Check: RHEL-09-213025
RHEL 9 STIG:
RHEL-09-213025
(in versions v1 r3 through v1 r2)
Title
RHEL 9 must restrict exposed kernel pointer addresses access. (Cat II impact)
Discussion
Exposing kernel pointers (through procfs or "seq_printf()") exposes kernel writeable structures, which may contain functions pointers. If a write vulnerability occurs in the kernel, allowing write access to any of this structure, the kernel can be compromised. This option disallows any program without the CAP_SYSLOG capability to get the addresses of kernel pointers by replacing them with "0". Satisfies: SRG-OS-000132-GPOS-00067, SRG-OS-000433-GPOS-00192, SRG-OS-000480-GPOS-00227
Check Content
Verify the runtime status of the kernel.kptr_restrict kernel parameter with the following command: $ sudo sysctl kernel.kptr_restrict kernel.kptr_restrict = 1 Verify the configuration of the kernel.kptr_restrict kernel parameter with the following command: $ sudo /usr/lib/systemd/systemd-sysctl --cat-config | egrep -v '^(#|;)' | grep -F kernel.kptr_restrict | tail -1 kernel.kptr_restrict =1 If "kernel.kptr_restrict" is not set to "1" or is missing, this is a finding.
Fix Text
Add or edit the following line in a system configuration file in the "/etc/sysctl.d/" directory: kernel.kptr_restrict = 1 Reload settings from all system configuration files with the following command: $ sudo sysctl --system
Additional Identifiers
Rule ID: SV-257800r942971_rule
Vulnerability ID: V-257800
Group Title: SRG-OS-000132-GPOS-00067
Expert Comments
CCIs
| Number | Definition |
|---|---|
| CCI-000366 |
The organization implements the security configuration settings. |
| CCI-001082 |
The information system separates user functionality (including user interface services) from information system management functionality. |
| CCI-002824 |
The information system implements organization-defined security safeguards to protect its memory from unauthorized code execution. |