AlmaLinux OS 9 must restrict access to the kernel message buffer.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-269425 | ALMA-09-041050 | SV-269425r1050308_rule | Medium |
| Description |
| Restricting access to the kernel message buffer limits access to only root. This prevents attackers from gaining additional system information as a nonprivileged user. Satisfies: SRG-OS-000132-GPOS-00067, SRG-OS-000138-GPOS-00069 |
| STIG | Date |
| CloudLinux AlmaLinux OS 9 Security Technical Implementation Guide | 2025-05-22 |
Details
| Check Text (C-73456r1049685_chk) |
| Verify AlmaLinux OS 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. $ 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. $ /usr/lib/systemd/systemd-sysctl --cat-config | egrep -v '^(#|;)' | grep -F kernel.dmesg_restrict | tail -1 kernel.dmesg_restrict = 1 If "kernel.dmesg_restrict" is not set to "1" or is missing, this is a finding. |
| Fix Text (F-73357r1049686_fix) |
| Configure AlmaLinux OS 9 to restrict access to the kernel message buffer with the following command: $ echo "kernel.dmesg_restrict = 1 > /etc/sysctl.d/60-dmesg.conf" Load settings from all system configuration files with the following command: $ sysctl --system |