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 | CCI-001082 | 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-269425r1050308_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