AlmaLinux OS 9 must restrict exposed kernel pointer addresses access.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-269423 | ALMA-09-040830 | SV-269423r1050306_rule | CCI-001082 | medium |
| Description | ||||
| 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". | ||||
| STIG | Date | |||
| CloudLinux AlmaLinux OS 9 Security Technical Implementation Guide | 2025-05-22 | |||
Details
Check Text (C-269423r1050306_chk)
Verify the runtime status of the kernel.kptr_restrict kernel parameter with the following command:
$ sysctl kernel.kptr_restrict
kernel.kptr_restrict = 1
Verify the configuration of the kernel.kptr_restrict kernel parameter with the following command:
$ /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 (F-73355r1049680_fix)
Configure AlmaLinux OS 9 to restrict exposed kernel pointer addresses access with the following command:
$ echo "kernel.kptr_restrict = 1" > /etc/sysctl.d/60-kptr.conf
Load settings from all system configuration files with the following command:
$ sysctl --system