory]

b

All RHEL 9 local files and directories must have a valid group owner.

CM-6 - Medium - CCI-000366 - V-257930 - SV-257930r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-232250

Vuln IDs

V-257930

Rule IDs

SV-257930r991589_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-61671r925775_chk

Verify all local files and directories on RHEL 9 have a valid group with the following command: $ df --local -P | awk {'if (NR!=1) print $6'} | sudo xargs -I '{}' find '{}' -xdev -nogroup If any files on the system do not have an assigned group, this is a finding.

Fix: F-61595r925776_fix

Either remove all files and directories from RHEL 9 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

All RHEL 9 local files and directories must have a valid owner.

CM-6 - Medium - CCI-000366 - V-257931 - SV-257931r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-232255

Vuln IDs

V-257931

Rule IDs

SV-257931r991589_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-61672r925778_chk

Verify all local files and directories on RHEL 9 have a valid owner with the following command: $ df --local -P | awk {'if (NR!=1) print $6'} | sudo xargs -I '{}' find '{}' -xdev -nouser If any files on the system do not have an assigned owner, this is a finding.

Fix: F-61596r925779_fix

Either remove all files and directories from the system that do not have a valid user, or assign a valid user to all unowned files and directories on RHEL 9 with the "chown" command: $ sudo chown <user> <file>

b

RHEL 9 must be configured so that all system device files are correctly labeled to prevent unauthorized modification.

CM-6 - Medium - CCI-000366 - V-257932 - SV-257932r1014838_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-232260

Vuln IDs

V-257932

Rule IDs

SV-257932r1014838_rule

If an unauthorized or modified device is allowed to exist on the system, there is the possibility the system may perform unintended or unauthorized operations.

Checks: C-61673r925781_chk

Verify that all system device files are correctly labeled to prevent unauthorized modification. List all device files on the system that are incorrectly labeled with the following commands: Note: Device files are normally found under "/dev", but applications may place device files in other directories and may necessitate a search of the entire system. # find /dev -context *:device_t:* $ -type c -o -type b $ -printf "%p %Z\n" # find /dev -context *:unlabeled_t:* $ -type c -o -type b $ -printf "%p %Z\n" Note: There are device files, such as "/dev/vmci", that are used when the operating system is a host virtual machine. They will not be owned by a user on the system and require the "device_t" label to operate. These device files are not a finding. If there is output from either of these commands, other than already noted, this is a finding.

Fix: F-61597r1014837_fix

Restore the SELinux policy for the affected device file from the system policy database using the following command: $ sudo restorecon -v <device_path> Substitute "<device_path>" with the path to the affected device file (from the output of the previous commands). An example device file path would be "/dev/ttyUSB0". If the output of the above command does not indicate that the device was relabeled to a more specific SELinux type label, then the SELinux policy of the system must be updated with more specific policy for the device class specified. If a package was used to install support for a device class, that package could be reinstalled using the following command: $ sudo dnf reinstall <package_name> If a package was not used to install the SELinux policy for a given device class, then it must be generated manually and provide specific type labels.

b

RHEL 9 /etc/shadow file must have mode 0000 to prevent unauthorized access.

CM-6 - Medium - CCI-000366 - V-257934 - SV-257934r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-232270

Vuln IDs

V-257934

Rule IDs

SV-257934r991589_rule

The "/etc/shadow" file contains the list of local system accounts and stores password hashes. Protection of this file is critical for system security. Failure to give ownership of this file to root provides the designated owner with access to sensitive information, which could weaken the system security posture.

Checks: C-61675r925787_chk

Verify that the "/etc/shadow" file has mode "0000" with the following command: $ sudo stat -c "%a %n" /etc/shadow 0 /etc/shadow If a value of "0" is not returned, this is a finding.

Fix: F-61599r925788_fix

Change the mode of the file "/etc/shadow" to "0000" by running the following command: $ sudo chmod 0000 /etc/shadow

b

RHEL 9 must have the firewalld package installed.

CM-7 - Medium - CCI-000382 - V-257935 - SV-257935r1044994_rule

RMF Control

CM-7

Severity

M

CCI

CCI-000382

Version

RHEL-09-251010

Vuln IDs

V-257935

Rule IDs

SV-257935r1044994_rule

"Firewalld" provides an easy and effective way to block/limit remote access to the system via ports, services, and protocols. Remote access services, such as those providing remote access to network devices and information systems, which lack automated control capabilities, increase risk and make remote user access management difficult at best. Remote access is access to DOD nonpublic information systems by an authorized user (or an information system) communicating through an external, nonorganization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless. RHEL 9 functionality (e.g., SSH) must be capable of taking enforcement action if the audit reveals unauthorized activity. Automated control of remote access sessions allows organizations to ensure ongoing compliance with remote access policies by enforcing connection rules of remote access applications on a variety of information system components (e.g., servers, workstations, notebook computers, smartphones, and tablets). Satisfies: SRG-OS-000096-GPOS-00050, SRG-OS-000297-GPOS-00115, SRG-OS-000298-GPOS-00116, SRG-OS-000480-GPOS-00227, SRG-OS-000480-GPOS-00232

Checks: C-61676r1044993_chk

Run the following command to determine if the firewalld package is installed with the following command: $ dnf list --installed firewalld Example output: firewalld.noarch 1.0.0-4.el9 If the "firewall" package is not installed, this is a finding.

Fix: F-61600r925791_fix

To install the "firewalld" package run the following command: $ sudo dnf install firewalld

b

The firewalld service on RHEL 9 must be active.

CM-7 - Medium - CCI-000382 - V-257936 - SV-257936r1044995_rule

RMF Control

CM-7

Severity

M

CCI

CCI-000382

Version

RHEL-09-251015

Vuln IDs

V-257936

Rule IDs

SV-257936r1044995_rule

"Firewalld" provides an easy and effective way to block/limit remote access to the system via ports, services, and protocols. Remote access services, such as those providing remote access to network devices and information systems, which lack automated control capabilities, increase risk and make remote user access management difficult at best. Remote access is access to DOD nonpublic information systems by an authorized user (or an information system) communicating through an external, non-organization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless. RHEL 9 functionality (e.g., RDP) must be capable of taking enforcement action if the audit reveals unauthorized activity. Automated control of remote access sessions allows organizations to ensure ongoing compliance with remote access policies by enforcing connection rules of remote access applications on a variety of information system components (e.g., servers, workstations, notebook computers, smartphones, and tablets). Satisfies: SRG-OS-000096-GPOS-00050, SRG-OS-000297-GPOS-00115, SRG-OS-000480-GPOS-00227, SRG-OS-000480-GPOS-00232

Checks: C-61677r925793_chk

Verify that "firewalld" is active with the following command: $ systemctl is-active firewalld active If the firewalld service is not active, this is a finding.

Fix: F-61601r925794_fix

To enable the firewalld service run the following command: $ sudo systemctl enable --now firewalld

b

The RHEL 9 firewall must employ a deny-all, allow-by-exception policy for allowing connections to other systems.

CM-6 - Medium - CCI-000366 - V-257937 - SV-257937r1106310_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-251020

Vuln IDs

V-257937

Rule IDs

SV-257937r1106310_rule

Failure to restrict network connectivity only to authorized systems permits inbound connections from malicious systems. It also permits outbound connections that may facilitate exfiltration of DOD data. RHEL 9 incorporates the "firewalld" daemon, which allows for many different configurations. One of these configurations is zones. Zones can be utilized to a deny-all, allow-by-exception approach. The default "drop" zone will drop all incoming network packets unless it is explicitly allowed by the configuration file or is related to an outgoing network connection.

Checks: C-61678r1106309_chk

Verify the RHEL 9 firewalld is configured to employ a deny-all, allow-by-exception policy for allowing connections to other systems with the following commands: Ensure firewalld is running: $ sudo firewall-cmd --state running Identify active zones: $ sudo firewall-cmd --get-active-zones drop interfaces: ens192 Check what rules are applied in that zone: $ sudo firewall-cmd --list-all --zone=$(firewall-cmd --get-default-zone) drop (active) target: DROP icmp-block-inversion: no interfaces: ens192 sources: services: ssh ports: protocols: forward: yes masquerade: no forward-ports: source-ports: icmp-blocks: rich rules: If no zones are active on the RHEL 9 interfaces or if runtime and permanent targets are set to a different option other than "DROP", this is a finding.

Fix: F-61602r1102092_fix

Configure the "firewalld" daemon to employ a deny-all, allow-by-exception policy with the following commands: Start by adding the exceptions that are required for mission functionality to the "drop" zone. If SSH access on port 22 is needed, for example, run the following: "sudo firewall-cmd --permanent --add-service=ssh --zone=drop" Reload the firewall rules to update the runtime configuration from the "--permanent" changes made above: $ sudo firewall-cmd --reload Set the default zone to the drop zone: $ sudo firewall-cmd --set-default-zone=drop Note: This is a runtime and permanent change. Add any interfaces to the newly modified "drop" zone: $ sudo firewall-cmd --permanent --zone=drop --change-interface=ens192 Reload the firewall rules for changes to take effect: $ sudo firewall-cmd --reload

b

RHEL 9 must protect against or limit the effects of denial-of-service (DoS) attacks by ensuring rate-limiting measures on impacted network interfaces are implemented.

SC-5 - Medium - CCI-002385 - V-257939 - SV-257939r1044997_rule

RMF Control

SC-5

Severity

M

CCI

CCI-002385

Version

RHEL-09-251030

Vuln IDs

V-257939

Rule IDs

SV-257939r1044997_rule

DoS is a condition when a resource is not available for legitimate users. When this occurs, the organization either cannot accomplish its mission or must operate at degraded capacity. This requirement addresses the configuration of RHEL 9 to mitigate the impact of DoS attacks that have occurred or are ongoing on system availability. For each system, known and potential DoS attacks must be identified and solutions for each type implemented. A variety of technologies exists to limit or, in some cases, eliminate the effects of DoS attacks (e.g., limiting processes or establishing memory partitions). Employing increased capacity and bandwidth, combined with service redundancy, may reduce the susceptibility to some DoS attacks.

Checks: C-61680r925802_chk

Verify "nftables" is configured to allow rate limits on any connection to the system with the following command: $ sudo grep -i firewallbackend /etc/firewalld/firewalld.conf # FirewallBackend FirewallBackend=nftables If the "nftables" is not set as the "FirewallBackend" default, this is a finding.

Fix: F-61604r1044996_fix

Configure "nftables" to be the default "firewallbackend" for "firewalld" by adding or editing the following line in "/etc/firewalld/firewalld.conf": FirewallBackend=nftables Establish rate-limiting rules based on organization-defined types of DoS attacks on impacted network interfaces.

b

RHEL 9 must be configured to prohibit or restrict the use of functions, ports, protocols, and/or services, as defined in the Ports, Protocols, and Services Management (PPSM) Category Assignments List (CAL) and vulnerability assessments.

CM-7 - Medium - CCI-000382 - V-257940 - SV-257940r1106312_rule

RMF Control

CM-7

Severity

M

CCI

CCI-000382

Version

RHEL-09-251035

Vuln IDs

V-257940

Rule IDs

SV-257940r1106312_rule

To prevent unauthorized connection of devices, unauthorized transfer of information, or unauthorized tunneling (i.e., embedding of data types within data types), organizations must disable or restrict unused or unnecessary ports, protocols, and services on information systems.

Checks: C-61681r1106311_chk

Inspect the firewall configuration and running services to verify it is configured to prohibit or restrict the use of functions, ports, protocols, and/or services that are unnecessary or prohibited. Check which services are currently active with the following command: $ sudo firewall-cmd --list-all-zones | grep -e "active" -e "services" Ask the system administrator for the site or program Ports, Protocols, and Services Management Component Local Service Assessment (PPSM CLSA). Verify the services allowed by the firewall match the PPSM CLSA. If there are additional ports, protocols, or services that are not in the PPSM CLSA, or there are ports, protocols, or services that are prohibited by the PPSM CAL, this is a finding.

Fix: F-61605r925806_fix

Update the host's firewall settings and/or running services to comply with the PPSM CLSA for the site or program and the PPSM CAL. Then run the following command to load the newly created rule(s): $ sudo firewall-cmd --reload

b

RHEL 9 network interfaces must not be in promiscuous mode.

CM-6 - Medium - CCI-000366 - V-257941 - SV-257941r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-251040

Vuln IDs

V-257941

Rule IDs

SV-257941r991589_rule

Network interfaces in promiscuous mode allow for the capture of all network traffic visible to the system. If unauthorized individuals can access these applications, it may allow them to collect information such as logon IDs, passwords, and key exchanges between systems. If the system is being used to perform a network troubleshooting function, the use of these tools must be documented with the information systems security officer (ISSO) and restricted to only authorized personnel.

Checks: C-61682r925808_chk

Verify network interfaces are not in promiscuous mode with the following command: $ ip link | grep -i promisc If network interfaces are found on the system in promiscuous mode and their use has not been approved by the ISSO and documented, this is a finding.

Fix: F-61606r925809_fix

Configure network interfaces to turn off promiscuous mode unless approved by the ISSO and documented. Set the promiscuous mode of an interface to off with the following command: $ sudo ip link set dev <devicename> multicast off promisc off

b

RHEL 9 must enable hardening for the Berkeley Packet Filter just-in-time compiler.

CM-6 - Medium - CCI-000366 - V-257942 - SV-257942r1106314_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-251045

Vuln IDs

V-257942

Rule IDs

SV-257942r1106314_rule

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Enabling hardening for the Berkeley Packet Filter (BPF) Just-in-time (JIT) compiler aids in mitigating JIT spraying attacks. Setting the value to "2" enables JIT hardening for all users. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of the directories in which they reside. 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-61683r1101971_chk

Verify RHEL 9 enables hardening for the BPF JIT with the following commands: $ sudo sysctl net.core.bpf_jit_harden net.core.bpf_jit_harden = 2 If the returned line does not have a value of "2", or a line is not returned, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r net.core.bpf_jit_harden /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: net.core.bpf_jit_harden = 2 If "net.core.bpf_jit_harden" is not set to "2", is missing or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-61607r1106313_fix

Configure RHEL 9 to enable hardening for the BPF JIT compiler by adding the following line to a file, in the "/etc/sysctl.d" directory: net.core.bpf_jit_harden = 2 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf The system configuration files must be reloaded for the changes to take effect. To reload the contents of the files, run the following command: $ sudo sysctl --system

b

RHEL 9 must have the chrony package installed.

Medium - CCI-004923 - V-257943 - SV-257943r1045001_rule

RMF Control

Severity

M

CCI

CCI-004923

Version

RHEL-09-252010

Vuln IDs

V-257943

Rule IDs

SV-257943r1045001_rule

Inaccurate time stamps make it more difficult to correlate events and can lead to an inaccurate analysis. Determining the correct time a particular event occurred on a system is critical when conducting forensic analysis and investigating system events. Sources outside the configured acceptable allowance (drift) may be inaccurate.

Checks: C-61684r1045000_chk

Verify that RHEL 9 has the chrony package installed with the following command: $ dnf list --installed chrony Example output: chrony.x86_64 4.1-3.el9 If the "chrony" package is not installed, this is a finding.

Fix: F-61608r925815_fix

The chrony package can be installed with the following command: $ sudo dnf install chrony

b

RHEL 9 chronyd service must be enabled.

Medium - CCI-004923 - V-257944 - SV-257944r1038944_rule

RMF Control

Severity

M

CCI

CCI-004923

Version

RHEL-09-252015

Vuln IDs

V-257944

Rule IDs

SV-257944r1038944_rule

Inaccurate time stamps make it more difficult to correlate events and can lead to an inaccurate analysis. Determining the correct time a particular event occurred on a system is critical when conducting forensic analysis and investigating system events. Sources outside the configured acceptable allowance (drift) may be inaccurate. Synchronizing internal information system clocks provides uniformity of time stamps for information systems with multiple system clocks and systems connected over a network.

Checks: C-61685r925817_chk

Verify the chronyd service is active with the following command: $ systemctl is-active chronyd active If the chronyd service is not active, this is a finding.

Fix: F-61609r925818_fix

To enable the chronyd service run the following command: $ sudo systemctl enable --now chronyd

b

RHEL 9 must securely compare internal information system clocks at least every 24 hours.

AU-8 - Medium - CCI-001890 - V-257945 - SV-257945r1038944_rule

RMF Control

AU-8

Severity

M

CCI

CCI-001890

Version

RHEL-09-252020

Vuln IDs

V-257945

Rule IDs

SV-257945r1038944_rule

Inaccurate time stamps make it more difficult to correlate events and can lead to an inaccurate analysis. Determining the correct time a particular event occurred on a system is critical when conducting forensic analysis and investigating system events. Sources outside the configured acceptable allowance (drift) may be inaccurate. Synchronizing internal information system clocks provides uniformity of time stamps for information systems with multiple system clocks and systems connected over a network. Depending on the infrastructure being used the "pool" directive may not be supported. Authoritative time sources include the United States Naval Observatory (USNO) time servers, a time server designated for the appropriate DOD network (NIPRNet/SIPRNet), and/or the Global Positioning System (GPS). Satisfies: SRG-OS-000355-GPOS-00143, SRG-OS-000356-GPOS-00144, SRG-OS-000359-GPOS-00146

Checks: C-61686r925820_chk

Verify RHEL 9 is securely comparing internal information system clocks at least every 24 hours with an NTP server with the following commands: $ sudo grep maxpoll /etc/chrony.conf server 0.us.pool.ntp.mil iburst maxpoll 16 If the "maxpoll" option is set to a number greater than 16 or the line is commented out, this is a finding. Verify the "chrony.conf" file is configured to an authoritative DOD time source by running the following command: $ sudo grep -i server /etc/chrony.conf server 0.us.pool.ntp.mil If the parameter "server" is not set or is not set to an authoritative DOD time source, this is a finding.

Fix: F-61610r925821_fix

Configure RHEL 9 to securely compare internal information system clocks at least every 24 hours with an NTP server by adding/modifying the following line in the /etc/chrony.conf file. server [ntp.server.name] iburst maxpoll 16

a

RHEL 9 must disable the chrony daemon from acting as a server.

CM-7 - Low - CCI-000381 - V-257946 - SV-257946r958480_rule

RMF Control

CM-7

Severity

L

CCI

Version

RHEL-09-252025

Vuln IDs

V-257946

Rule IDs

SV-257946r958480_rule

Minimizing the exposure of the server functionality of the chrony daemon diminishes the attack surface. Satisfies: SRG-OS-000096-GPOS-00050, SRG-OS-000095-GPOS-00049

Checks: C-61687r925823_chk

Verify RHEL 9 disables the chrony daemon from acting as a server with the following command: $ grep -w port /etc/chrony.conf port 0 If the "port" option is not set to "0", is commented out, or is missing, this is a finding.

Fix: F-61611r925824_fix

Configure RHEL 9 to disable the chrony daemon from acting as a server by adding/modifying the following line in the /etc/chrony.conf file: port 0

a

RHEL 9 must disable network management of the chrony daemon.

CM-7 - Low - CCI-000381 - V-257947 - SV-257947r958480_rule

RMF Control

CM-7

Severity

L

CCI

Version

RHEL-09-252030

Vuln IDs

V-257947

Rule IDs

SV-257947r958480_rule

Not exposing the management interface of the chrony daemon on the network diminishes the attack space. Satisfies: SRG-OS-000096-GPOS-00050, SRG-OS-000095-GPOS-00049

Checks: C-61688r925826_chk

Verify RHEL 9 disables network management of the chrony daemon with the following command: $ grep -w cmdport /etc/chrony.conf cmdport 0 If the "cmdport" option is not set to "0", is commented out, or is missing, this is a finding.

Fix: F-61612r925827_fix

Configure RHEL 9 to disable network management of the chrony daemon by adding/modifying the following line in the /etc/chrony.conf file: cmdport 0

b

RHEL 9 systems using Domain Name Servers (DNS) resolution must have at least two name servers configured.

CM-6 - Medium - CCI-000366 - V-257948 - SV-257948r1045004_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-252035

Vuln IDs

V-257948

Rule IDs

SV-257948r1045004_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-61689r1045002_chk

Note: If the system is running in a cloud platform and the cloud provider gives a single, highly available IP address for DNS configuration, this control is Not Applicable. Verify the name servers used by the system with the following command: $ 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-61613r1045003_fix

Configure the operating system to use two or more name servers for DNS resolution based on the DNS mode of the system. If the NetworkManager DNS mode is set to "none", add the following lines to "/etc/resolv.conf": nameserver [name server 1] nameserver [name server 2] Replace [name server 1] and [name server 2] with the IPs of two different DNS resolvers. If the NetworkManager DNS mode is set to "default", add two DNS servers to a NetworkManager connection using the following command: $ nmcli connection modify [connection name] ipv4.dns [name server 1],[name server 2] Replace [name server 1] and [name server 2] with the IPs of two different DNS resolvers. Replace [connection name] with a valid NetworkManager connection name on the system. Replace ipv4 with ipv6 if IPv6 DNS servers are used.

b

RHEL 9 must configure a DNS processing mode in Network Manager.

CM-6 - Medium - CCI-000366 - V-257949 - SV-257949r1134947_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-252040

Vuln IDs

V-257949

Rule IDs

SV-257949r1134947_rule

To ensure that DNS resolver settings are respected, a DNS mode in Network Manager must be configured. The following are common DNS values in NetworkManager.conf [main]: - default: NetworkManager will update /etc/resolv.conf to reflect the nameservers provided by currently active connections. - none: NetworkManager will not modify /etc/resolv.conf. Used when DNS is managed manually or by another service. - systemd-resolved: Uses systemd-resolved to manage DNS. - dnsmasq: Enables the internal dnsmasq plugin.

Checks: C-61690r1134911_chk

Verify that RHEL 9 has a DNS mode configured in Network Manager. $ NetworkManager --print-config [main] dns=none If the dns key under main does not exist or is not set to "default", "none", or "systemd-resolved", this is a finding. Note: If RHEL 9 is configured to use a DNS resolver other than Network Manager, the configuration must be documented and approved by the information system security officer (ISSO).

Fix: F-61614r1134912_fix

Configure NetworkManager in RHEL 9 to use a DNS mode. In "/etc/NetworkManager/NetworkManager.conf", add the following line in the "[main]" section: dns = <dns processing mode> Where <dns processing mode> is default, none, or systemd-resolved. NetworkManager must be reloaded for the change to take effect. $ sudo systemctl reload NetworkManager

b

RHEL 9 must not have unauthorized IP tunnels configured.

CM-6 - Medium - CCI-000366 - V-257950 - SV-257950r1045006_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-252045

Vuln IDs

V-257950

Rule IDs

SV-257950r1045006_rule

IP tunneling mechanisms can be used to bypass network filtering. If tunneling is required, it must be documented with the information system security officer (ISSO).

Checks: C-61691r1045005_chk

Verify that RHEL 9 does not have unauthorized IP tunnels configured. Determine if the "IPsec" service is active with the following command: $ systemctl is-active ipsec Inactive If the "IPsec" service is active, check for configured IPsec connections ("conn"), with the following command: $ sudo grep -rni conn /etc/ipsec.conf /etc/ipsec.d/ Verify any returned results are documented with the ISSO. If the IPsec tunnels are active and not approved, this is a finding.

Fix: F-61615r925836_fix

Remove all unapproved tunnels from the system, or document them with the ISSO.

b

RHEL 9 must be configured to prevent unrestricted mail relaying.

CM-6 - Medium - CCI-000366 - V-257951 - SV-257951r1014843_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-252050

Vuln IDs

V-257951

Rule IDs

SV-257951r1014843_rule

If unrestricted mail relaying is permitted, unauthorized senders could use this host as a mail relay for the purpose of sending spam or other unauthorized activity.

Checks: C-61692r1014842_chk

If postfix is not installed, this is Not Applicable. Verify RHEL 9 is configured to prevent unrestricted mail relaying with the following command: $ postconf -n smtpd_client_restrictions smtpd_client_restrictions = permit_mynetworks,reject If the "smtpd_client_restrictions" parameter contains any entries other than "permit_mynetworks" and "reject", and the additional entries have not been documented with the information system security officer (ISSO), this is a finding.

Fix: F-61616r925839_fix

Modify the postfix configuration file to restrict client connections to the local network with the following command: $ sudo postconf -e 'smtpd_client_restrictions = permit_mynetworks,reject'

b

RHEL 9 must forward mail from postmaster to the root account using a postfix alias.

AU-5 - Medium - CCI-000139 - V-257953 - SV-257953r958424_rule

RMF Control

AU-5

Severity

M

CCI

Version

RHEL-09-252060

Vuln IDs

V-257953

Rule IDs

SV-257953r958424_rule

It is critical for the appropriate personnel to be aware if a system is at risk of failing to process audit logs as required. Without this notification, the security personnel may be unaware of an impending failure of the audit capability, and system operation may be adversely affected. Audit processing failures include software/hardware errors, failures in the audit capturing mechanisms, and audit storage capacity being reached or exceeded.

Checks: C-61694r925844_chk

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

Fix: F-61618r925845_fix

Configure a valid email address as an alias for the root account. Append the following line to "/etc/aliases": postmaster: root Then, run the following command: $ sudo newaliases

b

RHEL 9 libreswan package must be installed.

IA-7 - Medium - CCI-000803 - V-257954 - SV-257954r1106315_rule

RMF Control

IA-7

Severity

M

CCI

CCI-000803

Version

RHEL-09-252065

Vuln IDs

V-257954

Rule IDs

SV-257954r1106315_rule

Providing the ability for remote users or systems to initiate a secure VPN connection protects information when it is transmitted over a wide area network. Satisfies: SRG-OS-000480-GPOS-00227, SRG-OS-000120-GPOS-00061

Checks: C-61695r1101930_chk

Note: If there is no operational need for Libreswan to be installed, this rule is not applicable. Verify that RHEL 9 libreswan service package is installed. Check that the libreswan service package is installed with the following command: $ dnf list --installed libreswan Example output: libreswan.x86_64 4.6-3.el9 If the "libreswan" package is not installed, this is a finding.

Fix: F-61619r925848_fix

Install the libreswan service (if it is not already installed) with the following command: $ sudo dnf install libreswan

c

There must be no shosts.equiv files on RHEL 9.

CM-6 - High - CCI-000366 - V-257955 - SV-257955r991589_rule

RMF Control

CM-6

Severity

H

CCI

Version

RHEL-09-252070

Vuln IDs

V-257955

Rule IDs

SV-257955r991589_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-61696r925850_chk

Verify there are no "shosts.equiv" files on RHEL 9 with the following command: $ sudo find / -name shosts.equiv If a "shosts.equiv" file is found, this is a finding.

Fix: F-61620r925851_fix

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

c

There must be no .shosts files on RHEL 9.

CM-6 - High - CCI-000366 - V-257956 - SV-257956r991589_rule

RMF Control

CM-6

Severity

H

CCI

Version

RHEL-09-252075

Vuln IDs

V-257956

Rule IDs

SV-257956r991589_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-61697r925853_chk

Verify there are no ".shosts" files on RHEL 9 with the following command: $ sudo find / -name .shosts If a ".shosts" file is found, this is a finding.

Fix: F-61621r925854_fix

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

b

RHEL 9 must be configured to use TCP syncookies.

SC-5 - Medium - CCI-001095 - V-257957 - SV-257957r1106317_rule

RMF Control

SC-5

Severity

M

CCI

CCI-001095

Version

RHEL-09-253010

Vuln IDs

V-257957

Rule IDs

SV-257957r1106317_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 nonprivileged 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 the directories in which they reside. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf Satisfies: SRG-OS-000480-GPOS-00227, SRG-OS-000420-GPOS-00186, SRG-OS-000142-GPOS-00071

Checks: C-61698r1106316_chk

Verify RHEL 9 is configured to use IPv4 TCP syncookies. Determine if syncookies are used with the following command: Check the status of TCP syncookies. $ sudo sysctl net.ipv4.tcp_syncookies net.ipv4.tcp_syncookies = 1 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:net.ipv4.tcp_syncookies = 1 If "net.ipv4.tcp_syncookies" is not set to "1", is missing, or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-61622r1101958_fix

Configure RHEL 9 to use TCP syncookies. Add or edit the following line in a system configuration file in the "/etc/sysctl.d/" directory: net.ipv4.tcp_syncookies = 1 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf Load settings from all system configuration files with the following command: $ sudo sysctl --system

b

RHEL 9 must ignore Internet Protocol version 4 (IPv4) Internet Control Message Protocol (ICMP) redirect messages.

CM-6 - Medium - CCI-000366 - V-257958 - SV-257958r1106319_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-253015

Vuln IDs

V-257958

Rule IDs

SV-257958r1106319_rule

ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages modify the host's route table and are unauthenticated. An illicit ICMP redirect message could result in a man-in-the-middle attack. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of the directories in which they reside. 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-61699r1106318_chk

Verify RHEL 9 ignores IPv4 ICMP redirect messages. Check the value of the "accept_redirects" variables with the following command: $ sudo sysctl net.ipv4.conf.all.accept_redirects net.ipv4.conf.all.accept_redirects = 0 If the returned line does not have a value of "0", a line is not returned, or the line is commented out, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r net.ipv4.conf.all.accept_redirects /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: net.ipv4.conf.all.accept_redirects = 0 If "net.ipv4.conf.all.accept_redirects" is not set to "0", is missing, or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-61623r1101988_fix

Configure RHEL 9 to ignore IPv4 ICMP redirect messages. Add or edit the following line in a system configuration file, in the "/etc/sysctl.d/" directory: net.ipv4.conf.all.accept_redirects = 0 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf Load settings from all system configuration files with the following command: $ sudo sysctl --system

b

RHEL 9 must not forward Internet Protocol version 4 (IPv4) source-routed packets.

CM-6 - Medium - CCI-000366 - V-257959 - SV-257959r1102024_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-253020

Vuln IDs

V-257959

Rule IDs

SV-257959r1102024_rule

Source-routed packets allow the source of the packet to suggest that routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures. This requirement applies only to the forwarding of source-routed traffic, such as when forwarding is enabled and the system is functioning as a router. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of which of the directories they reside in. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf

Checks: C-61700r1102022_chk

Verify RHEL 9 does not accept IPv4 source-routed packets. Check the value of the accept source route variable with the following command: $ sudo sysctl net.ipv4.conf.all.accept_source_route net.ipv4.conf.all.accept_source_route = 0 If the returned line does not have a value of "0", a line is not returned, or the line is commented out, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r net.ipv4.conf.all.accept_source_route /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: net.ipv4.conf.all.accept_source_route = 0 If "net.ipv4.conf.all.accept_source_route" is not set to "0", is missing or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-61624r1102023_fix

Configure RHEL 9 to not forward IPv4 source-routed packets. Add or edit the following line in a system configuration file, in the "/etc/sysctl.d/" directory: net.ipv4.conf.all.accept_source_route=0 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf Load settings from all system configuration files with the following command: $ sudo sysctl --system

b

RHEL 9 must log IPv4 packets with impossible addresses.

CM-6 - Medium - CCI-000366 - V-257960 - SV-257960r1106321_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-253025

Vuln IDs

V-257960

Rule IDs

SV-257960r1106321_rule

The presence of "martian" packets (which have impossible addresses) as well as spoofed packets, source-routed packets, and redirects could be a sign of nefarious network activity. Logging these packets enables this activity to be detected. 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 nonprivileged 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 the directories in which they reside. 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-61701r1102004_chk

Verify RHEL 9 logs IPv4 martian packets. Check the value of the accept source route variable with the following command: $ sudo sysctl net.ipv4.conf.all.log_martians net.ipv4.conf.all.log_martians = 1 If the returned line does not have a value of "1", a line is not returned, or the line is commented out, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r net.ipv4.conf.all.log_martians /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf:net.ipv4.conf.all.log_martians = 1 If "net.ipv4.conf.all.log_martians" is not set to "1" or is missing, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-61625r1106320_fix

Configure RHEL 9 to log martian packets on IPv4 interfaces. Add or edit the following line in a single system configuration file in the "/etc/sysctl.d/" directory: net.ipv4.conf.all.log_martians=1 Load settings from all system configuration files with the following command: $ sudo sysctl --system

b

RHEL 9 must log IPv4 packets with impossible addresses by default.

CM-6 - Medium - CCI-000366 - V-257961 - SV-257961r1106323_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-253030

Vuln IDs

V-257961

Rule IDs

SV-257961r1106323_rule

The presence of "martian" packets (which have impossible addresses) as well as spoofed packets, source-routed packets, and redirects could be a sign of nefarious network activity. Logging these packets enables this activity to be detected. 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 nonprivileged 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 the directories in which they reside. 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-61702r1102001_chk

Verify RHEL 9 logs IPv4 martian packets by default. Check the value of the accept source route variable with the following command: $ sudo sysctl net.ipv4.conf.default.log_martians net.ipv4.conf.default.log_martians = 1 If the returned line does not have a value of "1", a line is not returned, or the line is commented out, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r net.ipv4.conf.default.log_martians /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf:net.ipv4.conf.default.log_martians = 1 If "net.ipv4.conf.default.log_martians" is not set to "1" or is missing, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-61626r1106322_fix

Configure RHEL 9 to log martian packets on IPv4 interfaces by default. Add or edit the following line in a single system configuration file in the "/etc/sysctl.d/" directory: net.ipv4.conf.default.log_martians = 1 Load settings from all system configuration files with the following command: $ sudo sysctl --system

b

RHEL 9 must use reverse path filtering on all IPv4 interfaces.

CM-6 - Medium - CCI-000366 - V-257962 - SV-257962r1106437_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-253035

Vuln IDs

V-257962

Rule IDs

SV-257962r1106437_rule

Enabling reverse path filtering drops packets with source addresses that should not have been able to be received on the interface on which they were received. It must not be used on systems that are routers for complicated networks, but is helpful for end hosts and routers serving small networks. 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 the directories in which they reside. 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-61703r1106436_chk

Verify RHEL 9 uses reverse path filtering on all IPv4 interfaces with the following commands: $ sudo sysctl net.ipv4.conf.all.rp_filter net.ipv4.conf.all.rp_filter = 1 If the returned line does not have a value of "1" or "2", or a line is not returned, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r net.ipv4.conf.all.rp_filter /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: net.ipv4.conf.all.rp_filter = 1 If "net.ipv4.conf.all.rp_filter" is not set to "1" or "2", is missing, or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-61627r1106324_fix

Configure RHEL 9 to use reverse path filtering on all IPv4 interfaces by adding the following line to a file in the "/etc/sysctl.d" directory: net.ipv4.conf.all.rp_filter = 1 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf The system configuration files must be reloaded for the changes to take effect. To reload the contents of the files, run the following command: $ sudo sysctl --system

b

RHEL 9 must prevent IPv4 Internet Control Message Protocol (ICMP) redirect messages from being accepted.

CM-6 - Medium - CCI-000366 - V-257963 - SV-257963r1106328_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-253040

Vuln IDs

V-257963

Rule IDs

SV-257963r1106328_rule

ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages modify the host's route table and are unauthenticated. An illicit ICMP redirect message could result in a man-in-the-middle attack. This feature of the IPv4 protocol has few legitimate uses. It must be disabled unless absolutely required. 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 the directories in which they reside. 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-61704r1106326_chk

Verify RHEL 9 will not accept IPv4 ICMP redirect messages. Check the value of the default "accept_redirects" variables with the following command: $ sudo sysctl net.ipv4.conf.default.accept_redirects net.ipv4.conf.default.accept_redirects = 0 If the returned line does not have a value of "0", a line is not returned, or the line is commented out, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r net.ipv4.conf.default.accept_redirects /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: net.ipv4.conf.default.accept_redirects = 0 If "net.ipv4.conf.default.accept_redirects" is not set to "0", is missing, or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-61628r1106327_fix

Configure RHEL 9 to prevent IPv4 ICMP redirect messages from being accepted. Add or edit the following line in a system configuration file in the "/etc/sysctl.d/" directory: net.ipv4.conf.default.accept_redirects = 0 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf Load settings from all system configuration files with the following command: $ sudo sysctl --system

b

RHEL 9 must not forward IPv4 source-routed packets by default.

CM-6 - Medium - CCI-000366 - V-257964 - SV-257964r1106438_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-253045

Vuln IDs

V-257964

Rule IDs

SV-257964r1106438_rule

Source-routed packets allow the source of the packet to suggest routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures. This requirement applies only to the forwarding of source-routed traffic, such as when forwarding is enabled and the system is functioning as a router. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of the directories in which they reside. 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-61705r1106329_chk

Verify RHEL 9 does not accept IPv4 source-routed packets by default. Check the value of the accept source route variable with the following command: $ sudo sysctl net.ipv4.conf.default.accept_source_route net.ipv4.conf.default.accept_source_route = 0 If the returned line does not have a value of "0", a line is not returned, or the line is commented out, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r net.ipv4.conf.default.accept_source_route /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: net.ipv4.conf.default.accept_source_route = 0 If "net.ipv4.conf.default.accept_source_route" is not set to "0", is missing, or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-61629r1106330_fix

Configure RHEL 9 to not forward IPv4 source-routed packets by default. Add or edit the following line in a system configuration file in the "/etc/sysctl.d/" directory: net.ipv4.conf.default.accept_source_route=0 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf Load settings from all system configuration files with the following command: $ sudo sysctl --system

b

RHEL 9 must use a reverse-path filter for IPv4 network traffic when possible by default.

CM-6 - Medium - CCI-000366 - V-257965 - SV-257965r1106333_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-253050

Vuln IDs

V-257965

Rule IDs

SV-257965r1106333_rule

Enabling reverse path filtering drops packets with source addresses that should not have been able to be received on the interface on which they were received. It must not be used on systems that are routers for complicated networks, but is helpful for end hosts and routers serving small networks. 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 the directories in which they reside. 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-61706r1102078_chk

Verify RHEL 9 uses reverse path filtering on IPv4 interfaces with the following commands: $ sudo sysctl net.ipv4.conf.default.rp_filter net.ipv4.conf.default.rp_filter = 1 If the returned line does not have a value of "1", or a line is not returned, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r net.ipv4.conf.default.rp_filter /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf:net.ipv4.conf.default.rp_filter = 1 If "net.ipv4.conf.default.rp_filter" is not set to "1" or is missing, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-61630r1106332_fix

Configure RHEL 9 to use reverse path filtering on IPv4 interfaces by default. Add or edit the following line in a single system configuration file in the "/etc/sysctl.d/" directory: net.ipv4.conf.default.rp_filter = 1 Load settings from all system configuration files with the following command: $ sudo sysctl --system

b

RHEL 9 must not respond to Internet Control Message Protocol (ICMP) echoes sent to a broadcast address.

CM-6 - Medium - CCI-000366 - V-257966 - SV-257966r1106440_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-253055

Vuln IDs

V-257966

Rule IDs

SV-257966r1106440_rule

Responding to broadcast (ICMP) echoes facilitates network mapping and provides a vector for amplification attacks. Ignoring ICMP echo requests (pings) sent to broadcast or multicast addresses makes the system slightly more difficult to enumerate on the network. There are notable differences between Internet Protocol version 4 (IPv4) and Internet Protocol version 6 (IPv6). IPv6 does not implement the same method of broadcast as IPv4. Instead, IPv6 uses multicast addressing to the all-hosts multicast group. Refer to RFC4294 for an explanation of "IPv6 Node Requirements", which resulted in this difference between IPv4 and IPv6. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of the directories in which they reside. 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-61707r1106439_chk

Verify RHEL 9 does not respond to ICMP echoes sent to a broadcast address. Check the value of the "icmp_echo_ignore_broadcasts" variable with the following command: $ sudo sysctl net.ipv4.icmp_echo_ignore_broadcasts net.ipv4.icmp_echo_ignore_broadcasts = 1 If the returned line does not have a value of "1", a line is not returned, or the retuned line is commented out, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r net.ipv4.icmp_echo_ignore_broadcasts /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: net.ipv4.icmp_echo_ignore_broadcasts = 1 If "net.ipv4.icmp_echo_ignore_broadcasts" is not set to "1", is missing, or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-61631r1106334_fix

Configure RHEL 9 to not respond to IPv4 ICMP echoes sent to a broadcast address. Add or edit the following line in a system configuration file in the "/etc/sysctl.d/" directory: net.ipv4.icmp_echo_ignore_broadcasts=1 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf Load settings from all system configuration files with the following command: $ sudo sysctl --system

b

RHEL 9 must limit the number of bogus Internet Control Message Protocol (ICMP) response errors logs.

CM-6 - Medium - CCI-000366 - V-257967 - SV-257967r1106337_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-253060

Vuln IDs

V-257967

Rule IDs

SV-257967r1106337_rule

Some routers will send responses to broadcast frames that violate RFC-1122, which fills up a log file system with many useless error messages. An attacker may take advantage of this and attempt to flood the logs with bogus error logs. Ignoring bogus ICMP error responses reduces log size, although some activity would not be logged. 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 the directories in which they reside. 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-61708r1101999_chk

The runtime status of the net.ipv4.icmp_ignore_bogus_error_responses kernel parameter can be queried by running the following command: $ sudo sysctl net.ipv4.icmp_ignore_bogus_error_responses net.ipv4.icmp_ignore_bogus_error_responses = 1 If "net.ipv4.icmp_ignore_bogus_error_responses" is not set to "1", this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r net.ipv4.icmp_ignore_bogus_error_response /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf:net.ipv4.icmp_ignore_bogus_error_responses = 1 If "net.ipv4.icmp_ignore_bogus_error_response" is not set to "1" or is missing, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-61632r1106336_fix

Configure RHEL 9 to not log bogus ICMP errors: Add or edit the following line in a single system configuration file in the "/etc/sysctl.d/" directory: net.ipv4.icmp_ignore_bogus_error_responses = 1 Load settings from all system configuration files with the following command: $ sudo sysctl --system

b

RHEL 9 must not send Internet Control Message Protocol (ICMP) redirects.

CM-6 - Medium - CCI-000366 - V-257968 - SV-257968r1106339_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-253065

Vuln IDs

V-257968

Rule IDs

SV-257968r1106339_rule

ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages contain information from the system's route table possibly revealing portions of the network topology. The ability to send ICMP redirects is only appropriate for systems acting as routers. 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 the directories in which they reside. 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-61709r1102041_chk

Verify RHEL 9 does not IPv4 ICMP redirect messages. Check the value of the "all send_redirects" variables with the following command: $ sudo sysctl net.ipv4.conf.all.send_redirects net.ipv4.conf.all.send_redirects = 0 If the returned line does not have a value of "0", or a line is not returned, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r net.ipv4.conf.all.send_redirects /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: net.ipv4.conf.all.send_redirects = 0 If "net.ipv4.conf.all.send_redirects" is not set to "0", is missing or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-61633r1106338_fix

Configure RHEL 9 to not allow interfaces to perform IPv4 ICMP redirects. Add or edit the following line in a system configuration file in the "/etc/sysctl.d/" directory: net.ipv4.conf.all.send_redirects=0 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf Load settings from all system configuration files with the following command: $ sudo sysctl --system

b

RHEL 9 must not allow interfaces to perform Internet Control Message Protocol (ICMP) redirects by default.

CM-6 - Medium - CCI-000366 - V-257969 - SV-257969r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-253070

Vuln IDs

V-257969

Rule IDs

SV-257969r991589_rule

ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages contain information from the system's route table possibly revealing portions of the network topology. The ability to send ICMP redirects is only appropriate for systems acting as routers.

Checks: C-61710r942998_chk

Verify RHEL 9 does not allow interfaces to perform Internet Protocol version 4 (IPv4) ICMP redirects by default. Check the value of the "default send_redirects" variables with the following command: $ sudo sysctl net.ipv4.conf.default.send_redirects net.ipv4.conf.default.send_redirects=0 If the returned line does not have a value of "0", or a line is not returned, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo /usr/lib/systemd/systemd-sysctl --cat-config | egrep -v '^(#|;)' | grep -F net.ipv4.conf.default.send_redirects | tail -1 net.ipv4.conf.default.send_redirects = 0 If "net.ipv4.conf.default.send_redirects" is not set to "0" and is not documented with the information system security officer (ISSO) as an operational requirement or is missing, this is a finding.

Fix: F-61634r925893_fix

Configure RHEL 9 to not allow interfaces to perform Internet Protocol version 4 (IPv4) ICMP redirects by default. Add or edit the following line in a single system configuration file, in the "/etc/sysctl.d/" directory: net.ipv4.conf.default.send_redirects = 0 Load settings from all system configuration files with the following command: $ sudo sysctl --system

b

RHEL 9 must not enable IPv4 packet forwarding unless the system is a router.

CM-6 - Medium - CCI-000366 - V-257970 - SV-257970r1106442_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-253075

Vuln IDs

V-257970

Rule IDs

SV-257970r1106442_rule

Routing protocol daemons are typically used on routers to exchange network topology information with other routers. If this capability is used when not required, system network information may be unnecessarily transmitted across the network. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of the directories in which they reside. 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-61711r1106441_chk

Verify RHEL 9 is not performing IPv4 packet forwarding, unless the system is a router. Check that IPv4 forwarding is disabled using the following command: $ sudo sysctl net.ipv4.conf.all.forwarding net.ipv4.conf.all.forwarding = 0 If the IPv4 forwarding value is not "0" and is not documented with the information system security officer (ISSO) as an operational requirement, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r net.ipv4.conf.all.forwarding /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: net.ipv4.conf.all.forwarding = 0 If "net.ipv4.conf.all.forwarding" is not set to "0", is missing, or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-61635r1106341_fix

Configure RHEL 9 to not allow IPv4 packet forwarding, unless the system is a router. Add or edit the following line in a system configuration file in the "/etc/sysctl.d/" directory: net.ipv4.conf.all.forwarding=0 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf Load settings from all system configuration files with the following command: $ sudo sysctl --system

b

RHEL 9 must not accept router advertisements on all IPv6 interfaces.

CM-6 - Medium - CCI-000366 - V-257971 - SV-257971r1106444_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-254010

Vuln IDs

V-257971

Rule IDs

SV-257971r1106444_rule

Routing protocol daemons are typically used on routers to exchange network topology information with other routers. If this software is used when not required, system network information may be unnecessarily transmitted across the network. An illicit router advertisement message could result in a man-in-the-middle attack. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of the directories in which they reside. 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-61712r1106443_chk

Verify RHEL 9 does not accept router advertisements on all IPv6 interfaces, unless the system is a router. Note: If IPv6 is disabled on the system, this requirement is not applicable. Check to see if router advertisements are not accepted by using the following command: $ sudo sysctl net.ipv6.conf.all.accept_ra net.ipv6.conf.all.accept_ra = 0 If the "accept_ra" value is not "0" and is not documented with the information system security officer (ISSO) as an operational requirement, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r net.ipv6.conf.all.accept_ra /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: net.ipv6.conf.all.accept_ra = 0 If "net.ipv6.conf.all.accept_ra" is not set to "0", is missing, or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-61636r1106343_fix

Configure RHEL 9 to not accept router advertisements on all IPv6 interfaces unless the system is a router. Add or edit the following line in a system configuration file in the "/etc/sysctl.d/" directory: net.ipv6.conf.all.accept_ra=0 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf Load settings from all system configuration files with the following command: $ sudo sysctl --system

b

RHEL 9 must ignore IPv6 Internet Control Message Protocol (ICMP) redirect messages.

CM-6 - Medium - CCI-000366 - V-257972 - SV-257972r1106446_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-254015

Vuln IDs

V-257972

Rule IDs

SV-257972r1106446_rule

ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages modify the host's route table and are unauthenticated. An illicit ICMP redirect message could result in a man-in-the-middle attack. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of the directories in which they reside. 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-61713r1106445_chk

Verify RHEL 9 ignores IPv6 ICMP redirect messages. Note: If IPv6 is disabled on the system, this requirement is not applicable. Check the value of the "accept_redirects" variables with the following command: $ sudo sysctl net.ipv6.conf.all.accept_redirects net.ipv6.conf.all.accept_redirects = 0 If the returned line does not have a value of "0", a line is not returned, or the line is commented out, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r net.ipv6.conf.all.accept_redirects /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: net.ipv6.conf.all.accept_redirects = 0 If "net.ipv6.conf.all.accept_redirects" is not set to "0", is missing, or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-61637r1106345_fix

Configure RHEL 9 to ignore IPv6 ICMP redirect messages. Add or edit the following line in a system configuration file in the "/etc/sysctl.d/" directory: net.ipv6.conf.all.accept_redirects = 0 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf Load settings from all system configuration files with the following command: $ sudo sysctl --system

b

RHEL 9 must not forward IPv6 source-routed packets.

CM-6 - Medium - CCI-000366 - V-257973 - SV-257973r1106448_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-254020

Vuln IDs

V-257973

Rule IDs

SV-257973r1106448_rule

Source-routed packets allow the source of the packet to suggest that routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures. This requirement applies only to the forwarding of source-routed traffic, such as when forwarding is enabled and the system is functioning as a router. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of the directories in which they reside. 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-61714r1106447_chk

Verify RHEL 9 does not accept IPv6 source-routed packets. Note: If IPv6 is disabled on the system, this requirement is not applicable. Check the value of the accept source route variable with the following command: $ sudo sysctl net.ipv6.conf.all.accept_source_route net.ipv6.conf.all.accept_source_route = 0 If the returned line does not have a value of "0", a line is not returned, or the line is commented out, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r net.ipv6.conf.all.accept_source_route /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: net.ipv6.conf.all.accept_source_route = 0 If "net.ipv6.conf.all.accept_source_route" is not set to "0", is missing, or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-61638r1106347_fix

Configure RHEL 9 to not forward IPv6 source-routed packets. Add or edit the following line in a system configuration file in the "/etc/sysctl.d/" directory: net.ipv6.conf.all.accept_source_route=0 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf Load settings from all system configuration files with the following command: $ sudo sysctl --system

b

RHEL 9 must not enable IPv6 packet forwarding unless the system is a router.

CM-6 - Medium - CCI-000366 - V-257974 - SV-257974r1106450_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-254025

Vuln IDs

V-257974

Rule IDs

SV-257974r1106450_rule

Routing protocol daemons are typically used on routers to exchange network topology information with other routers. If this software is used when not required, system network information may be unnecessarily transmitted across the network. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of the directories in which they reside. 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-61715r1106449_chk

Verify RHEL 9 is not performing IPv6 packet forwarding, unless the system is a router. Note: If IPv6 is disabled on the system, this requirement is not applicable. Check that IPv6 forwarding is disabled using the following commands: $ sudo sysctl net.ipv6.conf.all.forwarding net.ipv6.conf.all.forwarding = 0 If the IPv6 forwarding value is not "0" and is not documented with the information system security officer (ISSO) as an operational requirement, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r net.ipv6.conf.all.forwarding /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: net.ipv6.conf.all.forwarding = 0 If "net.ipv6.conf.all.forwarding" is not set to "0", is missing, or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-61639r1106349_fix

Configure RHEL 9 to not allow IPv6 packet forwarding, unless the system is a router. Add or edit the following line in a system configuration file in the "/etc/sysctl.d/" directory: net.ipv6.conf.all.forwarding=0 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf Load settings from all system configuration files with the following command: $ sudo sysctl --system

b

RHEL 9 must not accept router advertisements on all IPv6 interfaces by default.

CM-6 - Medium - CCI-000366 - V-257975 - SV-257975r1106452_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-254030

Vuln IDs

V-257975

Rule IDs

SV-257975r1106452_rule

Routing protocol daemons are typically used on routers to exchange network topology information with other routers. If this software is used when not required, system network information may be unnecessarily transmitted across the network. An illicit router advertisement message could result in a man-in-the-middle attack. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of the directories in which they reside. 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-61716r1106451_chk

Verify RHEL 9 does not accept router advertisements on all IPv6 interfaces by default, unless the system is a router. Note: If IPv6 is disabled on the system, this requirement is not applicable. Check to see if router advertisements are not accepted by default by using the following command: $ sudo sysctl net.ipv6.conf.default.accept_ra net.ipv6.conf.default.accept_ra = 0 If the "accept_ra" value is not "0" and is not documented with the information system security officer (ISSO) as an operational requirement, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r net.ipv6.conf.default.accept_ra /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: net.ipv6.conf.default.accept_ra = 0 If "net.ipv6.conf.default.accept_ra" is not set to "0", is missing, or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-61640r1106351_fix

Configure RHEL 9 to not accept router advertisements on all IPv6 interfaces by default unless the system is a router. Add or edit the following line in a system configuration file in the "/etc/sysctl.d/" directory: net.ipv6.conf.default.accept_ra=0 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf Load settings from all system configuration files with the following command: $ sudo sysctl --system

b

RHEL 9 must prevent IPv6 Internet Control Message Protocol (ICMP) redirect messages from being accepted.

CM-6 - Medium - CCI-000366 - V-257976 - SV-257976r1106454_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-254035

Vuln IDs

V-257976

Rule IDs

SV-257976r1106454_rule

ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages modify the host's route table and are unauthenticated. An illicit ICMP redirect message could result in a man-in-the-middle attack. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of the directories in which they reside. 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-61717r1106453_chk

Verify RHEL 9 will not accept IPv6 ICMP redirect messages. Note: If IPv6 is disabled on the system, this requirement is not applicable. Check the value of the default "accept_redirects" variables with the following command: $ sudo sysctl net.ipv6.conf.default.accept_redirects net.ipv6.conf.default.accept_redirects = 0 If the returned line does not have a value of "0", a line is not returned, or the line is commented out, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r net.ipv6.conf.default.accept_redirects /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: net.ipv6.conf.default.accept_redirects = 0 If "net.ipv6.conf.default.accept_redirects" is not set to "0", is missing, or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-61641r1106353_fix

Configure RHEL 9 to prevent IPv6 ICMP redirect messages from being accepted. Add or edit the following line in a system configuration file in the "/etc/sysctl.d/" directory: net.ipv6.conf.default.accept_redirects = 0 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf Load settings from all system configuration files with the following command: $ sudo sysctl --system

b

RHEL 9 must not forward IPv6 source-routed packets by default.

CM-6 - Medium - CCI-000366 - V-257977 - SV-257977r1106456_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-254040

Vuln IDs

V-257977

Rule IDs

SV-257977r1106456_rule

Source-routed packets allow the source of the packet to suggest that routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures. This requirement applies only to the forwarding of source-routed traffic, such as when forwarding is enabled and the system is functioning as a router. Accepting source-routed packets in the IPv6 protocol has few legitimate uses. It must be disabled unless it is absolutely required. 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 the directories in which they reside. 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-61718r1106455_chk

Verify RHEL 9 does not accept IPv6 source-routed packets by default. Note: If IPv6 is disabled on the system, this requirement is not applicable. Check the value of the accept source route variable with the following command: $ sudo sysctl net.ipv6.conf.default.accept_source_route net.ipv6.conf.default.accept_source_route = 0 If the returned line does not have a value of "0", a line is not returned, or the line is commented out, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r net.ipv6.conf.default.accept_source_route /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: net.ipv6.conf.default.accept_source_route = 0 If "net.ipv6.conf.default.accept_source_route" is not set to "0", is missing, or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix: F-61642r1106355_fix

Configure RHEL 9 to not forward IPv6 source-routed packets by default. Add or edit the following line in a system configuration file in the "/etc/sysctl.d/" directory: net.ipv6.conf.default.accept_source_route=0 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf Load settings from all system configuration files with the following command: $ sudo sysctl --system

b

All RHEL 9 networked systems must have SSH installed.

SC-8 - Medium - CCI-002418 - V-257978 - SV-257978r1045013_rule

RMF Control

SC-8

Severity

M

CCI

CCI-002418

Version

RHEL-09-255010

Vuln IDs

V-257978

Rule IDs

SV-257978r1045013_rule

Without protection of the transmitted information, confidentiality and integrity may be compromised because unprotected communications can be intercepted and either read or altered. This requirement applies to both internal and external networks and all types of information system components from which information can be transmitted (e.g., servers, mobile devices, notebook computers, printers, copiers, scanners, and facsimile machines). Communication paths outside the physical protection of a controlled boundary are exposed to the possibility of interception and modification. Protecting the confidentiality and integrity of organizational information can be accomplished by physical means (e.g., employing physical distribution systems) or by logical means (e.g., employing cryptographic techniques). If physical means of protection are employed, then logical means (cryptography) do not have to be employed, and vice versa. Satisfies: SRG-OS-000423-GPOS-00187, SRG-OS-000424-GPOS-00188, SRG-OS-000425-GPOS-00189, SRG-OS-000426-GPOS-00190

Checks: C-61719r1045012_chk

Verify that RHEL 9 has the openssh-server package installed with the following command: $ dnf list --installed openssh-server Example output: openssh-server.x86_64 8.7p1-8.el9 If the "openssh-server" package is not installed, this is a finding.

Fix: F-61643r925920_fix

The openssh-server package can be installed with the following command: $ sudo dnf install openssh-server

b

All RHEL 9 networked systems must have and implement SSH to protect the confidentiality and integrity of transmitted and received information, as well as information during preparation for transmission.

SC-8 - Medium - CCI-002418 - V-257979 - SV-257979r958908_rule

RMF Control

SC-8

Severity

M

CCI

CCI-002418

Version

RHEL-09-255015

Vuln IDs

V-257979

Rule IDs

SV-257979r958908_rule

Without protection of the transmitted information, confidentiality and integrity may be compromised because unprotected communications can be intercepted and either read or altered. This requirement applies to both internal and external networks and all types of information system components from which information can be transmitted (e.g., servers, mobile devices, notebook computers, printers, copiers, scanners, and facsimile machines). Communication paths outside the physical protection of a controlled boundary are exposed to the possibility of interception and modification. Protecting the confidentiality and integrity of organizational information can be accomplished by physical means (e.g., employing physical distribution systems) or by logical means (e.g., employing cryptographic techniques). If physical means of protection are employed, then logical means (cryptography) do not have to be employed, and vice versa. Satisfies: SRG-OS-000423-GPOS-00187, SRG-OS-000424-GPOS-00188, SRG-OS-000425-GPOS-00189, SRG-OS-000426-GPOS-00190

Checks: C-61720r925922_chk

Verify that "sshd" is active with the following command: $ systemctl is-active sshd active If the "sshd" service is not active, this is a finding.

Fix: F-61644r925923_fix

To enable the sshd service run the following command: $ systemctl enable --now sshd

b

RHEL 9 must have the openssh-clients package installed.

CM-6 - Medium - CCI-000366 - V-257980 - SV-257980r1045016_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-255020

Vuln IDs

V-257980

Rule IDs

SV-257980r1045016_rule

This package includes utilities to make encrypted connections and transfer files securely to SSH servers.

Checks: C-61721r1045014_chk

Verify that RHEL 9 has the openssh-clients package installed with the following command: $ dnf list --installed openssh-clients Example output: openssh-clients.x86_64 8.7p1-8.el9 If the "openssh-clients" package is not installed, this is a finding.

Fix: F-61645r1045015_fix

The openssh-clients package can be installed with the following command: $ sudo dnf install openssh-clients

b

RHEL 9 must display the Standard Mandatory DOD Notice and Consent Banner before granting local or remote access to the system via a SSH logon.

AC-8 - Medium - CCI-000048 - V-257981 - SV-257981r1101970_rule

RMF Control

AC-8

Severity

M

CCI

Version

RHEL-09-255025

Vuln IDs

V-257981

Rule IDs

SV-257981r1101970_rule

The warning message reinforces policy awareness during the logon process and facilitates possible legal action against attackers. Alternatively, systems whose ownership should not be obvious should ensure usage of a banner that does not provide easy attribution. Satisfies: SRG-OS-000023-GPOS-00006, SRG-OS-000228-GPOS-00088

Checks: C-61722r1101969_chk

Verify any SSH connection to RHEL 9 displays the Standard Mandatory DOD Notice and Consent Banner before granting access to the system. Check for the location of the banner file being used with the following command: $ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH '^\s*banner' /etc/ssh/sshd_config.d/80-bannerPointer.conf: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.

Fix: F-61646r1045018_fix

Configure RHEL 9 to display the Standard Mandatory DOD Notice and Consent Banner before granting access to the system via ssh. Edit the "etc/ssh/sshd_config" file or a file in "/etc/ssh/sshd_config.d" 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

b

RHEL 9 must log SSH connection attempts and failures to the server.

AC-17 - Medium - CCI-000067 - V-257982 - SV-257982r1045021_rule

RMF Control

AC-17

Severity

M

CCI

CCI-000067

Version

RHEL-09-255030

Vuln IDs

V-257982

Rule IDs

SV-257982r1045021_rule

SSH provides several logging levels with varying amounts of verbosity. "DEBUG" is specifically not recommended other than strictly for debugging SSH communications since it provides so much data that it is difficult to identify important security information. "INFO" or "VERBOSE" level is the basic level that only records login activity of SSH users. In many situations, such as Incident Response, it is important to determine when a particular user was active on a system. The logout record can eliminate those users who disconnected, which helps narrow the field.

Checks: C-61723r952174_chk

Verify that RHEL 9 logs SSH connection attempts and failures to the server. Check what the SSH daemon's "LogLevel" option is set to 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*loglevel' LogLevel VERBOSE If a value of "VERBOSE" is not returned or the line is commented out or missing, this is a finding.

Fix: F-61647r1045020_fix

Configure RHEL 9 to log connection attempts add or modify the following line in "/etc/ssh/sshd_config" or in a file in "/etc/ssh/sshd_config.d". LogLevel VERBOSE Restart the SSH daemon for the settings to take effect: $ sudo systemctl restart sshd.service

b

RHEL 9 SSHD must accept public key authentication.

IA-2 - Medium - CCI-000765 - V-257983 - SV-257983r1045024_rule

RMF Control

IA-2

Severity

M

CCI

CCI-000765

Version

RHEL-09-255035

Vuln IDs

V-257983

Rule IDs

SV-257983r1045024_rule

Without the use of multifactor authentication, the ease of access to privileged functions is greatly increased. Multifactor authentication requires using two or more factors to achieve authentication. A privileged account is defined as an information system account with authorizations of a privileged user. A DOD common access card (CAC) with DOD-approved PKI is an example of multifactor authentication. Satisfies: SRG-OS-000105-GPOS-00052, SRG-OS-000106-GPOS-00053, SRG-OS-000107-GPOS-00054, SRG-OS-000108-GPOS-00055

Checks: C-61724r1045022_chk

Note: If the system administrator demonstrates the use of an approved alternate multifactor authentication method, this requirement is Not Applicable. Verify that RHEL 9 SSH daemon accepts public key encryption 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*pubkeyauthentication' PubkeyAuthentication yes If "PubkeyAuthentication" is set to no, the line is commented out, or the line is missing, this is a finding.

Fix: F-61648r1045023_fix

To configure the system, add or modify the following line in "/etc/ssh/sshd_config" or in a file in "/etc/ssh/sshd_config.d". PubkeyAuthentication yes Restart the SSH daemon for the settings to take effect: $ sudo systemctl restart sshd.service

c

RHEL 9 SSHD must not allow blank passwords.

IA-2 - High - CCI-000766 - V-257984 - SV-257984r1045026_rule

RMF Control

IA-2

Severity

H

CCI

CCI-000766

Version

RHEL-09-255040

Vuln IDs

V-257984

Rule IDs

SV-257984r1045026_rule

If an account has an empty password, anyone could log on and run commands with the privileges of that account. Accounts with empty passwords should never be used in operational environments. Satisfies: SRG-OS-000106-GPOS-00053, SRG-OS-000480-GPOS-00229, SRG-OS-000480-GPOS-00227

Checks: C-61725r1014847_chk

Verify that RHEL 9 remote access using SSH prevents logging on with a blank password 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*permitemptypasswords' PermitEmptyPasswords no If the "PermitEmptyPasswords" keyword is set to "yes", is missing, or is commented out, this is a finding.

Fix: F-61649r1045025_fix

To configure the system to prevent SSH users from logging on with blank passwords edit the following line in "/etc/ssh/sshd_config" or in a file in "/etc/ssh/sshd_config.d": PermitEmptyPasswords no Restart the SSH daemon for the settings to take effect: $ sudo systemctl restart sshd.service

b

RHEL 9 must not permit direct logons to the root account using remote access via SSH.

Medium - CCI-004045 - V-257985 - SV-257985r1069364_rule

RMF Control

Severity

M

CCI

CCI-004045

Version

RHEL-09-255045

Vuln IDs

V-257985

Rule IDs

SV-257985r1069364_rule

Even though the communications channel may be encrypted, an additional layer of security is gained by extending the policy of not logging directly on as root. In addition, logging in with a user-specific account provides individual accountability of actions performed on the system and also helps to minimize direct attack attempts on root's password. Satisfies: SRG-OS-000109-GPOS-00056, SRG-OS-000480-GPOS-00227

Checks: C-61726r1069363_chk

Verify RHEL 9 remote access using SSH prevents users from logging on directly as "root" with the following command: $ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH '^\s*permitrootlogin' PermitRootLogin no If the "PermitRootLogin" keyword is set to any value other than "no", is missing, or is commented out, this is a finding.

Fix: F-61650r1045027_fix

To configure the system to prevent SSH users from logging on directly as root add or modify the following line in "/etc/ssh/sshd_config" or in a file in "/etc/ssh/sshd_config.d". PermitRootLogin no Restart the SSH daemon for the settings to take effect: $ sudo systemctl restart sshd.service

c

RHEL 9 must enable the Pluggable Authentication Module (PAM) interface for SSHD.

MA-4 - High - CCI-000877 - V-257986 - SV-257986r1045030_rule

RMF Control

MA-4

Severity

H

CCI

CCI-000877

Version

RHEL-09-255050

Vuln IDs

V-257986

Rule IDs

SV-257986r1045030_rule

When UsePAM is set to "yes", PAM runs through account and session types properly. This is important when restricted access to services based off of IP, time, or other factors of the account is needed. Additionally, this ensures users can inherit certain environment variables on login or disallow access to the server.

Checks: C-61727r952182_chk

Verify the RHEL 9 SSHD is configured to allow for the UsePAM interface 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*usepam' UsePAM yes If the "UsePAM" keyword is set to "no", is missing, or is commented out, this is a finding.

Fix: F-61651r1045029_fix

Configure the RHEL 9 SSHD to use the UsePAM interface by adding or modifying the following line in "/etc/ssh/sshd_config" or in a file in "/etc/ssh/sshd_config.d". UsePAM yes Restart the SSH daemon for the settings to take effect: $ sudo systemctl restart sshd.service

b

The RHEL 9 SSH server must be configured to use only DOD-approved encryption ciphers employing FIPS 140-3 validated cryptographic hash algorithms to protect the confidentiality of SSH server connections.

AC-17 - Medium - CCI-001453 - V-257989 - SV-257989r1051240_rule

RMF Control

AC-17

Severity

M

CCI

Version

RHEL-09-255065

Vuln IDs

V-257989

Rule IDs

SV-257989r1051240_rule

Without cryptographic integrity protections, information can be altered by unauthorized users without detection. Remote access (e.g., RDP) is access to DOD nonpublic information systems by an authorized user (or an information system) communicating through an external, nonorganization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless. Cryptographic mechanisms used for protecting the integrity of information include, for example, signed hash functions using asymmetric cryptography enabling distribution of the public key to verify the hash information while maintaining the confidentiality of the secret key used to generate the hash. RHEL 9 incorporates systemwide crypto policies by default. The SSH configuration file has no effect on the ciphers, MACs, or algorithms unless specifically defined in the /etc/sysconfig/sshd file. The employed algorithms can be viewed in the /etc/crypto-policies/back-ends/opensshserver.config file.

Checks: C-61730r1051238_chk

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

Fix: F-61654r1051239_fix

Configure the RHEL 9 SSH server to use only ciphers employing FIPS 140-3 approved algorithms. Reinstall crypto-policies with the following command: $ sudo dnf -y reinstall crypto-policies Set the crypto-policy to FIPS with the following command: $ sudo update-crypto-policies --set FIPS Setting system policy to FIPS Note: Systemwide crypto policies are applied on application startup. It is recommended to restart the system for the change of policies to fully take place.

b

The RHEL 9 SSH server must be configured to use only Message Authentication Codes (MACs) employing FIPS 140-3 validated cryptographic hash algorithms to protect the confidentiality of SSH server connections.

AC-17 - Medium - CCI-001453 - V-257991 - SV-257991r1051246_rule

RMF Control

AC-17

Severity

M

CCI

Version

RHEL-09-255075

Vuln IDs

V-257991

Rule IDs

SV-257991r1051246_rule

Without cryptographic integrity protections, information can be altered by unauthorized users without detection. Remote access (e.g., RDP) is access to DOD nonpublic information systems by an authorized user (or an information system) communicating through an external, nonorganization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless. Cryptographic mechanisms used for protecting the integrity of information include, for example, signed hash functions using asymmetric cryptography enabling distribution of the public key to verify the hash information while maintaining the confidentiality of the secret key used to generate the hash. RHEL 9 incorporates systemwide crypto policies by default. The SSH configuration file has no effect on the ciphers, MACs, or algorithms unless specifically defined in the /etc/sysconfig/sshd file. The employed algorithms can be viewed in the /etc/crypto-policies/back-ends/opensshserver.config file.

Checks: C-61732r1051244_chk

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

Fix: F-61656r1051245_fix

Configure the RHEL 9 SSH server to use only MACs employing FIPS 140-3 approved algorithms. Reinstall crypto-policies with the following command: $ sudo dnf -y reinstall crypto-policies Set the crypto-policy to FIPS with the following command: $ sudo update-crypto-policies --set FIPS Setting system policy to FIPS Note: Systemwide crypto policies are applied on application startup. It is recommended to restart the system for the change of policies to fully take place.

b

RHEL 9 must not allow a noncertificate trusted host SSH logon to the system.

CM-6 - Medium - CCI-000366 - V-257992 - SV-257992r1045047_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-255080

Vuln IDs

V-257992

Rule IDs

SV-257992r1045047_rule

SSH trust relationships mean a compromise on one host can allow an attacker to move trivially to other hosts.

Checks: C-61733r952189_chk

Verify the operating system does not allow a noncertificate trusted host SSH logon to the system 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*hostbasedauthentication' HostbasedAuthentication no If the "HostbasedAuthentication" keyword is not set to "no", is missing, or is commented out, this is a finding. If the required value is not set, this is a finding.

Fix: F-61657r1045046_fix

To configure RHEL 9 to not allow a noncertificate trusted host SSH logon to the system, add or modify the following line in "/etc/ssh/sshd_config" or in a file in "/etc/ssh/sshd_config.d". HostbasedAuthentication no Restart the SSH daemon for the settings to take effect: $ sudo systemctl restart sshd.service

b

RHEL 9 must not allow users to override SSH environment variables.

CM-6 - Medium - CCI-000366 - V-257993 - SV-257993r1045049_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-255085

Vuln IDs

V-257993

Rule IDs

SV-257993r1045049_rule

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

Checks: C-61734r952191_chk

Verify that unattended or automatic logon via SSH is disabled with the following command: $ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH '^\s*permituserenvironment' PermitUserEnvironment no If "PermitUserEnvironment" is set to "yes", is missing completely, or is commented out, this is a finding. If the required value is not set, this is a finding.

Fix: F-61658r1045048_fix

Configure the RHEL 9 SSH daemon to not allow unattended or automatic logon to the system by editing the following line in the "/etc/ssh/sshd_config" or in a file in "/etc/ssh/sshd_config.d": PermitUserEnvironment no Restart the SSH daemon for the setting to take effect: $ sudo systemctl restart sshd.service

b

RHEL 9 must force a frequent session key renegotiation for SSH connections to the server.

AC-17 - Medium - CCI-000068 - V-257994 - SV-257994r1045051_rule

RMF Control

AC-17

Severity

M

CCI

CCI-000068

Version

RHEL-09-255090

Vuln IDs

V-257994

Rule IDs

SV-257994r1045051_rule

Without protection of the transmitted information, confidentiality and integrity may be compromised because unprotected communications can be intercepted and either read or altered. This requirement applies to both internal and external networks and all types of information system components from which information can be transmitted (e.g., servers, mobile devices, notebook computers, printers, copiers, scanners, and facsimile machines). Communication paths outside the physical protection of a controlled boundary are exposed to the possibility of interception and modification. Protecting the confidentiality and integrity of organizational information can be accomplished by physical means (e.g., employing physical distribution systems) or by logical means (e.g., employing cryptographic techniques). If physical means of protection are employed, then logical means (cryptography) do not have to be employed, and vice versa. Session key regeneration limits the chances of a session key becoming compromised. Satisfies: SRG-OS-000423-GPOS-00187, SRG-OS-000033-GPOS-00014, SRG-OS-000424-GPOS-00188

Checks: C-61735r952193_chk

Verify the SSH server is configured to force frequent session key renegotiation with the following command: $ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH '^\s*rekeylimit' RekeyLimit 1G 1h If "RekeyLimit" does not have a maximum data amount and maximum time defined, is missing, or is commented out, this is a finding.

Fix: F-61659r1045050_fix

Configure RHEL 9 to force a frequent session key renegotiation for SSH connections to the server by adding or modifying the following line in the "/etc/ssh/sshd_config" or in a file in "/etc/ssh/sshd_config.d": RekeyLimit 1G 1h Restart the SSH daemon for the settings to take effect. $ sudo systemctl restart sshd.service

b

RHEL 9 must be configured so that all network connections associated with SSH traffic terminate after becoming unresponsive.

SC-10 - Medium - CCI-001133 - V-257995 - SV-257995r1045053_rule

RMF Control

SC-10

Severity

M

CCI

CCI-001133

Version

RHEL-09-255095

Vuln IDs

V-257995

Rule IDs

SV-257995r1045053_rule

Terminating an unresponsive SSH session within a short time period reduces the window of opportunity for unauthorized personnel to take control of a management session enabled on the console or console port that has been left unattended. In addition, quickly terminating an idle SSH session will also free up resources committed by the managed network element. Terminating network connections associated with communications sessions includes, for example, deallocating associated TCP/IP address/port pairs at the operating system level and deallocating networking assignments at the application level if multiple application sessions are using a single operating system-level network connection. This does not mean the operating system terminates all sessions or network access; it only ends the unresponsive session and releases the resources associated with that session. RHEL 9 utilizes /etc/ssh/sshd_config for configurations of OpenSSH. Within the sshd_config, the product of the values of "ClientAliveInterval" and "ClientAliveCountMax" are used to establish the inactivity threshold. The "ClientAliveInterval" is a timeout interval in seconds, after which if no data has been received from the client, sshd will send a message through the encrypted channel to request a response from the client. The "ClientAliveCountMax" is the number of client alive messages that may be sent without sshd receiving any messages back from the client. If this threshold is met, sshd will disconnect the client. For more information on these settings and others, refer to the sshd_config man pages. Satisfies: SRG-OS-000163-GPOS-00072, SRG-OS-000279-GPOS-00109

Checks: C-61736r952195_chk

Verify the "ClientAliveCountMax" is set to "1" by performing the following command: $ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH '^\s*clientalivecountmax' ClientAliveCountMax 1 If "ClientAliveCountMax" does not exist, is not set to a value of "1" in "/etc/ssh/sshd_config", or is commented out, this is a finding.

Fix: F-61660r1045052_fix

Note: This setting must be applied in conjunction with RHEL-09-255100 to function correctly. Configure the SSH server to terminate a user session automatically after the SSH client has become unresponsive. Modify or append the following lines in the "/etc/ssh/sshd_config" or in a file in "/etc/ssh/sshd_config.d": ClientAliveCountMax 1 For the changes to take effect, the SSH daemon must be restarted. $ sudo systemctl restart sshd.service

b

RHEL 9 must be configured so that all network connections associated with SSH traffic are terminated after 10 minutes of becoming unresponsive.

SC-10 - Medium - CCI-001133 - V-257996 - SV-257996r1134915_rule

RMF Control

SC-10

Severity

M

CCI

CCI-001133

Version

RHEL-09-255100

Vuln IDs

V-257996

Rule IDs

SV-257996r1134915_rule

Terminating an unresponsive SSH session within a short time period reduces the window of opportunity for unauthorized personnel to take control of a management session enabled on the console or console port that has been left unattended. In addition, quickly terminating an idle SSH session will also free up resources committed by the managed network element. Terminating network connections associated with communications sessions includes, for example, deallocating associated TCP/IP address/port pairs at the operating system level and deallocating networking assignments at the application level if multiple application sessions are using a single operating system-level network connection. This does not mean the operating system terminates all sessions or network access; it only ends the unresponsive session and releases the resources associated with that session. RHEL 9 utilizes /etc/ssh/sshd_config for configurations of OpenSSH. Within the sshd_config, the product of the values of "ClientAliveInterval" and "ClientAliveCountMax" are 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, SRG-OS-000395-GPOS-00175

Checks: C-61737r1134914_chk

Verify the "ClientAliveInterval" variable is set to a value of "600" or less by performing the following command: $ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH '^\s*clientaliveinterval' /etc/ssh/sshd_config.d/ClientAliveInterval.conf:ClientAliveInterval 600 Verify the runtime value of "ClientAliveInterval" with the following command: $ sudo sshd -T | grep -i clientaliveinterval clientaliveinterval 600 If "ClientAliveInterval" does not exist, does not have a value of "600" or less in "/etc/ssh/sshd_config", or is commented out, this is a finding.

Fix: F-61661r1045054_fix

Note: This setting must be applied in conjunction with RHEL-09-255095 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" or in a file in "/etc/ssh/sshd_config.d": ClientAliveInterval 600 For the changes to take effect, the SSH daemon must be restarted. $ sudo systemctl restart sshd.service

b

RHEL 9 SSH server configuration file must be group-owned by root.

CM-6 - Medium - CCI-000366 - V-257997 - SV-257997r1069370_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-255105

Vuln IDs

V-257997

Rule IDs

SV-257997r1069370_rule

Service configuration files enable or disable features of their respective services, which if configured incorrectly, can lead to insecure and vulnerable configurations. Therefore, service configuration files must be owned by the correct group to prevent unauthorized changes.

Checks: C-61738r1045056_chk

Verify the group ownership of the "/etc/ssh/sshd_config" file and the contents of "/etc/ssh/sshd_config.d" with the following command: $ sudo find /etc/ssh/sshd_config /etc/ssh/sshd_config.d -exec stat -c "%G %n" {} \; root /etc/ssh/sshd_config root /etc/ssh/sshd_config.d root /etc/ssh/sshd_config.d/50-cloud-init.conf root /etc/ssh/sshd_config.d/50-redhat.conf If the "/etc/ssh/sshd_config" file or "/etc/ssh/sshd_config.d" or any files in the sshd_config.d directory do not have a group owner of "root", this is a finding.

Fix: F-61662r1069369_fix

Configure the "/etc/ssh/sshd_config" file and the contents of "/etc/ssh/sshd_config.d" to be group-owned by root with the following command: $ sudo chgrp root /etc/ssh/sshd_config /etc/ssh/sshd_config.d

b

The RHEL 9 SSH server configuration file must be owned by root.

CM-6 - Medium - CCI-000366 - V-257998 - SV-257998r1082181_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-255110

Vuln IDs

V-257998

Rule IDs

SV-257998r1082181_rule

Service configuration files enable or disable features of their respective services, which if configured incorrectly, can lead to insecure and vulnerable configurations. Therefore, service configuration files must be owned by the correct group to prevent unauthorized changes.

Checks: C-61739r1082179_chk

Verify the ownership of the "/etc/ssh/sshd_config" file and the contents of "/etc/ssh/sshd_config.d" with the following command: $ sudo find /etc/ssh/sshd_config /etc/ssh/sshd_config.d -exec stat -c "%U %n" {} \; root /etc/ssh/sshd_config root /etc/ssh/sshd_config.d root /etc/ssh/sshd_config.d/50-cloud-init.conf root /etc/ssh/sshd_config.d/50-redhat.conf If the "/etc/ssh/sshd_config" file or "/etc/ssh/sshd_config.d" or any files in the "sshd_config.d" directory do not have an owner of "root", this is a finding.

Fix: F-61663r1082180_fix

Configure the "/etc/ssh/sshd_config" file and the contents of "/etc/ssh/sshd_config.d" to be owned by root with the following command: $ sudo chown -R root /etc/ssh/sshd_config /etc/ssh/sshd_config.d

b

RHEL 9 SSH server configuration files' permissions must not be modified.

CM-6 - Medium - CCI-000366 - V-257999 - SV-257999r1134918_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-255115

Vuln IDs

V-257999

Rule IDs

SV-257999r1134918_rule

Service configuration files enable or disable features of their respective services, that if configured incorrectly, can lead to insecure and vulnerable configurations. Therefore, service configuration files must have correct permissions (owner, group owner, mode) to prevent unauthorized changes.

Checks: C-61740r1134916_chk

Verify the permissions of the "/etc/ssh/sshd_config" file with the following command: $ sudo rpm --verify openssh-server | awk '! ($2 == "c" && $1 ~ /^.\..\.\.\.\..\./) {print $0}' If the command returns any output, this is a finding.

Fix: F-61664r1134917_fix

Run the following commands to restore the correct permissions of OpenSSH server configuration files: $ rpm --setugids openssh-server $ rpm --setperms openssh-server

b

RHEL 9 SSH private host key files must have mode 0640 or less permissive.

CM-6 - Medium - CCI-000366 - V-258000 - SV-258000r1045063_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-255120

Vuln IDs

V-258000

Rule IDs

SV-258000r1045063_rule

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

Checks: C-61741r1045062_chk

Verify the SSH private host key files have a mode of "0640" or less permissive with the following command: $ stat -c "%a %n" /etc/ssh/*_key 640 /etc/ssh/ssh_host_dsa_key 640 /etc/ssh/ssh_host_ecdsa_key 640 /etc/ssh/ssh_host_ed25519_key 640 /etc/ssh/ssh_host_rsa_key If any private host key file has a mode more permissive than "0640", this is a finding.

Fix: F-61665r925986_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 Restart the SSH daemon for the changes to take effect: $ sudo systemctl restart sshd.service

b

RHEL 9 SSH public host key files must have mode 0644 or less permissive.

CM-6 - Medium - CCI-000366 - V-258001 - SV-258001r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-255125

Vuln IDs

V-258001

Rule IDs

SV-258001r991589_rule

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

Checks: C-61742r925988_chk

Verify the SSH public host key files have a mode of "0644" or less permissive with the following command: Note: SSH public key files may be found in other directories on the system depending on the installation. $ sudo stat -c "%a %n" /etc/ssh/*.pub 644 /etc/ssh/ssh_host_dsa_key.pub 644 /etc/ssh/ssh_host_ecdsa_key.pub 644 /etc/ssh/ssh_host_ed25519_key.pub 644 /etc/ssh/ssh_host_rsa_key.pub If any key.pub file has a mode more permissive than "0644", this is a finding.

Fix: F-61666r925989_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 Restart the SSH daemon for the changes to take effect: $ sudo systemctl restart sshd.service

b

RHEL 9 SSH daemon must not allow compression or must only allow compression after successful authentication.

CM-6 - Medium - CCI-000366 - V-258002 - SV-258002r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-255130

Vuln IDs

V-258002

Rule IDs

SV-258002r991589_rule

If compression is allowed in an SSH connection prior to authentication, vulnerabilities in the compression software could result in compromise of the system from an unauthenticated connection, potentially with root privileges.

Checks: C-61743r952199_chk

Verify the SSH daemon performs compression after a user successfully authenticates 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*compression' Compression delayed If the "Compression" keyword is set to "yes", is missing, or the returned line is commented out, this is a finding.

Fix: F-61667r925992_fix

Configure the SSH daemon to not allow compression. Uncomment the "Compression" keyword in "/etc/ssh/sshd_config" on the system and set the value to "delayed" or "no": Compression no The SSH service must be restarted for changes to take effect: $ sudo systemctl restart sshd.service

b

RHEL 9 SSH daemon must not allow GSSAPI authentication.

CM-5 - Medium - CCI-001813 - V-258003 - SV-258003r1045065_rule

RMF Control

CM-5

Severity

M

CCI

CCI-001813

Version

RHEL-09-255135

Vuln IDs

V-258003

Rule IDs

SV-258003r1045065_rule

Generic Security Service Application Program Interface (GSSAPI) authentication is used to provide additional authentication mechanisms to applications. Allowing GSSAPI authentication through SSH exposes the system's GSSAPI to remote hosts, increasing the attack surface of the system. Satisfies: SRG-OS-000364-GPOS-00151, SRG-OS-000480-GPOS-00227

Checks: C-61744r952201_chk

Verify the SSH daemon does not allow GSSAPI authentication with the following command: $ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH '^\s*gssapiauthentication' GSSAPIAuthentication no If the value is returned as "yes", the returned line is commented out, no output is returned, and the use of GSSAPI authentication has not been documented with the information system security officer (ISSO), this is a finding. If the required value is not set, this is a finding.

Fix: F-61668r1045064_fix

Configure the SSH daemon to not allow GSSAPI authentication. Add or uncomment the following line to "/etc/ssh/sshd_config" or to a file in "/etc/ssh/sshd_config.d" and set the value to "no": GSSAPIAuthentication no The SSH service must be restarted for changes to take effect: $ sudo systemctl restart sshd.service

b

RHEL 9 SSH daemon must not allow Kerberos authentication.

CM-5 - Medium - CCI-001813 - V-258004 - SV-258004r1045067_rule

RMF Control

CM-5

Severity

M

CCI

CCI-001813

Version

RHEL-09-255140

Vuln IDs

V-258004

Rule IDs

SV-258004r1045067_rule

Kerberos authentication for SSH is often implemented using Generic Security Service Application Program Interface (GSSAPI). If Kerberos is enabled through SSH, the SSH daemon provides a means of access to the system's Kerberos implementation. Vulnerabilities in the system's Kerberos implementations may be subject to exploitation. Satisfies: SRG-OS-000364-GPOS-00151, SRG-OS-000480-GPOS-00227

Checks: C-61745r952203_chk

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

Fix: F-61669r1045066_fix

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

b

RHEL 9 SSH daemon must not allow rhosts authentication.

CM-6 - Medium - CCI-000366 - V-258005 - SV-258005r1045069_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-255145

Vuln IDs

V-258005

Rule IDs

SV-258005r1045069_rule

SSH trust relationships mean a compromise on one host can allow an attacker to move trivially to other hosts.

Checks: C-61746r952205_chk

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

Fix: F-61670r1045068_fix

Configure the SSH daemon to not allow rhosts authentication. Add the following line to "/etc/ssh/sshd_config" or to a file in "/etc/ssh/sshd_config.d", or uncomment the line and set the value to "yes": IgnoreRhosts yes The SSH service must be restarted for changes to take effect: $ sudo systemctl restart sshd.service

b

RHEL 9 SSH daemon must not allow known hosts authentication.

CM-6 - Medium - CCI-000366 - V-258006 - SV-258006r1045071_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-255150

Vuln IDs

V-258006

Rule IDs

SV-258006r1045071_rule

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

Checks: C-61747r952207_chk

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

Fix: F-61671r1045070_fix

Configure the SSH daemon to not allow known hosts authentication. Add the following line to "/etc/ssh/sshd_config" or to a file in "/etc/ssh/sshd_config.d", or uncomment the line and set the value to "yes": IgnoreUserKnownHosts yes The SSH service must be restarted for changes to take effect: $ sudo systemctl restart sshd.service

b

RHEL 9 SSH daemon must disable remote X connections for interactive users.

CM-6 - Medium - CCI-000366 - V-258007 - SV-258007r1045073_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-255155

Vuln IDs

V-258007

Rule IDs

SV-258007r1045073_rule

When X11 forwarding is enabled, there may be additional exposure to the server and client displays if the sshd proxy display is configured to listen on the wildcard address. By default, sshd binds the forwarding server to the loopback address and sets the hostname part of the DISPLAY environment variable to localhost. This prevents remote hosts from connecting to the proxy display.

Checks: C-61748r952209_chk

Verify the SSH daemon does not allow X11Forwarding with the following command: $ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH '^\s*x11forwarding' X11forwarding no If the value is returned as "yes", the returned line is commented out, or no output is returned, and X11 forwarding is not documented with the information system security officer (ISSO) as an operational requirement, this is a finding.

Fix: F-61672r1045072_fix

Configure the SSH daemon to not allow X11 forwarding. Add the following line to "/etc/ssh/sshd_config" or to a file in "/etc/ssh/sshd_config.d", or uncomment the line and set the value to "no": X11forwarding no The SSH service must be restarted for changes to take effect: $ sudo systemctl restart sshd.service

b

RHEL 9 SSH daemon must perform strict mode checking of home directory configuration files.

CM-6 - Medium - CCI-000366 - V-258008 - SV-258008r1045075_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-255160

Vuln IDs

V-258008

Rule IDs

SV-258008r1045075_rule

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

Checks: C-61749r952211_chk

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

Fix: F-61673r1045074_fix

Configure the SSH daemon to perform strict mode checking of home directory configuration files. Add the following line to "/etc/ssh/sshd_config" or to a file in "/etc/ssh/sshd_config.d", or uncomment the line and set the value to "yes": StrictModes yes The SSH service must be restarted for changes to take effect: $ sudo systemctl restart sshd.service

b

RHEL 9 SSH daemon must display the date and time of the last successful account logon upon an SSH logon.

CM-6 - Medium - CCI-000366 - V-258009 - SV-258009r1045077_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-255165

Vuln IDs

V-258009

Rule IDs

SV-258009r1045077_rule

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

Checks: C-61750r952213_chk

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

Fix: F-61674r1045076_fix

Configure the SSH daemon to provide users with feedback on when account accesses last occurred. Add the following line to "/etc/ssh/sshd_config" or to a file in "/etc/ssh/sshd_config.d", or uncomment the line and set the value to "yes": PrintLastLog yes The SSH service must be restarted for changes to take effect: $ sudo systemctl restart sshd.service

b

RHEL 9 SSH daemon must prevent remote hosts from connecting to the proxy display.

CM-6 - Medium - CCI-000366 - V-258011 - SV-258011r1045079_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-255175

Vuln IDs

V-258011

Rule IDs

SV-258011r1045079_rule

When X11 forwarding is enabled, there may be additional exposure to the server and client displays if the sshd proxy display is configured to listen on the wildcard address. By default, sshd binds the forwarding server to the loopback address and sets the hostname part of the "DISPLAY" environment variable to localhost. This prevents remote hosts from connecting to the proxy display.

Checks: C-61752r952217_chk

Verify the SSH daemon prevents remote hosts from connecting to the proxy display with the following command: $ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH '^\s*x11uselocalhost' X11UseLocalhost yes If the "X11UseLocalhost" keyword is set to "no", is missing, or is commented out, this is a finding.

Fix: F-61676r1045078_fix

Configure the SSH daemon to prevent remote hosts from connecting to the proxy display. Add the following line to "/etc/ssh/sshd_config" or to a file in "/etc/ssh/sshd_config.d", or uncomment the line and set the value to "yes": X11UseLocalhost yes The SSH service must be restarted for changes to take effect: $ sudo systemctl restart sshd.service

b

RHEL 9 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-258012 - SV-258012r1014855_rule

RMF Control

AC-8

Severity

M

CCI

Version

RHEL-09-271010

Vuln IDs

V-258012

Rule IDs

SV-258012r1014855_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. For U.S. Government systems, system use notifications are required only for access via login 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-61753r1014854_chk

Verify RHEL 9 displays the Standard Mandatory DOD Notice and Consent Banner before granting access to the operating system via a graphical user logon. Note: This requirement assumes the use of the RHEL 9 default graphical user interface, the GNOME desktop environment. If the system does not have any graphical user interface installed, this requirement is Not Applicable. Determine if the operating system displays a banner at the logon screen with the following command: $ gsettings get org.gnome.login-screen banner-message-enable true If the result is "false", this is a finding.

Fix: F-61677r926022_fix

Configure RHEL 9 to display the Standard Mandatory DOD Notice and Consent Banner before granting access to the system via a graphical user logon. Create a database to contain the system-wide graphical user logon settings (if it does not already exist) with the following command: $ sudo touch /etc/dconf/db/local.d/01-banner-message Add the following lines to the [org/gnome/login-screen] section of the "/etc/dconf/db/local.d/01-banner-message": [org/gnome/login-screen] banner-message-enable=true Run the following command to update the database: $ sudo dconf update

b

RHEL 9 must prevent a user from overriding the banner-message-enable setting for the graphical user interface.

AC-8 - Medium - CCI-000048 - V-258013 - SV-258013r1045082_rule

RMF Control

AC-8

Severity

M

CCI

Version

RHEL-09-271015

Vuln IDs

V-258013

Rule IDs

SV-258013r1045082_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. For U.S. Government systems, system use notifications are required only for access via login 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-61754r1045080_chk

Note: This requirement assumes the use of the RHEL 9 default graphical user interface, the GNOME desktop environment. If the system does not have any graphical user interface installed, this requirement is Not Applicable. Verify RHEL 9 prevents a user from overriding settings for graphical user interfaces. Determine if the org.gnome.login-screen banner-message-enable key is writable with the following command: $ gsettings writable org.gnome.login-screen banner-message-enable false If "banner-message-enable" is writable or the result is "true", this is a finding.

Fix: F-61678r1045081_fix

Configure RHEL 9 to prevent a user from overriding the banner setting for graphical user interfaces. Create a database to contain the systemwide graphical user logon settings (if it does not already exist) with the following command: $ sudo touch /etc/dconf/db/local.d/locks/session Add the following setting to prevent nonprivileged users from modifying it: /org/gnome/login-screen/banner-message-enable Run the following command to update the database: $ sudo dconf update

b

RHEL 9 must disable the graphical user interface automount function unless required.

IA-3 - Medium - CCI-000778 - V-258014 - SV-258014r1045084_rule

RMF Control

IA-3

Severity

M

CCI

Version

RHEL-09-271020

Vuln IDs

V-258014

Rule IDs

SV-258014r1045084_rule

Automatically mounting file systems permits easy introduction of unknown devices, thereby facilitating malicious activity. Satisfies: SRG-OS-000114-GPOS-00059, SRG-OS-000378-GPOS-00163, SRG-OS-000480-GPOS-00227

Checks: C-61755r1045083_chk

Note: This requirement assumes the use of the RHEL 9 default graphical user interface, the GNOME desktop environment. If the system does not have any graphical user interface installed, this requirement is Not Applicable. Verify RHEL 9 disables the graphical user interface automount function with the following command: $ gsettings get org.gnome.desktop.media-handling automount-open false If "automount-open" is set to "true", and is not documented with the information system security officer (ISSO) as an operational requirement, this is a finding.

Fix: F-61679r926028_fix

Configure the GNOME desktop to disable automated mounting of removable media. The dconf settings can be edited in the /etc/dconf/db/* location. Update the [org/gnome/desktop/media-handling] section of the "/etc/dconf/db/local.d/00-security-settings" database file and add or update the following lines: [org/gnome/desktop/media-handling] automount-open=false Then update the dconf system databases: $ sudo dconf update

b

RHEL 9 must prevent a user from overriding the disabling of the graphical user interface automount function.

IA-3 - Medium - CCI-000778 - V-258015 - SV-258015r1045086_rule

RMF Control

IA-3

Severity

M

CCI

Version

RHEL-09-271025

Vuln IDs

V-258015

Rule IDs

SV-258015r1045086_rule

A nonprivileged account is any operating system account with authorizations of a nonprivileged user. Satisfies: SRG-OS-000114-GPOS-00059, SRG-OS-000378-GPOS-00163, SRG-OS-000480-GPOS-00227

Checks: C-61756r1045085_chk

Note: This requirement assumes the use of the RHEL 9 default graphical user interface, the GNOME desktop environment. If the system does not have any graphical user interface installed, this requirement is Not Applicable. Verify RHEL 9 disables the ability of the user to override the graphical user interface automount setting. 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 the automount setting is locked from nonprivileged 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. $ grep 'automount-open' /etc/dconf/db/local.d/locks/* /org/gnome/desktop/media-handling/automount-open If the command does not return at least the example result, this is a finding.

Fix: F-61680r926031_fix

Configure the GNOME desktop to not allow a user to change the setting that disables automated mounting of removable media. Add the following line to "/etc/dconf/db/local.d/locks/00-security-settings-lock" to prevent user modification: /org/gnome/desktop/media-handling/automount-open Then update the dconf system databases: $ sudo dconf update

b

RHEL 9 must disable the graphical user interface autorun function unless required.

CM-7 - Medium - CCI-001764 - V-258016 - SV-258016r958804_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-09-271030

Vuln IDs

V-258016

Rule IDs

SV-258016r958804_rule

Allowing autorun commands to execute may introduce malicious code to a system. Configuring this setting prevents autorun commands from executing.

Checks: C-61757r926033_chk

Verify RHEL 9 disables the graphical user interface autorun function with the following command: Note: This requirement assumes the use of the RHEL 9 default graphical user interface, the GNOME desktop environment. If the system does not have any graphical user interface installed, this requirement is Not Applicable. $ gsettings get org.gnome.desktop.media-handling autorun-never true If "autorun-never" is set to "false", and is not documented with the information system security officer (ISSO) as an operational requirement, this is a finding.

Fix: F-61681r926034_fix

Configure the GNOME desktop to disable the autorun function on removable media. The dconf settings can be edited in the /etc/dconf/db/* location. Update the [org/gnome/desktop/media-handling] section of the "/etc/dconf/db/local.d/00-security-settings" database file and add or update the following lines: [org/gnome/desktop/media-handling] autorun-never=true Then update the dconf system databases: $ sudo dconf update

b

RHEL 9 must prevent a user from overriding the disabling of the graphical user interface autorun function.

IA-3 - Medium - CCI-000778 - V-258017 - SV-258017r1045088_rule

RMF Control

IA-3

Severity

M

CCI

Version

RHEL-09-271035

Vuln IDs

V-258017

Rule IDs

SV-258017r1045088_rule

Techniques used to address this include protocols using nonces (e.g., numbers generated for a specific one-time use) or challenges (e.g., TLS, WS_Security). Additional techniques include time-synchronous or challenge-response one-time authenticators. Satisfies: SRG-OS-000114-GPOS-00059, SRG-OS-000378-GPOS-00163, SRG-OS-000480-GPOS-00227

Checks: C-61758r1045087_chk

Note: This requirement assumes the use of the RHEL 9 default graphical user interface, the GNOME desktop environment. If the system does not have any graphical user interface installed, this requirement is Not Applicable. Verify RHEL 9 disables ability of the user to override the graphical user interface autorun setting. Determine which profile the system database is using with the following command: $ gsettings writable org.gnome.desktop.media-handling autorun-never false If "autorun-never" is writable, the result is "true". If this is not documented with the information system security officer (ISSO) as an operational requirement, this is a finding.

Fix: F-61682r926037_fix

Configure the GNOME desktop to not allow a user to change the setting that disables autorun on removable media. Add the following line to "/etc/dconf/db/local.d/locks/00-security-settings-lock" to prevent user modification: /org/gnome/desktop/media-handling/autorun-never Then update the dconf system databases: $ sudo dconf update

c

RHEL 9 must not allow unattended or automatic logon via the graphical user interface.

CM-6 - High - CCI-000366 - V-258018 - SV-258018r1045090_rule

RMF Control

CM-6

Severity

H

CCI

Version

RHEL-09-271040

Vuln IDs

V-258018

Rule IDs

SV-258018r1045090_rule

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

Checks: C-61759r1045089_chk

Note: This requirement assumes the use of the RHEL 9 default graphical user interface, the GNOME desktop environment. If the system does not have any graphical user interface installed, this requirement is Not Applicable. Verify RHEL 9 does not allow an unattended or automatic logon to the system via a graphical user interface. Check for the value of the "AutomaticLoginEnable" in the "/etc/gdm/custom.conf" file with the following command: $ grep -i automaticlogin /etc/gdm/custom.conf AutomaticLoginEnable=false If the value of "AutomaticLoginEnable" is not set to "false", this is a finding.

Fix: F-61683r926040_fix

Configure the GNOME desktop display manager to disable automatic login. Set AutomaticLoginEnable to false in the [daemon] section in /etc/gdm/custom.conf. For example: [daemon] AutomaticLoginEnable=false

b

RHEL 9 must be able to initiate directly a session lock for all connection types using smart card when the smart card is removed.

AC-11 - Medium - CCI-000056 - V-258019 - SV-258019r1045092_rule

RMF Control

AC-11

Severity

M

CCI

Version

RHEL-09-271045

Vuln IDs

V-258019

Rule IDs

SV-258019r1045092_rule

A session lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not want to log out because of the temporary nature of the absence. The session lock is implemented at the point where session activity can be determined. Rather than be forced to wait for a period of time to expire before the user session can be locked, RHEL 9 needs to provide users with the ability to manually invoke a session lock so users can secure their session if it is necessary to temporarily vacate the immediate physical vicinity. Satisfies: SRG-OS-000028-GPOS-00009, SRG-OS-000030-GPOS-00011

Checks: C-61760r1045091_chk

Note: This requirement assumes the use of the RHEL 9 default graphical user interface, the GNOME desktop environment. If the system does not have any graphical user interface installed, this requirement is Not Applicable. Verify RHEL 9 enables a user's session lock until that user reestablishes access using established identification and authentication procedures with the following command: $ gsettings get org.gnome.settings-daemon.peripherals.smartcard removal-action 'lock-screen' If the result is not 'lock-screen', this is a finding.

Fix: F-61684r926043_fix

Configure RHEL 9 to enable a user's session lock until that user re-establishes access using established identification and authentication procedures. Select or create an authselect profile and incorporate the "with-smartcard-lock-on-removal" feature with the following example: $ sudo authselect select sssd with-smartcard with-smartcard-lock-on-removal Alternatively, the dconf settings can be edited in the /etc/dconf/db/* location. Add or update the [org/gnome/settings-daemon/peripherals/smartcard] section of the /etc/dconf/db/local.d/00-security-settings" database file and add or update the following lines: [org/gnome/settings-daemon/peripherals/smartcard] removal-action='lock-screen' Then update the dconf system databases: $ sudo dconf update

b

RHEL 9 must prevent a user from overriding the disabling of the graphical user smart card removal action.

AC-11 - Medium - CCI-000056 - V-258020 - SV-258020r1045094_rule

RMF Control

AC-11

Severity

M

CCI

Version

RHEL-09-271050

Vuln IDs

V-258020

Rule IDs

SV-258020r1045094_rule

A session lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not want to log out because of the temporary nature of the absence. The session lock is implemented at the point where session activity can be determined. Rather than be forced to wait for a period of time to expire before the user session can be locked, RHEL 9 needs to provide users with the ability to manually invoke a session lock so users can secure their session if it is necessary to temporarily vacate the immediate physical vicinity. Satisfies: SRG-OS-000028-GPOS-00009, SRG-OS-000030-GPOS-00011

Checks: C-61761r1045093_chk

Note: This requirement assumes the use of the RHEL 9 default graphical user interface, the GNOME desktop environment. If the system does not have any graphical user interface installed, this requirement is Not Applicable. Verify RHEL 9 disables ability of the user to override the smart card removal action setting. $ gsettings writable org.gnome.settings-daemon.peripherals.smartcard removal-action false If "removal-action" is writable and the result is "true", this is a finding.

Fix: F-61685r926046_fix

Add the following line to "/etc/dconf/db/local.d/locks/00-security-settings-lock" to prevent user override of the smart card removal action: /org/gnome/settings-daemon/peripherals/smartcard/removal-action Then update the dconf system databases: $ sudo dconf update

b

RHEL 9 must enable a user session lock until that user re-establishes access using established identification and authentication procedures for graphical user sessions.

AC-11 - Medium - CCI-000056 - V-258021 - SV-258021r1015088_rule

RMF Control

AC-11

Severity

M

CCI

Version

RHEL-09-271055

Vuln IDs

V-258021

Rule IDs

SV-258021r1015088_rule

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

Checks: C-61762r926048_chk

Verify RHEL 9 enables a user's session lock until that user re-establishes access using established identification and authentication procedures with the following command: Note: This requirement assumes the use of the RHEL 9 default graphical user interface, the GNOME desktop environment. If the system does not have any graphical user interface installed, this requirement is Not Applicable. $ gsettings get org.gnome.desktop.screensaver lock-enabled true If the setting is "false", this is a finding.

Fix: F-61686r926049_fix

Configure RHEL 9 to enable a user's session lock until that user re-establishes access using established identification and authentication procedures. Create a database to contain the system-wide screensaver settings (if it does not already exist) with the following example: $ sudo vi /etc/dconf/db/local.d/00-screensaver Edit the "[org/gnome/desktop/screensaver]" section of the database file and add or update the following lines: # Set this to true to lock the screen when the screensaver activates lock-enabled=true Update the system databases: $ sudo dconf update

b

RHEL 9 must prevent a user from overriding the screensaver lock-enabled setting for the graphical user interface.

AC-11 - Medium - CCI-000056 - V-258022 - SV-258022r1045097_rule

RMF Control

AC-11

Severity

M

CCI

Version

RHEL-09-271060

Vuln IDs

V-258022

Rule IDs

SV-258022r1045097_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. Satisfies: SRG-OS-000028-GPOS-00009, SRG-OS-000030-GPOS-00011

Checks: C-61763r1045095_chk

Note: This requirement assumes the use of the RHEL 9 default graphical user interface, Gnome Shell. If the system does not have any graphical user interface installed, this requirement is Not Applicable. Verify RHEL 9 prevents a user from overriding settings for graphical user interfaces. $ gsettings writable org.gnome.desktop.screensaver lock-enabled false If "lock-enabled" is writable and the result is "true", this is a finding.

Fix: F-61687r1045096_fix

Configure RHEL 9 to prevent a user from overriding settings for graphical user interfaces. Create a database to contain the systemwide screensaver settings (if it does not already exist) with the following command: Note: The example below is using the database "local" for the system. 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 nonprivileged users from modifying it: /org/gnome/desktop/screensaver/lock-enabled Run the following command to update the database: $ sudo dconf update

b

RHEL 9 must automatically lock graphical user sessions after 15 minutes of inactivity.

AC-11 - Medium - CCI-000057 - V-258023 - SV-258023r958402_rule

RMF Control

AC-11

Severity

M

CCI

Version

RHEL-09-271065

Vuln IDs

V-258023

Rule IDs

SV-258023r958402_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 logout 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, the GNOME desktop can be configured to identify when a user's session has idled and take action to initiate a session lock. Satisfies: SRG-OS-000029-GPOS-00010, SRG-OS-000031-GPOS-00012

Checks: C-61764r926054_chk

Verify RHEL 9 initiates a session lock after a 15-minute period of inactivity for graphical user interfaces with the following command: Note: This requirement assumes the use of the RHEL 9 default graphical user interface, the GNOME desktop environment. If the system does not have any graphical user interface installed, this requirement is Not Applicable. $ sudo gsettings get org.gnome.desktop.session idle-delay uint32 900 If "idle-delay" is set to "0" or a value greater than "900", this is a finding.

Fix: F-61688r926055_fix

Configure RHEL 9 to initiate a screensaver after a 15-minute period of inactivity for graphical user interfaces. Create a database to contain the system-wide screensaver settings (if it does not already exist) with the following command: $ sudo touch /etc/dconf/db/local.d/00-screensaver Edit /etc/dconf/db/local.d/00-screensaver and add or update the following lines: [org/gnome/desktop/session] # Set the lock time out to 900 seconds before the session is considered idle idle-delay=uint32 900 Update the system databases: $ sudo dconf update

b

RHEL 9 must prevent a user from overriding the session idle-delay setting for the graphical user interface.

AC-11 - Medium - CCI-000057 - V-258024 - SV-258024r1045100_rule

RMF Control

AC-11

Severity

M

CCI

Version

RHEL-09-271070

Vuln IDs

V-258024

Rule IDs

SV-258024r1045100_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 logout 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, the GNOME desktop can be configured to identify when a user's session has idled and take action to initiate the session lock. As such, users should not be allowed to change session settings. Satisfies: SRG-OS-000029-GPOS-00010, SRG-OS-000031-GPOS-00012

Checks: C-61765r1045098_chk

Note: This requirement assumes the use of the RHEL 9 default graphical user interface, the GNOME desktop environment. If the system does not have any graphical user interface installed, this requirement is Not Applicable. Verify RHEL 9 prevents a user from overriding settings for graphical user interfaces. $ gsettings writable org.gnome.desktop.session idle-delay false If "idle-delay" is writable and the result is "true", this is a finding.

Fix: F-61689r1045099_fix

Configure RHEL 9 to prevent a user from overriding settings for graphical user interfaces. Create a database to contain the systemwide screensaver settings (if it does not already exist) with the following command: Note: The example below is using the database "local" for the system. 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 nonprivileged users from modifying it: /org/gnome/desktop/session/idle-delay Run the following command to update the database: $ sudo dconf update

b

RHEL 9 must initiate a session lock for graphical user interfaces when the screensaver is activated.

AC-11 - Medium - CCI-000057 - V-258025 - SV-258025r958402_rule

RMF Control

AC-11

Severity

M

CCI

Version

RHEL-09-271075

Vuln IDs

V-258025

Rule IDs

SV-258025r958402_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 logout because of the temporary nature of the absence.

Checks: C-61766r926060_chk

Verify RHEL 9 initiates a session lock for graphical user interfaces when the screensaver is activated with the following command: Note: This requirement assumes the use of the RHEL 9 default graphical user interface, the GNOME desktop environment. If the system does not have any graphical user interface installed, this requirement is Not Applicable. $ gsettings get org.gnome.desktop.screensaver lock-delay uint32 5 If the "uint32" setting is not set to "5" or less, or is missing, this is a finding.

Fix: F-61690r926061_fix

Configure RHEL 9 to initiate a session lock for graphical user interfaces when a screensaver is activated. Create a database to contain the system-wide screensaver settings (if it does not already exist) with the following command: Note: The example below is using the database "local" for the system, so if the system is using another database in "/etc/dconf/profile/user", the file should be created under the appropriate subdirectory. $ sudo touch /etc/dconf/db/local.d/00-screensaver [org/gnome/desktop/screensaver] lock-delay=uint32 5 The "uint32" must be included along with the integer key values as shown. Update the system databases: $ sudo dconf update

b

RHEL 9 must prevent a user from overriding the session lock-delay setting for the graphical user interface.

AC-11 - Medium - CCI-000057 - V-258026 - SV-258026r1045103_rule

RMF Control

AC-11

Severity

M

CCI

Version

RHEL-09-271080

Vuln IDs

V-258026

Rule IDs

SV-258026r1045103_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 logout 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, the GNOME desktop can be configured to identify when a user's session has idled and take action to initiate the session lock. As such, users should not be allowed to change session settings.

Checks: C-61767r1045101_chk

Note: This requirement assumes the use of the RHEL 9 default graphical user interface, the GNOME desktop environment. If the system does not have any graphical user interface installed, this requirement is Not Applicable. Verify RHEL 9 prevents a user from overriding settings for graphical user interfaces. $ gsettings writable org.gnome.desktop.screensaver lock-delay false If "lock-delay" is writable and the result is "true", this is a finding.

Fix: F-61691r1045102_fix

Configure RHEL 9 to prevent a user from overriding settings for graphical user interfaces. Create a database to contain the systemwide screensaver settings (if it does not already exist) with the following command: Note: The example below is using the database "local" for the system. 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 nonprivileged users from modifying it: /org/gnome/desktop/screensaver/lock-delay Run the following command to update the database: $ sudo dconf update

b

RHEL 9 must conceal, via the session lock, information previously visible on the display with a publicly viewable image.

AC-11 - Medium - CCI-000060 - V-258027 - SV-258027r1045106_rule

RMF Control

AC-11

Severity

M

CCI

CCI-000060

Version

RHEL-09-271085

Vuln IDs

V-258027

Rule IDs

SV-258027r1045106_rule

Setting the screensaver mode to blank-only conceals the contents of the display from passersby.

Checks: C-61768r1045104_chk

Note: This requirement assumes the use of the RHEL 9 default graphical user interface, the GNOME desktop environment. If the system does not have any graphical user interface installed, this requirement is Not Applicable. To ensure the screensaver is configured to be blank, run the following command: $ gsettings writable org.gnome.desktop.screensaver picture-uri false If "picture-uri" is writable and the result is "true", this is a finding.

Fix: F-61692r1045105_fix

Configure RHEL 9 to prevent a user from overriding the picture-uri setting for graphical user interfaces. In the file "/etc/dconf/db/local.d/00-security-settings", add or update the following lines: [org/gnome/desktop/screensaver] picture-uri='' Prevent user modification by adding the following line to "/etc/dconf/db/local.d/locks/00-security-settings-lock": /org/gnome/desktop/screensaver/picture-uri Update the dconf system databases: $ sudo dconf update

b

RHEL 9 effective dconf policy must match the policy keyfiles.

CM-6 - Medium - CCI-000366 - V-258028 - SV-258028r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-271090

Vuln IDs

V-258028

Rule IDs

SV-258028r991589_rule

Unlike text-based keyfiles, the binary database is impossible to check through most automated and all manual means; therefore, in order to evaluate dconf configuration, both have to be true at the same time - configuration files have to be compliant, and the database needs to be more recent than those keyfiles, which gives confidence that it reflects them.

Checks: C-61769r926069_chk

Check the last modification time of the local databases, comparing it to the last modification time of the related keyfiles. The following command will check every dconf database and compare its modification time to the related system keyfiles: Note: This requirement assumes the use of the RHEL 9 default graphical user interface, the GNOME desktop environment. If the system does not have any graphical user interface installed, this requirement is Not Applicable. $ function dconf_needs_update { for db in $(find /etc/dconf/db -maxdepth 1 -type f); do db_mtime=$(stat -c %Y "$db"); keyfile_mtime=$(stat -c %Y "$db".d/* | sort -n | tail -1); if [ -n "$db_mtime" ] && [ -n "$keyfile_mtime" ] && [ "$db_mtime" -lt "$keyfile_mtime" ]; then echo "$db needs update"; return 1; fi; done; }; dconf_needs_update If the command has any output, then a dconf database needs to be updated, and this is a finding.

Fix: F-61693r926070_fix

Update the dconf databases by running the following command: $ sudo dconf update

b

RHEL 9 must disable the ability of a user to restart the system from the login screen.

CM-6 - Medium - CCI-000366 - V-258029 - SV-258029r1045109_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-271095

Vuln IDs

V-258029

Rule IDs

SV-258029r1045109_rule

A user who is at the console can reboot the system at the login screen. If restart or shutdown buttons are pressed at the login screen, this can create the risk of short-term loss of availability of systems due to reboot.

Checks: C-61770r1045107_chk

Note: This requirement assumes the use of the RHEL 9 default graphical user interface, Gnome Shell. If the system does not have any graphical user interface installed, this requirement is Not Applicable. Verify RHEL 9 disables a user's ability to restart the system with the following command: $ gsettings get org.gnome.login-screen disable-restart-buttons true If "disable-restart-buttons" is "false", this is a finding.

Fix: F-61694r1045108_fix

Configure RHEL 9 to disable a user's ability to restart the system. $ gsettings set org.gnome.login-screen disable-restart-buttons true Update the dconf system databases: $ sudo dconf update

b

RHEL 9 must prevent a user from overriding the disable-restart-buttons setting for the graphical user interface.

CM-6 - Medium - CCI-000366 - V-258030 - SV-258030r1045112_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-271100

Vuln IDs

V-258030

Rule IDs

SV-258030r1045112_rule

A user who is at the console can reboot the system at the login screen. If restart or shutdown buttons are pressed at the login screen, this can create the risk of short-term loss of availability of systems due to reboot.

Checks: C-61771r1045110_chk

Note: This requirement assumes the use of the RHEL 9 default graphical user interface, the GNOME desktop environment. If the system does not have any graphical user interface installed, this requirement is Not Applicable. Verify RHEL 9 prevents a user from overriding the disable-restart-buttons setting for graphical user interfaces. $ gsettings writable org.gnome.login-screen disable-restart-buttons false If "disable-restart-buttons" is writable and the result is "true", this is a finding.

Fix: F-61695r1045111_fix

Configure RHEL 9 to prevent a user from overriding the disable-restart-buttons setting for graphical user interfaces. Create a database to contain the systemwide graphical user logon settings (if it does not already exist) with the following command: $ sudo touch /etc/dconf/db/local.d/locks/session Add the following line to prevent nonprivileged users from modifying it: /org/gnome/login-screen/disable-restart-buttons Run the following command to update the database: $ sudo dconf update

b

RHEL 9 must disable the ability of a user to accidentally press Ctrl-Alt-Del and cause a system to shut down or reboot.

CM-6 - Medium - CCI-000366 - V-258031 - SV-258031r1134920_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-271105

Vuln IDs

V-258031

Rule IDs

SV-258031r1134920_rule

A locally logged-in user who presses Ctrl-Alt-Del, when at the console, can reboot the system. If accidentally pressed, as could happen in the case of mixed OS environment, this can create the risk of short-term loss of availability of systems due to unintentional reboot.

Checks: C-61772r1134919_chk

Verify RHEL 9 is configured to ignore the Ctrl-Alt-Del sequence in the GNOME desktop with the following command: Note: This requirement assumes the use of the RHEL 9 default graphical user interface, the GNOME desktop environment. If the system does not have any graphical user interface installed, this requirement is not applicable. $ gsettings get org.gnome.settings-daemon.plugins.media-keys logout [''] If the GNOME desktop is configured to shut down when Ctrl-Alt-Del is pressed, this is a finding.

Fix: F-61696r1045113_fix

Configure RHEL 9 to ignore the Ctrl-Alt-Del sequence in the GNOME desktop. Run the following command to set the media-keys logout setting: $ gsettings set org.gnome.settings-daemon.plugins.media-keys logout "['']" Run the following command to update the database: $ sudo dconf update

b

RHEL 9 must prevent a user from overriding the Ctrl-Alt-Del sequence settings for the graphical user interface.

CM-6 - Medium - CCI-000366 - V-258032 - SV-258032r1045117_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-271110

Vuln IDs

V-258032

Rule IDs

SV-258032r1045117_rule

A locally logged-in user who presses Ctrl-Alt-Del, when at the console, can reboot the system. If accidentally pressed, as could happen in the case of mixed OS environment, this can create the risk of short-term loss of availability of systems due to unintentional reboot.

Checks: C-61773r1045115_chk

Note: This requirement assumes the use of the RHEL 9 default graphical user interface, the GNOME desktop environment. If the system does not have any graphical user interface installed, this requirement is Not Applicable. Verify that users cannot enable the Ctrl-Alt-Del sequence in the GNOME desktop with the following command: $ gsettings writable org.gnome.settings-daemon.plugins.media-keys logout false If "logout" is writable and the result is "true", this is a finding.

Fix: F-61697r1045116_fix

Configure RHEL 9 to disallow the user changing the Ctrl-Alt-Del sequence in the GNOME desktop. Create a database to contain the systemwide graphical user logon settings (if it does not already exist) with the following command: $ sudo touch /etc/dconf/db/local.d/locks/session Add the following line to the session locks file to prevent nonprivileged users from modifying the Ctrl-Alt-Del setting: /org/gnome/settings-daemon/plugins/media-keys/logout Run the following command to update the database: $ sudo dconf update

b

RHEL 9 must disable the user list at logon for graphical user interfaces.

CM-6 - Medium - CCI-000366 - V-258033 - SV-258033r1045120_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-271115

Vuln IDs

V-258033

Rule IDs

SV-258033r1045120_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-61774r1045118_chk

Note: This requirement assumes the use of the RHEL 9 default graphical user interface, the GNOME desktop environment. If the system does not have any graphical user interface installed, this requirement is Not Applicable. Verify that RHEL 9 disables the user logon list for graphical user interfaces with the following command: $ gsettings get org.gnome.login-screen disable-user-list true If the setting is "false", this is a finding.

Fix: F-61698r1045119_fix

Configure RHEL 9 to disable the user list at logon for graphical user interfaces. Create a database to contain the systemwide screensaver settings (if it does not already exist) with the following command: Note: The example below is using the database "local" for the system. If the system is using another database in "/etc/dconf/profile/user", the file should be created under the appropriate subdirectory. $ sudo touch /etc/dconf/db/local.d/02-login-screen [org/gnome/login-screen] disable-user-list=true Update the system databases: $ sudo dconf update

b

RHEL 9 must be configured to disable USB mass storage.

IA-3 - Medium - CCI-000778 - V-258034 - SV-258034r1051267_rule

RMF Control

IA-3

Severity

M

CCI

Version

RHEL-09-291010

Vuln IDs

V-258034

Rule IDs

SV-258034r1051267_rule

USB mass storage permits easy introduction of unknown devices, thereby facilitating malicious activity. Satisfies: SRG-OS-000114-GPOS-00059, SRG-OS-000378-GPOS-00163, SRG-OS-000480-GPOS-00227

Checks: C-61775r1051266_chk

Verify that RHEL 9 disables the ability to load the USB Storage kernel module with the following command: $ grep -r usb-storage /etc/modprobe.conf /etc/modprobe.d/* install usb-storage /bin/false blacklist usb-storage If the command does not return any output, or either line is commented out, and use of USB Storage is not documented with the information system security officer (ISSO) as an operational requirement, this is a finding.

Fix: F-61699r1045122_fix

To configure the system to prevent the usb-storage kernel module from being loaded, add the following lines to the file "/etc/modprobe.d/usb-storage.conf" (or create "usb-storage.conf" if it does not exist): install usb-storage /bin/false blacklist usb-storage

b

RHEL 9 must have the USBGuard package installed.

IA-3 - Medium - CCI-001958 - V-258035 - SV-258035r1045125_rule

RMF Control

IA-3

Severity

M

CCI

CCI-001958

Version

RHEL-09-291015

Vuln IDs

V-258035

Rule IDs

SV-258035r1045125_rule

The USBguard-daemon is the main component of the USBGuard software framework. It runs as a service in the background and enforces the USB device authorization policy for all USB devices. The policy is defined by a set of rules using a rule language described in the usbguard-rules.conf file. The policy and the authorization state of USB devices can be modified during runtime using the usbguard tool. The system administrator (SA) must work with the site information system security officer (ISSO) to determine a list of authorized peripherals and establish rules within the USBGuard software framework to allow only authorized devices.

Checks: C-61776r1014858_chk

Verify USBGuard is installed on the operating system with the following command: $ sudo dnf list installed usbguard Example output: Installed Packages usbguard.x86_64 1.0.0-10.el9_1.2 @rhel-9-for-x86_64-appstream-rpms If the USBGuard package is not installed, ask the SA to indicate how unauthorized peripherals are being blocked. If there is no evidence that unauthorized peripherals are being blocked before establishing a connection, this is a finding. If the system is virtual machine with no virtual or physical USB peripherals attached, this is not a finding.

Fix: F-61700r1045124_fix

Install the usbguard package with the following command: $ sudo dnf install usbguard Enable the service to start on boot and then start it with the following commands: $ sudo systemctl enable usbguard $ sudo systemctl start usbguard Verify the status of the service with the following command: $ sudo systemctl status usbguard Note: usbguard will need to be configured to allow authorized devices once it is enabled on RHEL 9.

b

RHEL 9 must have the USBGuard package enabled.

IA-3 - Medium - CCI-001958 - V-258036 - SV-258036r1014861_rule

RMF Control

IA-3

Severity

M

CCI

CCI-001958

Version

RHEL-09-291020

Vuln IDs

V-258036

Rule IDs

SV-258036r1014861_rule

The USBguard-daemon is the main component of the USBGuard software framework. It runs as a service in the background and enforces the USB device authorization policy for all USB devices. The policy is defined by a set of rules using a rule language described in the usbguard-rules.conf file. The policy and the authorization state of USB devices can be modified during runtime using the usbguard tool. The system administrator (SA) must work with the site information system security officer (ISSO) to determine a list of authorized peripherals and establish rules within the USBGuard software framework to allow only authorized devices.

Checks: C-61777r1014860_chk

Verify RHEL 9 has USBGuard enabled with the following command: $ systemctl is-active usbguard active If usbguard is not active, ask the SA to indicate how unauthorized peripherals are being blocked. If there is no evidence that unauthorized peripherals are being blocked before establishing a connection, this is a finding. If the system is virtual machine with no virtual or physical USB peripherals attached, this is not a finding.

Fix: F-61701r926094_fix

To enable the USBGuard service run the following command: $ sudo systemctl enable --now usbguard

a

RHEL 9 must enable Linux audit logging for the USBGuard daemon.

AU-12 - Low - CCI-000169 - V-258037 - SV-258037r1014863_rule

RMF Control

AU-12

Severity

L

CCI

CCI-000169

Version

RHEL-09-291025

Vuln IDs

V-258037

Rule IDs

SV-258037r1014863_rule

Without the capability to generate audit records, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. If auditing is enabled late in the startup process, the actions of some startup processes may not be audited. Some audit systems also maintain state information only available if auditing is enabled before a given process is created. Audit records can be generated from various components within the information system (e.g., module or policy filter). The list of audited events is the set of events for which audits are to be generated. This set of events is typically a subset of the list of all events for which the system is capable of generating audit records. DOD has defined the list of events for which RHEL 9 will provide an audit record generation capability as the following: 1) Successful and unsuccessful attempts to access, modify, or delete privileges, security objects, security levels, or categories of information (e.g., classification levels); 2) Access actions, such as successful and unsuccessful logon attempts, privileged activities or other system-level access, starting and ending time for user access to the system, concurrent logons from different workstations, successful and unsuccessful accesses to objects, all program initiations, and all direct access to the information system; 3) All account creations, modifications, disabling, and terminations; and 4) All kernel module load, unload, and restart actions.

Checks: C-61778r1014862_chk

To verify that Linux Audit logging is enabled for the USBGuard daemon with the following command: $ sudo grep AuditBackend /etc/usbguard/usbguard-daemon.conf AuditBackend=LinuxAudit If "AuditBackend" is not set to "LinuxAudit", this is a finding. If the system is virtual machine with no virtual or physical USB peripherals attached, this is not a finding.

Fix: F-61702r926097_fix

Configure RHEL 9 USBGuard AuditBackend to use the audit system. Add or edit the following line in /etc/usbguard/usbguard-daemon.conf AuditBackend=LinuxAudit

b

RHEL 9 must block unauthorized peripherals before establishing a connection.

IA-3 - Medium - CCI-001958 - V-258038 - SV-258038r1045128_rule

RMF Control

IA-3

Severity

M

CCI

CCI-001958

Version

RHEL-09-291030

Vuln IDs

V-258038

Rule IDs

SV-258038r1045128_rule

The USBguard-daemon is the main component of the USBGuard software framework. It runs as a service in the background and enforces the USB device authorization policy for all USB devices. The policy is defined by a set of rules using a rule language described in the usbguard-rules.conf file. The policy and the authorization state of USB devices can be modified during runtime using the usbguard tool. The system administrator (SA) must work with the site information system security officer (ISSO) to determine a list of authorized peripherals and establish rules within the USBGuard software framework to allow only authorized devices.

Checks: C-61779r1045126_chk

Note: If the system is virtual machine with no virtual or physical USB peripherals attached, this is Not Applicable. Verify the USBGuard has a policy configured with the following command: $ sudo usbguard list-rules allow id 1d6b:0001 serial If the command does not return results or an error is returned, ask the SA to indicate how unauthorized peripherals are being blocked. If there is no evidence that unauthorized peripherals are being blocked before establishing a connection, this is a finding.

Fix: F-61703r1045127_fix

Configure the operating system to enable the blocking of unauthorized peripherals with the following command: Note: This command must be run from a root shell and will create an allow list for any usb devices currently connected to the system. # usbguard generate-policy --no-hash > /etc/usbguard/rules.conf Note: Enabling and starting usbguard without properly configuring it for an individual system will immediately prevent any access over a usb device such as a keyboard or mouse.

b

RHEL 9 Bluetooth must be disabled.

CM-7 - Medium - CCI-000381 - V-258039 - SV-258039r1045131_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-09-291035

Vuln IDs

V-258039

Rule IDs

SV-258039r1045131_rule

This requirement applies to wireless peripheral technologies (e.g., wireless mice, keyboards, displays, etc.) used with RHEL 9 systems. Wireless peripherals (e.g., Wi-Fi/Bluetooth/IR keyboards, mice and pointing devices, and near field communications [NFC]) present a unique challenge by creating an open, unsecured port on a computer. Wireless peripherals must meet DOD requirements for wireless data transmission and be approved for use by the Authorizing Official (AO). Even though some wireless peripherals, such as mice and pointing devices, do not ordinarily carry information that need to be protected, modification of communications with these wireless peripherals may be used to compromise the RHEL 9 operating system. Satisfies: SRG-OS-000095-GPOS-00049, SRG-OS-000300-GPOS-00118

Checks: C-61780r1045129_chk

Verify that RHEL 9 disables the ability to load the Bluetooth kernel module with the following command: $ sudo grep -r bluetooth /etc/modprobe.conf /etc/modprobe.d/* install bluetooth /bin/false blacklist bluetooth If the command does not return any output, or the lines are commented out, and use of Bluetooth is not documented with the information system security officer (ISSO) as an operational requirement, this is a finding.

Fix: F-61704r1045130_fix

Configure RHEL 9 to disable the Bluetooth adapter when not in use. Create or modify the "/etc/modprobe.d/bluetooth.conf" file with the following lines: install bluetooth /bin/false blacklist bluetooth Reboot the system for the settings to take effect.

b

RHEL 9 wireless network adapters must be disabled.

AC-18 - Medium - CCI-001443 - V-258040 - SV-258040r991568_rule

RMF Control

AC-18

Severity

M

CCI

CCI-001443

Version

RHEL-09-291040

Vuln IDs

V-258040

Rule IDs

SV-258040r991568_rule

This requirement applies to wireless peripheral technologies (e.g., wireless mice, keyboards, displays, etc.) used with RHEL 9 systems. Wireless peripherals (e.g., Wi-Fi/Bluetooth/IR keyboards, mice and pointing devices, and near field communications [NFC]) present a unique challenge by creating an open, unsecured port on a computer. Wireless peripherals must meet DOD requirements for wireless data transmission and be approved for use by the Authorizing Official (AO). Even though some wireless peripherals, such as mice and pointing devices, do not ordinarily carry information that need to be protected, modification of communications with these wireless peripherals may be used to compromise the RHEL 9 operating system. Satisfies: SRG-OS-000299-GPOS-00117, SRG-OS-000300-GPOS-00118, SRG-OS-000424-GPOS-00188, SRG-OS-000481-GPOS-00481

Checks: C-61781r926105_chk

Verify there are no wireless interfaces configured on the system with the following command: Note: This requirement is Not Applicable for systems that do not have physical wireless network radios. $ nmcli device status DEVICE TYPE STATE CONNECTION virbr0 bridge connected virbr0 wlp7s0 wifi connected wifiSSID enp6s0 ethernet disconnected -- p2p-dev-wlp7s0 wifi-p2p disconnected -- lo loopback unmanaged -- virbr0-nic tun unmanaged -- If a wireless interface is configured and has not been documented and approved by the information system security officer (ISSO), this is a finding.

Fix: F-61705r926106_fix

Configure the system to disable all wireless network interfaces with the following command: $ nmcli radio all off

b

RHEL 9 user account passwords for new users or password changes must have a 60-day maximum password lifetime restriction in /etc/login.defs.

Medium - CCI-004066 - V-258041 - SV-258041r1038967_rule

RMF Control

Severity

M

CCI

Version

RHEL-09-411010

Vuln IDs

V-258041

Rule IDs

SV-258041r1038967_rule

Any password, no matter how complex, can eventually be cracked; therefore, passwords need to be changed periodically. If the operating system does not limit the lifetime of passwords and force users to change their passwords, there is the risk that the operating system passwords could be compromised. Setting the password maximum age ensures users are required to periodically change their passwords. Requiring shorter password lifetimes increases the risk of users writing down the password in a convenient location subject to physical compromise.

Checks: C-61782r926108_chk

Verify that RHEL 9 enforces a 60-day maximum password lifetime for new user accounts by running the following command: $ 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-61706r926109_fix

Configure RHEL 9 to enforce a 60-day maximum password lifetime. Add or modify the following line in the "/etc/login.defs" file: PASS_MAX_DAYS 60

b

RHEL 9 user account passwords must have a 60-day maximum password lifetime restriction.

Medium - CCI-004066 - V-258042 - SV-258042r1045133_rule

RMF Control

Severity

M

CCI

Version

RHEL-09-411015

Vuln IDs

V-258042

Rule IDs

SV-258042r1045133_rule

Any password, no matter how complex, can eventually be cracked; therefore, passwords need to be changed periodically. If RHEL 9 does not limit the lifetime of passwords and force users to change their passwords, there is the risk that RHEL 9 passwords could be compromised.

Checks: C-61783r1045132_chk

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

Fix: F-61707r926112_fix

Configure noncompliant accounts to enforce a 60-day maximum password lifetime restriction. passwd -x 60 [user]

b

All RHEL 9 local interactive user accounts must be assigned a home directory upon creation.

CM-6 - Medium - CCI-000366 - V-258043 - SV-258043r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-411020

Vuln IDs

V-258043

Rule IDs

SV-258043r991589_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-61784r926114_chk

Verify all local interactive users on RHEL 9 are assigned a home directory upon creation with the following command: $ 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-61708r926115_fix

Configure RHEL 9 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

RHEL 9 must set the umask value to 077 for all local interactive user accounts.

CM-6 - Medium - CCI-000366 - V-258044 - SV-258044r1045135_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-411025

Vuln IDs

V-258044

Rule IDs

SV-258044r1045135_rule

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

Checks: C-61785r1045134_chk

Verify that the default umask for all local interactive users is "077". Identify the locations of all local interactive user home directories by looking at the "/etc/passwd" file. Check all local interactive user initialization files for interactive users with the following command: Note: The example is for a system that is configured to create users home directories in the "/home" directory. $ sudo find /home -maxdepth 2 -type f -name ".[^.]*" -exec grep -iH -d skip --exclude=.bash_history umask {} \; /home/wadea/.bash_history:grep -i umask /etc/bashrc /etc/csh.cshrc /etc/profile /home/wadea/.bash_history:grep -i umask /etc/login.defs If any local interactive user initialization files are found to have a umask statement that sets a value less restrictive than "077", this is a finding.

Fix: F-61709r926118_fix

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

b

RHEL 9 duplicate User IDs (UIDs) must not exist for interactive users.

AU-3 - Medium - CCI-000135 - V-258045 - SV-258045r958482_rule

RMF Control

AU-3

Severity

M

CCI

CCI-000135

Version

RHEL-09-411030

Vuln IDs

V-258045

Rule IDs

SV-258045r958482_rule

To ensure accountability and prevent unauthenticated access, interactive users must be identified and authenticated to prevent potential misuse and compromise of the system. Satisfies: SRG-OS-000104-GPOS-00051, SRG-OS-000121-GPOS-00062, SRG-OS-000042-GPOS-00020

Checks: C-61786r926120_chk

Verify that RHEL 9 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-61710r926121_fix

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

b

RHEL 9 system accounts must not have an interactive login shell.

CM-6 - Medium - CCI-000366 - V-258046 - SV-258046r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-411035

Vuln IDs

V-258046

Rule IDs

SV-258046r991589_rule

Ensuring shells are not given to system accounts upon login makes it more difficult for attackers to make use of system accounts.

Checks: C-61787r926123_chk

Verify that system accounts must not have an interactive login shell with the following command: $ awk -F: '($3<1000){print $1 ":" $3 ":" $7}' /etc/passwd root:0:/bin/bash bin:1:/sbin/nologin daemon:2:/sbin/nologin adm:3:/sbin/nologin lp:4:/sbin/nologin Identify the system accounts from this listing that do not have a nologin shell. If any system account (other than the root account) has a login shell and it is not documented with the information system security officer (ISSO), this is a finding.

Fix: F-61711r926124_fix

Configure RHEL 9 so that all noninteractive accounts on the system do not have an interactive shell assigned to them. If the system account needs a shell assigned for mission operations, document the need with the information system security officer (ISSO). Run the following command to disable the interactive shell for a specific noninteractive user account: Replace <user> with the user that has a login shell. $ sudo usermod --shell /sbin/nologin <user> Do not perform the steps in this section on the root account. Doing so will cause the system to become inaccessible.

b

RHEL 9 must automatically expire temporary accounts within 72 hours.

AC-2 - Medium - CCI-000016 - V-258047 - SV-258047r1101951_rule

RMF Control

AC-2

Severity

M

CCI

CCI-000016

Version

RHEL-09-411040

Vuln IDs

V-258047

Rule IDs

SV-258047r1101951_rule

Temporary accounts are privileged or nonprivileged accounts that are established during pressing circumstances, such as new software or hardware configuration or an incident response, where the need for prompt account activation requires bypassing normal account authorization procedures. If any inactive temporary accounts are left enabled on the system and are not either manually removed or automatically expired within 72 hours, the security posture of the system will be degraded and exposed to exploitation by unauthorized users or insider threat actors. Temporary accounts are different from emergency accounts. Emergency accounts, also known as "last resort" or "break glass" accounts, are local logon accounts enabled on the system for emergency use by authorized system administrators to manage a system when standard logon methods are failing or not available. Emergency accounts are not subject to manual removal or scheduled expiration requirements. The automatic expiration of temporary accounts may be extended as needed by the circumstances but it must not be extended indefinitely. A documented permanent account should be established for privileged users who need long-term maintenance accounts. Satisfies: SRG-OS-000123-GPOS-00064, SRG-OS-000002-GPOS-00002

Checks: C-61788r926126_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 <temporary_account_name> | grep -i "account expires" Verify each of these accounts has an expiration date set within 72 hours. If any temporary accounts have no expiration date set or do not expire within 72 hours, this is a finding.

Fix: F-61712r926127_fix

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

b

All RHEL 9 interactive users must have a primary group that exists.

IA-2 - Medium - CCI-000764 - V-258048 - SV-258048r1069380_rule

RMF Control

IA-2

Severity

M

CCI

CCI-000764

Version

RHEL-09-411045

Vuln IDs

V-258048

Rule IDs

SV-258048r1069380_rule

If a user is assigned the Group Identifier (GID) of a group that does not exist on the system, and a group with the GID is subsequently created, the user may have unintended rights to any files associated with the group.

Checks: C-61789r1069379_chk

Verify that all RHEL 9 interactive users have a valid GID. Check that the interactive users have a valid GID with the following command: $ sudo pwck -r If pwck reports "no group" for any interactive user, this is a finding.

Fix: F-61713r926130_fix

Configure the system so that all GIDs are referenced in "/etc/passwd" are defined in "/etc/group". Edit the file "/etc/passwd" and ensure that every user's GID is a valid GID.

b

RHEL 9 must disable account identifiers (individuals, groups, roles, and devices) after 35 days of inactivity.

Medium - CCI-003627 - V-258049 - SV-258049r1015092_rule

RMF Control

Severity

M

CCI

CCI-003627

Version

RHEL-09-411050

Vuln IDs

V-258049

Rule IDs

SV-258049r1015092_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. Disabling inactive accounts ensures that accounts which may not have been responsibly removed are not available to attackers who may have compromised their credentials. Owners of inactive accounts will not notice if unauthorized access to their user account has been obtained.

Checks: C-61790r926132_chk

Verify that RHEL 9 account identifiers (individuals, groups, roles, and devices) are disabled after 35 days of inactivity with the following command: Check the account inactivity value by performing the following command: $ sudo grep -i inactive /etc/default/useradd INACTIVE=35 If "INACTIVE" is set to "-1", a value greater than "35", or is commented out, this is a finding.

Fix: F-61714r926133_fix

Configure RHEL 9 to disable account identifiers after 35 days of inactivity after the password expiration. Run the following command to change the configuration for useradd: $ sudo useradd -D -f 35 The recommendation is 35 days, but a lower value is acceptable.

b

Executable search paths within the initialization files of all local interactive RHEL 9 users must only contain paths that resolve to the system default or the users home directory.

CM-6 - Medium - CCI-000366 - V-258050 - SV-258050r1045137_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-411055

Vuln IDs

V-258050

Rule IDs

SV-258050r1045137_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 users 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-61791r1045136_chk

Verify that all local interactive user initialization file executable search path statements do not contain statements that will reference a working directory other than user home directories with the following commands: $ sudo find /home -maxdepth 2 -type f -name ".[^.]*" -exec grep -iH path= {} \; PATH="$HOME/.local/bin:$HOME/bin:$PATH" If any local interactive user initialization files have executable search path statements that include directories outside of their home directory, and this is not documented with the ISSO as an operational requirement, this is a finding.

Fix: F-61715r926136_fix

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

b

All RHEL 9 local interactive users must have a home directory assigned in the /etc/passwd file.

CM-6 - Medium - CCI-000366 - V-258051 - SV-258051r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-411060

Vuln IDs

V-258051

Rule IDs

SV-258051r991589_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-61792r926138_chk

Verify that interactive users on the system have a home directory assigned with the following command: $ sudo awk -F: '($3>=1000)&&($7 !~ /nologin/){print $1, $3, $6}' /etc/passwd smithk:x:1000:1000:smithk:/home/smithk:/bin/bash scsaustin:x:1001:1001:scsaustin:/home/scsaustin:/bin/bash djohnson:x:1002:1002:djohnson:/home/djohnson:/bin/bash Inspect the output and verify that all interactive users (normally users with a user identifier (UID) greater that 1000) have a home directory defined. If users home directory is not defined, this is a finding.

Fix: F-61716r926139_fix

Create and assign home directories to all local interactive users on RHEL 9 that currently do not have a home directory assigned.

b

All RHEL 9 local interactive user home directories defined in the /etc/passwd file must exist.

CM-6 - Medium - CCI-000366 - V-258052 - SV-258052r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-411065

Vuln IDs

V-258052

Rule IDs

SV-258052r991589_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-61793r926141_chk

Verify the assigned home directories of all interactive users on the system exist with the following command: $ sudo pwck -r user 'mailnull': directory 'var/spool/mqueue' does not exist The output should not return any interactive users. If users home directory does not exist, this is a finding.

Fix: F-61717r926142_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 wadea, who has a home directory of "/home/wadea", a user identifier (UID) of "wadea", and a Group Identifier (GID) of "users assigned" in "/etc/passwd". $ sudo mkdir /home/wadea $ sudo chown wadea /home/wadea $ sudo chgrp users /home/wadea $ sudo chmod 0750 /home/wadea

b

All RHEL 9 local interactive user home directories must be group-owned by the home directory owner's primary group.

CM-6 - Medium - CCI-000366 - V-258053 - SV-258053r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-411070

Vuln IDs

V-258053

Rule IDs

SV-258053r991589_rule

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

Checks: C-61794r926144_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/wadea" is used as an example. $ sudo ls -ld $(awk -F: '($3>=1000)&&($7 !~ /nologin/){print $6}' /etc/passwd) drwxr-x--- 2 wadea admin 4096 Jun 5 12:41 wadea Check the user's primary group with the following command: $ sudo grep $(grep wadea /etc/passwd | awk -F: ‘{print $4}') /etc/group admin:x:250:wadea,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-61718r926145_fix

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

b

RHEL 9 must automatically lock an account when three unsuccessful logon attempts occur.

AC-7 - Medium - CCI-000044 - V-258054 - SV-258054r958736_rule

RMF Control

AC-7

Severity

M

CCI

Version

RHEL-09-411075

Vuln IDs

V-258054

Rule IDs

SV-258054r958736_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. Satisfies: SRG-OS-000329-GPOS-00128, SRG-OS-000021-GPOS-00005

Checks: C-61795r926147_chk

Verify RHEL 9 is configured to lock an account after three unsuccessful logon attempts with the command: $ grep 'deny =' /etc/security/faillock.conf deny = 3 If the "deny" option is not set to "3" or less (but not "0"), is missing or commented out, this is a finding.

Fix: F-61719r926148_fix

Configure RHEL 9 to lock an account when three unsuccessful logon attempts occur. Add/modify the "/etc/security/faillock.conf" file to match the following line: deny = 3

b

RHEL 9 must automatically lock the root account until the root account is released by an administrator when three unsuccessful logon attempts occur during a 15-minute time period.

AC-7 - Medium - CCI-000044 - V-258055 - SV-258055r1045140_rule

RMF Control

AC-7

Severity

M

CCI

Version

RHEL-09-411080

Vuln IDs

V-258055

Rule IDs

SV-258055r1045140_rule

By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, also known as brute-forcing, is reduced. Limits are imposed by locking the account. Satisfies: SRG-OS-000329-GPOS-00128, SRG-OS-000021-GPOS-00005

Checks: C-61796r1045138_chk

Verify RHEL 9 is configured to lock the root account after three unsuccessful logon attempts with the command: $ 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-61720r1045139_fix

To configure RHEL 9 to lock out the "root" account after a number of incorrect logon attempts using "pam_faillock.so", first enable the feature using the following command: $ sudo authselect enable-feature with-faillock Edit the "/etc/security/faillock.conf" by uncommenting or adding the following line: even_deny_root

b

RHEL 9 must automatically lock an account when three unsuccessful logon attempts occur during a 15-minute time period.

AC-7 - Medium - CCI-000044 - V-258056 - SV-258056r1045143_rule

RMF Control

AC-7

Severity

M

CCI

Version

RHEL-09-411085

Vuln IDs

V-258056

Rule IDs

SV-258056r1045143_rule

By limiting the number of failed logon attempts the risk of unauthorized system access via user password guessing, otherwise known as brute-forcing, is reduced. Limits are imposed by locking the account. Satisfies: SRG-OS-000329-GPOS-00128, SRG-OS-000021-GPOS-00005

Checks: C-61797r1045141_chk

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. Verify RHEL 9 locks an account after three unsuccessful logon attempts within a period of 15 minutes with the following command: $ sudo grep fail_interval /etc/security/faillock.conf fail_interval = 900 If the "fail_interval" option is not set to "900" or less (but not "0"), the line is commented out, or the line is missing, this is a finding.

Fix: F-61721r1045142_fix

To configure RHEL 9 to lock out the "root" account after a number of incorrect logon attempts within 15 minutes using "pam_faillock.so", enable the feature using the following command: $ sudo authselect enable-feature with-faillock Then edit the "/etc/security/faillock.conf" file as follows: fail_interval = 900

b

RHEL 9 must maintain an account lock until the locked account is released by an administrator.

AC-7 - Medium - CCI-000044 - V-258057 - SV-258057r1045146_rule

RMF Control

AC-7

Severity

M

CCI

Version

RHEL-09-411090

Vuln IDs

V-258057

Rule IDs

SV-258057r1045146_rule

By limiting the number of failed logon attempts the risk of unauthorized system access via user password guessing, otherwise known as brute-forcing, is reduced. Limits are imposed by locking the account. Satisfies: SRG-OS-000329-GPOS-00128, SRG-OS-000021-GPOS-00005

Checks: C-61798r1045144_chk

Verify RHEL 9 is configured to lock an account until released by an administrator after three unsuccessful logon attempts with the command: $ sudo grep -w unlock_time /etc/security/faillock.conf unlock_time = 0 If the "unlock_time" option is not set to "0" or the line is missing or commented out, this is a finding.

Fix: F-61722r1045145_fix

Configure RHEL 9 to lock an account until released by an administrator after three unsuccessful logon attempts with the command: $ sudo authselect enable-feature with-faillock Edit the "/etc/security/faillock.conf" file as follows: unlock_time = 0

b

RHEL 9 must not have unauthorized accounts.

CM-6 - Medium - CCI-000366 - V-258058 - SV-258058r1045148_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-411095

Vuln IDs

V-258058

Rule IDs

SV-258058r1045148_rule

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

Checks: C-61799r1045147_chk

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

Fix: F-61723r926160_fix

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

c

The root account must be the only account having unrestricted access to RHEL 9 system.

CM-6 - High - CCI-000366 - V-258059 - SV-258059r991589_rule

RMF Control

CM-6

Severity

H

CCI

Version

RHEL-09-411100

Vuln IDs

V-258059

Rule IDs

SV-258059r991589_rule

An account has root authority if it has a user identifier (UID) of "0". Multiple accounts with a UID of "0" afford more opportunity for potential intruders to guess a password for a privileged account. Proper configuration of sudo is recommended to afford multiple system administrators access to root privileges in an accountable manner.

Checks: C-61800r926162_chk

Verify that only the "root" account has a UID "0" assignment with the following command: $ awk -F: '$3 == 0 {print $1}' /etc/passwd root If any accounts other than "root" have a UID of "0", this is a finding.

Fix: F-61724r926163_fix

Change the UID of any account on the system, other than root, that has a UID of "0". If the account is associated with system commands or applications, the UID should be changed to one greater than "0" but less than "1000". Otherwise, assign a UID of greater than "1000" that has not already been assigned.

b

RHEL 9 must ensure account lockouts persist.

AC-7 - Medium - CCI-000044 - V-258060 - SV-258060r1045150_rule

RMF Control

AC-7

Severity

M

CCI

Version

RHEL-09-411105

Vuln IDs

V-258060

Rule IDs

SV-258060r1045150_rule

Having lockouts persist across reboots ensures that account is only unlocked by an administrator. If the lockouts did not persist across reboots, an attacker could simply reboot the system to continue brute force attacks against the accounts on the system.

Checks: C-61801r1045149_chk

Verify the "/etc/security/faillock.conf" file is configured to use a nondefault faillock directory to ensure contents persist after reboot with the following command: $ sudo grep -w dir /etc/security/faillock.conf dir = /var/log/faillock If the "dir" option is not set to a nondefault documented tally log directory or is missing or commented out, this is a finding.

Fix: F-61725r926166_fix

Configure RHEL 9 maintain the contents of the faillock directory after a reboot. Add/modify the "/etc/security/faillock.conf" file to match the following line: dir = /var/log/faillock

b

RHEL 9 groups must have unique Group ID (GID).

IA-2 - Medium - CCI-000764 - V-258061 - SV-258061r958482_rule

RMF Control

IA-2

Severity

M

CCI

CCI-000764

Version

RHEL-09-411110

Vuln IDs

V-258061

Rule IDs

SV-258061r958482_rule

To ensure accountability and prevent unauthenticated access, groups must be identified uniquely to prevent potential misuse and compromise of the system.

Checks: C-61802r926168_chk

Verify that RHEL 9 contains no duplicate GIDs for interactive users with the following command: $ cut -d : -f 3 /etc/group | uniq -d If the system has duplicate GIDs, this is a finding.

Fix: F-61726r926169_fix

Edit the file "/etc/group" and provide each group that has a duplicate GID with a unique GID.

b

Local RHEL 9 initialization files must not execute world-writable programs.

CM-6 - Medium - CCI-000366 - V-258062 - SV-258062r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-411115

Vuln IDs

V-258062

Rule IDs

SV-258062r991589_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-61803r926171_chk

Verify that local initialization files do not execute world-writable programs with the following command: Note: The example will be for a system that is configured to create user home directories in the "/home" directory. $ sudo find /home -perm -002 -type f -name ".[^.]*" -exec ls -ld {} \; If any local initialization files are found to reference world-writable files, this is a finding.

Fix: F-61727r926172_fix

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

b

RHEL 9 must automatically exit interactive command shell user sessions after 10 minutes of inactivity.

AC-11 - Medium - CCI-000057 - V-258068 - SV-258068r1101950_rule

RMF Control

AC-11

Severity

M

CCI

Version

RHEL-09-412035

Vuln IDs

V-258068

Rule IDs

SV-258068r1101950_rule

Terminating an idle interactive command shell user session within a short time period reduces the window of opportunity for unauthorized personnel to take control of it when left unattended in a virtual terminal or physical console. Satisfies: SRG-OS-000163-GPOS-00072, SRG-OS-000029-GPOS-00010

Checks: C-61809r1014870_chk

Verify RHEL 9 is configured to exit interactive command shell user sessions after 10 minutes of inactivity or less with the following command: $ sudo grep -i tmout /etc/profile /etc/profile.d/*.sh /etc/profile.d/tmout.sh:declare -xr TMOUT=600 If "TMOUT" is not set to "600" or less in a script located in the "/etc/'profile.d/ directory, is missing or is commented out, this is a finding.

Fix: F-61733r1014871_fix

Configure RHEL 9 to exit interactive command shell user sessions after 10 minutes of inactivity. Add or edit the following line in "/etc/profile.d/tmout.sh": #!/bin/bash declare -xr TMOUT=600

a

RHEL 9 must limit the number of concurrent sessions to ten for all accounts and/or account types.

AC-10 - Low - CCI-000054 - V-258069 - SV-258069r958398_rule

RMF Control

AC-10

Severity

L

CCI

CCI-000054

Version

RHEL-09-412040

Vuln IDs

V-258069

Rule IDs

SV-258069r958398_rule

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

Checks: C-61810r926192_chk

Verify RHEL 9 limits the number of concurrent sessions to "10" for all accounts and/or account types with the following command: $ grep -r -s maxlogins /etc/security/limits.conf /etc/security/limits.d/*.conf /etc/security/limits.conf:* hard maxlogins 10 This can be set as a global domain (with the * wildcard) but may be set differently for multiple domains. If the "maxlogins" item is missing, commented out, or the value is set greater than "10" and is not documented with the information system security officer (ISSO) as an operational requirement for all domains that have the "maxlogins" item assigned, this is a finding.

Fix: F-61734r926193_fix

Configure RHEL 9 to limit the number of concurrent sessions to "10" for all accounts and/or account types. Add the following line to the top of the /etc/security/limits.conf or in a ".conf" file defined in /etc/security/limits.d/: * hard maxlogins 10

b

RHEL 9 must log username information when unsuccessful logon attempts occur.

AC-7 - Medium - CCI-000044 - V-258070 - SV-258070r1045153_rule

RMF Control

AC-7

Severity

M

CCI

Version

RHEL-09-412045

Vuln IDs

V-258070

Rule IDs

SV-258070r1045153_rule

Without auditing of these events, it may be harder or impossible to identify what an attacker did after an attack.

Checks: C-61811r1045151_chk

Verify the "/etc/security/faillock.conf" file is configured to log username information when unsuccessful logon attempts occur with the following command: $ sudo grep audit /etc/security/faillock.conf audit If the "audit" option is not set, is missing, or is commented out, this is a finding.

Fix: F-61735r1045152_fix

Configure RHEL 9 to log username information when unsuccessful logon attempts occur. Enable the feature using the following command: $ sudo authselect enable-feature with-faillock Add/modify the "/etc/security/faillock.conf" file to match the following line: audit

b

RHEL 9 must enforce a delay of at least four seconds between logon prompts following a failed logon attempt.

CM-6 - Medium - CCI-000366 - V-258071 - SV-258071r991588_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-412050

Vuln IDs

V-258071

Rule IDs

SV-258071r991588_rule

Increasing the time between a failed authentication attempt and reprompting to enter credentials helps to slow a single-threaded brute force attack.

Checks: C-61812r926198_chk

Verify RHEL 9 enforces a delay of at least four seconds between console logon prompts following a failed logon attempt with the following command: $ grep -i fail_delay /etc/login.defs FAIL_DELAY 4 If the value of "FAIL_DELAY" is not set to "4" or greater, or the line is commented out, this is a finding.

Fix: F-61736r926199_fix

Configure the RHEL 9 to enforce a delay of at least four seconds between logon prompts following a failed console logon attempt. Modify the "/etc/login.defs" file to set the "FAIL_DELAY" parameter to 4 or greater: FAIL_DELAY 4

b

RHEL 9 must define default permissions for the bash shell.

CM-6 - Medium - CCI-000366 - V-258072 - SV-258072r1045155_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-412055

Vuln IDs

V-258072

Rule IDs

SV-258072r1045155_rule

The umask controls the default access mode assigned to newly created files. A umask of 077 limits new files to mode 600 or less permissive. Although umask can be represented as a four-digit number, the first digit representing special access modes is typically ignored or required to be "0". This requirement applies to the globally configured system defaults and the local interactive user defaults for each account on the system. Satisfies: SRG-OS-000480-GPOS-00228, SRG-OS-000480-GPOS-00227

Checks: C-61813r1045154_chk

Verify the "umask" setting is configured correctly in the "/etc/bashrc" file with the following command: Note: If the value of the "umask" parameter is set to "000" "/etc/bashrc" file, the Severity is raised to a CAT I. $ grep umask /etc/bashrc [ `umask` -eq 0 ] && umask 077 If the value for the "umask" parameter is not "077", or the "umask" parameter is missing or is commented out, this is a finding.

Fix: F-61737r926202_fix

Configure RHEL 9 to define default permissions for all authenticated users using the bash shell. Add or edit the lines for the "umask" parameter in the "/etc/bashrc" file to "077": umask 077

b

RHEL 9 must define default permissions for the c shell.

CM-6 - Medium - CCI-000366 - V-258073 - SV-258073r1045157_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-412060

Vuln IDs

V-258073

Rule IDs

SV-258073r1045157_rule

The umask controls the default access mode assigned to newly created files. A umask of 077 limits new files to mode 600 or less permissive. Although umask can be represented as a four-digit number, the first digit representing special access modes is typically ignored or required to be "0". This requirement applies to the globally configured system defaults and the local interactive user defaults for each account on the system. Satisfies: SRG-OS-000480-GPOS-00228, SRG-OS-000480-GPOS-00227

Checks: C-61814r1045156_chk

Verify the "umask" setting is configured correctly in the "/etc/csh.cshrc" file with the following command: Note: If the value of the "umask" parameter is set to "000" "/etc/csh.cshrc" file, the Severity is raised to a CAT I. $ grep umask /etc/csh.cshrc umask 077 If the value for the "umask" parameter is not "077", or the "umask" parameter is missing or is commented out, this is a finding.

Fix: F-61738r926205_fix

Configure RHEL 9 to define default permissions for all authenticated users using the c shell. Add or edit the lines for the "umask" parameter in the "/etc/csh.cshrc" file to "077": umask 077

b

RHEL 9 must define default permissions for all authenticated users in such a way that the user can only read and modify their own files.

CM-6 - Medium - CCI-000366 - V-258074 - SV-258074r991590_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-412065

Vuln IDs

V-258074

Rule IDs

SV-258074r991590_rule

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

Checks: C-61815r926207_chk

Verify RHEL 9 defines default permissions for all authenticated users in such a way that the user can only read and modify their own files with the following command: Note: If the value of the "UMASK" parameter is set to "000" in "/etc/login.defs" file, the Severity is raised to a CAT I. # grep -i umask /etc/login.defs UMASK 077 If the value for the "UMASK" parameter is not "077", or the "UMASK" parameter is missing or is commented out, this is a finding.

Fix: F-61739r926208_fix

Configure RHEL 9 to define default permissions for all authenticated users in such a way that the user can only read and modify their own files. Add or edit the lines for the "UMASK" parameter in the "/etc/login.defs" file to "077": UMASK 077

b

RHEL 9 must define default permissions for the system default profile.

CM-6 - Medium - CCI-000366 - V-258075 - SV-258075r991590_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-412070

Vuln IDs

V-258075

Rule IDs

SV-258075r991590_rule

The umask controls the default access mode assigned to newly created files. A umask of 077 limits new files to mode 600 or less permissive. Although umask can be represented as a four-digit number, the first digit representing special access modes is typically ignored or required to be "0". This requirement applies to the globally configured system defaults and the local interactive user defaults for each account on the system. Satisfies: SRG-OS-000480-GPOS-00228, SRG-OS-000480-GPOS-00227

Checks: C-61816r926210_chk

Verify the "umask" setting is configured correctly in the "/etc/profile" file with the following command: Note: If the value of the "umask" parameter is set to "000" "/etc/profile" file, the Severity is raised to a CAT I. $ grep umask /etc/profile umask 077 If the value for the "umask" parameter is not "077", or the "umask" parameter is missing or is commented out, this is a finding.

Fix: F-61740r926211_fix

Configure RHEL 9 to define default permissions for all authenticated users in such a way that the user can only read and modify their own files. Add or edit the lines for the "umask" parameter in the "/etc/profile" file to "077": umask 077

a

RHEL 9 must display the date and time of the last successful account logon upon logon.

CM-6 - Low - CCI-000366 - V-258076 - SV-258076r991589_rule

RMF Control

CM-6

Severity

L

CCI

Version

RHEL-09-412075

Vuln IDs

V-258076

Rule IDs

SV-258076r991589_rule

Users need to be aware of activity that occurs regarding their account. Providing users with information regarding the number of unsuccessful attempts that were made to login to their account allows the user to determine if any unauthorized activity has occurred and gives them an opportunity to notify administrators.

Checks: C-61817r926213_chk

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

Fix: F-61741r926214_fix

Configure RHEL 9 to provide users with feedback on when account accesses last occurred by setting the required configuration options in "/etc/pam.d/postlogin". Add the following line to the top of "/etc/pam.d/postlogin": session required pam_lastlog.so showfailed

b

RHEL 9 must terminate idle user sessions.

SC-10 - Medium - CCI-001133 - V-258077 - SV-258077r1014874_rule

RMF Control

SC-10

Severity

M

CCI

CCI-001133

Version

RHEL-09-412080

Vuln IDs

V-258077

Rule IDs

SV-258077r1014874_rule

Terminating an idle session within a short time period reduces the window of opportunity for unauthorized personnel to take control of a management session enabled on the console or console port that has been left unattended.

Checks: C-61818r926216_chk

Verify that RHEL 9 logs out sessions that are idle for 15 minutes with the following command: $ sudo grep -i ^StopIdleSessionSec /etc/systemd/logind.conf StopIdleSessionSec=900 If "StopIdleSessionSec" is not configured to "900" seconds, this is a finding.

Fix: F-61742r1014873_fix

Configure RHEL 9 to log out idle sessions by editing the /etc/systemd/logind.conf file with the following line: StopIdleSessionSec=900 The "logind" service must be restarted for the changes to take effect. To restart the "logind" service, run the following command: $ sudo systemctl restart systemd-logind

c

RHEL 9 must use a Linux Security Module configured to enforce limits on system services.

SC-3 - High - CCI-001084 - V-258078 - SV-258078r958944_rule

RMF Control

SC-3

Severity

H

CCI

Version

RHEL-09-431010

Vuln IDs

V-258078

Rule IDs

SV-258078r958944_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. Satisfies: SRG-OS-000445-GPOS-00199, SRG-OS-000134-GPOS-00068

Checks: C-61819r926219_chk

Ensure that RHEL 9 verifies correct operation of security functions through the use of SELinux with the following command: $ getenforce Enforcing If SELINUX is not set to "Enforcing", this is a finding. Verify that SELinux is configured to be enforcing at boot. grep "SELINUX=" /etc/selinux/config # SELINUX= can take one of these three values: # NOTE: In earlier Fedora kernel builds, SELINUX=disabled would also SELINUX=enforcing If SELINUX line is missing, commented out, or not set to "enforcing", this is a finding.

Fix: F-61743r926220_fix

Configure RHEL 9 to verify correct operation of security functions. Edit the file "/etc/selinux/config" and add or modify the following line: SELINUX=enforcing A reboot is required for the changes to take effect.

b

RHEL 9 must enable the SELinux targeted policy.

SI-6 - Medium - CCI-002696 - V-258079 - SV-258079r1045159_rule

RMF Control

SI-6

Severity

M

CCI

CCI-002696

Version

RHEL-09-431015

Vuln IDs

V-258079

Rule IDs

SV-258079r1045159_rule

Setting the SELinux policy to "targeted" or a more specialized policy ensures the system will confine processes that are likely to be targeted for exploitation, such as network or system services. Note: During the development or debugging of SELinux modules, it is common to temporarily place nonproduction systems in "permissive" mode. In such temporary cases, SELinux policies should be developed, and once work is completed, the system should be reconfigured to "targeted".

Checks: C-61820r1045158_chk

Verify the SELINUX on RHEL 9 is using the targeted policy with the following command: $ sestatus | grep "policy name" Loaded policy name: targeted If the loaded policy name is not "targeted", this is a finding.

Fix: F-61744r926223_fix

Configure RHEL 9 to use the targetd SELINUX policy. Edit the file "/etc/selinux/config" and add or modify the following line: SELINUXTYPE=targeted A reboot is required for the changes to take effect.

b

RHEL 9 must configure SELinux context type to allow the use of a nondefault faillock tally directory.

AC-7 - Medium - CCI-000044 - V-258080 - SV-258080r1045162_rule

RMF Control

AC-7

Severity

M

CCI

Version

RHEL-09-431020

Vuln IDs

V-258080

Rule IDs

SV-258080r1045162_rule

Not having the correct SELinux context on the faillock directory may lead to unauthorized access to the directory.

Checks: C-61821r1045160_chk

Verify the location of the nondefault tally directory for the pam_faillock module with the following command: Note: 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. $ sudo grep -w dir /etc/security/faillock.conf dir = /var/log/faillock Check the security context type of the nondefault tally directory with the following command: $ ls -Zd /var/log/faillock unconfined_u:object_r:faillog_t:s0 /var/log/faillock If the security context type of the nondefault tally directory is not "faillog_t", this is a finding.

Fix: F-61745r1045161_fix

Configure RHEL 9 to allow the use of a nondefault faillock tally directory while SELinux enforces a targeted policy. First enable the feature using the following command: $ sudo authselect enable-feature with-faillock Create a nondefault faillock tally directory (if it does not already exist) with the following example: $ sudo mkdir /var/log/faillock Then add/modify the "/etc/security/faillock.conf" file to match the following line: dir = /var/log/faillock Update the /etc/selinux/targeted/contexts/files/file_contexts.local with "faillog_t" context type for the nondefault faillock tally directory with the following command: $ sudo semanage fcontext -a -t faillog_t "/var/log/faillock(/.*)?" Next, update the context type of the nondefault faillock directory/subdirectories and files with the following command: $ sudo restorecon -R -v /var/log/faillock

b

RHEL 9 must have policycoreutils package installed.

SC-3 - Medium - CCI-001084 - V-258081 - SV-258081r1045164_rule

RMF Control

SC-3

Severity

M

CCI

Version

RHEL-09-431025

Vuln IDs

V-258081

Rule IDs

SV-258081r1045164_rule

Without verification of the security functions, security functions may not operate correctly and the failure may go unnoticed. Security function is defined as the hardware, software, and/or firmware of the information system responsible for enforcing the system security policy and supporting the isolation of code and data on which the protection is based. Security functionality includes, but is not limited to, establishing system accounts, configuring access authorizations (i.e., permissions, privileges), setting events to be audited, and setting intrusion detection parameters. Policycoreutils contains the policy core utilities that are required for basic operation of an SELinux-enabled system. These utilities include load_policy to load SELinux policies, setfile to label filesystems, newrole to switch roles, and run_init to run /etc/init.d scripts in the proper context. Satisfies: SRG-OS-000480-GPOS-00227, SRG-OS-000134-GPOS-00068

Checks: C-61822r1045163_chk

Verify RHEL 9 has the policycoreutils package installed with the following command: $ dnf list --installed policycoreutils Example output: policycoreutils.x86_64 3.3-6.el9_0 If the "policycoreutils" package is not installed, this is a finding.

Fix: F-61746r926229_fix

The policycoreutils package can be installed with the following command: $ sudo dnf install policycoreutils

b

RHEL 9 policycoreutils-python-utils package must be installed.

CM-6 - Medium - CCI-000366 - V-258082 - SV-258082r1045166_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-431030

Vuln IDs

V-258082

Rule IDs

SV-258082r1045166_rule

The policycoreutils-python-utils package is required to operate and manage an SELinux environment and its policies. It provides utilities such as semanage, audit2allow, audit2why, chcat, and sandbox.

Checks: C-61823r1045165_chk

Verify that RHEL 9 policycoreutils-python-utils service package is installed with the following command: $ dnf list --installed policycoreutils-python-utils Example output: policycoreutils-python-utils.noarch 3.3-6.el9_0 If the "policycoreutils-python-utils" package is not installed, this is a finding.

Fix: F-61747r926232_fix

Install the policycoreutils-python-utils service package (if the policycoreutils-python-utils service is not already installed) with the following command: $ sudo dnf install policycoreutils-python-utils

b

RHEL 9 must have the sudo package installed.

AC-6 - Medium - CCI-002235 - V-258083 - SV-258083r1045168_rule

RMF Control

AC-6

Severity

M

CCI

Version

RHEL-09-432010

Vuln IDs

V-258083

Rule IDs

SV-258083r1045168_rule

"sudo" is a program designed to allow a system administrator to give limited root privileges to users and log root activity. The basic philosophy is to give as few privileges as possible but still allow system users to get their work done.

Checks: C-61824r1045167_chk

Verify that RHEL 9 sudo package is installed with the following command: $ dnf list --installed sudo Example output: sudo.x86_64 1.9.5p2-7.el9 If the "sudo" package is not installed, this is a finding.

Fix: F-61748r926235_fix

The sudo package can be installed with the following command: $ sudo dnf install sudo

b

RHEL 9 must require reauthentication when using the "sudo" command.

Medium - CCI-004895 - V-258084 - SV-258084r1050789_rule

RMF Control

Severity

M

CCI

Version

RHEL-09-432015

Vuln IDs

V-258084

Rule IDs

SV-258084r1050789_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 organization requires the user to reauthenticate 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 reauthenticate for privileged actions until the user's session is terminated.

Checks: C-61825r1045169_chk

Verify RHEL 9 requires reauthentication when using the "sudo" command to elevate privileges with the following command: $ sudo grep -ir 'timestamp_timeout' /etc/sudoers /etc/sudoers.d/ /etc/sudoers:Defaults timestamp_timeout=0 If results are returned from more than one file location, 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-61749r1045170_fix

Configure RHEL 9 to reauthenticate "sudo" commands after the specified timeout: Add the following line to "/etc/sudoers" or a file in "/etc/sudoers.d": Defaults timestamp_timeout=0

b

RHEL 9 must use the invoking user's password for privilege escalation when using "sudo".

CM-6 - Medium - CCI-000366 - V-258085 - SV-258085r1045173_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-432020

Vuln IDs

V-258085

Rule IDs

SV-258085r1045173_rule

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.

Checks: C-61826r1045172_chk

Verify that the sudoers security policy is configured to use the invoking user's password for privilege escalation with the following command: $ sudo egrep -ir '(!rootpw|!targetpw|!runaspw)' /etc/sudoers /etc/sudoers.d/ | grep -v '#' /etc/sudoers:Defaults !targetpw /etc/sudoers:Defaults !rootpw /etc/sudoers:Defaults !runaspw If no results are returned, this is a finding. If results are returned from more than one file location, 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-61750r926241_fix

Define the following in the Defaults section of the /etc/sudoers file or a single configuration file in the /etc/sudoers.d/ directory: Defaults !targetpw Defaults !rootpw Defaults !runaspw

b

RHEL 9 must require users to reauthenticate for privilege escalation.

Medium - CCI-004895 - V-258086 - SV-258086r1102063_rule

RMF Control

Severity

M

CCI

Version

RHEL-09-432025

Vuln IDs

V-258086

Rule IDs

SV-258086r1102063_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 that the user reauthenticate. Satisfies: SRG-OS-000373-GPOS-00156, SRG-OS-000373-GPOS-00157, SRG-OS-000373-GPOS-00158

Checks: C-61827r1102062_chk

Verify that "/etc/sudoers" has no occurrences of "!authenticate" with the following command: $ sudo egrep -iR '!authenticate' /etc/sudoers /etc/sudoers.d/ If any occurrences of "!authenticate" are returned, this is a finding.

Fix: F-61751r926244_fix

Configure RHEL 9 to not allow users to execute privileged actions without authenticating. Remove any occurrence of "!authenticate" found in "/etc/sudoers" file or files in the "/etc/sudoers.d" directory. $ sudo sed -i '/\!authenticate/ s/^/# /g' /etc/sudoers /etc/sudoers.d/*

b

RHEL 9 must restrict privilege elevation to authorized personnel.

CM-6 - Medium - CCI-000366 - V-258087 - SV-258087r1102071_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-432030

Vuln IDs

V-258087

Rule IDs

SV-258087r1102071_rule

If the "sudoers" file is not configured correctly, any user defined on the system can initiate privileged actions on the target system.

Checks: C-61828r1102070_chk

Verify RHEL 9 restricts privilege elevation to authorized personnel with the following command: $ sudo grep -iwR 'ALL' /etc/sudoers /etc/sudoers.d/ | grep -v '#' If the either of the following entries are returned, this is a finding: ALL ALL=(ALL) ALL ALL ALL=(ALL:ALL) ALL

Fix: F-61752r926247_fix

Remove the following entries from the /etc/sudoers file or configuration file under /etc/sudoers.d/: ALL ALL=(ALL) ALL ALL ALL=(ALL:ALL) ALL

b

RHEL 9 must restrict the use of the "su" command.

Medium - CCI-004895 - V-258088 - SV-258088r1050789_rule

RMF Control

Severity

M

CCI

Version

RHEL-09-432035

Vuln IDs

V-258088

Rule IDs

SV-258088r1050789_rule

The "su" program allows to run commands with a substitute user and group ID. It is commonly used to run commands as the root user. Limiting access to such commands is considered a good security practice. Satisfies: SRG-OS-000373-GPOS-00156, SRG-OS-000312-GPOS-00123

Checks: C-61829r926249_chk

Verify that RHEL 9 requires uses to be members of the "wheel" group with the following command: $ grep pam_wheel /etc/pam.d/su auth required pam_wheel.so use_uid If a line for "pam_wheel.so" does not exist, or is commented out, this is a finding.

Fix: F-61753r926250_fix

Configure RHEL 9 to require users to be in the "wheel" group to run "su" command. In file "/etc/pam.d/su", uncomment the following line: "#auth required pam_wheel.so use_uid" $ sed '/^[[:space:]]*#[[:space:]]*auth[[:space:]]\+required[[:space:]]\+pam_wheel\.so[[:space:]]\+use_uid$/s/^[[:space:]]*#//' -i /etc/pam.d/su If necessary, create a "wheel" group and add administrative users to the group.

b

RHEL 9 fapolicy module must be installed.

CM-7 - Medium - CCI-001764 - V-258089 - SV-258089r1045179_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-09-433010

Vuln IDs

V-258089

Rule IDs

SV-258089r1045179_rule

The organization must identify authorized software programs and permit execution of authorized software. The process used to identify software programs that are authorized to execute on organizational information systems is commonly referred to as allow listing. Utilizing an allow list provides a configuration management method for allowing the execution of only authorized software. Using only authorized software decreases risk by limiting the number of potential vulnerabilities. Verification of allow listed software occurs prior to execution or at system startup. User home directories/folders may contain information of a sensitive nature. Nonprivileged users should coordinate any sharing of information with an SA through shared resources. RHEL 9 ships with many optional packages. One such package is a file access policy daemon called "fapolicyd". "fapolicyd" is a userspace daemon that determines access rights to files based on attributes of the process and file. It can be used to either blocklist or allow list processes or file access. Proceed with caution with enforcing the use of this daemon. Improper configuration may render the system nonfunctional. The "fapolicyd" API is not namespace aware and can cause issues when launching or running containers. Satisfies: SRG-OS-000370-GPOS-00155, SRG-OS-000368-GPOS-00154

Checks: C-61830r1045178_chk

Verify that RHEL 9 fapolicyd package is installed with the following command: $ dnf list --installed fapolicyd Example output: fapolicyd.x86_64 1.1-103.el9_0 If the "fapolicyd" package is not installed, this is a finding.

Fix: F-61754r926253_fix

The fapolicyd package can be installed with the following command: $ sudo dnf install fapolicyd

b

RHEL 9 fapolicy module must be enabled.

CM-7 - Medium - CCI-001764 - V-258090 - SV-258090r958808_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-09-433015

Vuln IDs

V-258090

Rule IDs

SV-258090r958808_rule

The organization must identify authorized software programs and permit execution of authorized software. The process used to identify software programs that are authorized to execute on organizational information systems is commonly referred to as allowlisting. Utilizing an allowlist provides a configuration management method for allowing the execution of only authorized software. Using only authorized software decreases risk by limiting the number of potential vulnerabilities. Verification of allowlisted software occurs prior to execution or at system startup. User home directories/folders may contain information of a sensitive nature. Nonprivileged users should coordinate any sharing of information with an SA through shared resources. RHEL 9 ships with many optional packages. One such package is a file access policy daemon called "fapolicyd". "fapolicyd" is a userspace daemon that determines access rights to files based on attributes of the process and file. It can be used to either blocklist or allowlist processes or file access. Proceed with caution with enforcing the use of this daemon. Improper configuration may render the system nonfunctional. The "fapolicyd" API is not namespace aware and can cause issues when launching or running containers. Satisfies: SRG-OS-000370-GPOS-00155, SRG-OS-000368-GPOS-00154

Checks: C-61831r926255_chk

Verify that RHEL 9 fapolicyd is active with the following command: $ systemctl is-active fapolicyd active If fapolicyd module is not active, this is a finding.

Fix: F-61755r926256_fix

Enable the fapolicyd with the following command: $ systemctl enable --now fapolicyd

b

RHEL 9 must ensure the password complexity module in the system-auth file is configured for three retries or less.

Medium - CCI-004066 - V-258091 - SV-258091r1045185_rule

RMF Control

Severity

M

CCI

Version

RHEL-09-611010

Vuln IDs

V-258091

Rule IDs

SV-258091r1045185_rule

Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. "pwquality" enforces complex password construction configuration and has the ability to limit brute-force attacks on the system. RHEL 9 uses "pwquality" as a mechanism to enforce password complexity. This is set in both: /etc/pam.d/password-auth /etc/pam.d/system-auth By limiting the number of attempts to meet the pwquality module complexity requirements before returning with an error, the system will audit abnormal attempts at password changes.

Checks: C-61832r1045183_chk

Verify RHEL 9 is configured to limit the "pwquality" retry option to "3". Check for the use of the retry option in the security directory with the following command: $ grep -w retry /etc/security/pwquality.conf /etc/security/pwquality.conf.d/*.conf retry = 3 If the value of "retry" is set to "0" or greater than "3", or is missing, this is a finding.

Fix: F-61756r1045184_fix

Configure RHEL 9 to limit the "pwquality" retry option to "3". Add or update the following line in the "/etc/security/pwquality.conf" file or a file in the "/etc/security/pwquality.conf.d/" directory to contain the "retry" parameter: retry = 3

c

RHEL 9 must not allow blank or null passwords.

CM-6 - High - CCI-000366 - V-258094 - SV-258094r1045187_rule

RMF Control

CM-6

Severity

H

CCI

Version

RHEL-09-611025

Vuln IDs

V-258094

Rule IDs

SV-258094r1045187_rule

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

Checks: C-61835r1014877_chk

Verify that null passwords cannot be used with the following command: $ sudo grep -i nullok /etc/pam.d/system-auth /etc/pam.d/password-auth If output is produced, this is a finding. If the system administrator (SA) can demonstrate that the required configuration is contained in a PAM configuration file included or substacked from the system-auth file, this is not a finding.

Fix: F-61759r1045186_fix

If PAM is managed with authselect, use the following command to remove instances of "nullok": $ sudo authselect enable-feature without-nullok Otherwise, remove any instances of the "nullok" option in the "/etc/pam.d/password-auth" and "/etc/pam.d/system-auth" files to prevent logons with empty passwords. Note: Manual changes to the listed file may be overwritten by the "authselect" program.

b

RHEL 9 must configure the use of the pam_faillock.so module in the /etc/pam.d/system-auth file.

AC-7 - Medium - CCI-000044 - V-258095 - SV-258095r1045189_rule

RMF Control

AC-7

Severity

M

CCI

Version

RHEL-09-611030

Vuln IDs

V-258095

Rule IDs

SV-258095r1045189_rule

If the pam_faillock.so module is not loaded, the system will not correctly lockout accounts to prevent password guessing attacks.

Checks: C-61836r1014879_chk

Verify the pam_faillock.so module is present in the "/etc/pam.d/system-auth" file: $ 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. If the system administrator (SA) can demonstrate that the required configuration is contained in a PAM configuration file included or substacked from the system-auth file, this is not a finding.

Fix: F-61760r1045188_fix

Configure RHEL 9 to include the use of the pam_faillock.so module in the /etc/pam.d/system-auth file. If PAM is managed with authselect, enable the feature with the following command: $ sudo authselect enable-feature with-faillock Otherwise, add/modify the appropriate sections of the "/etc/pam.d/system-auth" file to match the following lines: Note: The "preauth" line must be listed before pam_unix.so. auth required pam_faillock.so preauth auth required pam_faillock.so authfail account required pam_faillock.so

b

RHEL 9 must configure the use of the pam_faillock.so module in the /etc/pam.d/password-auth file.

AC-7 - Medium - CCI-000044 - V-258096 - SV-258096r1045191_rule

RMF Control

AC-7

Severity

M

CCI

Version

RHEL-09-611035

Vuln IDs

V-258096

Rule IDs

SV-258096r1045191_rule

If the pam_faillock.so module is not loaded, the system will not correctly lockout accounts to prevent password guessing attacks.

Checks: C-61837r1014882_chk

Verify the pam_faillock.so module is present in the "/etc/pam.d/password-auth" file: $ 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. If the system administrator (SA) can demonstrate that the required configuration is contained in a PAM configuration file included or substacked from the system-auth file, this is not a finding.

Fix: F-61761r1045190_fix

Configure RHEL 9 to include the use of the pam_faillock.so module in the /etc/pam.d/password-auth file. If PAM is managed with authselect, enable the feature with the following command: $ sudo authselect enable-feature with-faillock Otherwise, add/modify the appropriate sections of the "/etc/pam.d/password-auth" file to match the following lines: Note: The "preauth" line must be listed before pam_unix.so. auth required pam_faillock.so preauth auth required pam_faillock.so authfail account required pam_faillock.so

b

RHEL 9 must ensure the password complexity module is enabled in the password-auth file.

Medium - CCI-004066 - V-258097 - SV-258097r1045193_rule

RMF Control

Severity

M

CCI

Version

RHEL-09-611040

Vuln IDs

V-258097

Rule IDs

SV-258097r1045193_rule

Enabling PAM password complexity permits enforcement of strong passwords and consequently makes the system less prone to dictionary attacks. Satisfies: SRG-OS-000069-GPOS-00037, SRG-OS-000070-GPOS-00038, SRG-OS-000480-GPOS-00227

Checks: C-61838r1045192_chk

Verify RHEL 9 uses "pwquality" to enforce the password complexity rules in the password-auth file with the following command: $ grep pam_pwquality /etc/pam.d/password-auth password required pam_pwquality.so If the command does not return a line containing the value "pam_pwquality.so", or the line is commented out, this is a finding. If the system administrator (SA) can demonstrate that the required configuration is contained in a PAM configuration file included or substacked from the system-auth file, this is not a finding.

Fix: F-61762r926277_fix

Configure RHEL 9 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 required pam_pwquality.so

b

RHEL 9 must ensure the password complexity module is enabled in the system-auth file.

CM-6 - Medium - CCI-000366 - V-258098 - SV-258098r1045195_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-611045

Vuln IDs

V-258098

Rule IDs

SV-258098r1045195_rule

Enabling PAM password complexity permits enforcement of strong passwords and consequently makes the system less prone to dictionary attacks.

Checks: C-61839r1045194_chk

Verify RHEL 9 uses "pwquality" to enforce the password complexity rules in the system-auth file with the following command: $ grep pam_pwquality /etc/pam.d/system-auth password required pam_pwquality.so If the command does not return a line containing the value "pam_pwquality.so", or the line is commented out, this is a finding. If the system administrator (SA) can demonstrate that the required configuration is contained in a PAM configuration file included or substacked from the system-auth file, this is not a finding.

Fix: F-61763r926280_fix

Configure RHEL 9 to use "pwquality" to enforce password complexity rules. Add the following line to the "/etc/pam.d/system-auth" file(or modify the line to have the required value): password required pam_pwquality.so

b

RHEL 9 password-auth must be configured to use a sufficient number of hashing rounds.

Medium - CCI-004062 - V-258099 - SV-258099r1045198_rule

RMF Control

Severity

M

CCI

Version

RHEL-09-611050

Vuln IDs

V-258099

Rule IDs

SV-258099r1045198_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. Passwords that are encrypted with a weak algorithm are no more protected than if they are kept in plain text. Using more hashing rounds makes password cracking attacks more difficult. Satisfies: SRG-OS-000073-GPOS-00041, SRG-OS-000120-GPOS-00061

Checks: C-61840r1045196_chk

Verify the number of rounds for the password hashing algorithm is configured with the following command: $ grep rounds /etc/pam.d/password-auth password sufficient pam_unix.so sha512 rounds=100000 If a matching line is not returned or "rounds" is less than "100000", this a finding.

Fix: F-61764r1045197_fix

Configure RHEL 9 to use 100000 hashing rounds for hashing passwords. Add or modify the following line in "/etc/pam.d/password-auth" and set "rounds" to "100000". password sufficient pam_unix.so sha512 rounds=100000 Note: Running authselect will overwrite this value unless a custom authselect policy is created.

b

RHEL 9 system-auth must be configured to use a sufficient number of hashing rounds.

Medium - CCI-004062 - V-258100 - SV-258100r1045201_rule

RMF Control

Severity

M

CCI

Version

RHEL-09-611055

Vuln IDs

V-258100

Rule IDs

SV-258100r1045201_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. Passwords that are encrypted with a weak algorithm are no more protected than if they are kept in plain text. Using more hashing rounds makes password cracking attacks more difficult. Satisfies: SRG-OS-000073-GPOS-00041, SRG-OS-000120-GPOS-00061

Checks: C-61841r1045199_chk

Verify the number of rounds for the password hashing algorithm is configured with the following command: $ sudo grep rounds /etc/pam.d/system-auth password sufficient pam_unix.so sha512 rounds=100000 If a matching line is not returned or "rounds" is less than 100000, this a finding.

Fix: F-61765r1045200_fix

Configure RHEL 9 to use 100000 hashing rounds for hashing passwords. Add or modify the following line in "/etc/pam.d/system-auth" and set "rounds" to 100000. password sufficient pam_unix.so sha512 rounds=100000 Note: Running authselect will overwrite this value unless a custom authselect policy is created.

b

RHEL 9 must enforce password complexity rules for the root account.

Medium - CCI-004066 - V-258101 - SV-258101r1045204_rule

RMF Control

Severity

M

CCI

Version

RHEL-09-611060

Vuln IDs

V-258101

Rule IDs

SV-258101r1045204_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. Satisfies: SRG-OS-000072-GPOS-00040, SRG-OS-000071-GPOS-00039, SRG-OS-000070-GPOS-00038, SRG-OS-000266-GPOS-00101, SRG-OS-000078-GPOS-00046, SRG-OS-000480-GPOS-00225, SRG-OS-000069-GPOS-00037

Checks: C-61842r1045202_chk

Verify that RHEL 9 enforces password complexity rules for the root account. Check if root user is required to use complex passwords with the following command: $ grep enforce_for_root /etc/security/pwquality.conf /etc/security/pwquality.conf.d/*.conf /etc/security/pwquality.conf:enforce_for_root If "enforce_for_root" is commented or missing, this is a finding.

Fix: F-61766r1045203_fix

Configure RHEL 9 to enforce password complexity on the root account. 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 to contain the "enforce_for_root" parameter: enforce_for_root

b

RHEL 9 must enforce password complexity by requiring that at least one lowercase character be used.

Medium - CCI-004066 - V-258102 - SV-258102r1045207_rule

RMF Control

Severity

M

CCI

Version

RHEL-09-611065

Vuln IDs

V-258102

Rule IDs

SV-258102r1045207_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. Requiring a minimum number of lowercase characters makes password guessing attacks more difficult by ensuring a larger search space.

Checks: C-61843r1045205_chk

Verify that RHEL 9 enforces password complexity by requiring at least one lowercase character. Check the value for "lcredit" with the following command: $ grep lcredit /etc/security/pwquality.conf /etc/security/pwquality.conf.d/*.conf /etc/security/pwquality.conf:lcredit = -1 If the value of "lcredit" is a positive number or is commented out, this is a finding.

Fix: F-61767r1045206_fix

Configure RHEL 9 to enforce password complexity by requiring 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 to contain the "lcredit" parameter: lcredit = -1

b

RHEL 9 must enforce password complexity by requiring that at least one numeric character be used.

Medium - CCI-004066 - V-258103 - SV-258103r1045210_rule

RMF Control

Severity

M

CCI

Version

RHEL-09-611070

Vuln IDs

V-258103

Rule IDs

SV-258103r1045210_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. Requiring digits makes password guessing attacks more difficult by ensuring a larger search space.

Checks: C-61844r1045208_chk

Verify that RHEL 9 enforces password complexity by requiring at least one numeric character. Check the value for "dcredit" with the following command: $ grep dcredit /etc/security/pwquality.conf /etc/security/pwquality.conf.d/*.conf /etc/security/pwquality.conf:dcredit = -1 If the value of "dcredit" is a positive number or is commented out, this is a finding.

Fix: F-61768r1045209_fix

Configure RHEL 9 to enforce password complexity by requiring 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 to contain the "dcredit" parameter: dcredit = -1

b

RHEL 9 passwords for new users or password changes must have a 24 hours minimum password lifetime restriction in /etc/login.defs.

Medium - CCI-004066 - V-258104 - SV-258104r1015104_rule

RMF Control

Severity

M

CCI

Version

RHEL-09-611075

Vuln IDs

V-258104

Rule IDs

SV-258104r1015104_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, then the password could be repeatedly changed in a short period of time to defeat the organization's policy regarding password reuse. Setting the minimum password age protects against users cycling back to a favorite password after satisfying the password reuse requirement.

Checks: C-61845r926297_chk

Verify RHEL 9 enforces 24 hours 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: $ 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-61769r926298_fix

Configure RHEL 9 to enforce 24 hours as the minimum password lifetime. Add the following line in "/etc/login.defs" (or modify the line to have the required value): PASS_MIN_DAYS 1

b

RHEL 9 passwords must have a 24 hours minimum password lifetime restriction in /etc/shadow.

Medium - CCI-004066 - V-258105 - SV-258105r1045212_rule

RMF Control

Severity

M

CCI

Version

RHEL-09-611080

Vuln IDs

V-258105

Rule IDs

SV-258105r1045212_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-61846r1045211_chk

Verify that RHEL 9 has configured the minimum time period between password changes for each user account as one day or greater with the following command: $ sudo awk -F: '$4 < 1 {printf "%s %d\n", $1, $4}' /etc/shadow If any results are returned that are not associated with a system account, this is a finding.

Fix: F-61770r926301_fix

Configure noncompliant accounts to enforce a 24 hour minimum password lifetime: $ sudo passwd -n 1 [user]

b

RHEL 9 must require users to provide a password for privilege escalation.

Medium - CCI-004895 - V-258106 - SV-258106r1102061_rule

RMF Control

Severity

M

CCI

Version

RHEL-09-611085

Vuln IDs

V-258106

Rule IDs

SV-258106r1102061_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 that the user reauthenticate. Satisfies: SRG-OS-000373-GPOS-00156, SRG-OS-000373-GPOS-00157, SRG-OS-000373-GPOS-00158

Checks: C-61847r1102060_chk

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

Fix: F-61771r1045214_fix

Configure RHEL 9 to not allow users to execute privileged actions without authenticating with a password. Remove any occurrence of "NOPASSWD" found in "/etc/sudoers" file or files in the "/etc/sudoers.d" directory. $ sudo find /etc/sudoers /etc/sudoers.d -type f -exec sed -i '/NOPASSWD/ s/^/# /g' {} \;

b

RHEL 9 passwords must be created with a minimum of 15 characters.

Medium - CCI-004066 - V-258107 - SV-258107r1045218_rule

RMF Control

Severity

M

CCI

Version

RHEL-09-611090

Vuln IDs

V-258107

Rule IDs

SV-258107r1045218_rule

The shorter the password, the lower the number of possible combinations that need to be tested before the password is compromised. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Password length is one factor of several that helps to determine strength and how long it takes to crack a password. Use of more characters in a password helps to increase exponentially the time and/or resources required to compromise the password. RHEL 9 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. The DOD minimum password requirement is 15 characters.

Checks: C-61848r1045216_chk

Verify that RHEL 9 enforces a minimum 15-character password length with the following command: $ grep minlen /etc/security/pwquality.conf /etc/security/pwquality.conf.d/*.conf minlen = 15 If the command does not return a "minlen" value of "15" or greater, does not return a line, or the line is commented out, this is a finding.

Fix: F-61772r1045217_fix

Configure RHEL 9 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 to contain the "minlen" parameter: minlen = 15

b

RHEL 9 must enforce password complexity by requiring that at least one special character be used.

Medium - CCI-004066 - V-258109 - SV-258109r1045220_rule

RMF Control

Severity

M

CCI

Version

RHEL-09-611100

Vuln IDs

V-258109

Rule IDs

SV-258109r1045220_rule

Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Password complexity is one factor of several that determines how long it takes to crack a password. The more complex the password, the greater the number of possible combinations that need to be tested before the password is compromised. RHEL 9 utilizes "pwquality" as a mechanism to enforce password complexity. Note that to require special characters without degrading the "minlen" value, the credit value must be expressed as a negative number in "/etc/security/pwquality.conf".

Checks: C-61850r926312_chk

Verify that RHEL 9 enforces password complexity by requiring at least one special character with the following command: $ sudo grep ocredit /etc/security/pwquality.conf /etc/security/pwquality.conf.d/*.conf ocredit = -1 If the value of "ocredit" is a positive number or is commented out, this is a finding.

Fix: F-61774r1045219_fix

Configure RHEL 9 to enforce password complexity by requiring 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 to contain the "ocredit" parameter: ocredit = -1

b

RHEL 9 must prevent the use of dictionary words for passwords.

CM-6 - Medium - CCI-000366 - V-258110 - SV-258110r1045223_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-611105

Vuln IDs

V-258110

Rule IDs

SV-258110r1045223_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. If RHEL 9 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-61851r1045221_chk

Verify RHEL 9 prevents the use of dictionary words for passwords with the following command: $ grep dictcheck /etc/security/pwquality.conf /etc/security/pwquality.conf.d/*.conf /etc/security/pwquality.conf:dictcheck = 1 If "dictcheck" does not have a value other than "0", or is commented out, this is a finding.

Fix: F-61775r1045222_fix

Configure RHEL 9 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 to contain the "dictcheck" parameter: dictcheck=1

b

RHEL 9 must enforce password complexity by requiring that at least one uppercase character be used.

Medium - CCI-004066 - V-258111 - SV-258111r1045226_rule

RMF Control

Severity

M

CCI

Version

RHEL-09-611110

Vuln IDs

V-258111

Rule IDs

SV-258111r1045226_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. Requiring a minimum number of uppercase characters makes password guessing attacks more difficult by ensuring a larger search space.

Checks: C-61852r1045224_chk

Verify that RHEL 9 enforces password complexity by requiring that at least one uppercase character be used. Check the value for "ucredit" with the following command: $ grep ucredit /etc/security/pwquality.conf /etc/security/pwquality.conf.d/*.conf ucredit = -1 If the value of "ucredit" is a positive number or is commented out, this is a finding.

Fix: F-61776r1045225_fix

Configure RHEL 9 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 to contain the "ucredit" parameter: ucredit = -1

b

RHEL 9 must require the change of at least eight characters when passwords are changed.

Medium - CCI-004066 - V-258112 - SV-258112r1045229_rule

RMF Control

Severity

M

CCI

Version

RHEL-09-611115

Vuln IDs

V-258112

Rule IDs

SV-258112r1045229_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. Requiring a minimum number of different characters during password changes ensures that newly changed passwords will not resemble previously compromised ones. Note that passwords changed on compromised systems will still be compromised.

Checks: C-61853r1045227_chk

Verify that RHEL 9 requires the change of at least eight of the total number of characters when passwords are changed. $ grep difok /etc/security/pwquality.conf /etc/security/pwquality.conf.d/*.conf difok = 8 If the value of "difok" is set to less than "8", or is commented out, this is a finding.

Fix: F-61777r1045228_fix

Configure RHEL 9 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 to contain the "difok" parameter: difok = 8

b

RHEL 9 must require the maximum number of repeating characters of the same character class be limited to four when passwords are changed.

Medium - CCI-004066 - V-258113 - SV-258113r1045232_rule

RMF Control

Severity

M

CCI

Version

RHEL-09-611120

Vuln IDs

V-258113

Rule IDs

SV-258113r1045232_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 a password, the greater the number of possible combinations that need to be tested before the password is compromised.

Checks: C-61854r1045230_chk

Verify that RHEL 9 requires that passwords can have a maximum of four repeating characters of the same character class. $ grep maxclassrepeat /etc/security/pwquality.conf /etc/security/pwquality.conf.d/*.conf maxclassrepeat = 4 If the value of "maxclassrepeat" is set to "0", more than "4", or is commented out, this is a finding.

Fix: F-61778r1045231_fix

Configure RHEL 9 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 to contain the "maxclassrepeat" parameter: maxclassrepeat = 4

b

RHEL 9 must require the maximum number of repeating characters be limited to three when passwords are changed.

Medium - CCI-004066 - V-258114 - SV-258114r1045235_rule

RMF Control

Severity

M

CCI

Version

RHEL-09-611125

Vuln IDs

V-258114

Rule IDs

SV-258114r1045235_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 a password, the greater the number of possible combinations that need to be tested before the password is compromised.

Checks: C-61855r1045233_chk

Verify that RHEL 9 requires that passwords can have a maximum of three of the same consecutive character. $ grep maxrepeat /etc/security/pwquality.conf /etc/security/pwquality.conf.d/*.conf maxrepeat = 3 If the value of "maxrepeat" is set to more than "3", or is commented out, this is a finding.

Fix: F-61779r1045234_fix

Configure RHEL 9 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 to contain the "maxrepeat" parameter: maxrepeat = 3

b

RHEL 9 must require the change of at least four character classes when passwords are changed.

Medium - CCI-004066 - V-258115 - SV-258115r1045238_rule

RMF Control

Severity

M

CCI

Version

RHEL-09-611130

Vuln IDs

V-258115

Rule IDs

SV-258115r1045238_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 a password, the greater the number of possible combinations that need to be tested before the password is compromised.

Checks: C-61856r1045236_chk

Verify that RHEL 9 requires passwords to contain at least four character classes. $ grep minclass /etc/security/pwquality.conf /etc/security/pwquality.conf.d/*.conf minclass = 4 If the value of "minclass" is set to less than "4", or is commented out, this is a finding.

Fix: F-61780r1045237_fix

Configure RHEL 9 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 to contain the "minclass" parameter: minclass = 4

b

RHEL 9 must be configured so that user and group account administration utilities are configured to store only encrypted representations of passwords.

Medium - CCI-004062 - V-258116 - SV-258116r1045240_rule

RMF Control

Severity

M

CCI

Version

RHEL-09-611135

Vuln IDs

V-258116

Rule IDs

SV-258116r1045240_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. Passwords that are encrypted with a weak algorithm are no more protected than if they are kept in plain text. This setting ensures user and group account administration utilities are configured to store only encrypted representations of passwords. Additionally, the "crypt_style" configuration option ensures the use of a strong hashing algorithm that makes password cracking attacks more difficult.

Checks: C-61857r1045239_chk

Verify the user and group account administration utilities are configured to store only encrypted representations of passwords with the following command: $ grep crypt_style /etc/libuser.conf crypt_style = sha512 If the "crypt_style" variable is not set to "sha512", is not in the defaults section, is commented out, or does not exist, this is a finding.

Fix: F-61781r1014895_fix

Configure RHEL 9 to use the SHA-512 algorithm for password hashing. Add or change the following line in the "[defaults]" section of "/etc/libuser.conf" file: crypt_style = sha512

b

RHEL 9 must be configured to use the shadow file to store only encrypted representations of passwords.

Medium - CCI-004062 - V-258117 - SV-258117r1015116_rule

RMF Control

Severity

M

CCI

Version

RHEL-09-611140

Vuln IDs

V-258117

Rule IDs

SV-258117r1015116_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. Passwords that are encrypted with a weak algorithm are no more protected than if they are kept in plain text. This setting ensures user and group account administration utilities are configured to store only encrypted representations of passwords. Additionally, the "crypt_style" configuration option ensures the use of a strong hashing algorithm that makes password cracking attacks more difficult.

Checks: C-61858r926336_chk

Verify the system's shadow file is configured to store only encrypted representations of passwords with a hash value of SHA512 with the following command: # grep -i encrypt_method /etc/login.defs ENCRYPT_METHOD SHA512 If "ENCRYPT_METHOD" does not have a value of "SHA512", or the line is commented out, this is a finding.

Fix: F-61782r926337_fix

Configure RHEL 9 to store only SHA512 encrypted representations of passwords. Add or update the following line in the "/etc/login.defs" file: ENCRYPT_METHOD SHA512

b

RHEL 9 must not be configured to bypass password requirements for privilege escalation.

Medium - CCI-004895 - V-258118 - SV-258118r1050789_rule

RMF Control

Severity

M

CCI

Version

RHEL-09-611145

Vuln IDs

V-258118

Rule IDs

SV-258118r1050789_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-61859r926339_chk

Verify the operating system is not configured to bypass password requirements for privilege escalation with the following command: $ sudo grep pam_succeed_if /etc/pam.d/sudo If any occurrences of "pam_succeed_if" are returned, this is a finding.

Fix: F-61783r926340_fix

Configure the operating system to require users to supply a password for privilege escalation. Remove any occurrences of " pam_succeed_if " in the "/etc/pam.d/sudo" file.

b

RHEL 9 must not have accounts configured with blank or null passwords.

CM-6 - Medium - CCI-000366 - V-258120 - SV-258120r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-611155

Vuln IDs

V-258120

Rule IDs

SV-258120r991589_rule

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

Checks: C-61861r926345_chk

Verify that null or blank passwords cannot be used with the following command: $ sudo awk -F: '!$2 {print $1}' /etc/shadow If the command returns any results, this is a finding.

Fix: F-61785r926346_fix

Configure all accounts on RHEL 9 to have a password or lock the account with the following commands: Perform a password reset: $ sudo passwd [username] To lock an account: $ sudo passwd -l [username]

b

RHEL 9 must use the common access card (CAC) smart card driver.

IA-2 - Medium - CCI-000764 - V-258121 - SV-258121r1102086_rule

RMF Control

IA-2

Severity

M

CCI

CCI-000764

Version

RHEL-09-611160

Vuln IDs

V-258121

Rule IDs

SV-258121r1102086_rule

Smart card login provides two-factor authentication stronger than that provided by a username and password combination. Smart cards leverage public key infrastructure to provide and verify credentials. Configuring the smart card driver in use by the organization helps to prevent users from using unauthorized smart cards. Satisfies: SRG-OS-000104-GPOS-00051, SRG-OS-000106-GPOS-00053, SRG-OS-000107-GPOS-00054, SRG-OS-000109-GPOS-00056, SRG-OS-000108-GPOS-00055, SRG-OS-000112-GPOS-00057, SRG-OS-000113-GPOS-00058

Checks: C-61862r1102085_chk

Verify that RHEL loads the CAC driver with the following command: $ sudo opensc-tool --get-conf-entry app:default:card_drivers cac cac If "cac" is not listed as a card driver, or no line is returned for "card_drivers", this is a finding.

Fix: F-61786r1045242_fix

Configure RHEL 9 to load the CAC driver. $ sudo opensc-tool --set-conf-entry app:default:card_driver:cac Restart the pcscd service to apply the changes: $ sudo systemctl restart pcscd

b

RHEL 9 must enable certificate based smart card authentication.

IA-2 - Medium - CCI-000765 - V-258122 - SV-258122r1045246_rule

RMF Control

IA-2

Severity

M

CCI

CCI-000765

Version

RHEL-09-611165

Vuln IDs

V-258122

Rule IDs

SV-258122r1045246_rule

Without the use of multifactor authentication, the ease of access to privileged functions is greatly increased. Multifactor authentication requires using two or more factors to achieve authentication. A privileged account is defined as an information system account with authorizations of a privileged user. The DOD Common Access Card (CAC) with DOD-approved PKI is an example of multifactor authentication. Satisfies: SRG-OS-000375-GPOS-00160, SRG-OS-000105-GPOS-00052

Checks: C-61863r1045244_chk

Note: If the system administrator (SA) demonstrates the use of an approved alternate multifactor authentication method, this requirement is Not Applicable. To verify that RHEL 9 has smart cards enabled in System Security Services Daemon (SSSD), run the following command: $ sudo grep -ir pam_cert_auth /etc/sssd/sssd.conf /etc/sssd/conf.d/ pam_cert_auth = True If "pam_cert_auth" is not set to "True", the line is commented out, or the line is missing, this is a finding.

Fix: F-61787r1045245_fix

Edit the file "/etc/sssd/sssd.conf" or a configuration file in "/etc/sssd/conf.d" and add or edit the following line: pam_cert_auth = True

b

RHEL 9 must implement certificate status checking for multifactor authentication.

Medium - CCI-004046 - V-258123 - SV-258123r1134923_rule

RMF Control

Severity

M

CCI

Version

RHEL-09-611170

Vuln IDs

V-258123

Rule IDs

SV-258123r1134923_rule

Using an authentication device, such as a DOD common access card (CAC) or token that is separate from the information system, ensures that even if the information system is compromised, credentials stored on the authentication device will not be affected. Multifactor solutions that require devices separate from information systems gaining access include, for example, hardware tokens providing time-based or challenge-response authenticators and smart cards such as the U.S. Government Personal Identity Verification (PIV) card and the DOD CAC. RHEL 9 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-61864r1134922_chk

Note: If the system administrator (SA) demonstrates the use of an approved alternate multifactor authentication method, this requirement is not applicable. Verify the operating system implements Online Certificate Status Protocol (OCSP) and is using the proper digest value on the system with the following command: $ sudo grep -sir certificate_verification /etc/sssd/sssd.conf /etc/sssd/conf.d/ | grep -v "^#" /etc/sssd/conf.d/certificate_verification:certificate_verification = ocsp_dgst=sha512 If the certificate_verification line is missing from the [sssd] section, or is missing "ocsp_dgst=sha512", 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-61788r926355_fix

Configure RHEL 9 to implement certificate status checking for multifactor authentication. Review the "/etc/sssd/conf.d/certificate_verification.conf" file to determine if the system is configured to prevent OCSP or certificate verification. Add the following line to the "/etc/sssd/conf.d/certificate_verification.conf" file: certificate_verification = ocsp_dgst=sha512 Set the correct ownership and permissions on the "/etc/sssd/conf.d/certificate_verification.conf" file by running these commands: $ sudo chown root:root "/etc/sssd/conf.d/certificate_verification.conf" $ sudo chmod 600 "/etc/sssd/conf.d/certificate_verification.conf" The "sssd" service must be restarted for the changes to take effect. To restart the "sssd" service, run the following command: $ sudo systemctl restart sssd.service

b

RHEL 9 must have the pcsc-lite package installed.

Medium - CCI-004046 - V-258124 - SV-258124r1045250_rule

RMF Control

Severity

M

CCI

Version

RHEL-09-611175

Vuln IDs

V-258124

Rule IDs

SV-258124r1045250_rule

The pcsc-lite package must be installed if it is to be available for multifactor authentication using smart cards.

Checks: C-61865r1045249_chk

Note: If the system administrator (SA) demonstrates the use of an approved alternate multifactor authentication method, this requirement is Not Applicable. Verify that RHEL 9 has the pcsc-lite package installed with the following command: $ dnf list --installed pcsc-lite Example output: pcsc-lite.x86_64 1.9.4-1.el9 If the "pcsc-lite" package is not installed, this is a finding.

Fix: F-61789r926358_fix

The pcsc-lite package can be installed with the following command: $ sudo dnf install pcsc-lite

b

The pcscd service on RHEL 9 must be active.

Medium - CCI-004046 - V-258125 - SV-258125r1045253_rule

RMF Control

Severity

M

CCI

Version

RHEL-09-611180

Vuln IDs

V-258125

Rule IDs

SV-258125r1045253_rule

The information system ensures that even if the information system is compromised, that compromise will not affect credentials stored on the authentication device. The daemon program for pcsc-lite and the MuscleCard framework is pcscd. It is a resource manager that coordinates communications with smart card readers and smart cards and cryptographic tokens that are connected to the system.

Checks: C-61866r1045251_chk

Verify that the "pcscd" socket is active with the following command: $ systemctl is-active pcscd.socket active If the pcscd socket is not active, this is a finding.

Fix: F-61790r1045252_fix

To enable the pcscd socket, run the following command: $ sudo systemctl enable --now pcscd.socket

b

RHEL 9 must have the opensc package installed.

Medium - CCI-004046 - V-258126 - SV-258126r1045255_rule

RMF Control

Severity

M

CCI

Version

RHEL-09-611185

Vuln IDs

V-258126

Rule IDs

SV-258126r1045255_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. Satisfies: SRG-OS-000375-GPOS-00160, SRG-OS-000376-GPOS-00161

Checks: C-61867r1045254_chk

Verify that RHEL 9 has the opensc package installed with the following command: $ dnf list --installed opensc Example output: opensc.x86_64 0.22.0-2.el9 If the "opensc" package is not installed, this is a finding.

Fix: F-61791r926364_fix

The opensc package can be installed with the following command: $ sudo dnf install opensc

b

RHEL 9, for PKI-based authentication, must enforce authorized access to the corresponding private key.

IA-5 - Medium - CCI-000186 - V-258127 - SV-258127r1134925_rule

RMF Control

IA-5

Severity

M

CCI

CCI-000186

Version

RHEL-09-611190

Vuln IDs

V-258127

Rule IDs

SV-258127r1134925_rule

If the private key is discovered, an attacker can use the key to authenticate as an authorized user and gain access to the network infrastructure. The cornerstone of the PKI is the private key used to encrypt or digitally sign information. If the private key is stolen, this will lead to the compromise of the authentication and nonrepudiation gained through PKI because the attacker can use the private key to digitally sign documents and pretend to be the authorized user. Both the holders of a digital certificate and the issuing authority must protect the computers, storage devices, or whatever they use to keep the private keys.

Checks: C-61868r1134924_chk

Note: If the system administrator demonstrates the use of an approved alternate multifactor authentication method, this requirement is not applicable. 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 The expected output is a password prompt: "Enter passphrase:" If the password prompt is not displayed, and the contents of the key are displayed, this is a finding.

Fix: F-61792r926367_fix

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

b

RHEL 9 must require authentication to access emergency mode.

AC-3 - Medium - CCI-000213 - V-258128 - SV-258128r1117265_rule

RMF Control

AC-3

Severity

M

CCI

Version

RHEL-09-611195

Vuln IDs

V-258128

Rule IDs

SV-258128r1117265_rule

To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DOD-approved PKIs, all DOD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. This requirement prevents attackers with physical access from trivially bypassing security on the machine and gaining root access. Such accesses are further prevented by configuring the bootloader password.

Checks: C-61869r926369_chk

Verify that RHEL 9 requires authentication for emergency mode with the following command: $ grep sulogin /usr/lib/systemd/system/emergency.service ExecStart=-/usr/lib/systemd/systemd-sulogin-shell emergency If this line is not returned, or is commented out, this is a finding. If the output is different, this is a finding.

Fix: F-61793r926370_fix

Configure RHEL 9 to require authentication for emergency mode. Add or modify the following line in the "/usr/lib/systemd/system/emergency.service" file: ExecStart=-/usr/lib/systemd/systemd-sulogin-shell emergency

b

RHEL 9 must require authentication to access single-user mode.

AC-3 - Medium - CCI-000213 - V-258129 - SV-258129r1117265_rule

RMF Control

AC-3

Severity

M

CCI

Version

RHEL-09-611200

Vuln IDs

V-258129

Rule IDs

SV-258129r1117265_rule

To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DOD-approved PKIs, all DOD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. This requirement prevents attackers with physical access from trivially bypassing security on the machine and gaining root access. Such accesses are further prevented by configuring the bootloader password. To modify properties, such as dependencies or timeouts, of a service that is handled by a SysV initscript, do not modify the initscript itself. Instead, create a systemd drop-in configuration file for the service. Then manage this service in the same way as a normal systemd service. For example, to extend the configuration of the network service, do not modify the /etc/rc.d/init.d/network initscript file. Instead, create new directory /etc/systemd/system/network.service.d/ and a systemd drop-in file /etc/systemd/system/network.service.d/my_config.conf. Then, put the modified values into the drop-in file. Note: systemd knows the network service as network.service, which is why the created directory must be called "network.service.d".

Checks: C-61870r1106457_chk

Verify RHEL 9 requires authentication for single-user mode with the following command: $ grep sulogin /usr/lib/systemd/system/rescue.service ExecStart=-/usr/lib/systemd/systemd-sulogin-shell rescue If the line is not returned from the default systemd file, use the following command to look for modifications to the rescue.service: $ grep sulogin /etc/systemd/system/rescue.service.d/*.conf If the line is not returned from either location this is a finding. Note: The configuration setting can only be in either the default location, or in the drop in file, not both locations.

Fix: F-61794r1102058_fix

Configure RHEL 9 to require authentication for single-user mode. Create a directory for supplementary configuration files at /etc/systemd/system/rescue.service.d/ Copy the original file rescue.service file to the new directory with: $ sudo cp /usr/lib/systemd/system/rescue.service /etc/systemd/system/rescue.service.d/rescue.service.conf Add or modify the following line in the "etc/systemd/system/rescue.service.d/rescue.service.conf" file: ExecStart=-/usr/lib/systemd/systemd-sulogin-shell rescue Apply changes to unit files without rebooting the system: $ sudo systemctl daemon-reload If the modified unit file belongs to a running service, restart the service: $ sudo systemctl restart rescue.service

b

RHEL 9, 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-258131 - SV-258131r1134927_rule

RMF Control

IA-5

Severity

M

CCI

CCI-000185

Version

RHEL-09-631010

Vuln IDs

V-258131

Rule IDs

SV-258131r1134927_rule

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

Checks: C-61872r1134926_chk

Note: If the system administrator demonstrates the use of an approved alternate multifactor authentication method, this requirement is not applicable. Verify RHEL 9 for PKI-based authentication has valid certificates by constructing a certification path (which includes status information) to an accepted trust anchor. 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 Example output: Certificate: Data: Version: 3 (0x2) Serial Number: 1 (0x1) Signature Algorithm: sha256WithRSAEncryption Issuer: C = US, O = U.S. Government, OU = DoD, OU = PKI, CN = DoD Root CA 3 Validity Not Before: Mar 20 18:46:41 2012 GMT Not After: Dec 30 18:46:41 2029 GMT Subject: C = US, O = U.S. Government, OU = DoD, OU = PKI, CN = DoD Root CA 3 Subject Public Key Info: Public Key Algorithm: rsaEncryption If the root CA file is not a DOD-issued certificate with a valid date and installed in the "/etc/sssd/pki/sssd_auth_ca_db.pem" location, this is a finding.

Fix: F-61796r997112_fix

Configure RHEL 9, 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 from cyber.mil and copy the DoD_PKE_CA_chain.pem into the following file: /etc/sssd/pki/sssd_auth_ca_db.pem

b

RHEL 9 must map the authenticated identity to the user or group account for PKI-based authentication.

IA-5 - Medium - CCI-000187 - V-258132 - SV-258132r1134929_rule

RMF Control

IA-5

Severity

M

CCI

CCI-000187

Version

RHEL-09-631015

Vuln IDs

V-258132

Rule IDs

SV-258132r1134929_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.

Checks: C-61873r1134928_chk

Note: If the system administrator (SA) demonstrates the use of an approved alternate multifactor authentication method, this requirement is not applicable. 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: $ sudo find /etc/sssd/sssd.conf /etc/sssd/conf.d/ -type f -exec cat {} \; [certmap/testing.test/rule_name] matchrule =<SAN>.*EDIPI@mil maprule = (userCertificate;binary={cert!bin}) domains = testing.test If the certmap section does not exist, ask the SA to indicate how certificates are mapped to accounts. If there is no evidence of certificate mapping, this is a finding.

Fix: F-61797r1014904_fix

Configure RHEL 9 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 = .*EDIPI@mil maprule = (userCertificate;binary={cert!bin}) domains = testing.test The "sssd" service must be restarted for the changes to take effect. To restart the "sssd" service, run the following command: $ sudo systemctl restart sssd.service

b

RHEL 9 must prohibit the use of cached authenticators after one day.

IA-5 - Medium - CCI-002007 - V-258133 - SV-258133r1045263_rule

RMF Control

IA-5

Severity

M

CCI

CCI-002007

Version

RHEL-09-631020

Vuln IDs

V-258133

Rule IDs

SV-258133r1045263_rule

If cached authentication information is out-of-date, the validity of the authentication information may be questionable.

Checks: C-61874r1045261_chk

Verify that the System Security Services Daemon (SSSD) prohibits the use of cached authentications after one day. Note: Cached authentication settings should be configured even if smart card authentication is not used on the system. Check that SSSD allows cached authentications with the following command: $ sudo grep -ir cache_credentials /etc/sssd/sssd.conf /etc/sssd/conf.d/ cache_credentials = true If "cache_credentials" is set to "false" or missing from the configuration file, this is not a finding and no further checks are required. If "cache_credentials" is set to "true", check that SSSD prohibits the use of cached authentications after one day with the following command: $ sudo grep -ir offline_credentials_expiration /etc/sssd/sssd.conf /etc/sssd/conf.d/ offline_credentials_expiration = 1 If "offline_credentials_expiration" is not set to a value of "1", this is a finding.

Fix: F-61798r1045262_fix

Configure the SSSD to prohibit the use of cached authentications after one day. Edit the file "/etc/sssd/sssd.conf" or a configuration file in "/etc/sssd/conf.d" and add or edit the following line just below the line [pam]: offline_credentials_expiration = 1

b

RHEL 9 must have the AIDE package installed.

CM-3 - Medium - CCI-001744 - V-258134 - SV-258134r1101983_rule

RMF Control

CM-3

Severity

M

CCI

CCI-001744

Version

RHEL-09-651010

Vuln IDs

V-258134

Rule IDs

SV-258134r1101983_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. Selection lines in the aide.conf file determine which files and directories AIDE will monitor for changes. They follow this format: The specifies a file, directory or wildcard pattern to monitor. The define which attributes (hashes, permissions, timestamps, etc.) to check. Satisfies: SRG-OS-000363-GPOS-00150, SRG-OS-000445-GPOS-00199

Checks: C-61875r1101982_chk

Verify the file integrity tool is configured to verify ACLs. Note: AIDE is highly configurable at install time. This requirement assumes the "aide.conf" file is under the "/etc" directory. If AIDE is not installed, ask the system administrator (SA) how file integrity checks are performed on the system. Use the following command to determine if the file is in a location other than "/etc/aide/aide.conf": $ sudo find / -name aide.conf Use the following command to review the "aide.conf" file to determine if the "acl" rule has been added to the rule list being applied to the files and directories selection lists: $ sudo cat /etc/aide.conf | more If the "acl" rule is not being used on all selection lines in the "/etc/aide.conf" file, is commented out, or ACLs are not being checked by another file integrity tool, this is a finding.

Fix: F-61799r926388_fix

Install AIDE, initialize it, and perform a manual check. Install AIDE: $ sudo dnf install aide Initialize AIDE: $ sudo /usr/sbin/aide --init Example output: Start timestamp: 2023-06-05 10:09:04 -0600 (AIDE 0.16) AIDE initialized database at /var/lib/aide/aide.db.new.gz Number of entries: 86833 --------------------------------------------------- The attributes of the (uncompressed) database(s): --------------------------------------------------- /var/lib/aide/aide.db.new.gz MD5 : coZUtPHhoFoeD7+k54fUvQ== SHA1 : DVpOEMWJwo0uPgrKZAygIUgSxeM= SHA256 : EQiZH0XNEk001tcDmJa+5STFEjDb4MPE TGdBJ/uvZKc= SHA512 : 86KUqw++PZhoPK0SZvT3zuFq9yu9nnPP toei0nENVELJ1LPurjoMlRig6q69VR8l +44EwO9eYyy9nnbzQsfG1g== End timestamp: 2023-06-05 10:09:57 -0600 (run time: 0m 53s) The new database will need to be renamed to be read by AIDE: $ sudo mv /var/lib/aide/aide.db.new.gz /var/lib/aide/aide.db.gz Perform a manual check: $ sudo /usr/sbin/aide --check Example output: 2023-06-05 10:16:08 -0600 (AIDE 0.16) AIDE found NO differences between database and filesystem. Looks okay!! ...

b

RHEL 9 must routinely check the baseline configuration for unauthorized changes and notify the system administrator when anomalies in the operation of any security functions are discovered.

CM-3 - Medium - CCI-001744 - V-258135 - SV-258135r1045267_rule

RMF Control

CM-3

Severity

M

CCI

CCI-001744

Version

RHEL-09-651015

Vuln IDs

V-258135

Rule IDs

SV-258135r1045267_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 management officer (IMO)/information system security officer (ISSO) and system administrators (SAs) must be notified via email and/or monitoring system trap when there is an unauthorized modification of a configuration item. Notifications provided by information systems include messages to local computer consoles, and/or hardware indications, such as lights. This capability must take into account operational requirements for availability for selecting an appropriate response. The organization may choose to shut down or restart the information system upon security function anomaly detection. Satisfies: SRG-OS-000363-GPOS-00150, SRG-OS-000446-GPOS-00200, SRG-OS-000447-GPOS-00201

Checks: C-61876r1045266_chk

Verify that RHEL 9 routinely executes a file integrity scan for changes to the system baseline. The command used in the example will use a daily occurrence. Check the cron directories for scripts controlling the execution and notification of results of the file integrity application. For example, if AIDE is installed on the system, use the following commands: $ sudo ls -al /etc/cron.* | grep aide -rwxr-xr-x 1 root root 29 Nov 22 2015 aide $ sudo grep aide /etc/crontab /var/spool/cron/root /etc/crontab: 30 04 * * * root usr/sbin/aide /var/spool/cron/root: 30 04 * * * root usr/sbin/aide $ sudo more /etc/cron.daily/aide #!/bin/bash /usr/sbin/aide --check | /bin/mail -s "$HOSTNAME - Daily aide integrity check run" root@sysname.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-61800r926391_fix

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

b

RHEL 9 must use a file integrity tool that is configured to use FIPS 140-3-approved cryptographic hashes for validating file contents and directories.

CM-6 - Medium - CCI-000366 - V-258136 - SV-258136r1045270_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-651020

Vuln IDs

V-258136

Rule IDs

SV-258136r1045270_rule

RHEL 9 installation media ships with an optional file integrity tool called Advanced Intrusion Detection Environment (AIDE). AIDE is highly configurable at install time. This requirement assumes the "aide.conf" file is under the "/etc" directory. File integrity tools use cryptographic hashes for verifying file contents and directories have not been altered. These hashes must be FIPS 140-3-approved cryptographic hashes.

Checks: C-61877r1045268_chk

Verify that AIDE is configured to use FIPS 140-3 file hashing with the following command: $ sudo grep sha512 /etc/aide.conf All=p+i+n+u+g+s+m+S+sha512+acl+xattrs+selinux If the "sha512" rule is not being used on all uncommented selection lines in the "/etc/aide.conf" file, or another file integrity tool is not using FIPS 140-3-approved cryptographic hashes for validating file contents and directories, this is a finding.

Fix: F-61801r1045269_fix

Configure the file integrity tool to use FIPS 140-3 cryptographic hashes for validating file and directory contents. If AIDE is installed, ensure the "sha512" rule is present on all uncommented file and directory selection lists. Exclude any log files, or files expected to change frequently, to reduce unnecessary notifications.

b

RHEL 9 must use cryptographic mechanisms to protect the integrity of audit tools.

AU-9 - Medium - CCI-001493 - V-258137 - SV-258137r1102081_rule

RMF Control

AU-9

Severity

M

CCI

Version

RHEL-09-651025

Vuln IDs

V-258137

Rule IDs

SV-258137r1102081_rule

Protecting the integrity of the tools used for auditing purposes is a critical step toward ensuring the integrity of audit information. Audit information includes all information (e.g., audit records, audit settings, and audit reports) needed to successfully audit information system activity. Audit tools include, but are not limited to, vendor-provided and open-source audit tools needed to successfully view and manipulate audit information system activity and records. Audit tools include custom queries and report generators. It is not uncommon for attackers to replace the audit tools or inject code into the existing tools to provide the capability to hide or erase system activity from the audit logs. To address this risk, audit tools must be cryptographically signed to provide the capability to identify when the audit tools have been modified, manipulated, or replaced. An example is a checksum hash of the file or files. Satisfies: SRG-OS-000256-GPOS-00097, SRG-OS-000257-GPOS-00098, SRG-OS-000258-GPOS-00099, SRG-OS-000278-GPOS-00108

Checks: C-61878r1102080_chk

Check that AIDE is properly configured to protect the integrity of the audit tools with the following command: $ sudo grep /usr/sbin/au /etc/aide.conf /usr/sbin/auditctl p+i+n+u+g+s+b+acl+xattrs+sha512 /usr/sbin/auditd p+i+n+u+g+s+b+acl+xattrs+sha512 /usr/sbin/ausearch p+i+n+u+g+s+b+acl+xattrs+sha512 /usr/sbin/aureport p+i+n+u+g+s+b+acl+xattrs+sha512 /usr/sbin/autrace p+i+n+u+g+s+b+acl+xattrs+sha512 /usr/sbin/augenrules p+i+n+u+g+s+b+acl+xattrs+sha512 If AIDE is not installed, ask the system administrator (SA) how file integrity checks are performed on the system. If any of the audit tools listed above do not have a corresponding line, ask the SA to indicate what cryptographic mechanisms are being used to protect the integrity of the audit tools. If there is no evidence of integrity protection, this is a finding.

Fix: F-61802r943020_fix

Add or update the following lines to "/etc/aide.conf", to protect the integrity of the audit tools. /usr/sbin/auditctl p+i+n+u+g+s+b+acl+xattrs+sha512 /usr/sbin/auditd p+i+n+u+g+s+b+acl+xattrs+sha512 /usr/sbin/ausearch p+i+n+u+g+s+b+acl+xattrs+sha512 /usr/sbin/aureport p+i+n+u+g+s+b+acl+xattrs+sha512 /usr/sbin/autrace p+i+n+u+g+s+b+acl+xattrs+sha512 /usr/sbin/augenrules p+i+n+u+g+s+b+acl+xattrs+sha512

a

RHEL 9 must be configured so that the file integrity tool verifies Access Control Lists (ACLs).

CM-6 - Low - CCI-000366 - V-258138 - SV-258138r1045274_rule

RMF Control

CM-6

Severity

L

CCI

Version

RHEL-09-651030

Vuln IDs

V-258138

Rule IDs

SV-258138r1045274_rule

RHEL 9 installation media ships with an optional file integrity tool called Advanced Intrusion Detection Environment (AIDE). AIDE is highly configurable at install time. This requirement assumes the "aide.conf" file is under the "/etc" directory. ACLs can provide permissions beyond those permitted through the file mode and must be verified by the file integrity tools.

Checks: C-61879r1045273_chk

Verify that AIDE is verifying ACLs with the following command: $ sudo grep acl /etc/aide.conf All= p+i+n+u+g+s+m+S+sha512+acl+xattrs+selinux If the "acl" rule is not being used on all uncommented selection lines in the "/etc/aide.conf" file, or ACLs are not being checked by another file integrity tool, this is a finding.

Fix: F-61803r926400_fix

Configure the file integrity tool to check file and directory ACLs. If AIDE is installed, ensure the "acl" rule is present on all uncommented file and directory selection lists.

a

RHEL 9 must be configured so that the file integrity tool verifies extended attributes.

CM-6 - Low - CCI-000366 - V-258139 - SV-258139r1045276_rule

RMF Control

CM-6

Severity

L

CCI

Version

RHEL-09-651035

Vuln IDs

V-258139

Rule IDs

SV-258139r1045276_rule

RHEL 9 installation media ships with an optional file integrity tool called Advanced Intrusion Detection Environment (AIDE). AIDE is highly configurable at install time. This requirement assumes the "aide.conf" file is under the "/etc" directory. Extended attributes in file systems are used to contain arbitrary data and file metadata with security implications.

Checks: C-61880r1045275_chk

Verify that AIDE is configured to verify extended attributes with the following command: $ sudo grep xattrs /etc/aide.conf All= p+i+n+u+g+s+m+S+sha512+acl+xattrs+selinux If the "xattrs" rule is not being used on all uncommented selection lines in the "/etc/aide.conf" file, or extended attributes are not being checked by another file integrity tool, this is a finding.

Fix: F-61804r926403_fix

Configure the file integrity tool to check file and directory extended attributes. If AIDE is installed, ensure the "xattrs" rule is present on all uncommented file and directory selection lists.

b

RHEL 9 must have the rsyslog package installed.

AU-6 - Medium - CCI-000154 - V-258140 - SV-258140r1106460_rule

RMF Control

AU-6

Severity

M

CCI

CCI-000154

Version

RHEL-09-652010

Vuln IDs

V-258140

Rule IDs

SV-258140r1106460_rule

rsyslogd is a system utility providing support for message logging. Support for both internet and Unix domain sockets enables this utility to support both local and remote logging. Couple this utility with "gnutls" (which is a secure communications library implementing the SSL, TLS, and DTLS protocols), to create a method to securely encrypt and offload auditing. Satisfies: SRG-OS-000479-GPOS-00224, SRG-OS-000051-GPOS-00024, SRG-OS-000480-GPOS-00227

Checks: C-61881r1106459_chk

Verify RHEL 9 has the rsyslog package installed with the following command: $ dnf list --installed rsyslog Example output: rsyslog.x86_64 8.2102.0-101.el9_0.1 If the "rsyslog" package is not installed, this is a finding.

Fix: F-61805r1106358_fix

Install the rsyslog package with the following command: $ sudo dnf install rsyslog

b

RHEL 9 must have the packages required for encrypting offloaded audit logs installed.

IA-7 - Medium - CCI-000803 - V-258141 - SV-258141r1045280_rule

RMF Control

IA-7

Severity

M

CCI

CCI-000803

Version

RHEL-09-652015

Vuln IDs

V-258141

Rule IDs

SV-258141r1045280_rule

The rsyslog-gnutls package provides Transport Layer Security (TLS) support for the rsyslog daemon, which enables secure remote logging. Satisfies: SRG-OS-000480-GPOS-00227, SRG-OS-000120-GPOS-00061

Checks: C-61882r1045279_chk

Verify that RHEL 9 has the rsyslog-gnutls package installed with the following command: $ dnf list --installed rsyslog-gnutls Example output: rsyslog-gnutls.x86_64 8.2102.0-101.el9_0.1 If the "rsyslog-gnutls" package is not installed, this is a finding.

Fix: F-61806r926409_fix

The rsyslog-gnutls package can be installed with the following command: $ sudo dnf install rsyslog-gnutls

b

The rsyslog service on RHEL 9 must be active.

CM-6 - Medium - CCI-000366 - V-258142 - SV-258142r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-652020

Vuln IDs

V-258142

Rule IDs

SV-258142r991589_rule

The "rsyslog" service must be running to provide logging services, which are essential to system administration.

Checks: C-61883r926411_chk

Verify that "rsyslog" is active with the following command: $ systemctl is-active rsyslog active If the rsyslog service is not active, this is a finding.

Fix: F-61807r926412_fix

To enable the rsyslog service, run the following command: $ sudo systemctl enable --now rsyslog

b

RHEL 9 must be configured so that the rsyslog daemon does not accept log messages from other servers unless the server is being used for log aggregation.

CM-6 - Medium - CCI-000366 - V-258143 - SV-258143r1134931_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-652025

Vuln IDs

V-258143

Rule IDs

SV-258143r1134931_rule

Unintentionally running a rsyslog server accepting remote messages puts the system at increased risk. Malicious rsyslog messages sent to the server could exploit vulnerabilities in the server software itself, could introduce misleading information into the system's logs, or could fill the system's storage leading to a denial of service. If the system is intended to be a log aggregation server, its use must be documented with the information system security officer (ISSO).

Checks: C-61884r1134930_chk

Note: If the system administrator can demonstrate that another tool (e.g., SPLUNK) is being used to manage log offload and aggregation in lieu of rsyslog, this check is not applicable. Verify that RHEL 9 is not configured to receive remote logs using rsyslog with the following commands: $ ss -tulnp | grep rsyslog If no output is returned, rsyslog is not listening for remote logs. If output appears, check for configured ports (514 is the default for syslog). Check for remote logging configuration in rsyslog by examining the rsyslog configuration files: $ sudo grep -E 'InputTCPServerRun | UDPServerRun' /etc/rsyslog.conf /etc/rsyslog.d/* If uncommented lines are returned, this is a finding.

Fix: F-61808r1045282_fix

Configure RHEL 9 to not receive remote logs using rsyslog. Remove the lines in /etc/rsyslog.conf and any files in the /etc/rsyslog.d directory that match any of the following: module(load="imtcp") module(load="imudp") module(load="imrelp") input(type="imudp" port="514") input(type="imtcp" port="514") input(type="imrelp" port="514") The rsyslog daemon must be restarted for the changes to take effect: $ sudo systemctl restart rsyslog.service

b

All RHEL 9 remote access methods must be monitored.

AC-17 - Medium - CCI-000067 - V-258144 - SV-258144r1045286_rule

RMF Control

AC-17

Severity

M

CCI

CCI-000067

Version

RHEL-09-652030

Vuln IDs

V-258144

Rule IDs

SV-258144r1045286_rule

Logging remote access methods can be used to trace the decrease in the risks associated with remote user access management. It can also be used to spot cyberattacks and ensure ongoing compliance with organizational policies surrounding the use of remote access methods.

Checks: C-61885r1045284_chk

Verify that RHEL 9 monitors all remote access methods. Check that remote access methods are being logged by running the following command: $ grep -rE '(auth.\*|authpriv.\*|daemon.\*)' /etc/rsyslog.conf /etc/rsyslog.d/ /etc/rsyslog.conf:authpriv.* If "auth.*", "authpriv.*" or "daemon.*" are not configured to be logged, this is a finding.

Fix: F-61809r1045285_fix

Add or update the following lines to the "/etc/rsyslog.conf" file or a file in "/etc/rsyslog.d": auth.*;authpriv.*;daemon.* /var/log/secure The "rsyslog" service must be restarted for the changes to take effect with the following command: $ sudo systemctl restart rsyslog.service

b

RHEL 9 must authenticate the remote logging server for offloading audit logs via rsyslog.

AU-4 - Medium - CCI-001851 - V-258146 - SV-258146r1045288_rule

RMF Control

AU-4

Severity

M

CCI

Version

RHEL-09-652040

Vuln IDs

V-258146

Rule IDs

SV-258146r1045288_rule

Information stored in one location is vulnerable to accidental or incidental deletion or alteration. Offloading is a common process in information systems with limited audit storage capacity. RHEL 9 installation media provides "rsyslogd", a system utility providing support for message logging. Support for both internet and Unix domain sockets enables this utility to support both local and remote logging. Coupling this utility with "gnutls" (a secure communications library implementing the SSL, TLS and DTLS protocols) creates a method to securely encrypt and offload auditing. "Rsyslog" supported authentication modes include: anon - anonymous authentication x509/fingerprint - certificate fingerprint authentication x509/certvalid - certificate validation only x509/name - certificate validation and subject name authentication Satisfies: SRG-OS-000342-GPOS-00133, SRG-OS-000479-GPOS-00224

Checks: C-61887r1045287_chk

Verify RHEL 9 authenticates the remote logging server for offloading audit logs with the following command: $ grep -i 'StreamDriver[\.]*AuthMode' /etc/rsyslog.conf /etc/rsyslog.d/*.conf /etc/rsyslog.conf:$ActionSendStreamDriverAuthMode x509/name If the variable name "StreamDriverAuthMode" is present in an omfwd statement block, this is not a finding. However, if the "StreamDriverAuthMode" variable is in a module block, this is a finding. If the value of the "$ActionSendStreamDriverAuthMode or StreamDriver.AuthMode" option is not set to "x509/name" or the line is commented out, ask the system administrator (SA) to indicate how the audit logs are offloaded to a different system or media. If there is no evidence that the transfer of the audit logs being offloaded to another system or media is encrypted, this is a finding.

Fix: F-61811r926424_fix

Configure RHEL 9 to authenticate the remote logging server for offloading audit logs by setting the following option in "/etc/rsyslog.conf" or "/etc/rsyslog.d/[customfile].conf": $ActionSendStreamDriverAuthMode x509/name

b

RHEL 9 must encrypt the transfer of audit records offloaded onto a different system or media from the system being audited via rsyslog.

AU-4 - Medium - CCI-001851 - V-258147 - SV-258147r1045290_rule

RMF Control

AU-4

Severity

M

CCI

Version

RHEL-09-652045

Vuln IDs

V-258147

Rule IDs

SV-258147r1045290_rule

Information stored in one location is vulnerable to accidental or incidental deletion or alteration. Offloading is a common process in information systems with limited audit storage capacity. RHEL 9 installation media provides "rsyslogd", a system utility providing support for message logging. Support for both internet and Unix domain sockets enables this utility to support both local and remote logging. Coupling this utility with "gnutls" (a secure communications library implementing the SSL, TLS and DTLS protocols) creates a method to securely encrypt and offload auditing. "Rsyslog" supported authentication modes include: anon - anonymous authentication x509/fingerprint - certificate fingerprint authentication x509/certvalid - certificate validation only x509/name - certificate validation and subject name authentication Satisfies: SRG-OS-000342-GPOS-00133, SRG-OS-000479-GPOS-00224

Checks: C-61888r1045289_chk

Verify RHEL 9 encrypts audit records offloaded onto a different system or media from the system being audited via rsyslog with the following command: $ grep -i 'StreamDriver[\.]*Mode' /etc/rsyslog.conf /etc/rsyslog.d/*.conf /etc/rsyslog.conf:$ActionSendStreamDriverMode 1 If the value of the "$ActionSendStreamDriverMode or StreamDriver.Mode" option is not set to "1" or the line is commented out, this is a finding. If the variable name "StreamDriverAuthMode" is present in an omfwd statement block, this is not a finding. However, if the "StreamDriverAuthMode" variable is in a module block, this is a finding.

Fix: F-61812r926427_fix

Configure RHEL 9 to encrypt offloaded audit records via rsyslog by setting the following options in "/etc/rsyslog.conf" or "/etc/rsyslog.d/[customfile].conf": $ActionSendStreamDriverMode 1

b

RHEL 9 must encrypt via the gtls driver the transfer of audit records offloaded onto a different system or media from the system being audited via rsyslog.

AU-4 - Medium - CCI-001851 - V-258148 - SV-258148r1045292_rule

RMF Control

AU-4

Severity

M

CCI

Version

RHEL-09-652050

Vuln IDs

V-258148

Rule IDs

SV-258148r1045292_rule

Information stored in one location is vulnerable to accidental or incidental deletion or alteration. Offloading is a common process in information systems with limited audit storage capacity. RHEL 9 installation media provides "rsyslogd", a system utility providing support for message logging. Support for both internet and Unix domain sockets enables this utility to support both local and remote logging. Coupling this utility with "gnutls" (a secure communications library implementing the SSL, TLS and DTLS protocols) creates a method to securely encrypt and offload auditing. Satisfies: SRG-OS-000342-GPOS-00133, SRG-OS-000479-GPOS-00224

Checks: C-61889r1045291_chk

Verify RHEL 9 uses the gtls driver to encrypt audit records offloaded onto a different system or media from the system being audited with the following command: $ grep -Ei 'DefaultNetStreamDriver\b|StreamDriver.Name' /etc/rsyslog.conf /etc/rsyslog.d/*.conf /etc/rsyslog.conf:$DefaultNetstreamDriver gtls If the value of the "$DefaultNetstreamDriver or StreamDriver" option is not set to "gtls" or the line is commented out, this is a finding. If the variable name "StreamDriver" is present in an omfwd statement block, this is not a finding. However, if the "StreamDriver" variable is in a module block, this is a finding.

Fix: F-61813r926430_fix

Configure RHEL 9 to use the gtls driver to encrypt offloaded audit records by setting the following options in "/etc/rsyslog.conf" or "/etc/rsyslog.d/[customfile].conf": $DefaultNetstreamDriver gtls

b

RHEL 9 must be configured to forward audit records via TCP to a different system or media from the system being audited via rsyslog.

AU-4 - Medium - CCI-001851 - V-258149 - SV-258149r1106462_rule

RMF Control

AU-4

Severity

M

CCI

Version

RHEL-09-652055

Vuln IDs

V-258149

Rule IDs

SV-258149r1106462_rule

Information stored in one location is vulnerable to accidental or incidental deletion or alteration. Off-loading is a common process in information systems with limited audit storage capacity. RHEL 9 installation media provides "rsyslogd", a system utility providing support for message logging. Support for both internet and Unix domain sockets enables this utility to support both local and remote logging. Coupling this utility with "gnutls" (a secure communications library implementing the SSL, TLS and DTLS protocols) creates a method to securely encrypt and off-load auditing. Rsyslog provides three ways to forward message: the traditional UDP transport, which is extremely lossy but standard; the plain TCP based transport, which loses messages only during certain situations but is widely available; and the RELP transport, which does not lose messages but is currently available only as part of the rsyslogd 3.15.0 and above. Examples of each configuration: UDP *.* @remotesystemname TCP *.* @@remotesystemname RELP *.* :omrelp:remotesystemname:2514 Note that a port number was given as there is no standard port for RELP. Satisfies: SRG-OS-000479-GPOS-00224, SRG-OS-000480-GPOS-00227, SRG-OS-000342-GPOS-00133

Checks: C-61890r1106461_chk

Verify RHEL 9 audit system off-loads audit records onto a different system or media from the system being audited via rsyslog using TCP with the following command: $ sudo grep -iR '@@' /etc/rsyslog.conf /etc/rsyslog.d/ /etc/rsyslog.d/remoteLogging.conf:*.* @@[remoteloggingserver]:[port] If a remote server is not configured, or the line is commented out, ask the system administrator (SA) to indicate how the audit logs are off-loaded to a different system or media. If there is no evidence that the audit logs are being off-loaded to another system or media, this is a finding.

Fix: F-61814r1106361_fix

Configure RHEL 9 to off-load audit records onto a different system or media from the system being audited via TCP using rsyslog by specifying the remote logging server in "/etc/rsyslog.conf" or "/etc/rsyslog.d/[customfile].conf" with the name or IP address of the log aggregation server. *.* @@[remoteloggingserver]:[port]

b

RHEL 9 must use cron logging.

CM-6 - Medium - CCI-000366 - V-258150 - SV-258150r1045296_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-652060

Vuln IDs

V-258150

Rule IDs

SV-258150r1045296_rule

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

Checks: C-61891r1045295_chk

Verify that "rsyslog" is configured to log cron events with the following command: Note: If another logging package is used, substitute the utility configuration file for "/etc/rsyslog.conf" or "/etc/rsyslog.d/*.conf" files. $ grep -s cron /etc/rsyslog.conf /etc/rsyslog.d/*.conf /etc/rsyslog.conf:*.info;mail.none;authpriv.none;cron.none /var/log/messages /etc/rsyslog.conf:cron.* /var/log/cron If the command does not return a response, check for cron logging all facilities with the following command: $ logger -p local0.info "Test message for all facilities." Check the logs for the test message with: $ sudo tail /var/log/messages If "rsyslog" is not logging messages for the cron facility or all facilities, this is a finding.

Fix: F-61815r926436_fix

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

b

RHEL 9 audit package must be installed.

AU-3 - Medium - CCI-000130 - V-258151 - SV-258151r1045298_rule

RMF Control

AU-3

Severity

M

CCI

Version

RHEL-09-653010

Vuln IDs

V-258151

Rule IDs

SV-258151r1045298_rule

Without establishing what type of events occurred, the source of events, where events occurred, and the outcome of events, it would be difficult to establish, correlate, and investigate the events leading up to an outage or attack. Audit record content that may be necessary to satisfy this requirement includes, for example, time stamps, source and destination addresses, user/process identifiers, event descriptions, success/fail indications, filenames involved, and access control or flow control rules invoked. Associating event types with detected events in audit logs provides a means of investigating an attack, recognizing resource utilization or capacity thresholds, or identifying an improperly configured RHEL 9 system. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000038-GPOS-00016, SRG-OS-000039-GPOS-00017, SRG-OS-000040-GPOS-00018, SRG-OS-000041-GPOS-00019, SRG-OS-000042-GPOS-00021, SRG-OS-000051-GPOS-00024, SRG-OS-000054-GPOS-00025, SRG-OS-000122-GPOS-00063, SRG-OS-000254-GPOS-00095, SRG-OS-000255-GPOS-00096, SRG-OS-000337-GPOS-00129, SRG-OS-000348-GPOS-00136, SRG-OS-000349-GPOS-00137, SRG-OS-000350-GPOS-00138, SRG-OS-000351-GPOS-00139, SRG-OS-000352-GPOS-00140, SRG-OS-000353-GPOS-00141, SRG-OS-000354-GPOS-00142, SRG-OS-000358-GPOS-00145, SRG-OS-000365-GPOS-00152, SRG-OS-000392-GPOS-00172, SRG-OS-000475-GPOS-00220, SRG-OS-000055-GPOS-00026

Checks: C-61892r1045297_chk

Verify that the RHEL 9 audit service package is installed. Check that the audit service package is installed with the following command: $ dnf list --installed audit Example output: audit-3.0.7-101.el9_0.2.x86_64 If the "audit" package is not installed, this is a finding.

Fix: F-61816r926439_fix

Install the audit service package (if the audit service is not already installed) with the following command: $ sudo dnf install audit

b

RHEL 9 audit service must be enabled.

AU-3 - Medium - CCI-000130 - V-258152 - SV-258152r1015127_rule

RMF Control

AU-3

Severity

M

CCI

Version

RHEL-09-653015

Vuln IDs

V-258152

Rule IDs

SV-258152r1015127_rule

Without establishing what type of events occurred, it would be difficult to establish, correlate, and investigate the events leading up to an outage or attack. Ensuring the "auditd" service is active ensures audit records generated by the kernel are appropriately recorded. Additionally, a properly configured audit subsystem ensures that actions of individual system users can be uniquely traced to those users so they can be held accountable for their actions. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000038-GPOS-00016, SRG-OS-000039-GPOS-00017, SRG-OS-000040-GPOS-00018, SRG-OS-000041-GPOS-00019, SRG-OS-000042-GPOS-00021, SRG-OS-000051-GPOS-00024, SRG-OS-000054-GPOS-00025, SRG-OS-000122-GPOS-00063, SRG-OS-000254-GPOS-00095, SRG-OS-000255-GPOS-00096, SRG-OS-000337-GPOS-00129, SRG-OS-000348-GPOS-00136, SRG-OS-000349-GPOS-00137, SRG-OS-000350-GPOS-00138, SRG-OS-000351-GPOS-00139, SRG-OS-000352-GPOS-00140, SRG-OS-000353-GPOS-00141, SRG-OS-000354-GPOS-00142, SRG-OS-000358-GPOS-00145, SRG-OS-000365-GPOS-00152, SRG-OS-000392-GPOS-00172, SRG-OS-000475-GPOS-00220

Checks: C-61893r926441_chk

Verify the audit service is configured to produce audit records with the following command: $ 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 2022-05-24 12:56:56 EST; 4 weeks 0 days ago If the audit service is not "active" and "running", this is a finding.

Fix: F-61817r926442_fix

To enable the auditd service run the following command: $ sudo systemctl enable --now auditd

b

RHEL 9 audit system must take appropriate action when an error writing to the audit storage volume occurs.

AU-5 - Medium - CCI-000140 - V-258153 - SV-258153r1038966_rule

RMF Control

AU-5

Severity

M

CCI

CCI-000140

Version

RHEL-09-653020

Vuln IDs

V-258153

Rule IDs

SV-258153r1038966_rule

It is critical that when the operating system is at risk of failing to process audit logs as required, it takes action to mitigate the failure. Audit processing failures include software/hardware errors; failures in the audit capturing mechanisms; and audit storage capacity being reached or exceeded. Responses to audit failure depend upon the nature of the failure mode.

Checks: C-61894r926444_chk

Verify RHEL 9 takes the appropriate action when an audit processing failure occurs. Check that RHEL 9 takes the appropriate action when an audit processing failure occurs with the following command: $ sudo grep disk_error_action /etc/audit/auditd.conf disk_error_action = HALT If the value of the "disk_error_action" option is not "SYSLOG", "SINGLE", or "HALT", or the line is commented out, ask the system administrator (SA) to indicate how the system takes appropriate action when an audit process failure occurs. If there is no evidence of appropriate action, this is a finding.

Fix: F-61818r926445_fix

Configure RHEL 9 to shut down by default upon audit failure (unless availability is an overriding concern). Add or update the following line (depending on configuration "disk_error_action" can be set to "SYSLOG" or "SINGLE" depending on configuration) in "/etc/audit/auditd.conf" file: disk_error_action = HALT If availability has been determined to be more important, and this decision is documented with the information system security officer (ISSO), configure the operating system to notify SA staff and ISSO staff in the event of an audit processing failure by setting the "disk_error_action" to "SYSLOG".

b

RHEL 9 audit system must take appropriate action when the audit storage volume is full.

AU-5 - Medium - CCI-000140 - V-258154 - SV-258154r1038966_rule

RMF Control

AU-5

Severity

M

CCI

CCI-000140

Version

RHEL-09-653025

Vuln IDs

V-258154

Rule IDs

SV-258154r1038966_rule

It is critical that when the operating system is at risk of failing to process audit logs as required, it takes action to mitigate the failure. Audit processing failures include software/hardware errors; failures in the audit capturing mechanisms; and audit storage capacity being reached or exceeded. Responses to audit failure depend upon the nature of the failure mode.

Checks: C-61895r926447_chk

Verify RHEL 9 takes the appropriate action when the audit storage volume is full. Check that RHEL 9 takes the appropriate action when the audit storage volume is full with the following command: $ sudo grep disk_full_action /etc/audit/auditd.conf disk_full_action = HALT If the value of the "disk_full_action" option is not "SYSLOG", "SINGLE", or "HALT", or the line is commented out, ask the system administrator (SA) to indicate how the system takes appropriate action when an audit storage volume is full. If there is no evidence of appropriate action, this is a finding.

Fix: F-61819r926448_fix

Configure RHEL 9 to shut down by default upon audit failure (unless availability is an overriding concern). Add or update the following line (depending on configuration "disk_full_action" can be set to "SYSLOG" or "SINGLE" depending on configuration) in "/etc/audit/auditd.conf" file: disk_full_action = HALT If availability has been determined to be more important, and this decision is documented with the information system security officer (ISSO), configure the operating system to notify SA staff and ISSO staff in the event of an audit processing failure by setting the "disk_full_action" to "SYSLOG".

b

RHEL 9 must allocate audit record storage capacity to store at least one week's worth of audit records.

AU-4 - Medium - CCI-001849 - V-258155 - SV-258155r1045300_rule

RMF Control

AU-4

Severity

M

CCI

CCI-001849

Version

RHEL-09-653030

Vuln IDs

V-258155

Rule IDs

SV-258155r1045300_rule

To ensure RHEL 9 systems have a sufficient storage capacity in which to write the audit logs, RHEL 9 needs to be able to allocate audit record storage capacity. The task of allocating audit record storage capacity is usually performed during initial installation of RHEL 9. Satisfies: SRG-OS-000341-GPOS-00132, SRG-OS-000342-GPOS-00133

Checks: C-61896r1045299_chk

Verify RHEL 9 allocates audit record storage capacity to store at least one week of audit records when audit records are not immediately sent to a central audit record storage facility. Note: The partition size needed to capture a week of audit records is based on the activity level of the system and the total storage capacity available. Typically 10.0GB of storage space for audit records should be sufficient. Determine which partition the audit records are being written to with the following command: $ sudo grep -w log_file /etc/audit/auditd.conf log_file = /var/log/audit/audit.log Check the size of the partition that audit records are written to with the following command and verify whether it is sufficiently large: # df -h /var/log/audit/ /dev/sda2 24G 10.4G 13.6G 43% /var/log/audit If the audit record partition is not allocated for sufficient storage capacity, this is a finding.

Fix: F-61820r926451_fix

Allocate enough storage capacity for at least one week of audit records when audit records are not immediately sent to a central audit record storage facility. If audit records are stored on a partition made specifically for audit records, resize the partition with sufficient space to contain one week of audit records. If audit records are not stored on a partition made specifically for audit records, a new partition with sufficient space will need be to be created.

b

RHEL 9 must take action when allocated audit record storage volume reaches 75 percent of the repository maximum audit record storage capacity.

AU-5 - Medium - CCI-001855 - V-258156 - SV-258156r1106364_rule

RMF Control

AU-5

Severity

M

CCI

Version

RHEL-09-653035

Vuln IDs

V-258156

Rule IDs

SV-258156r1106364_rule

If security personnel are not notified immediately when storage volume reaches a maximum of 75 percent utilization, they are unable to plan for audit record storage capacity expansion. The notification can be set to trigger at lower utilization thresholds at the information system security officer's (ISSO's) discretion.

Checks: C-61897r1106363_chk

Verify RHEL 9 takes action when allocated audit record storage volume reaches 75 percent of the repository maximum audit record storage capacity with the following command: $ sudo grep -w space_left /etc/audit/auditd.conf space_left = 25% If the value of the "space_left" keyword is not set to 25 percent or greater of the storage volume allocated to audit logs, or if the line is commented out, ask the system administrator (SA) to indicate how the system is providing real-time alerts to the SA and ISSO. If the "space_left" value is not configured to the value 25 percent or more, this is a finding.

Fix: F-61821r1102076_fix

Configure RHEL 9 to initiate an action to notify the SA and ISSO (at a minimum) when allocated audit record storage volume reaches (at most) 75 percent of the repository maximum audit record storage capacity by adding/modifying the following line in the /etc/audit/auditd.conf file. space_left = 25%

b

RHEL 9 must notify the system administrator (SA) and information system security officer (ISSO) (at a minimum) when allocated audit record storage volume reaches 75 percent utilization.

AU-5 - Medium - CCI-001855 - V-258157 - SV-258157r1134932_rule

RMF Control

AU-5

Severity

M

CCI

Version

RHEL-09-653040

Vuln IDs

V-258157

Rule IDs

SV-258157r1134932_rule

If security personnel are not notified immediately when storage volume reaches 75 percent utilization, they are unable to plan for audit record storage capacity expansion.

Checks: C-61898r926456_chk

Verify RHEL 9 notifies the SA and ISSO (at a minimum) when allocated audit record storage volume reaches 75 percent of the repository maximum audit record storage capacity with the following command: $ sudo grep -w space_left_action /etc/audit/auditd.conf space_left_action = email If the value of the "space_left_action" is not set to "email", or if the line is commented out, ask the SA to indicate how the system is providing real-time alerts to the SA and ISSO. If there is no evidence that real-time alerts are configured on the system, this is a finding.

Fix: F-61822r926457_fix

Configure RHEL 9 to initiate an action to notify the SA and ISSO (at a minimum) when allocated audit record storage volume reaches 75 percent of the repository maximum audit record storage capacity by adding/modifying the following line in the /etc/audit/auditd.conf file. space_left_action = email

b

RHEL 9 must take action when allocated audit record storage volume reaches 95 percent of the audit record storage capacity.

AU-5 - Medium - CCI-001855 - V-258158 - SV-258158r971542_rule

RMF Control

AU-5

Severity

M

CCI

Version

RHEL-09-653045

Vuln IDs

V-258158

Rule IDs

SV-258158r971542_rule

If action is not taken when storage volume reaches 95 percent utilization, the auditing system may fail when the storage volume reaches capacity.

Checks: C-61899r926459_chk

Verify RHEL 9 takes action when allocated audit record storage volume reaches 95 percent of the repository maximum audit record storage capacity with the following command: $ sudo grep -w admin_space_left /etc/audit/auditd.conf admin_space_left = 5% If the value of the "admin_space_left" keyword is not set to 5 percent of the storage volume allocated to audit logs, or if the line is commented out, ask the system administrator (SA) to indicate how the system is taking action if the allocated storage is about to reach capacity. If the "space_left" value is not configured to the correct value, this is a finding.

Fix: F-61823r926460_fix

Configure RHEL 9 to initiate an action when allocated audit record storage volume reaches 95 percent of the repository maximum audit record storage capacity by adding/modifying the following line in the /etc/audit/auditd.conf file. admin_space_left = 5%

b

RHEL 9 must take action when allocated audit record storage volume reaches 95 percent of the repository maximum audit record storage capacity.

AU-5 - Medium - CCI-001855 - V-258159 - SV-258159r971542_rule

RMF Control

AU-5

Severity

M

CCI

Version

RHEL-09-653050

Vuln IDs

V-258159

Rule IDs

SV-258159r971542_rule

If action is not taken when storage volume reaches 95 percent utilization, the auditing system may fail when the storage volume reaches capacity.

Checks: C-61900r926462_chk

Verify that RHEL 9 is configured to take action in the event of allocated audit record storage volume reaches 95 percent of the repository maximum audit record storage capacity with the following command: $ sudo grep admin_space_left_action /etc/audit/auditd.conf admin_space_left_action = single If the value of the "admin_space_left_action" is not set to "single", or if the line is commented out, ask the system administrator (SA) to indicate how the system is providing real-time alerts to the SA and information system security officer (ISSO). If there is no evidence that real-time alerts are configured on the system, this is a finding.

Fix: F-61824r926463_fix

Configure "auditd" service to take action in the event of allocated audit record storage volume reaches 95 percent of the repository maximum audit record storage capacity. Edit the following line in "/etc/audit/auditd.conf" to ensure that the system is forced into single user mode in the event the audit record storage volume is about to reach maximum capacity: admin_space_left_action = single The audit daemon must be restarted for changes to take effect.

b

RHEL 9 audit system must take appropriate action when the audit files have reached maximum size.

AU-5 - Medium - CCI-000140 - V-258160 - SV-258160r1038966_rule

RMF Control

AU-5

Severity

M

CCI

CCI-000140

Version

RHEL-09-653055

Vuln IDs

V-258160

Rule IDs

SV-258160r1038966_rule

It is critical that when the operating system is at risk of failing to process audit logs as required, it takes action to mitigate the failure. Audit processing failures include software/hardware errors; failures in the audit capturing mechanisms; and audit storage capacity being reached or exceeded. Responses to audit failure depend upon the nature of the failure mode.

Checks: C-61901r926465_chk

Verify that RHEL 9 takes the appropriate action when the audit files have reached maximum size with the following command: $ sudo grep max_log_file_action /etc/audit/auditd.conf max_log_file_action = ROTATE If the value of the "max_log_file_action" option is not "ROTATE", "SINGLE", or the line is commented out, ask the system administrator (SA)to indicate how the system takes appropriate action when an audit storage volume is full. If there is no evidence of appropriate action, this is a finding.

Fix: F-61825r926466_fix

Configure RHEL 9 to rotate the audit log when it reaches maximum size. Add or update the following line in "/etc/audit/auditd.conf" file: max_log_file_action = ROTATE

b

RHEL 9 must label all offloaded audit logs before sending them to the central log server.

AU-3 - Medium - CCI-000132 - V-258161 - SV-258161r958416_rule

RMF Control

AU-3

Severity

M

CCI

CCI-000132

Version

RHEL-09-653060

Vuln IDs

V-258161

Rule IDs

SV-258161r958416_rule

Enriched logging is needed to determine who, what, and when events occur on a system. Without this, determining root cause of an event will be much more difficult. When audit logs are not labeled before they are sent to a central log server, the audit data will not be able to be analyzed and tied back to the correct system. Satisfies: SRG-OS-000039-GPOS-00017, SRG-OS-000342-GPOS-00133, SRG-OS-000479-GPOS-00224

Checks: C-61902r926468_chk

Verify that RHEL 9 Audit Daemon is configured to label all offloaded audit logs, with the following command: $ sudo grep name_format /etc/audit/auditd.conf name_format = hostname If the "name_format" option is not "hostname", "fqd", or "numeric", or the line is commented out, this is a finding.

Fix: F-61826r926469_fix

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

b

RHEL 9 must take appropriate action when the internal event queue is full.

AU-4 - Medium - CCI-001851 - V-258162 - SV-258162r958754_rule

RMF Control

AU-4

Severity

M

CCI

Version

RHEL-09-653065

Vuln IDs

V-258162

Rule IDs

SV-258162r958754_rule

The audit system should have an action setup in the event the internal event queue becomes full so that no data is lost. Information stored in one location is vulnerable to accidental or incidental deletion or alteration. Offloading is a common process in information systems with limited audit storage capacity. Satisfies: SRG-OS-000342-GPOS-00133, SRG-OS-000479-GPOS-00224

Checks: C-61903r926471_chk

Verify that RHEL 9 audit system is configured to take an appropriate action when the internal event queue is full: $ sudo grep -i overflow_action /etc/audit/auditd.conf overflow_action = syslog If the value of the "overflow_action" option is not set to "syslog", "single", "halt" or the line is commented out, ask the system administrator (SA) to indicate how the audit logs are offloaded to a different system or media. If there is no evidence that the transfer of the audit logs being offloaded to another system or media takes appropriate action if the internal event queue becomes full, this is a finding.

Fix: F-61827r926472_fix

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

b

RHEL 9 System Administrator (SA) and/or information system security officer (ISSO) (at a minimum) must be alerted of an audit processing failure event.

AU-5 - Medium - CCI-000139 - V-258163 - SV-258163r958424_rule

RMF Control

AU-5

Severity

M

CCI

Version

RHEL-09-653070

Vuln IDs

V-258163

Rule IDs

SV-258163r958424_rule

It is critical for the appropriate personnel to be aware if a system is at risk of failing to process audit logs as required. Without this notification, the security personnel may be unaware of an impending failure of the audit capability, and system operation may be adversely affected. Audit processing failures include software/hardware errors, failures in the audit capturing mechanisms, and audit storage capacity being reached or exceeded. This requirement applies to each audit data storage repository (i.e., distinct information system component where audit records are stored), the centralized audit storage capacity of organizations (i.e., all audit data storage repositories combined), or both. Satisfies: SRG-OS-000046-GPOS-00022, SRG-OS-000343-GPOS-00134

Checks: C-61904r926474_chk

Verify that RHEL 9 is configured to notify the SA and/or ISSO (at a minimum) in the event of an audit processing failure with the following command: $ sudo grep action_mail_acct /etc/audit/auditd.conf action_mail_acct = root If the value of the "action_mail_acct" keyword is not set to "root" and/or other accounts for security personnel, the "action_mail_acct" keyword is missing, or the retuned line is commented out, ask the SA to indicate how they and the ISSO are notified of an audit process failure. If there is no evidence of the proper personnel being notified of an audit processing failure, this is a finding.

Fix: F-61828r926475_fix

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

b

RHEL 9 audit system must audit local events.

AU-12 - Medium - CCI-000169 - V-258164 - SV-258164r1045301_rule

RMF Control

AU-12

Severity

M

CCI

CCI-000169

Version

RHEL-09-653075

Vuln IDs

V-258164

Rule IDs

SV-258164r1045301_rule

Without establishing what type of events occurred, the source of events, where events occurred, and the outcome of events, it would be difficult to establish, correlate, and investigate the events leading up to an outage or attack. If option "local_events" isn't set to "yes" only events from network will be aggregated. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000480-GPOS-00227

Checks: C-61905r926477_chk

Verify that the RHEL 9 audit system is configured to audit local events with the following command: $ sudo grep local_events /etc/audit/auditd.conf local_events = yes If "local_events" isn't set to "yes", if the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61829r926478_fix

Configure RHEL 9 to generate audit records for local events by adding or updating the following line in "/etc/audit/auditd.conf": local_events = yes The audit daemon must be restarted for the changes to take effect.

b

RHEL 9 audit logs must be group-owned by root or by a restricted logging group to prevent unauthorized read access.

AU-9 - Medium - CCI-000162 - V-258165 - SV-258165r958434_rule

RMF Control

AU-9

Severity

M

CCI

Version

RHEL-09-653080

Vuln IDs

V-258165

Rule IDs

SV-258165r958434_rule

Unauthorized disclosure of audit records can reveal system and configuration data to attackers, thus compromising its confidentiality. Satisfies: SRG-OS-000057-GPOS-00027, SRG-OS-000058-GPOS-00028, SRG-OS-000059-GPOS-00029, SRG-OS-000206-GPOS-00084

Checks: C-61906r926480_chk

Verify the audit logs are group-owned by "root" or a restricted logging group. First determine if a group other than "root" has been assigned to the audit logs with the following command: $ sudo grep log_group /etc/audit/auditd.conf Then determine where the audit logs are stored with the following command: $ sudo grep -iw log_file /etc/audit/auditd.conf log_file = /var/log/audit/audit.log Then using the location of the audit log file, determine if the audit log is group-owned by "root" using the following command: $ sudo stat -c "%G %n" /var/log/audit/audit.log root /var/log/audit/audit.log If the audit log is not group-owned by "root" or the configured alternative logging group, this is a finding.

Fix: F-61830r926481_fix

Change the group of the directory of "/var/log/audit" to be owned by a correct group. Identify the group that is configured to own audit log: $ sudo grep -P '^[ ]*log_group[ ]+=.*$' /etc/audit/auditd.conf Change the ownership to that group: $ sudo chgrp ${GROUP} /var/log/audit

b

RHEL 9 audit log directory must be owned by root to prevent unauthorized read access.

AU-9 - Medium - CCI-000162 - V-258166 - SV-258166r1045303_rule

RMF Control

AU-9

Severity

M

CCI

Version

RHEL-09-653085

Vuln IDs

V-258166

Rule IDs

SV-258166r1045303_rule

Unauthorized disclosure of audit records can reveal system and configuration data to attackers, thus compromising its confidentiality. Satisfies: SRG-OS-000057-GPOS-00027, SRG-OS-000058-GPOS-00028, SRG-OS-000059-GPOS-00029, SRG-OS-000206-GPOS-00084

Checks: C-61907r1045302_chk

Verify the audit logs directory is owned by "root". Determine where the audit logs are stored with the following command: $ sudo grep -iw log_file /etc/audit/auditd.conf log_file = /var/log/audit/audit.log Using the location of the audit log file, determine if the audit log directory is owned by "root" using the following command: $ sudo stat -c '%U %n' /var/log/audit root /var/log/audit If the audit log directory is not owned by "root", this is a finding.

Fix: F-61831r926484_fix

Configure the audit log to be protected from unauthorized read access by setting the correct owner as "root" with the following command: $ sudo chown root /var/log/audit

b

RHEL 9 audit logs file must have mode 0600 or less permissive to prevent unauthorized access to the audit log.

AU-9 - Medium - CCI-000162 - V-258167 - SV-258167r1101918_rule

RMF Control

AU-9

Severity

M

CCI

Version

RHEL-09-653090

Vuln IDs

V-258167

Rule IDs

SV-258167r1101918_rule

Only authorized personnel should be aware of errors and the details of the errors. Error messages are an indicator of an organization's operational state or can identify the RHEL 9 system or platform. Additionally, Personally Identifiable Information (PII) and operational information must not be revealed through error messages to unauthorized personnel or their designated representatives. The structure and content of error messages must be carefully considered by the organization and development team. The extent to which the information system is able to identify and handle error conditions is guided by organizational policy and operational requirements. Satisfies: SRG-OS-000057-GPOS-00027, SRG-OS-000058-GPOS-00028, SRG-OS-000059-GPOS-00029, SRG-OS-000206-GPOS-00084

Checks: C-61908r1101917_chk

Verify the audit logs have a mode of "0600". Determine where the audit logs are stored with the following command: $ sudo find /var/log/audit/ -type f -exec stat -c '%a %n' {} \; 600 /var/log/audit/audit.log Using the location of the audit log file, determine the mode of each audit log with the following command: $ sudo find /var/log/audit/ -type f -exec stat -c '%a %n' {} \; rw-------. 2 root root 237923 Jun 11 11:56 /var/log/audit/audit.log If the audit logs have a mode more permissive than "0600", this is a finding.

Fix: F-61832r1045305_fix

Configure the audit logs to have a mode of "0600" with the following command: Replace "[audit_log_file]" with the path to each audit log file. By default, these logs are located in "/var/log/audit/. $ sudo chmod 0600 /var/log/audit/[audit_log_file] Check the group that owns the system audit logs: $ sudo grep -iw log_group /etc/audit/auditd.conf If log_group is set to a user other than root, configure the permissions the following way: $ sudo chmod 0640 $log_file $ sudo chmod 0440 $log_file.* Otherwise, configure the permissions the following way: $ sudo chmod 0600 $log_file $ sudo chmod 0400 $log_file.*

b

RHEL 9 must periodically flush audit records to disk to prevent the loss of audit records.

AU-6 - Medium - CCI-000154 - V-258168 - SV-258168r958428_rule

RMF Control

AU-6

Severity

M

CCI

CCI-000154

Version

RHEL-09-653095

Vuln IDs

V-258168

Rule IDs

SV-258168r958428_rule

If option "freq" is not set to a value that requires audit records being written to disk after a threshold number is reached, then audit records may be lost.

Checks: C-61909r943022_chk

Verify that audit system is configured to flush to disk after every 100 records with the following command: $ sudo grep freq /etc/audit/auditd.conf freq = 100 If "freq" isn't set to a value between "1" and "100", the value is missing, or the line is commented out, this is a finding.

Fix: F-61833r943023_fix

Configure RHEL 9 to flush audit to disk by adding or updating the following rule in "/etc/audit/auditd.conf": freq = 100 The audit daemon must be restarted for the changes to take effect.

b

RHEL 9 must produce audit records containing information to establish the identity of any individual or process associated with the event.

CM-6 - Medium - CCI-000366 - V-258169 - SV-258169r991556_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-653100

Vuln IDs

V-258169

Rule IDs

SV-258169r991556_rule

Without establishing what type of events occurred, the source of events, where events occurred, and the outcome of events, it would be difficult to establish, correlate, and investigate the events leading up to an outage or attack. Audit record content that may be necessary to satisfy this requirement includes, for example, time stamps, source and destination addresses, user/process identifiers, event descriptions, success/fail indications, filenames involved, and access control or flow control rules invoked. Enriched logging aids in making sense of who, what, and when events occur on a system. Without this, determining root cause of an event will be much more difficult. Satisfies: SRG-OS-000255-GPOS-00096, SRG-OS-000480-GPOS-00227

Checks: C-61910r926492_chk

Verify that RHEL 9 audit system is configured to resolve audit information before writing to disk, with the following command: $ sudo grep log_format /etc/audit/auditd.conf log_format = ENRICHED If the "log_format" option is not "ENRICHED", or the line is commented out, this is a finding.

Fix: F-61834r926493_fix

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

b

RHEL 9 must write audit records to disk.

CM-6 - Medium - CCI-000366 - V-258170 - SV-258170r991589_rule

RMF Control

CM-6

Severity

M

CCI

Version

RHEL-09-653105

Vuln IDs

V-258170

Rule IDs

SV-258170r991589_rule

Audit data should be synchronously written to disk to ensure log integrity. This setting assures that all audit event data is written disk.

Checks: C-61911r926495_chk

Verify that the audit system is configured to write logs to the disk with the following command: $ sudo grep write_logs /etc/audit/auditd.conf write_logs = yes If "write_logs" does not have a value of "yes", the line is commented out, or the line is missing, this is a finding.

Fix: F-61835r926496_fix

Configure the audit system to write log files to the disk. Edit the /etc/audit/auditd.conf file and add or update the "write_logs" option to "yes": write_logs = yes The audit daemon must be restarted for changes to take effect.

b

RHEL 9 must allow only the information system security manager (ISSM) (or individuals or roles appointed by the ISSM) to select which auditable events are to be audited.

AU-12 - Medium - CCI-000171 - V-258171 - SV-258171r1134934_rule

RMF Control

AU-12

Severity

M

CCI

CCI-000171

Version

RHEL-09-653110

Vuln IDs

V-258171

Rule IDs

SV-258171r1134934_rule

Without the capability to restrict the roles and individuals that can select which events are audited, unauthorized personnel may be able to prevent the auditing of critical events. Misconfigured audits may degrade the system's performance by overwhelming the audit log. Misconfigured audits may also make it more difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one.

Checks: C-61912r1134933_chk

Verify that the files in directory "/etc/audit/rules.d/" and "/etc/audit/auditd.conf" file have a mode of "0640" or less permissive with the following command: $ sudo find /etc/audit/rules.d/ /etc/audit/audit.rules /etc/audit/auditd.conf -type f -exec stat -c "%a %n" {} \; 600 /etc/audit/rules.d/audit.rules 640 /etc/audit/audit.rules 640 /etc/audit/auditd.conf If the audit configuration files have a mode more permissive than those shown, this is a finding.

Fix: F-61836r926499_fix

Configure the files in directory "/etc/audit/rules.d/" and the "/etc/audit/auditd.conf" file to have a mode of "0640" with the following commands: $ sudo chmod 0640 /etc/audit/rules.d/audit.rules $ sudo chmod 0640 /etc/audit/rules.d/[customrulesfile].rules $ sudo chmod 0640 /etc/audit/auditd.conf

a

RHEL 9 must allocate an audit_backlog_limit of sufficient size to capture processes that start prior to the audit daemon.

AU-14 - Low - CCI-001464 - V-258173 - SV-258173r1101933_rule

RMF Control

AU-14

Severity

L

CCI

CCI-001464

Version

RHEL-09-653120

Vuln IDs

V-258173

Rule IDs

SV-258173r1101933_rule

Without the capability to generate audit records, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. If auditing is enabled late in the startup process, the actions of some startup processes may not be audited. Some audit systems also maintain state information only available if auditing is enabled before a given process is created. Audit records can be generated from various components within the information system (e.g., module or policy filter). Allocating an audit_backlog_limit of sufficient size is critical in maintaining a stable boot process. With an insufficient limit allocated, the system is susceptible to boot failures and crashes. Satisfies: SRG-OS-000254-GPOS-00095, SRG-OS-000341-GPOS-00132

Checks: C-61914r1101932_chk

Verify RHEL 9 allocates a sufficient audit_backlog_limit to capture processes that start prior to the audit daemon with the following command: $ sudo grubby --info=ALL | grep args | grep 'audit_backlog_limit' If the command returns any outputs, and audit_backlog_limit is less than "8192", this is a finding.

Fix: F-61838r926505_fix

Configure RHEL 9 to allocate sufficient audit_backlog_limit to capture processes that start prior to the audit daemon with the following command: $ sudo grubby --update-kernel=ALL --args=audit_backlog_limit=8192

b

RHEL 9 must have mail aliases to notify the information system security officer (ISSO) and system administrator (SA) (at a minimum) in the event of an audit processing failure.

AU-5 - Medium - CCI-000139 - V-258174 - SV-258174r958424_rule

RMF Control

AU-5

Severity

M

CCI

Version

RHEL-09-653125

Vuln IDs

V-258174

Rule IDs

SV-258174r958424_rule

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

Checks: C-61915r926507_chk

Verify that RHEL 9 is configured to notify the appropriate interactive users in the event of an audit processing failure. Find the alias maps that are being used with the following command: $ postconf alias_maps alias_maps = hash:/etc/aliases Query the Postfix alias maps for an alias for the root user with the following command: $ postmap -q root hash:/etc/aliases isso If an alias is not set, this is a finding.

Fix: F-61839r926508_fix

Edit the aliases map file (by default /etc/aliases) used by Postfix and configure a root alias (using the user ISSO as an example): root: ISSO and then update the aliases database with the command: $ sudo newaliases

b

RHEL 9 audispd-plugins package must be installed.

AU-4 - Medium - CCI-001851 - V-258175 - SV-258175r1045310_rule

RMF Control

AU-4

Severity

M

CCI

Version

RHEL-09-653130

Vuln IDs

V-258175

Rule IDs

SV-258175r1045310_rule

"audispd-plugins" provides plugins for the real-time interface to the audit subsystem, "audispd". These plugins can do things like relay events to remote machines or analyze events for suspicious behavior.

Checks: C-61916r1045309_chk

Verify that RHEL 9 has the audispd-plugins package installed with the following command: $ dnf list --installed audispd-plugins Example output: audispd-plugins.x86_64 3.0.7-101.el9_0.2 If the "audispd-plugins" package is not installed, this is a finding.

Fix: F-61840r926511_fix

The audispd-plugins package can be installed with the following command: $ sudo dnf install audispd-plugins

b

RHEL 9 must audit uses of the "execve" system call.

AC-6 - Medium - CCI-002233 - V-258176 - SV-258176r1106366_rule

RMF Control

AC-6

Severity

M

CCI

CCI-002233

Version

RHEL-09-654010

Vuln IDs

V-258176

Rule IDs

SV-258176r1106366_rule

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

Checks: C-61917r1106365_chk

Verify RHEL 9 is configured to audit the execution of the "execve" system call with the following command: $ sudo auditctl -l | grep execve -a always,exit -S arch=b32 -S execve -C uid!=euid -F euid=0 -F key=execpriv -a always,exit -S arch=b64 -S execve -C uid!=euid -F euid=0 -F key=execpriv -a always,exit -S arch=b32 -S execve -C gid!=egid -F egid=0 -F key=execpriv -a always,exit -S arch=b64 -S execve -C gid!=egid -F egid=0 -F key=execpriv If the command does not return all lines, or the lines are commented out, this is a finding.

Fix: F-61841r1045312_fix

Configure RHEL 9 to audit the execution of the "execve" system call. Add or update the following file system rules to "/etc/audit/rules.d/audit.rules": -a always,exit -F arch=b32 -S execve -C uid!=euid -F euid=0 -k execpriv -a always,exit -F arch=b64 -S execve -C uid!=euid -F euid=0 -k execpriv -a always,exit -F arch=b32 -S execve -C gid!=egid -F egid=0 -k execpriv -a always,exit -F arch=b64 -S execve -C gid!=egid -F egid=0 -k execpriv To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

RHEL 9 must audit all uses of the chmod, fchmod, and fchmodat system calls.

AU-3 - Medium - CCI-000130 - V-258177 - SV-258177r1106368_rule

RMF Control

AU-3

Severity

M

CCI

Version

RHEL-09-654015

Vuln IDs

V-258177

Rule IDs

SV-258177r1106368_rule

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). When a user logs on, the auid is set to the uid of the account being authenticated. Daemons are not user sessions and have the loginuid set to -1. The auid representation is an unsigned 32-bit integer, which equals 4294967295. The audit system interprets -1, 4294967295, and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each system call made by all programs on the system. Therefore, it is very important to use system call rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance can be helped, however, by combining system calls into one rule whenever possible. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203

Checks: C-61918r1106367_chk

Verify RHEL 9 is configured to audit the execution of the "chmod", "fchmod", and "fchmodat" system calls with the following command: $ sudo auditctl -l | grep chmod -a always,exit -S arch=b32 -S chmod,fchmod,fchmodat -F auid>=1000 -F auid!=-1 -F key=perm_mod -a always,exit -S arch=b64 -S chmod,fchmod,fchmodat -F auid>=1000 -F auid!=-1 -F key=perm_mod If both the "b32" and "b64" audit rules are not defined for the "chmod", "fchmod", and "fchmodat" system calls, this is a finding.

Fix: F-61842r1045315_fix

Configure RHEL 9 to generate audit records upon successful/unsuccessful attempts to use the "chmod", "fchmod", and "fchmodat" syscalls. Add or update the following rules in "/etc/audit/rules.d/audit.rules": -a always,exit -F arch=b32 -S chmod,fchmod,fchmodat -F auid>=1000 -F auid!=unset -k perm_mod -a always,exit -F arch=b64 -S chmod,fchmod,fchmodat -F auid>=1000 -F auid!=unset -k perm_mod To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

RHEL 9 must audit all uses of the chown, fchown, fchownat, and lchown system calls.

AU-3 - Medium - CCI-000130 - V-258178 - SV-258178r1106370_rule

RMF Control

AU-3

Severity

M

CCI

Version

RHEL-09-654020

Vuln IDs

V-258178

Rule IDs

SV-258178r1106370_rule

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). When a user logs on, the auid is set to the uid of the account being authenticated. Daemons are not user sessions and have the loginuid set to -1. The auid representation is an unsigned 32-bit integer, which equals 4294967295. The audit system interprets -1, 4294967295, and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each system call made by all programs on the system. Therefore, it is very important to use system call rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance can be helped, however, by combining system calls into one rule whenever possible. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SRG-OS-000474-GPOS-00219

Checks: C-61919r1106369_chk

Verify RHEL 9 is configured to audit the execution of the "chown", "fchown", "fchownat", and "lchown" system calls with the following command: $ sudo auditctl -l | grep chown -a always,exit -S arch=b32 -S lchown,fchown,chown,fchownat -F auid>=1000 -F auid!=-1 -F key=perm_mod -a always,exit -S arch=b64 -S chown,fchown,lchown,fchownat -F auid>=1000 -F auid!=-1 -F key=perm_mod If both the "b32" and "b64" audit rules are not defined for the "chown", "fchown", "fchownat", and "lchown" system calls, this is a finding.

Fix: F-61843r1045318_fix

Configure RHEL 9 to generate audit records upon successful/unsuccessful attempts to use the "chown", "fchown", "fchownat", and "lchown"" system calls. Add or update the following rules in "/etc/audit/rules.d/audit.rules": -a always,exit -F arch=b32 -S chown,fchown,fchownat,lchown -F auid>=1000 -F auid!=unset -k perm_mod -a always,exit -F arch=b64 -S chown,fchown,fchownat,lchown -F auid>=1000 -F auid!=unset -k perm_mod To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

RHEL 9 must audit all uses of the setxattr, fsetxattr, lsetxattr, removexattr, fremovexattr, and lremovexattr system calls.

AU-3 - Medium - CCI-000130 - V-258179 - SV-258179r1106371_rule

RMF Control

AU-3

Severity

M

CCI

Version

RHEL-09-654025

Vuln IDs

V-258179

Rule IDs

SV-258179r1106371_rule

Without generating audit records specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). When a user logs on, the auid is set to the uid of the account being authenticated. Daemons are not user sessions and have the loginuid set to -1. The auid representation is an unsigned 32-bit integer, which equals 4294967295. The audit system interprets -1, 4294967295, and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each system call made by all programs on the system. Therefore, it is very important to use system call rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance can be helped, however, by combining system calls into one rule whenever possible. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000462-GPOS-00206, SRG-OS-000463-GPOS-00207, SRG-OS-000471-GPOS-00215, SRG-OS-000474-GPOS-00219, SRG-OS-000466-GPOS-00210, SRG-OS-000064-GPOS-00033

Checks: C-61920r1101944_chk

Verify RHEL 9 is configured to audit the execution of the "setxattr", "fsetxattr", "lsetxattr", "removexattr", "fremovexattr", and "lremovexattr" system calls with the following command: $ sudo auditctl -l | grep xattr -a always,exit -S arch=b32 -S setxattr,lsetxattr,fsetxattr,removexattr,lremovexattr,fremovexattr -F auid>=1000 -F auid!=-1 -F key=perm_mod -a always,exit -S arch=b64 -S setxattr,lsetxattr,fsetxattr,removexattr,lremovexattr,fremovexattr -F auid>=1000 -F auid!=-1 -F key=perm_mod -a always,exit -S arch=b32 -S setxattr,lsetxattr,fsetxattr,removexattr,lremovexattr,fremovexattr -F auid=0 -F key=perm_mod -a always,exit -S arch=b64 -S setxattr,lsetxattr,fsetxattr,removexattr,lremovexattr,fremovexattr -F auid=0 -F key=perm_mod If both the "b32" and "b64" audit rules are not defined for the "setxattr", "fsetxattr", "lsetxattr", "removexattr", "fremovexattr", and "lremovexattr" system calls, or any of the lines returned are commented out, this is a finding.

Fix: F-61844r1045321_fix

Configure RHEL 9 to audit the execution of the "setxattr", "fsetxattr", "lsetxattr", "removexattr", "fremovexattr", and "lremovexattr" system calls by adding or updating the following lines to "/etc/audit/rules.d/audit.rules": -a always,exit -F arch=b32 -S setxattr,fsetxattr,lsetxattr,removexattr,fremovexattr,lremovexattr -F auid>=1000 -F auid!=unset -k perm_mod -a always,exit -F arch=b64 -S setxattr,fsetxattr,lsetxattr,removexattr,fremovexattr,lremovexattr -F auid>=1000 -F auid!=unset -k perm_mod -a always,exit -F arch=b32 -S setxattr,fsetxattr,lsetxattr,removexattr,fremovexattr,lremovexattr -F auid=0 -k perm_mod -a always,exit -F arch=b64 -S setxattr,fsetxattr,lsetxattr,removexattr,fremovexattr,lremovexattr -F auid=0 -k perm_mod To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

RHEL 9 must audit all uses of umount system calls.

AU-3 - Medium - CCI-000130 - V-258180 - SV-258180r1045325_rule

RMF Control

AU-3

Severity

M

CCI

Version

RHEL-09-654030

Vuln IDs

V-258180

Rule IDs

SV-258180r1045325_rule

Without generating audit records specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). When a user logs on, the auid is set to the uid of the account being authenticated. Daemons are not user sessions and have the loginuid set to -1. The auid representation is an unsigned 32-bit integer, which equals 4294967295. The audit system interprets -1, 4294967295, and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each system call made by all programs on the system. Therefore, it is very important to use system call rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance can be helped, however, by combining system calls into one rule whenever possible. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-61921r1045323_chk

Verify that RHEL 9 is configured to audit the execution of the "umount" command with the following command: $ sudo auditctl -l | grep /usr/bin/umount -a always,exit -S all -F path=/usr/bin/umount -F perm=x -F auid>=1000 -F auid!=-1 -F key=privileged-mount If the command does not return an audit rule for "umount" or any of the lines returned are commented out, this is a finding.

Fix: F-61845r1045324_fix

Configure RHEL 9 to generate audit records upon successful/unsuccessful attempts to use the "umount" command by adding or updating the following rules in "/etc/audit/rules.d/audit.rules": -a always,exit -F path=/usr/bin/umount -F perm=x -F auid>=1000 -F auid!=unset -k privileged-mount To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

RHEL 9 must audit all uses of the chacl command.

AU-3 - Medium - CCI-000130 - V-258181 - SV-258181r1045328_rule

RMF Control

AU-3

Severity

M

CCI

Version

RHEL-09-654035

Vuln IDs

V-258181

Rule IDs

SV-258181r1045328_rule

Without generating audit records specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). When a user logs on, the auid is set to the uid of the account being authenticated. Daemons are not user sessions and have the loginuid set to -1. The auid representation is an unsigned 32-bit integer, which equals 4294967295. The audit system interprets -1, 4294967295, and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each system call made by all programs on the system. Therefore, it is very important to use system call rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance can be helped, however, by combining system calls into one rule whenever possible. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210

Checks: C-61922r1045326_chk

Verify that RHEL 9 is configured to audit the execution of the "chacl" command with the following command: $ sudo auditctl -l | grep chacl -a always,exit -S all -F path=/usr/bin/chacl -F perm=x -F auid>=1000 -F auid!=-1 -F key=perm_mod If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61846r1045327_fix

Configure RHEL 9 to generate audit records upon successful/unsuccessful attempts to use the "chacl" command by adding or updating the following rule in "/etc/audit/rules.d/audit.rules": -a always,exit -F path=/usr/bin/chacl -F perm=x -F auid>=1000 -F auid!=unset -k perm_mod To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

RHEL 9 must audit all uses of the setfacl command.

AU-3 - Medium - CCI-000130 - V-258182 - SV-258182r1045331_rule

RMF Control

AU-3

Severity

M

CCI

Version

RHEL-09-654040

Vuln IDs

V-258182

Rule IDs

SV-258182r1045331_rule

Without generating audit records specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). When a user logs on, the auid is set to the uid of the account being authenticated. Daemons are not user sessions and have the loginuid set to -1. The auid representation is an unsigned 32-bit integer, which equals 4294967295. The audit system interprets -1, 4294967295, and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each system call made by all programs on the system. Therefore, it is very important to use system call rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance can be helped, however, by combining system calls into one rule whenever possible. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-61923r1045329_chk

Verify that RHEL 9 is configured to audit the execution of the "setfacl" command with the following command: $ sudo auditctl -l | grep setfacl -a always,exit -S all -F path=/usr/bin/setfacl -F perm=x -F auid>=1000 -F auid!=-1 -F key=perm_mod If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61847r1045330_fix

Configure RHEL 9 to generate audit records upon successful/unsuccessful attempts to use the "setfacl" command by adding or updating the following rule in "/etc/audit/rules.d/audit.rules": -a always,exit -F path=/usr/bin/setfacl -F perm=x -F auid>=1000 -F auid!=unset -k perm_mod To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

RHEL 9 must audit all uses of the chcon command.

AU-3 - Medium - CCI-000130 - V-258183 - SV-258183r1045334_rule

RMF Control

AU-3

Severity

M

CCI

Version

RHEL-09-654045

Vuln IDs

V-258183

Rule IDs

SV-258183r1045334_rule

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). When a user logs on, the auid is set to the uid of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to -1. The auid representation is an unsigned 32-bit integer, which equals 4294967295. The audit system interprets -1, 4294967295, and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each system call made by all programs on the system. Therefore, it is very important to use system call rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance can be helped, however, by combining system calls into one rule whenever possible. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000468-GPOS-00212, SRG-OS-000471-GPOS-00215, SRG-OS-000463-GPOS-00207, SRG-OS-000465-GPOS-00209

Checks: C-61924r1045332_chk

Verify that RHEL 9 is configured to audit the execution of the "chcon" command with the following command: $ sudo auditctl -l | grep chcon -a always,exit -S all -F path=/usr/bin/chcon -F perm=x -F auid>=1000 -F auid!=-1 -F key=perm_mod If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61848r1045333_fix

Configure RHEL 9 to generate audit records upon successful/unsuccessful attempts to use the "chcon" command by adding or updating the following rule in "/etc/audit/rules.d/audit.rules": -a always,exit -F path=/usr/bin/chcon -F perm=x -F auid>=1000 -F auid!=unset -k perm_mod To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

RHEL 9 must audit all uses of the semanage command.

AU-3 - Medium - CCI-000130 - V-258184 - SV-258184r1045337_rule

RMF Control

AU-3

Severity

M

CCI

Version

RHEL-09-654050

Vuln IDs

V-258184

Rule IDs

SV-258184r1045337_rule

Without generating audit records specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). When a user logs on, the auid is set to the uid of the account being authenticated. Daemons are not user sessions and have the loginuid set to -1. The auid representation is an unsigned 32-bit integer, which equals 4294967295. The audit system interprets -1, 4294967295, and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each system call made by all programs on the system. Therefore, it is very important to use system call rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance can be helped, however, by combining system calls into one rule whenever possible. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000463-GPOS-00207, SRG-OS-000465-GPOS-00209

Checks: C-61925r1045335_chk

Verify that RHEL 9 is configured to audit the execution of the "semanage" command with the following command: $ sudo auditctl -l | grep semanage -a always,exit -S all -F path=/usr/sbin/semanage -F perm=x -F auid>=1000 -F auid!=-1 -F key=privileged-unix-update If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61849r1045336_fix

Configure RHEL 9 to generate audit records upon successful/unsuccessful attempts to use the "semanage" command by adding or updating the following rule in "/etc/audit/rules.d/audit.rules": -a always,exit -F path=/usr/sbin/semanage -F perm=x -F auid>=1000 -F auid!=unset -k privileged-unix-update To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

RHEL 9 must audit all uses of the setfiles command.

AU-3 - Medium - CCI-000130 - V-258185 - SV-258185r1045340_rule

RMF Control

AU-3

Severity

M

CCI

Version

RHEL-09-654055

Vuln IDs

V-258185

Rule IDs

SV-258185r1045340_rule

Without generating audit records specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). When a user logs on, the auid is set to the uid of the account being authenticated. Daemons are not user sessions and have the loginuid set to -1. The auid representation is an unsigned 32-bit integer, which equals 4294967295. The audit system interprets -1, 4294967295, and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each system call made by all programs on the system. Therefore, it is very important to use system call rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance can be helped, however, by combining system calls into one rule whenever possible. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000463-GPOS-00207, SRG-OS-000465-GPOS-00209

Checks: C-61926r1045338_chk

Verify that RHEL 9 is configured to audit the execution of the "setfiles" command with the following command: $ sudo auditctl -l | grep setfiles -a always,exit -S all -F path=/usr/sbin/setfiles -F perm=x -F auid>=1000 -F auid!=-1 -F key=privileged-unix-update If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61850r1045339_fix

Configure RHEL 9 to generate audit records upon successful/unsuccessful attempts to use the "setfiles" command by adding or updating the following rule in "/etc/audit/rules.d/audit.rules": -a always,exit -F path=/usr/sbin/setfiles -F perm=x -F auid>=1000 -F auid!=unset -k privileged-unix-update To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

RHEL 9 must audit all uses of the setsebool command.

AU-3 - Medium - CCI-000130 - V-258186 - SV-258186r1045343_rule

RMF Control

AU-3

Severity

M

CCI

Version

RHEL-09-654060

Vuln IDs

V-258186

Rule IDs

SV-258186r1045343_rule

Without generating audit records specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). When a user logs on, the auid is set to the uid of the account being authenticated. Daemons are not user sessions and have the loginuid set to -1. The auid representation is an unsigned 32-bit integer, which equals 4294967295. The audit system interprets -1, 4294967295, and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each system call made by all programs on the system. Therefore, it is very important to use system call rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance can be helped, however, by combining system calls into one rule whenever possible. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000463-GPOS-00207, SRG-OS-000465-GPOS-00209

Checks: C-61927r1045341_chk

Verify that RHEL 9 is configured to audit the execution of the "setsebool" command with the following command: $ sudo auditctl -l | grep setsebool -a always,exit -S all -F path=/usr/sbin/setsebool -F perm=x -F auid>=1000 -F auid!=-1 -F key=privileged If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61851r1045342_fix

Configure RHEL 9 to generate an audit event for any successful/unsuccessful use of the "setsebool " command by adding or updating the following rules in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F path=/usr/sbin/setsebool -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

RHEL 9 must audit all uses of the rename, unlink, rmdir, renameat, and unlinkat system calls.

AU-3 - Medium - CCI-000130 - V-258187 - SV-258187r1106373_rule

RMF Control

AU-3

Severity

M

CCI

Version

RHEL-09-654065

Vuln IDs

V-258187

Rule IDs

SV-258187r1106373_rule

Without generating audit records specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). When a user logs on, the auid is set to the uid of the account being authenticated. Daemons are not user sessions and have the loginuid set to -1. The auid representation is an unsigned 32-bit integer, which equals 4294967295. The audit system interprets -1, 4294967295, and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each system call made by all programs on the system. Therefore, it is very important to use system call rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance can be helped, however, by combining system calls into one rule whenever possible. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210, SRG-OS-000467-GPOS-00211, SRG-OS-000468-GPOS-00212

Checks: C-61928r1106372_chk

Verify RHEL 9 is configured to audit successful/unsuccessful attempts to use the "rename", "unlink", "rmdir", "renameat", and "unlinkat" system calls with the following command: $ sudo auditctl -l | grep 'rename\|unlink\|rmdir' -a always,exit -S arch=b32 -S unlink,rename,rmdir,unlinkat,renameat -F auid>=1000 -F auid!=-1 -F key=delete -a always,exit -S arch=b64 -S rename,rmdir,unlink,unlinkat,renameat -F auid>=1000 -F auid!=-1 -F key=delete If the command does not return an audit rule for "rename", "unlink", "rmdir", "renameat", and "unlinkat" or any of the lines returned are commented out, this is a finding.

Fix: F-61852r1045345_fix

Configure RHEL 9 to generate an audit event for any successful/unsuccessful use of the "rename", "unlink", "rmdir", "renameat", and "unlinkat" system calls by adding or updating the following rules in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F arch=b32 -S rename,unlink,rmdir,renameat,unlinkat -F auid>=1000 -F auid!=unset -k delete -a always,exit -F arch=b64 -S rename,unlink,rmdir,renameat,unlinkat -F auid>=1000 -F auid!=unset -k delete To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

RHEL 9 must audit all uses of the truncate, ftruncate, creat, open, openat, and open_by_handle_at system calls.

AU-3 - Medium - CCI-000130 - V-258188 - SV-258188r1106375_rule

RMF Control

AU-3

Severity

M

CCI

Version

RHEL-09-654070

Vuln IDs

V-258188

Rule IDs

SV-258188r1106375_rule

Without generating audit records specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). When a user logs on, the auid is set to the uid of the account being authenticated. Daemons are not user sessions and have the loginuid set to -1. The auid representation is an unsigned 32-bit integer, which equals 4294967295. The audit system interprets -1, 4294967295, and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each system call made by all programs on the system. Therefore, it is very important to use system call rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance can be helped, however, by combining system calls into one rule whenever possible. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000458-GPOS-00203, SRG-OS-000461-GPOS-00205

Checks: C-61929r1106374_chk

Verify RHEL 9 is configured to audit successful/unsuccessful attempts to use the "truncate", "ftruncate", "creat", "open", "openat", and "open_by_handle_at" system calls with the following command: $ sudo auditctl -l | grep 'open\b\|openat\|open_by_handle_at\|truncate\|creat' -a always,exit -S arch=b32 -S open,creat,truncate,ftruncate,openat,open_by_handle_at -F exit=-EPERM -F auid>=1000 -S auid!=-1 -F key=perm_access -a always,exit -F arch=b64 -S open,truncate,ftruncate,creat,openat,open_by_handle_at -F exit=-EPERM -F auid>=1000 -S auid!=-1 -F key=perm_access -a always,exit -F arch=b32 -S open,creat,truncate,ftruncate,openat,open_by_handle_at -F exit=-EACCES -F auid>=1000 -S auid!=-1 -F key=perm_access -a always,exit -F arch=b64 -S open,truncate,ftruncate,creat,openat,open_by_handle_at -F exit=-EACCES -F auid>=1000 -S auid!=-1 -F key=perm_access If the output does not produce rules containing "-F exit=-EPERM", this is a finding. If the output does not produce rules containing "-F exit=-EACCES", this is a finding. If the command does not return an audit rule for "truncate", "ftruncate", "creat", "open", "openat", and "open_by_handle_at" or any of the lines returned are commented out, this is a finding.

Fix: F-61853r1045348_fix

Configure RHEL 9 to generate an audit event for any successful/unsuccessful use of the "truncate", "ftruncate", "creat", "open", "openat", and "open_by_handle_at" system calls by adding or updating the following rules in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F arch=b32 -S truncate,ftruncate,creat,open,openat,open_by_handle_at -F exit=-EPERM -F auid>=1000 -F auid!=unset -k perm_access -a always,exit -F arch=b64 -S truncate,ftruncate,creat,open,openat,open_by_handle_at -F exit=-EPERM -F auid>=1000 -F auid!=unset -k perm_access -a always,exit -F arch=b32 -S truncate,ftruncate,creat,open,openat,open_by_handle_at -F exit=-EACCES -F auid>=1000 -F auid!=unset -k perm_access -a always,exit -F arch=b64 -S truncate,ftruncate,creat,open,openat,open_by_handle_at -F exit=-EACCES -F auid>=1000 -F auid!=unset -k perm_access To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

RHEL 9 must audit all uses of the delete_module system call.

AU-3 - Medium - CCI-000130 - V-258189 - SV-258189r1106377_rule

RMF Control

AU-3

Severity

M

CCI

Version

RHEL-09-654075

Vuln IDs

V-258189

Rule IDs

SV-258189r1106377_rule

Without generating audit records specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). When a user logs on, the auid is set to the uid of the account being authenticated. Daemons are not user sessions and have the loginuid set to -1. The auid representation is an unsigned 32-bit integer, which equals 4294967295. The audit system interprets -1, 4294967295, and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each system call made by all programs on the system. Therefore, it is very important to use system call rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance can be helped, however, by combining system calls into one rule whenever possible. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000471-GPOS-00216, SRG-OS-000477-GPOS-00222

Checks: C-61930r1106376_chk

Verify RHEL 9 is configured to audit the execution of the "delete_module" system call with the following command: $ sudo auditctl -l | grep delete_module -a always,exit -S arch=b32 -S delete_module -F auid>=1000 -F auid!=-1 -F key=module_chng -a always,exit -S arch=b64 -S delete_module -F auid>=1000 -F auid!=-1 -F key=module_chng If both the "b32" and "b64" audit rules are not defined for the "delete_module" system call, or any of the lines returned are commented out, this is a finding.

Fix: F-61854r1045351_fix

Configure RHEL 9 to generate an audit event for any successful/unsuccessful use of the "delete_module" system call by adding or updating the following rules in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F arch=b32 -S delete_module -F auid>=1000 -F auid!=unset -k module_chng -a always,exit -F arch=b64 -S delete_module -F auid>=1000 -F auid!=unset -k module_chng To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

RHEL 9 must audit all uses of the init_module and finit_module system calls.

AU-3 - Medium - CCI-000130 - V-258190 - SV-258190r1106379_rule

RMF Control

AU-3

Severity

M

CCI

Version

RHEL-09-654080

Vuln IDs

V-258190

Rule IDs

SV-258190r1106379_rule

Without generating audit records specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). When a user logs on, the auid is set to the uid of the account being authenticated. Daemons are not user sessions and have the loginuid set to -1. The auid representation is an unsigned 32-bit integer, which equals 4294967295. The audit system interprets -1, 4294967295, and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each system call made by all programs on the system. Therefore, it is very important to use system call rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance can be helped, however, by combining system calls into one rule whenever possible. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000471-GPOS-00216, SRG-OS-000477-GPOS-00222

Checks: C-61931r1106378_chk

Verify RHEL 9 is configured to audit the execution of the "init_module" and "finit_module" system calls with the following command: $ sudo auditctl -l | grep init_module -a always,exit -S arch=b32 -S init_module,finit_module -F auid>=1000 -F auid!=-1 -F key=module_chng -a always,exit -S arch=b64 -S init_module,finit_module -F auid>=1000 -F auid!=-1 -F key=module_chng If both the "b32" and "b64" audit rules are not defined for the "init_module" system call, or any of the lines returned are commented out, this is a finding.

Fix: F-61855r1045354_fix

Configure RHEL 9 to generate an audit event for any successful/unsuccessful use of the "init_module" and "finit_module" system calls by adding or updating the following rules in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F arch=b32 -S init_module,finit_module -F auid>=1000 -F auid!=unset -k module_chng -a always,exit -F arch=b64 -S init_module,finit_module -F auid>=1000 -F auid!=unset -k module_chng To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

RHEL 9 must audit all uses of the chage command.

AU-3 - Medium - CCI-000130 - V-258191 - SV-258191r1045358_rule

RMF Control

AU-3

Severity

M

CCI

Version

RHEL-09-654085

Vuln IDs

V-258191

Rule IDs

SV-258191r1045358_rule

Without generating audit records specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). When a user logs on, the auid is set to the uid of the account being authenticated. Daemons are not user sessions and have the loginuid set to -1. The auid representation is an unsigned 32-bit integer, which equals 4294967295. The audit system interprets -1, 4294967295, and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each system call made by all programs on the system. Therefore, it is very important to use system call rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance can be helped, however, by combining system calls into one rule whenever possible. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000468-GPOS-00212, SRG-OS-000471-GPOS-00215

Checks: C-61932r1045356_chk

Verify that RHEL 9 is configured to audit the execution of the "chage" command with the following command: $ sudo auditctl -l | grep chage -a always,exit -S all -F path=/usr/bin/chage -F perm=x -F auid>=1000 -F auid!=-1 -F key=privileged-chage If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61856r1045357_fix

Configure RHEL 9 to generate audit records upon successful/unsuccessful attempts to use the "chage" command by adding or updating the following rule in "/etc/audit/rules.d/audit.rules": -a always,exit -F path=/usr/bin/chage -F perm=x -F auid>=1000 -F auid!=unset -k privileged-chage To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

RHEL 9 must audit all uses of the chsh command.

AU-3 - Medium - CCI-000130 - V-258192 - SV-258192r1045361_rule

RMF Control

AU-3

Severity

M

CCI

Version

RHEL-09-654090

Vuln IDs

V-258192

Rule IDs

SV-258192r1045361_rule

Without generating audit records specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). When a user logs on, the auid is set to the uid of the account being authenticated. Daemons are not user sessions and have the loginuid set to -1. The auid representation is an unsigned 32-bit integer, which equals 4294967295. The audit system interprets -1, 4294967295, and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each system call made by all programs on the system. Therefore, it is very important to use system call rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance can be helped, however, by combining system calls into one rule whenever possible. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-61933r1045359_chk

Verify that RHEL 9 is configured to audit the execution of the "chsh" command with the following command: $ sudo auditctl -l | grep chsh -a always,exit -S all -F path=/usr/bin/chsh -F perm=x -F auid>=1000 -F auid!=-1 -F key=priv_cmd If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61857r1045360_fix

Configure RHEL 9 to generate audit records upon successful/unsuccessful attempts to use the "chsh" command by adding or updating the following rule in "/etc/audit/rules.d/audit.rules": -a always,exit -F path=/usr/bin/chsh -F perm=x -F auid>=1000 -F auid!=unset -k priv_cmd To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

RHEL 9 must audit all uses of the crontab command.

AU-3 - Medium - CCI-000130 - V-258193 - SV-258193r1045364_rule

RMF Control

AU-3

Severity

M

CCI

Version

RHEL-09-654095

Vuln IDs

V-258193

Rule IDs

SV-258193r1045364_rule

Without generating audit records specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). When a user logs on, the auid is set to the uid of the account being authenticated. Daemons are not user sessions and have the loginuid set to -1. The auid representation is an unsigned 32-bit integer, which equals 4294967295. The audit system interprets -1, 4294967295, and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each system call made by all programs on the system. Therefore, it is very important to use system call rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance can be helped, however, by combining system calls into one rule whenever possible. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-61934r1045362_chk

Verify that RHEL 9 is configured to audit the execution of the "crontab" command with the following command: $ sudo auditctl -l | grep crontab -a always,exit -S all -F path=/usr/bin/crontab -F perm=x -F auid>=1000 -F auid!=-1 -F key=privileged-crontab If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61858r1045363_fix

Configure RHEL 9 to generate audit records upon successful/unsuccessful attempts to use the "crontab" command by adding or updating the following rule in "/etc/audit/rules.d/audit.rules": -a always,exit -F path=/usr/bin/crontab -F perm=x -F auid>=1000 -F auid!=unset -k privileged-crontab To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

RHEL 9 must audit all uses of the gpasswd command.

AU-3 - Medium - CCI-000130 - V-258194 - SV-258194r1045367_rule

RMF Control

AU-3

Severity

M

CCI

Version

RHEL-09-654100

Vuln IDs

V-258194

Rule IDs

SV-258194r1045367_rule

Without generating audit records specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). When a user logs on, the auid is set to the uid of the account being authenticated. Daemons are not user sessions and have the loginuid set to -1. The auid representation is an unsigned 32-bit integer, which equals 4294967295. The audit system interprets -1, 4294967295, and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each system call made by all programs on the system. Therefore, it is very important to use system call rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance can be helped, however, by combining system calls into one rule whenever possible. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-61935r1045365_chk

Verify that RHEL 9 is configured to audit the execution of the "gpasswd" command with the following command: $ sudo auditctl -l | grep gpasswd -a always,exit -S all -F path=/usr/bin/gpasswd -F perm=x -F auid>=1000 -F auid!=-1 -F key=privileged-gpasswd If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61859r1045366_fix

Configure RHEL 9 to generate audit records upon successful/unsuccessful attempts to use the "gpasswd" command by adding or updating the following rule in "/etc/audit/rules.d/audit.rules": -a always,exit -F path=/usr/bin/gpasswd -F perm=x -F auid>=1000 -F auid!=unset -k privileged-gpasswd To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

RHEL 9 must audit all uses of the kmod command.

AU-3 - Medium - CCI-000130 - V-258195 - SV-258195r1045370_rule

RMF Control

AU-3

Severity

M

CCI

Version

RHEL-09-654105

Vuln IDs

V-258195

Rule IDs

SV-258195r1045370_rule

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). When a user logs on, the auid is set to the uid of the account being authenticated. Daemons are not user sessions and have the loginuid set to -1. The auid representation is an unsigned 32-bit integer, which equals 4294967295. The audit system interprets -1, 4294967295, and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each system call made by all programs on the system. Therefore, it is very important to use system call rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance can be helped, however, by combining system calls into one rule whenever possible. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000471-GPOS-00216, SRG-OS-000477-GPOS-00222

Checks: C-61936r1045368_chk

Verify that RHEL 9 is configured to audit the execution of the "kmod" command with the following command: $ sudo auditctl -l | grep kmod -a always,exit -S all -F path=/usr/bin/kmod -F perm=x -F auid>=1000 -F auid!=-1 -F key=modules If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61860r1045369_fix

Configure RHEL 9 to generate audit records upon successful/unsuccessful attempts to use the "kmod" command by adding or updating the following rule in "/etc/audit/rules.d/audit.rules": -a always,exit -F path=/usr/bin/kmod -F perm=x -F auid>=1000 -F auid!=unset -k modules To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

RHEL 9 must audit all uses of the newgrp command.

AU-3 - Medium - CCI-000130 - V-258196 - SV-258196r1045373_rule

RMF Control

AU-3

Severity

M

CCI

Version

RHEL-09-654110

Vuln IDs

V-258196

Rule IDs

SV-258196r1045373_rule

Without generating audit records specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). When a user logs on, the auid is set to the uid of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to -1. The auid representation is an unsigned 32-bit integer, which equals 4294967295. The audit system interprets -1, 4294967295, and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each system call made by all programs on the system. Therefore, it is very important to use system call rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance can be helped, however, by combining system calls into one rule whenever possible. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-61937r1045371_chk

Verify that RHEL 9 is configured to audit the execution of the "newgrp" command with the following command: $ sudo auditctl -l | grep newgrp -a always,exit -S all -F path=/usr/bin/newgrp -F perm=x -F auid>=1000 -F auid!=-1 -F key=priv_cmd If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61861r1045372_fix

Configure RHEL 9 to generate audit records upon successful/unsuccessful attempts to use the "newgrp" command by adding or updating the following rule in "/etc/audit/rules.d/audit.rules": -a always,exit -F path=/usr/bin/newgrp -F perm=x -F auid>=1000 -F auid!=unset -k priv_cmd To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

RHEL 9 must audit all uses of the pam_timestamp_check command.

AU-3 - Medium - CCI-000130 - V-258197 - SV-258197r1045376_rule

RMF Control

AU-3

Severity

M

CCI

Version

RHEL-09-654115

Vuln IDs

V-258197

Rule IDs

SV-258197r1045376_rule

Without generating audit records specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). When a user logs on, the auid is set to the uid of the account being authenticated. Daemons are not user sessions and have the loginuid set to -1. The auid representation is an unsigned 32-bit integer, which equals 4294967295. The audit system interprets -1, 4294967295, and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each system call made by all programs on the system. Therefore, it is very important to use system call rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance can be helped, however, by combining system calls into one rule whenever possible. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-61938r1045374_chk

Verify that RHEL 9 is configured to audit the execution of the "pam_timestamp_check" command with the following command: $ sudo auditctl -l | grep timestamp -a always,exit -S all -F path=/usr/sbin/pam_timestamp_check -F perm=x -F auid>=1000 -F auid!=-1 -F key=privileged-pam_timestamp_check If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61862r1045375_fix

Configure RHEL 9 to generate audit records upon successful/unsuccessful attempts to use the "pam_timestamp_check" command by adding or updating the following rule in "/etc/audit/rules.d/audit.rules": -a always,exit -F path=/usr/sbin/pam_timestamp_check -F perm=x -F auid>=1000 -F auid!=unset -k privileged-pam_timestamp_check To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

RHEL 9 must audit all uses of the passwd command.

AU-3 - Medium - CCI-000130 - V-258198 - SV-258198r1045379_rule

RMF Control

AU-3

Severity

M

CCI

Version

RHEL-09-654120

Vuln IDs

V-258198

Rule IDs

SV-258198r1045379_rule

Without generating audit records specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). When a user logs on, the auid is set to the uid of the account being authenticated. Daemons are not user sessions and have the loginuid set to -1. The auid representation is an unsigned 32-bit integer, which equals 4294967295. The audit system interprets -1, 4294967295, and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each system call made by all programs on the system. Therefore, it is very important to use system call rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance can be helped, however, by combining system calls into one rule whenever possible. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-61939r1045377_chk

Verify RHEL 9 generates audit records for all account creations, modifications, disabling, and termination events that affect "/etc/gshadow" with the following command: $ sudo auditctl -l | egrep '(/usr/bin/passwd)' -a always,exit -S all -F path=/usr/bin/passwd -F perm=x -F auid>=1000 -F auid!=-1 -F key=privileged-passwd If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61863r1045378_fix

Configure RHEL 9 to generate audit records upon successful/unsuccessful attempts to use the "passwd" command by adding or updating the following rule in "/etc/audit/rules.d/audit.rules": -a always,exit -F path=/usr/bin/passwd -F perm=x -F auid>=1000 -F auid!=unset -k privileged-passwd To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

RHEL 9 must audit all uses of the postdrop command.

AU-3 - Medium - CCI-000130 - V-258199 - SV-258199r1045382_rule

RMF Control

AU-3

Severity

M

CCI

Version

RHEL-09-654125

Vuln IDs

V-258199

Rule IDs

SV-258199r1045382_rule

Without generating audit records specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). When a user logs on, the auid is set to the uid of the account being authenticated. Daemons are not user sessions and have the loginuid set to -1. The auid representation is an unsigned 32-bit integer, which equals 4294967295. The audit system interprets -1, 4294967295, and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each system call made by all programs on the system. Therefore, it is very important to use system call rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance can be helped however, by combining system calls into one rule whenever possible. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-61940r1045380_chk

Verify that RHEL 9 is configured to audit the execution of the "postdrop" command with the following command: $ sudo auditctl -l | grep postdrop -a always,exit -S all -F path=/usr/sbin/postdrop -F perm=x -F auid>=1000 -F auid!=-1 -F key=privileged-unix-update If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61864r1045381_fix

Configure RHEL 9 to generate audit records upon successful/unsuccessful attempts to use the "postdrop" command by adding or updating the following rule in "/etc/audit/rules.d/audit.rules": -a always,exit -F path=/usr/sbin/postdrop -F perm=x -F auid>=1000 -F auid!=unset -k privileged-unix-update To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

RHEL 9 must audit all uses of the postqueue command.

AU-3 - Medium - CCI-000130 - V-258200 - SV-258200r1045385_rule

RMF Control

AU-3

Severity

M

CCI

Version

RHEL-09-654130

Vuln IDs

V-258200

Rule IDs

SV-258200r1045385_rule

Without generating audit record specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). When a user logs on, the auid is set to the uid of the account being authenticated. Daemons are not user sessions and have the loginuid set to -1. The auid representation is an unsigned 32-bit integer, which equals 4294967295. The audit system interprets -1, 4294967295, and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each system call made by all programs on the system. Therefore, it is very important to use system call rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance can be helped, however, by combining system calls into one rule whenever possible. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-61941r1045383_chk

Verify that RHEL 9 is configured to audit the execution of the "postqueue" command with the following command: $ sudo auditctl -l | grep postqueue -a always,exit -S all -F path=/usr/sbin/postqueue -F perm=x -F auid>=1000 -F auid!=-1 -F key=privileged-unix-update If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61865r1045384_fix

Configure RHEL 9 to generate audit records upon successful/unsuccessful attempts to use the "postqueue" command by adding or updating the following rule in "/etc/audit/rules.d/audit.rules": -a always,exit -F path=/usr/sbin/postqueue -F perm=x -F auid>=1000 -F auid!=unset -k privileged-unix-update To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

RHEL 9 must audit all uses of the ssh-agent command.

AU-3 - Medium - CCI-000130 - V-258201 - SV-258201r1045388_rule

RMF Control

AU-3

Severity

M

CCI

Version

RHEL-09-654135

Vuln IDs

V-258201

Rule IDs

SV-258201r1045388_rule

Without generating audit record specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). When a user logs on, the auid is set to the uid of the account being authenticated. Daemons are not user sessions and have the loginuid set to -1. The auid representation is an unsigned 32-bit integer, which equals 4294967295. The audit system interprets -1, 4294967295, and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each system call made by all programs on the system. Therefore, it is very important to use system call rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance can be helped, however, by combining system calls into one rule whenever possible. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-61942r1045386_chk

Verify that RHEL 9 is configured to audit the execution of the "ssh-agent" command with the following command: $ sudo auditctl -l | grep ssh-agent -a always,exit -S all -F path=/usr/bin/ssh-agent -F perm=x -F auid>=1000 -F auid!=-1 -F key=privileged-ssh If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61866r1045387_fix

Configure RHEL 9 to generate audit records upon successful/unsuccessful attempts to use the "ssh-agent" command by adding or updating the following rule in "/etc/audit/rules.d/audit.rules": -a always,exit -F path=/usr/bin/ssh-agent -F perm=x -F auid>=1000 -F auid!=unset -k privileged-ssh To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

RHEL 9 must audit all uses of the ssh-keysign command.

AU-3 - Medium - CCI-000130 - V-258202 - SV-258202r1045391_rule

RMF Control

AU-3

Severity

M

CCI

Version

RHEL-09-654140

Vuln IDs

V-258202

Rule IDs

SV-258202r1045391_rule

Without generating audit record specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). When a user logs on, the auid is set to the uid of the account being authenticated. Daemons are not user sessions and have the loginuid set to -1. The auid representation is an unsigned 32-bit integer, which equals 4294967295. The audit system interprets -1, 4294967295, and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each system call made by all programs on the system. Therefore, it is very important to use system call rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance can be helped, however, by combining system calls into one rule whenever possible. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-61943r1045389_chk

Verify that RHEL 9 is configured to audit the execution of the "ssh-keysign" command with the following command: $ sudo auditctl -l | grep ssh-keysign -a always,exit -S all -F path=/usr/libexec/openssh/ssh-keysign -F perm=x -F auid>=1000 -F auid!=-1 -F key=privileged-ssh If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61867r1045390_fix

Configure RHEL 9 to generate audit records upon successful/unsuccessful attempts to use the "ssh-keysign" command by adding or updating the following rule in "/etc/audit/rules.d/audit.rules": -a always,exit -F path=/usr/libexec/openssh/ssh-keysign -F perm=x -F auid>=1000 -F auid!=unset -k privileged-ssh To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

RHEL 9 must audit all uses of the su command.

AU-3 - Medium - CCI-000130 - V-258203 - SV-258203r1045394_rule

RMF Control

AU-3

Severity

M

CCI

Version

RHEL-09-654145

Vuln IDs

V-258203

Rule IDs

SV-258203r1045394_rule

Without generating audit record specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). When a user logs on, the auid is set to the uid of the account being authenticated. Daemons are not user sessions and have the loginuid set to -1. The auid representation is an unsigned 32-bit integer, which equals 4294967295. The audit system interprets -1, 4294967295, and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each system call made by all programs on the system. Therefore, it is very important to use system call rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance can be helped, however, by combining system calls into one rule whenever possible. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000064-GPOS-00033, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210

Checks: C-61944r1045392_chk

Verify that RHEL 9 is configured to audit the execution of the "su" command with the following command: $ sudo auditctl -l | grep '/usr/bin/su\b' -a always,exit -S all -F path=/usr/bin/su -F perm=x -F auid>=1000 -F auid!=-1 -F key=privileged-priv_change If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61868r1045393_fix

Configure RHEL 9 to generate audit records upon successful/unsuccessful attempts to use the "su" command by adding or updating the following rule in "/etc/audit/rules.d/audit.rules": -a always,exit -F path=/usr/bin/su -F perm=x -F auid>=1000 -F auid!=unset -k privileged-priv_change To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

RHEL 9 must audit all uses of the sudo command.

AU-3 - Medium - CCI-000130 - V-258204 - SV-258204r1045397_rule

RMF Control

AU-3

Severity

M

CCI

Version

RHEL-09-654150

Vuln IDs

V-258204

Rule IDs

SV-258204r1045397_rule

Without generating audit record specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). When a user logs on, the auid is set to the uid of the account being authenticated. Daemons are not user sessions and have the loginuid set to -1. The auid representation is an unsigned 32-bit integer, which equals 4294967295. The audit system interprets -1, 4294967295, and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each system call made by all programs on the system. Therefore, it is very important to use system call rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance can be helped, however, by combining system calls into one rule whenever possible. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210

Checks: C-61945r1045395_chk

Verify that RHEL 9 is configured to audit the execution of the "sudo" command with the following command: $ sudo auditctl -l | grep '/usr/bin/sudo\b' -a always,exit -S all -F path=/usr/bin/sudo -F perm=x -F auid>=1000 -F auid!=-1 -F key=priv_cmd If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61869r1045396_fix

Configure RHEL 9 to generate audit records upon successful/unsuccessful attempts to use the "sudo" command by adding or updating the following rule in "/etc/audit/rules.d/audit.rules": -a always,exit -F path=/usr/bin/sudo -F perm=x -F auid>=1000 -F auid!=unset -k priv_cmd To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

RHEL 9 must audit all uses of the sudoedit command.

AU-3 - Medium - CCI-000130 - V-258205 - SV-258205r1045400_rule

RMF Control

AU-3

Severity

M

CCI

Version

RHEL-09-654155

Vuln IDs

V-258205

Rule IDs

SV-258205r1045400_rule

Without generating audit record specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). When a user logs on, the auid is set to the uid of the account being authenticated. Daemons are not user sessions and have the loginuid set to -1. The auid representation is an unsigned 32-bit integer, which equals 4294967295. The audit system interprets -1, 4294967295, and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each system call made by all programs on the system. Therefore, it is very important to use system call rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance can be helped, however, by combining system calls into one rule whenever possible. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-61946r1045398_chk

Verify that RHEL 9 is configured to audit the execution of the "sudoedit" command with the following command: $ sudo auditctl -l | grep /usr/bin/sudoedit -a always,exit -S all -F path=/usr/bin/sudoedit -F perm=x -F auid>=1000 -F auid!=-1 -F key=priv_cmd If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61870r1045399_fix

Configure RHEL 9 to generate audit records upon successful/unsuccessful attempts to use the "sudoedit" command by adding or updating the following rule in "/etc/audit/rules.d/audit.rules": -a always,exit -F path=/usr/bin/sudoedit -F perm=x -F auid>=1000 -F auid!=unset -k priv_cmd To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

RHEL 9 must audit all uses of the unix_chkpwd command.

AU-3 - Medium - CCI-000130 - V-258206 - SV-258206r1045403_rule

RMF Control

AU-3

Severity

M

CCI

Version

RHEL-09-654160

Vuln IDs

V-258206

Rule IDs

SV-258206r1045403_rule

Without generating audit record specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). When a user logs on, the auid is set to the uid of the account being authenticated. Daemons are not user sessions and have the loginuid set to -1. The auid representation is an unsigned 32-bit integer, which equals 4294967295. The audit system interprets -1, 4294967295, and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each system call made by all programs on the system. Therefore, it is very important to use system call rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance can be helped, however, by combining system calls into one rule whenever possible. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-61947r1045401_chk

Verify that RHEL 9 is configured to audit the execution of the "unix_chkpwd" command with the following command: $ sudo auditctl -l | grep unix_chkpwd -a always,exit -S all -F path=/usr/sbin/unix_chkpwd -F perm=x -F auid>=1000 -F auid!=-1 -F key=privileged-unix-update If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61871r1045402_fix

Configure RHEL 9 to generate audit records upon successful/unsuccessful attempts to use the "unix_chkpwd" command by adding or updating the following rule in "/etc/audit/rules.d/audit.rules": -a always,exit -F path=/usr/sbin/unix_chkpwd -F perm=x -F auid>=1000 -F auid!=unset -k privileged-unix-update To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

RHEL 9 must audit all uses of the unix_update command.

AU-3 - Medium - CCI-000130 - V-258207 - SV-258207r1045406_rule

RMF Control

AU-3

Severity

M

CCI

Version

RHEL-09-654165

Vuln IDs

V-258207

Rule IDs

SV-258207r1045406_rule

Without generating audit record specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). When a user logs on, the auid is set to the uid of the account being authenticated. Daemons are not user sessions and have the loginuid set to -1. The auid representation is an unsigned 32-bit integer, which equals 4294967295. The audit system interprets -1, 4294967295, and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each system call made by all programs on the system. Therefore, it is very important to use system call rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance can be helped, however, by combining system calls into one rule whenever possible. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000064-GPOS-00033, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-61948r1045404_chk

Verify that RHEL 9 is configured to audit the execution of the "unix_update" command with the following command: $ sudo auditctl -l | grep unix_update -a always,exit -S all -F path=/usr/sbin/unix_update -F perm=x -F auid>=1000 -F auid!=-1 -F key=privileged-unix-update If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61872r1045405_fix

Configure RHEL 9 to generate audit records upon successful/unsuccessful attempts to use the "unix_update" command by adding or updating the following rule in "/etc/audit/rules.d/audit.rules": -a always,exit -F path=/usr/sbin/unix_update -F perm=x -F auid>=1000 -F auid!=unset -k privileged-unix-update To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

RHEL 9 must audit all uses of the userhelper command.

AU-3 - Medium - CCI-000130 - V-258208 - SV-258208r1045409_rule

RMF Control

AU-3

Severity

M

CCI

Version

RHEL-09-654170

Vuln IDs

V-258208

Rule IDs

SV-258208r1045409_rule

Without generating audit record specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). When a user logs on, the auid is set to the uid of the account being authenticated. Daemons are not user sessions and have the loginuid set to -1. The auid representation is an unsigned 32-bit integer, which equals 4294967295. The audit system interprets -1, 4294967295, and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each system call made by all programs on the system. Therefore, it is very important to use system call rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance can be helped, however, by combining system calls into one rule whenever possible. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-61949r1045407_chk

Verify that RHEL 9 is configured to audit the execution of the "userhelper" command with the following command: $ sudo auditctl -l | grep userhelper -a always,exit -S all -F path=/usr/sbin/userhelper -F perm=x -F auid>=1000 -F auid!=-1 -F key=privileged-unix-update If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61873r1045408_fix

Configure RHEL 9 to generate audit records upon successful/unsuccessful attempts to use the "userhelper" command by adding or updating the following rule in "/etc/audit/rules.d/audit.rules": -a always,exit -F path=/usr/sbin/userhelper -F perm=x -F auid>=1000 -F auid!=unset -k privileged-unix-update To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

RHEL 9 must audit all uses of the usermod command.

AU-3 - Medium - CCI-000130 - V-258209 - SV-258209r1045412_rule

RMF Control

AU-3

Severity

M

CCI

Version

RHEL-09-654175

Vuln IDs

V-258209

Rule IDs

SV-258209r1045412_rule

Without generating audit record specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). When a user logs on, the auid is set to the uid of the account being authenticated. Daemons are not user sessions and have the loginuid set to -1. The auid representation is an unsigned 32-bit integer, which equals 4294967295. The audit system interprets -1, 4294967295, and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each system call made by all programs on the system. Therefore, it is very important to use system call rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance can be helped, however, by combining system calls into one rule whenever possible. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210

Checks: C-61950r1045410_chk

Verify that RHEL 9 is configured to audit the execution of the "usermod" command with the following command: $ sudo auditctl -l | grep usermod -a always,exit -S all -F path=/usr/sbin/usermod -F perm=x -F auid>=1000 -F auid!=-1 -F key=privileged-usermod If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61874r1045411_fix

Configure RHEL 9 to generate audit records upon successful/unsuccessful attempts to use the "usermod " command by adding or updating the following rule in "/etc/audit/rules.d/audit.rules": -a always,exit -F path=/usr/sbin/usermod -F perm=x -F auid>=1000 -F auid!=unset -k privileged-usermod To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

RHEL 9 must audit all uses of the mount command.

AU-3 - Medium - CCI-000130 - V-258210 - SV-258210r1045415_rule

RMF Control

AU-3

Severity

M

CCI

Version

RHEL-09-654180

Vuln IDs

V-258210

Rule IDs

SV-258210r1045415_rule

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). When a user logs on, the auid is set to the uid of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to -1. The auid representation is an unsigned 32-bit integer, which equals 4294967295. The audit system interprets -1, 4294967295, and "unset" in the same way. The system call rules are loaded into a matching engine that intercepts each system call made by all programs on the system. Therefore, it is very important to use system call rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance can be helped, however, by combining system calls into one rule whenever possible. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-61951r1045413_chk

Verify that RHEL 9 is configured to audit the execution of the "mount" command with the following command: $ sudo auditctl -l | grep /usr/bin/mount -a always,exit -S all -F path=/usr/bin/mount -F perm=x -F auid>=1000 -F auid!=-1 -F key=privileged-mount If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61875r1045414_fix

Configure RHEL 9 to generate audit records upon successful/unsuccessful attempts to use the "mount" command by adding or updating the following rule in "/etc/audit/rules.d/audit.rules": -a always,exit -F path=/usr/bin/mount -F perm=x -F auid>=1000 -F auid!=unset -k privileged-mount To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

Successful/unsuccessful uses of the init command in RHEL 9 must generate an audit record.

AU-12 - Medium - CCI-000172 - V-258211 - SV-258211r1045418_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-09-654185

Vuln IDs

V-258211

Rule IDs

SV-258211r1045418_rule

Misuse of the init command may cause availability issues for the system.

Checks: C-61952r1045416_chk

Verify that RHEL 9 is configured to audit the execution of the "init" command with the following command: $ sudo auditctl -l | grep /usr/sbin/init -a always,exit -S all -F path=/usr/sbin/init -F perm=x -F auid>=1000 -F auid!=-1 -F key=privileged-init If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61876r1045417_fix

Configure the audit system to generate an audit event for any successful/unsuccessful uses of the "init" command by adding or updating the following rule in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F path=/usr/sbin/init -F perm=x -F auid>=1000 -F auid!=unset -k privileged-init To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

Successful/unsuccessful uses of the poweroff command in RHEL 9 must generate an audit record.

AU-12 - Medium - CCI-000172 - V-258212 - SV-258212r1045421_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-09-654190

Vuln IDs

V-258212

Rule IDs

SV-258212r1045421_rule

Misuse of the poweroff command may cause availability issues for the system.

Checks: C-61953r1045419_chk

Verify that RHEL 9 is configured to audit the execution of the "poweroff" command with the following command: $ sudo auditctl -l | grep poweroff -a always,exit -S all -F path=/usr/sbin/poweroff -F perm=x -F auid>=1000 -F auid!=-1 -F key=privileged-poweroff If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61877r1045420_fix

Configure the audit system to generate an audit event for any successful/unsuccessful uses of the "poweroff" command by adding or updating the following rule in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F path=/usr/sbin/poweroff -F perm=x -F auid>=1000 -F auid!=unset -k privileged-poweroff To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

Successful/unsuccessful uses of the reboot command in RHEL 9 must generate an audit record.

AU-12 - Medium - CCI-000172 - V-258213 - SV-258213r1045424_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-09-654195

Vuln IDs

V-258213

Rule IDs

SV-258213r1045424_rule

Misuse of the reboot command may cause availability issues for the system.

Checks: C-61954r1045422_chk

Verify that RHEL 9 is configured to audit the execution of the "reboot" command with the following command: $ sudo auditctl -l | grep reboot -a always,exit -S all -F path=/usr/sbin/reboot -F perm=x -F auid>=1000 -F auid!=-1 -F key=privileged-reboot If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61878r1045423_fix

Configure the audit system to generate an audit event for any successful/unsuccessful uses of the "reboot" command by adding or updating the following rule in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F path=/usr/sbin/reboot -F perm=x -F auid>=1000 -F auid!=unset -k privileged-reboot To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

Successful/unsuccessful uses of the shutdown command in RHEL 9 must generate an audit record.

AU-12 - Medium - CCI-000172 - V-258214 - SV-258214r1045427_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-09-654200

Vuln IDs

V-258214

Rule IDs

SV-258214r1045427_rule

Misuse of the shutdown command may cause availability issues for the system.

Checks: C-61955r1045425_chk

Verify that RHEL 9 is configured to audit the execution of the "shutdown" command with the following command: $ sudo cat /etc/audit/rules.d/* | grep shutdown -a always,exit -S all -F path=/usr/sbin/shutdown -F perm=x -F auid>=1000 -F auid!=-1 -F key=privileged-shutdown If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61879r1045426_fix

Configure the audit system to generate an audit event for any successful/unsuccessful uses of the "shutdown" command by adding or updating the following rule in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F path=/usr/sbin/shutdown -F perm=x -F auid>=1000 -F auid!=unset -k privileged-shutdown To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

Successful/unsuccessful uses of the umount system call in RHEL 9 must generate an audit record.

AU-3 - Medium - CCI-000130 - V-258215 - SV-258215r1106381_rule

RMF Control

AU-3

Severity

M

CCI

Version

RHEL-09-654205

Vuln IDs

V-258215

Rule IDs

SV-258215r1106381_rule

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-61956r1106380_chk

Verify RHEL 9 generates an audit record for all uses of the "umount" and system call with the following command: $ sudo auditctl -l | grep b32 | grep 'umount\b' -a always,exit -S arch=b32 -S umount -F auid>=1000 -F auid!=-1 -F key=privileged-umount If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61880r1045429_fix

Configure the audit system to generate an audit event for any successful/unsuccessful use of the "umount" system call by adding or updating the following rules in "/etc/audit/audit.rules" and adding the following rules to "/etc/audit/rules.d/perm_mod.rules" or updating the existing rules in files in the "/etc/audit/rules.d/" directory: -a always,exit -F arch=b32 -S umount -F auid>=1000 -F auid!=unset -k privileged-umount To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

Successful/unsuccessful uses of the umount2 system call in RHEL 9 must generate an audit record.

AU-3 - Medium - CCI-000130 - V-258216 - SV-258216r1102090_rule

RMF Control

AU-3

Severity

M

CCI

Version

RHEL-09-654210

Vuln IDs

V-258216

Rule IDs

SV-258216r1102090_rule

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Checks: C-61957r1102089_chk

To determine if the system is configured to audit calls to the umount2 system call, run the following command: $ sudo auditctl -l | grep umount2 -a always,exit -S arch=b64 -S umount2 -F auid>=1000 -F auid!=-1 -F key=privileged-umount -a always,exit -S arch=b32 -S umount2 -F auid>=1000 -F auid!=-1 -F key=privileged-umount If no line is returned, this is a finding.

Fix: F-61881r1045432_fix

Configure the audit system to generate an audit event for any successful/unsuccessful use of the "umount2" system call by adding or updating the following rules in a file in "/etc/audit/rules.d". -a always,exit -F arch=b32 -S umount2 -F auid>=1000 -F auid!=unset -k privileged-umount -a always,exit -F arch=b64 -S umount2 -F auid>=1000 -F auid!=unset -k privileged-umount To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

RHEL 9 must generate audit records for all account creations, modifications, disabling, and termination events that affect /etc/sudoers.

AC-2 - Medium - CCI-000018 - V-258217 - SV-258217r1045436_rule

RMF Control

AC-2

Severity

M

CCI

Version

RHEL-09-654215

Vuln IDs

V-258217

Rule IDs

SV-258217r1045436_rule

The actions taken by system administrators must be audited to keep a record of what was executed on the system, as well as for accountability purposes. Editing the sudoers file may be sign of an attacker trying to establish persistent methods to a system, auditing the editing of the sudoers files mitigates this risk. Satisfies: SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221

Checks: C-61958r1045434_chk

Verify RHEL 9 generates audit records for all account creations, modifications, disabling, and termination events that affect "/etc/sudoers" with the following command: $ sudo auditctl -l | grep '/etc/sudoers[^.]' -w /etc/sudoers -p wa -k identity If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61882r1045435_fix

Configure RHEL 9 to generate audit records for all account creations, modifications, disabling, and termination events that affect "/etc/sudoers". Add or update the following file system rule to "/etc/audit/rules.d/audit.rules": -w /etc/sudoers -p wa -k identity To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

RHEL 9 must generate audit records for all account creations, modifications, disabling, and termination events that affect /etc/sudoers.d/ directory.

AC-2 - Medium - CCI-000018 - V-258218 - SV-258218r1101981_rule

RMF Control

AC-2

Severity

M

CCI

Version

RHEL-09-654220

Vuln IDs

V-258218

Rule IDs

SV-258218r1101981_rule

The actions taken by system administrators must be audited to keep a record of what was executed on the system, as well as for accountability purposes. Editing the sudoers file may be sign of an attacker trying to establish persistent methods to a system, auditing the editing of the sudoers files mitigates this risk. Satisfies: SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221

Checks: C-61959r1101980_chk

Verify RHEL 9 generates audit records for all account creations, modifications, disabling, and termination events that affect "/etc/sudoers.d/" with the following command: $ sudo auditctl -l | grep /etc/sudoers.d -w /etc/sudoers.d/ -p wa -k identity If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61883r1045438_fix

Configure RHEL 9 to generate audit records for all account creations, modifications, disabling, and termination events that affect "/etc/sudoers.d/". Add or update the following file system rule to "/etc/audit/rules.d/audit.rules": -w /etc/sudoers.d/ -p wa -k identity To load the rules to the kernel immediately, use the following command: $ sudo augenrules --load

b

RHEL 9 must generate audit records for all account creations, modifications, disabling, and termination events that affect /etc/group.

AC-2 - Medium - CCI-000018 - V-258219 - SV-258219r1015130_rule

RMF Control

AC-2

Severity

M

CCI

Version

RHEL-09-654225

Vuln IDs

V-258219

Rule IDs

SV-258219r1015130_rule

In addition to auditing new user and group accounts, these watches will alert the system administrator(s) to any modifications. Any unexpected users, groups, or modifications must be investigated for legitimacy. Satisfies: SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221

Checks: C-61960r926642_chk

Verify RHEL 9 generates audit records for all account creations, modifications, disabling, and termination events that affect "/etc/group" with the following command: $ sudo auditctl -l | egrep '(/etc/group)' -w /etc/group -p wa -k identity If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61884r926643_fix

Configure RHEL 9 to generate audit records for all account creations, modifications, disabling, and termination events that affect "/etc/group". Add or update the following file system rule to "/etc/audit/rules.d/audit.rules": -w /etc/group -p wa -k identity The audit daemon must be restarted for the changes to take effect.

b

RHEL 9 must generate audit records for all account creations, modifications, disabling, and termination events that affect /etc/gshadow.

AC-2 - Medium - CCI-000018 - V-258220 - SV-258220r1015131_rule

RMF Control

AC-2

Severity

M

CCI

Version

RHEL-09-654230

Vuln IDs

V-258220

Rule IDs

SV-258220r1015131_rule

In addition to auditing new user and group accounts, these watches will alert the system administrator(s) to any modifications. Any unexpected users, groups, or modifications should be investigated for legitimacy. Satisfies: SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221

Checks: C-61961r926645_chk

Verify RHEL 9 generates audit records for all account creations, modifications, disabling, and termination events that affect "/etc/gshadow" with the following command: $ sudo auditctl -l | egrep '(/etc/gshadow)' -w /etc/gshadow -p wa -k identity If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61885r926646_fix

Configure RHEL 9 to generate audit records for all account creations, modifications, disabling, and termination events that affect "/etc/gshadow". Add or update the following file system rule to "/etc/audit/rules.d/audit.rules": -w /etc/gshadow -p wa -k identity The audit daemon must be restarted for the changes to take effect.

b

RHEL 9 must generate audit records for all account creations, modifications, disabling, and termination events that affect /etc/opasswd.

AC-2 - Medium - CCI-000018 - V-258221 - SV-258221r1015132_rule

RMF Control

AC-2

Severity

M

CCI

Version

RHEL-09-654235

Vuln IDs

V-258221

Rule IDs

SV-258221r1015132_rule

In addition to auditing new user and group accounts, these watches will alert the system administrator(s) to any modifications. Any unexpected users, groups, or modifications should be investigated for legitimacy. Satisfies: SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221

Checks: C-61962r926648_chk

Verify RHEL 9 generates audit records for all account creations, modifications, disabling, and termination events that affect "/etc/security/opasswd" with the following command: $ sudo auditctl -l | egrep '(/etc/security/opasswd)' -w /etc/security/opasswd -p wa -k identity If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61886r926649_fix

Configure RHEL 9 to generate audit records for all account creations, modifications, disabling, and termination events that affect "/etc/security/opasswd". Add or update the following file system rule to "/etc/audit/rules.d/audit.rules": -w /etc/security/opasswd -p wa -k identity The audit daemon must be restarted for the changes to take effect.

b

RHEL 9 must generate audit records for all account creations, modifications, disabling, and termination events that affect /etc/passwd.

AC-2 - Medium - CCI-000015 - V-258222 - SV-258222r1015133_rule

RMF Control

AC-2

Severity

M

CCI

CCI-000015

Version

RHEL-09-654240

Vuln IDs

V-258222

Rule IDs

SV-258222r1015133_rule

In addition to auditing new user and group accounts, these watches will alert the system administrator(s) to any modifications. Any unexpected users, groups, or modifications should be investigated for legitimacy. Satisfies: SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221, SRG-OS-000274-GPOS-00104, SRG-OS-000275-GPOS-00105, SRG-OS-000276-GPOS-00106, SRG-OS-000277-GPOS-00107

Checks: C-61963r926651_chk

Verify RHEL 9 generates audit records for all account creations, modifications, disabling, and termination events that affect "/etc/passwd" with the following command: $ sudo auditctl -l | egrep '(/etc/passwd)' -w /etc/passwd -p wa -k identity If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61887r926652_fix

Configure RHEL 9 to generate audit records for all account creations, modifications, disabling, and termination events that affect "/etc/passwd". Add or update the following file system rule to "/etc/audit/rules.d/audit.rules": -w /etc/passwd -p wa -k identity The audit daemon must be restarted for the changes to take effect.

b

RHEL 9 must generate audit records for all account creations, modifications, disabling, and termination events that affect /etc/shadow.

AC-2 - Medium - CCI-000018 - V-258223 - SV-258223r1015134_rule

RMF Control

AC-2

Severity

M

CCI

Version

RHEL-09-654245

Vuln IDs

V-258223

Rule IDs

SV-258223r1015134_rule

In addition to auditing new user and group accounts, these watches will alert the system administrator(s) to any modifications. Any unexpected users, groups, or modifications should be investigated for legitimacy. Satisfies: SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221

Checks: C-61964r926654_chk

Verify RHEL 9 generates audit records for all account creations, modifications, disabling, and termination events that affect "/etc/passwd with the following command: $ sudo auditctl -l | egrep '(/etc/shadow)' -w /etc/shadow -p wa -k identity If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61888r926655_fix

Configure RHEL 9 to generate audit records for all account creations, modifications, disabling, and termination events that affect "/etc/shadow". Add or update the following file system rule to "/etc/audit/rules.d/audit.rules": -w /etc/shadow -p wa -k identity The audit daemon must be restarted for the changes to take effect.

b

RHEL 9 must generate audit records for all account creations, modifications, disabling, and termination events that affect /var/log/faillock.

AU-12 - Medium - CCI-000172 - V-258224 - SV-258224r1014988_rule

RMF Control

AU-12

Severity

M

CCI

Version

RHEL-09-654250

Vuln IDs

V-258224

Rule IDs

SV-258224r1014988_rule

Without generating audit records specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Satisfies: SRG-OS-000392-GPOS-00172, SRG-OS-000470-GPOS-00214, SRG-OS-000473-GPOS-00218

Checks: C-61965r926657_chk

Verify RHEL 9 generates audit records for all account creations, modifications, disabling, and termination events that affect "/var/log/faillock" with the following command: $ sudo auditctl -l | grep /var/log/faillock -w /var/log/faillock -p wa -k logins If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61889r1014987_fix

Configure RHEL 9 to generate audit records for all account creations, modifications, disabling, and termination events that affect "/var/log/faillock". Add or update the following file system rule to "/etc/audit/rules.d/audit.rules": -w /var/log/faillock -p wa -k logins The audit daemon must be restarted for the changes to take effect. $ sudo service auditd restart

b

RHEL 9 must generate audit records for all account creations, modifications, disabling, and termination events that affect /var/log/lastlog.

AU-3 - Medium - CCI-000130 - V-258225 - SV-258225r1014990_rule

RMF Control

AU-3

Severity

M

CCI

Version

RHEL-09-654255

Vuln IDs

V-258225

Rule IDs

SV-258225r1014990_rule

Without generating audit records specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000473-GPOS-00218, SRG-OS-000470-GPOS-00214

Checks: C-61966r926660_chk

Verify RHEL 9 generates audit records for all account creations, modifications, disabling, and termination events that affect "/var/log/lastlog" with the following command: $ sudo auditctl -l | grep /var/log/lastlog -w /var/log/lastlog -p wa -k logins If the command does not return a line, or the line is commented out, this is a finding.

Fix: F-61890r1014989_fix

Configure RHEL 9 to generate audit records for all account creations, modifications, disabling, and termination events that affect "/var/log/lastlog". Add or update the following file system rule to "/etc/audit/rules.d/audit.rules": -w /var/log/lastlog -p wa -k logins The audit daemon must be restarted for the changes to take effect. $ sudo service auditd restart

b

RHEL 9 must take appropriate action when a critical audit processing failure occurs.

AU-5 - Medium - CCI-000139 - V-258227 - SV-258227r1014992_rule

RMF Control

AU-5

Severity

M

CCI

Version

RHEL-09-654265

Vuln IDs

V-258227

Rule IDs

SV-258227r1014992_rule

It is critical for the appropriate personnel to be aware if a system is at risk of failing to process audit logs as required. Without this notification, the security personnel may be unaware of an impending failure of the audit capability, and system operation may be adversely affected. Audit processing failures include software/hardware errors, failures in the audit capturing mechanisms, and audit storage capacity being reached or exceeded. Satisfies: SRG-OS-000046-GPOS-00022, SRG-OS-000047-GPOS-00023

Checks: C-61968r926666_chk

Verify the audit service is configured to panic on a critical error with the following command: $ sudo grep "\-f" /etc/audit/audit.rules -f 2 If the value for "-f" is not "2", and availability is not documented as an overriding concern, this is a finding.

Fix: F-61892r1014991_fix

Configure RHEL 9 to shut down when auditing failures occur. Add the following line to the bottom of the /etc/audit/rules.d/audit.rules file: -f 2

b

RHEL 9 audit system must protect logon UIDs from unauthorized change.

AU-9 - Medium - CCI-000162 - V-258228 - SV-258228r991572_rule

RMF Control

AU-9

Severity

M

CCI

Version

RHEL-09-654270

Vuln IDs

V-258228

Rule IDs

SV-258228r991572_rule

If modification of login user identifiers (UIDs) is not prevented, they can be changed by nonprivileged users and make auditing complicated or impossible. Satisfies: SRG-OS-000462-GPOS-00206, SRG-OS-000475-GPOS-00220, SRG-OS-000057-GPOS-00027, SRG-OS-000058-GPOS-00028, SRG-OS-000059-GPOS-00029

Checks: C-61969r926669_chk

Verify the audit system prevents unauthorized changes to logon UIDs with the following command: $ sudo grep -i immutable /etc/audit/audit.rules --loginuid-immutable If the "--loginuid-immutable" option is not returned in the "/etc/audit/audit.rules", or the line is commented out, this is a finding.

Fix: F-61893r926670_fix

Configure RHEL 9 auditing to prevent modification of login UIDs once they are set by adding the following line to /etc/audit/rules.d/audit.rules: --loginuid-immutable The audit daemon must be restarted for the changes to take effect.

b

RHEL 9 audit system must protect auditing rules from unauthorized change.

AU-9 - Medium - CCI-000162 - V-258229 - SV-258229r958434_rule

RMF Control

AU-9

Severity

M

CCI

Version

RHEL-09-654275

Vuln IDs

V-258229

Rule IDs

SV-258229r958434_rule

Unauthorized disclosure of audit records can reveal system and configuration data to attackers, thus compromising its confidentiality. Audit information includes all information (e.g., audit records, audit settings, audit reports) needed to successfully audit RHEL 9 system activity. In immutable mode, unauthorized users cannot execute changes to the audit system to potentially hide malicious activity and then put the audit rules back. A system reboot would be noticeable, and a system administrator could then investigate the unauthorized changes. Satisfies: SRG-OS-000057-GPOS-00027, SRG-OS-000058-GPOS-00028, SRG-OS-000059-GPOS-00029

Checks: C-61970r926672_chk

Verify the audit system prevents unauthorized changes with the following command: $ sudo grep "^\s*[^#]" /etc/audit/audit.rules | tail -1 -e 2 If the audit system is not set to be immutable by adding the "-e 2" option to the end of "/etc/audit/audit.rules", this is a finding.

Fix: F-61894r926673_fix

Configure the audit system to set the audit rules to be immutable by adding the following line to end of "/etc/audit/rules.d/audit.rules" -e 2 The audit daemon must be restarted for the changes to take effect.

c

RHEL 9 must enable FIPS mode.

AC-17 - High - CCI-000068 - V-258230 - SV-258230r1134936_rule

RMF Control

AC-17

Severity

H

CCI

CCI-000068

Version

RHEL-09-671010

Vuln IDs

V-258230

Rule IDs

SV-258230r1134936_rule

Use of weak or untested encryption algorithms undermines the purposes of utilizing 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. This includes NIST FIPS-validated cryptography for the following: Provisioning digital signatures, generating cryptographic hashes, and to protect data requiring data-at-rest protections in accordance with applicable federal laws, Executive Orders, directives, policies, regulations, and standards. Satisfies: SRG-OS-000033-GPOS-00014, SRG-OS-000125-GPOS-00065, SRG-OS-000396-GPOS-00176, SRG-OS-000423-GPOS-00187, SRG-OS-000478-GPOS-00223

Checks: C-61971r1134935_chk

Verify that RHEL 9 is in FIPS mode with the following command: $ sudo fips-mode-setup --check FIPS mode is enabled. If FIPS mode is not enabled, this is a finding. If any other lines are returned by the above command, run the following command to see the currently applied crypto-policy: $ update-crypto-policies --show FIPS If the policy is not "FIPS" or a FIPS policy authorized by and documented with the ISSO, this is a finding.

Fix: F-61895r926676_fix

Configure the operating system to implement FIPS mode with the following command $ sudo fips-mode-setup --enable Reboot the system for the changes to take effect.

b

RHEL 9 must employ FIPS 140-3 approved cryptographic hashing algorithms for all stored passwords.

Medium - CCI-004062 - V-258231 - SV-258231r1069375_rule

RMF Control

Severity

M

CCI

Version

RHEL-09-671015

Vuln IDs

V-258231

Rule IDs

SV-258231r1069375_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. Satisfies: SRG-OS-000073-GPOS-00041, SRG-OS-000120-GPOS-00061

Checks: C-61972r1069374_chk

Verify 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-61896r926679_fix

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

b

RHEL 9 IP tunnels must use FIPS 140-3 approved cryptographic algorithms.

AC-17 - Medium - CCI-000068 - V-258232 - SV-258232r1045440_rule

RMF Control

AC-17

Severity

M

CCI

CCI-000068

Version

RHEL-09-671020

Vuln IDs

V-258232

Rule IDs

SV-258232r1045440_rule

Overriding the system crypto policy makes the behavior of the Libreswan service violate expectations, and makes system configuration more fragmented.

Checks: C-61973r926681_chk

Verify that the IPsec service uses the system crypto policy with the following command: Note: If the ipsec service is not installed, this requirement is Not Applicable. $ sudo grep include /etc/ipsec.conf /etc/ipsec.d/*.conf /etc/ipsec.conf:include /etc/crypto-policies/back-ends/libreswan.config If the ipsec configuration file does not contain "include /etc/crypto-policies/back-ends/libreswan.config", this is a finding.

Fix: F-61897r926682_fix

Configure Libreswan to use the system cryptographic policy. Add the following line to "/etc/ipsec.conf": include /etc/crypto-policies/back-ends/libreswan.config

b

RHEL 9 pam_unix.so module must be configured in the password-auth file to use a FIPS 140-3 approved cryptographic hashing algorithm for system authentication.

Medium - CCI-004062 - V-258233 - SV-258233r1015136_rule

RMF Control

Severity

M

CCI

Version

RHEL-09-671025

Vuln IDs

V-258233

Rule IDs

SV-258233r1015136_rule

Unapproved mechanisms that are used for authentication to the cryptographic module are not verified and; therefore, cannot be relied upon to provide confidentiality or integrity, and DOD data may be compromised. RHEL 9 systems utilizing encryption are required to use FIPS-compliant mechanisms for authenticating to cryptographic modules. FIPS 140-3 is the current standard for validating that mechanisms used to access cryptographic modules utilize authentication that meets DOD requirements. This allows for Security Levels 1, 2, 3, or 4 for use on a general-purpose computing system.

Checks: C-61974r1014993_chk

Verify that the pam_unix.so module is configured to use sha512 in /etc/pam.d/password-auth with the following command: $ grep "^password.*pam_unix.so.*sha512" /etc/pam.d/password-auth password sufficient pam_unix.so sha512 If "sha512" is missing, or the line is commented out, this is a finding. If the system administrator (SA) can demonstrate that the required configuration is contained in a PAM configuration file included or substacked from the system-auth file, this is not a finding.

Fix: F-61898r926685_fix

Configure RHEL 9 to use a FIPS 140-3 approved cryptographic hashing algorithm for system authentication. Edit/modify the following line in the "/etc/pam.d/password-auth" file to include the sha512 option for pam_unix.so: password sufficient pam_unix.so sha512

b

RHEL 9 must have the crypto-policies package installed.

SC-13 - Medium - CCI-002450 - V-258234 - SV-258234r1051250_rule

RMF Control

SC-13

Severity

M

CCI

CCI-002450

Version

RHEL-09-215100

Vuln IDs

V-258234

Rule IDs

SV-258234r1051250_rule

Centralized cryptographic policies simplify applying secure ciphers across an operating system and the applications that run on that operating system. Use of weak or untested encryption algorithms undermines the purposes of using encryption to protect data. Satisfies: SRG-OS-000396-GPOS-00176, SRG-OS-000393-GPOS-00173, SRG-OS-000394-GPOS-00174

Checks: C-61975r1051248_chk

Verify that the RHEL 9 crypto-policies package is installed with the following command: $ dnf list --installed crypto-policies Example output: crypto-policies.noarch 20240828-2.git626aa59.el9_5 If the crypto-policies package is not installed, this is a finding.

Fix: F-61899r1051249_fix

Install the crypto-policies package (if the package is not already installed) with the following command: $ sudo dnf -y install crypto-policies

c

RHEL 9 cryptographic policy must not be overridden.

SC-13 - High - CCI-002450 - V-258236 - SV-258236r1101920_rule

RMF Control

SC-13

Severity

H

CCI

CCI-002450

Version

RHEL-09-672020

Vuln IDs

V-258236

Rule IDs

SV-258236r1101920_rule

Centralized cryptographic policies simplify applying secure ciphers across an operating system and the applications that run on that operating system. Use of weak or untested encryption algorithms undermines the purposes of using encryption to protect data. Satisfies: SRG-OS-000396-GPOS-00176, SRG-OS-000393-GPOS-00173, SRG-OS-000394-GPOS-00174

Checks: C-61977r1101919_chk

Verify that RHEL 9 cryptographic policies are not overridden. Verify that the configured policy matches the generated policy with the following command: $ sudo update-crypto-policies --check The configured policy matches the generated policy If the returned message does not match the above, but instead matches the following, this is a finding: The configured policy does NOT match the generated policy List all of the crypto backends configured on the system with the following command: $ ls -l /etc/crypto-policies/back-ends/ lrwxrwxrwx. 1 root root 40 Nov 13 16:29 bind.config -> /usr/share/crypto-policies/FIPS/bind.txt lrwxrwxrwx. 1 root root 42 Nov 13 16:29 gnutls.config -> /usr/share/crypto-policies/FIPS/gnutls.txt lrwxrwxrwx. 1 root root 40 Nov 13 16:29 java.config -> /usr/share/crypto-policies/FIPS/java.txt lrwxrwxrwx. 1 root root 46 Nov 13 16:29 javasystem.config -> /usr/share/crypto-policies/FIPS/javasystem.txt lrwxrwxrwx. 1 root root 40 Nov 13 16:29 krb5.config -> /usr/share/crypto-policies/FIPS/krb5.txt lrwxrwxrwx. 1 root root 45 Nov 13 16:29 libreswan.config -> /usr/share/crypto-policies/FIPS/libreswan.txt lrwxrwxrwx. 1 root root 42 Nov 13 16:29 libssh.config -> /usr/share/crypto-policies/FIPS/libssh.txt -rw-r--r--. 1 root root 398 Nov 13 16:29 nss.config lrwxrwxrwx. 1 root root 43 Nov 13 16:29 openssh.config -> /usr/share/crypto-policies/FIPS/openssh.txt lrwxrwxrwx. 1 root root 49 Nov 13 16:29 opensshserver.config -> /usr/share/crypto-policies/FIPS/opensshserver.txt lrwxrwxrwx. 1 root root 46 Nov 13 16:29 opensslcnf.config -> /usr/share/crypto-policies/FIPS/opensslcnf.txt lrwxrwxrwx. 1 root root 43 Nov 13 16:29 openssl.config -> /usr/share/crypto-policies/FIPS/openssl.txt lrwxrwxrwx. 1 root root 48 Nov 13 16:29 openssl_fips.config -> /usr/share/crypto-policies/FIPS/openssl_fips.txt If the paths do not point to the respective files under /usr/share/crypto-policies/FIPS path, this is a finding. Note: nss.config should not be symlinked. Note: If there is an operational need to use a subpolicy that causes the links to the crypto backends to break, this is a finding, and exceptions will need to be made by the authorizing official (AO) and documented with the information system security officer (ISSO).

Fix: F-61901r1051252_fix

Configure RHEL 9 to correctly implement the systemwide cryptographic policies by reinstalling the crypto-policies package contents. Reinstall crypto-policies with the following command: $ sudo dnf -y reinstall crypto-policies Set the crypto-policy to FIPS with the following command: $ sudo update-crypto-policies --set FIPS Setting system policy to FIPS Note: Systemwide crypto policies are applied on application startup. It is recommended to restart the system for the change of policies to fully take place.

b

RHEL 9 must implement a FIPS 140-3-compliant systemwide cryptographic policy.

SC-13 - Medium - CCI-002450 - V-258241 - SV-258241r1106302_rule

RMF Control

SC-13

Severity

M

CCI

CCI-002450

Version

RHEL-09-215105

Vuln IDs

V-258241

Rule IDs

SV-258241r1106302_rule

Centralized cryptographic policies simplify applying secure ciphers across an operating system and the applications that run on that operating system. Use of weak or untested encryption algorithms undermines the purposes of using encryption to protect data. Satisfies: SRG-OS-000396-GPOS-00176, SRG-OS-000393-GPOS-00173, SRG-OS-000394-GPOS-00174

Checks: C-61982r1106300_chk

Verify RHEL 9 is set to use a FIPS 140-3-compliant systemwide cryptographic policy with the following command: $ update-crypto-policies --show FIPS If the systemwide crypto policy is not set to "FIPS", this is a finding. Note: If subpolicies have been configured, they could be listed in a colon-separated list starting with "FIPS" as follows FIPS:<SUBPOLICY-NAME>. This is not a finding. Note: Subpolicies like AD-SUPPORT must be configured according to the latest guidance from the operating system vendor. Verify the current minimum crypto-policy configuration with the following commands: $ grep -E 'rsa_size|hash' /etc/crypto-policies/state/CURRENT.pol hash = SHA2-256 SHA2-384 SHA2-512 SHA2-224 SHA3-256 SHA3-384 SHA3-512 SHAKE-256 min_rsa_size = 2048 If the "hash" values do not include at least the following FIPS 140-3-compliant algorithms "SHA2-256 SHA2-384 SHA2-512 SHA2-224 SHA3-256 SHA3-384 SHA3-512 SHAKE-256", this is a finding. If there are algorithms that include "SHA1" or a hash value less than "224" this is a finding. If the "min_rsa_size" is not set to a value of at least "2048", this is a finding. If these commands do not return any output, this is a finding.

Fix: F-61906r1106301_fix

Configure RHEL 9 to use a FIPS 140-3-compliant systemwide cryptographic policy. Create a subpolicy for enhancements to the base systemwide crypto-policy by creating the file /etc/crypto-policies/policies/modules/STIG.pmod with the following content: # Define ciphers and MACs for OpenSSH and libssh cipher@SSH=AES-256-GCM AES-256-CTR AES-128-GCM AES-128-CTR mac@SSH=HMAC-SHA2-512 HMAC-SHA2-256 Apply the policy enhancements to the FIPS systemwide cryptographic policy level with the following command: $ sudo update-crypto-policies --set FIPS:STIG Note: If additional subpolicies are being employed, they must be added to the update-crypto-policies command. To make the cryptographic settings effective for already running services and applications, restart the system: $ sudo reboot

b

RHEL 9 must implement DOD-approved encryption in the bind package.

SC-8 - Medium - CCI-002418 - V-258242 - SV-258242r958908_rule

RMF Control

SC-8

Severity

M

CCI

CCI-002418

Version

RHEL-09-672050

Vuln IDs

V-258242

Rule IDs

SV-258242r958908_rule

Without cryptographic integrity protections, information can be altered by unauthorized users without detection. Cryptographic mechanisms used for protecting the integrity of information include, for example, signed hash functions using asymmetric cryptography enabling distribution of the public key to verify the hash information while maintaining the confidentiality of the secret key used to generate the hash. RHEL 9 incorporates system-wide crypto policies by default. The employed algorithms can be viewed in the /etc/crypto-policies/back-ends/ directory. Satisfies: SRG-OS-000423-GPOS-00187, SRG-OS-000426-GPOS-00190

Checks: C-61983r926711_chk

Verify that BIND uses the system crypto policy with the following command: Note: If the "bind" package is not installed, this requirement is Not Applicable. $ sudo grep include /etc/named.conf include "/etc/crypto-policies/back-ends/bind.config";' If BIND is installed and the BIND config file doesn't contain the include "/etc/crypto-policies/back-ends/bind.config" directive, or the line is commented out, this is a finding.

Fix: F-61907r926712_fix

Configure BIND to use the system crypto policy. Add the following line to the "options" section in "/etc/named.conf": include "/etc/crypto-policies/back-ends/bind.config";

b

RHEL 9 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-270174 - SV-270174r1044831_rule

RMF Control

AC-8

Severity

M

CCI

Version

RHEL-09-171011

Vuln IDs

V-270174

Rule IDs

SV-270174r1044831_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-74207r1044829_chk

Note: This requirement assumes the use of the RHEL 9 default graphical user interface, Gnome Shell. If the system does not have any graphical user interface installed, this requirement is Not Applicable. Verify RHEL 9 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: $ gsettings get org.gnome.login-screen banner-message-text 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-74108r1044830_fix

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

b

RHEL 9 "/etc/audit/" must be owned by root.

AU-9 - Medium - CCI-000162 - V-270175 - SV-270175r1117265_rule

RMF Control

AU-9

Severity

M

CCI

Version

RHEL-09-232103

Vuln IDs

V-270175

Rule IDs

SV-270175r1117265_rule

The "/etc/audit/" directory contains files that ensure the proper auditing of command execution, privilege escalation, file manipulation, and more. Protection of this directory is critical for system security.

Checks: C-74208r1044962_chk

Verify the ownership of the "/etc/audit/" directory with the following command: $ sudo stat -c "%U %n" /etc/audit/ root /etc/audit/ If the "/etc/audit/" directory does not have an owner of "root", this is a finding.

Fix: F-74109r1044963_fix

Change the owner of the file "/etc/audit/" to "root" by running the following command: $ sudo chown root /etc/audit/

b

RHEL 9 "/etc/audit/" must be group-owned by root.

AU-9 - Medium - CCI-000162 - V-270176 - SV-270176r1117265_rule

RMF Control

AU-9

Severity

M

CCI

Version

RHEL-09-232104

Vuln IDs

V-270176

Rule IDs

SV-270176r1117265_rule

The "/etc/audit/" directory contains files that ensure the proper auditing of command execution, privilege escalation, file manipulation, and more. Protection of this directory is critical for system security.

Checks: C-74209r1044965_chk

Verify the group ownership of the "/etc/audit/" directory with the following command: $ sudo stat -c "%G %n" /etc/audit/ root /etc/audit/ If "/etc/audit/" does not have a group owner of "root", this is a finding.

Fix: F-74110r1044966_fix

Change the group of the file "/etc/audit/" to "root" by running the following command: $ sudo chgrp root /etc/audit/

b

The RHEL 9 SSH client must be configured to use only DOD-approved encryption ciphers employing FIPS 140-3 validated cryptographic hash algorithms to protect the confidentiality of SSH client connections.

AC-17 - Medium - CCI-001453 - V-270177 - SV-270177r1051237_rule

RMF Control

AC-17

Severity

M

CCI

Version

RHEL-09-255064

Vuln IDs

V-270177

Rule IDs

SV-270177r1051237_rule

Without cryptographic integrity protections, information can be altered by unauthorized users without detection. Remote access (e.g., RDP) is access to DOD nonpublic information systems by an authorized user (or an information system) communicating through an external, nonorganization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless. Cryptographic mechanisms used for protecting the integrity of information include, for example, signed hash functions using asymmetric cryptography, enabling distribution of the public key to verify the hash information while maintaining the confidentiality of the secret key used to generate the hash. RHEL 9 incorporates systemwide crypto policies by default. The SSH configuration file has no effect on the ciphers, MACs, or algorithms unless specifically defined in the /etc/sysconfig/sshd file. The employed algorithms can be viewed in the /etc/crypto-policies/back-ends/openssh.config file.

Checks: C-74210r1051235_chk

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

Fix: F-74111r1051236_fix

Configure the SSH client to use only ciphers employing FIPS 140-3 approved algorithms. Reinstall crypto-policies with the following command: $ sudo dnf -y reinstall crypto-policies Set the crypto-policy to FIPS with the following command: $ sudo update-crypto-policies --set FIPS Setting system policy to FIPS Note: Systemwide crypto policies are applied on application startup. It is recommended to restart the system for the change of policies to fully take place.

b

The RHEL 9 SSH client must be configured to use only DOD-approved Message Authentication Codes (MACs) employing FIPS 140-3 validated cryptographic hash algorithms to protect the confidentiality of SSH client connections.

AC-17 - Medium - CCI-001453 - V-270178 - SV-270178r1051243_rule

RMF Control

AC-17

Severity

M

CCI

Version

RHEL-09-255070

Vuln IDs

V-270178

Rule IDs

SV-270178r1051243_rule

Without cryptographic integrity protections, information can be altered by unauthorized users without detection. Remote access (e.g., RDP) is access to DOD nonpublic information systems by an authorized user (or an information system) communicating through an external, nonorganization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless. Cryptographic mechanisms used for protecting the integrity of information include, for example, signed hash functions using asymmetric cryptography, enabling distribution of the public key to verify the hash information while maintaining the confidentiality of the secret key used to generate the hash. RHEL 9 incorporates systemwide crypto policies by default. The SSH configuration file has no effect on the ciphers, MACs, or algorithms unless specifically defined in the /etc/sysconfig/sshd file. The employed algorithms can be viewed in the /etc/crypto-policies/back-ends/openssh.config file.

Checks: C-74211r1051241_chk

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

Fix: F-74112r1051242_fix

Configure the SSH client to use only MACs employing FIPS 140-3 approved algorithms. Reinstall crypto-policies with the following command: $ sudo dnf -y reinstall crypto-policies Set the crypto-policy to FIPS with the following command: $ sudo update-crypto-policies --set FIPS Setting system policy to FIPS Note: Systemwide crypto policies are applied on application startup. It is recommended to restart the system for the change of policies to fully take place.

b

The RHEL 9 fapolicy module must be configured to employ a deny-all, permit-by-exception policy to allow the execution of authorized software programs.

CM-7 - Medium - CCI-001764 - V-270180 - SV-270180r1045182_rule

RMF Control

CM-7

Severity

M

CCI

Version

RHEL-09-433016

Vuln IDs

V-270180

Rule IDs

SV-270180r1045182_rule

The organization must identify authorized software programs and permit execution of authorized software. The process used to identify software programs that are authorized to execute on organizational information systems is commonly referred to as allow listing. Using an allow list provides a configuration management method for allowing the execution of only authorized software. Using only authorized software decreases risk by limiting the number of potential vulnerabilities. Verification of allow listed software occurs prior to execution or at system startup. User home directories/folders may contain information of a sensitive nature. Nonprivileged users should coordinate any sharing of information with an SA through shared resources. RHEL 9 ships with many optional packages. One such package is a file access policy daemon called "fapolicyd". "fapolicyd" is a userspace daemon that determines access rights to files based on attributes of the process and file. It can be used to either block list or allow list processes or file access. Proceed with caution with enforcing the use of this daemon. Improper configuration may render the system nonfunctional. The "fapolicyd" API is not namespace aware and can cause issues when launching or running containers. Satisfies: SRG-OS-000368-GPOS-00154, SRG-OS-000370-GPOS-00155, SRG-OS-000480-GPOS-00232

Checks: C-74213r1045180_chk

Verify the RHEL 9 "fapolicyd" employs a deny-all, permit-by-exception policy. Check that "fapolicyd" is in enforcement mode with the following command: $ sudo grep permissive /etc/fapolicyd/fapolicyd.conf permissive = 0 Check that "fapolicyd" employs a deny-all policy on system mounts with the following commands: $ sudo tail /etc/fapolicyd/compiled.rules allow exe=/usr/bin/python3.7 : ftype=text/x-python deny_audit perm=any pattern=ld_so : all deny perm=any all : all If "fapolicyd" is not running in enforcement mode with a deny-all, permit-by-exception policy, this is a finding.

Fix: F-74114r1045181_fix

Configure RHEL 9 to employ a deny-all, permit-by-exception application allow listing policy with "fapolicyd". With the "fapolicyd" installed and enabled, configure the daemon to function in permissive mode until the allow list is built correctly to avoid system lockout. Do this by editing the "/etc/fapolicyd/fapolicyd.conf" file with the following line: permissive = 1 Build the allow list in a file within the "/etc/fapolicyd/rules.d" directory, ensuring the last rule is "deny perm=any all : all". Once it is determined the allow list is built correctly, set the "fapolicyd" to enforcing mode by editing the "permissive" line in the /etc/fapolicyd/fapolicyd.conf file. permissive = 0

b

RHEL 9 must have the Postfix package installed.

AC-2 - Medium - CCI-000015 - V-272488 - SV-272488r1082178_rule

RMF Control

AC-2

Severity

M

CCI

CCI-000015

Version

RHEL-09-215101

Vuln IDs

V-272488

Rule IDs

SV-272488r1082178_rule

Postfix is a free, open-source mail transfer agent (MTA) that sends and receives emails. It is a server-side application that can be used to set up a local mail server, create a null-client mail relay, use a Postfix server as a destination for multiple domains, or choose an LDAP directory instead of files for lookups. Postfix supports protocols such as LDAP, SMTP AUTH (SASL), and TLS. It uses the Simple Mail Transfer Protocol (SMTP) to transfer emails between servers. Satisfies: SRG-OS-000304-GPOS-00121, SRG-OS-000343-GPOS-00134, SRG-OS-000363-GPOS-00150, SRG-OS-000447-GPOS-00201

Checks: C-76542r1082176_chk

Verify that RHEL 9 has the Postfix package installed with the following command: $ sudo dnf list --installed postfix Example output: postfix.x86_64 2:3.5.25-1.el9 If the "postfix" package is not installed, this is a finding.

Fix: F-76447r1082177_fix

Install the Postfix package with the following command: $ sudo dnf install postfix

b

RHEL 9 must elevate the SELinux context when an administrator calls the sudo command.

AC-6 - Medium - CCI-002235 - V-272496 - SV-272496r1134956_rule

RMF Control

AC-6

Severity

M

CCI