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 | 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-73454r1048645_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 |