STIGUI
V-255915CAT III — Low severitySV-255915r1137695_rule

The SUSE operating system must restrict access to the kernel message buffer.

Rule version SLES-12-010375 · STIG v3 · 2025-11-24

Discussion

Restricting access to the kernel message buffer limits access only to root. This prevents attackers from gaining additional system information as a nonprivileged user.

Check

Verify the operating system is configured to restrict access to the kernel message buffer with the following commands:

     $ sudo 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:

     $ sudo grep -r kernel.dmesg_restrict /run/sysctl.d/* /etc/sysctl.d/* /usr/local/lib/sysctl.d/* /usr/lib/sysctl.d/* /lib/sysctl.d/* /etc/sysctl.conf 2> /dev/null
     /etc/sysctl.conf:kernel.dmesg_restrict = 1
     /etc/sysctl.d/99-sysctl.conf:kernel.dmesg_restrict = 1

If "kernel.dmesg_restrict" is not set to "1", is missing or commented out, this is a finding.

If conflicting results are returned, this is a finding.

Fix

Configure the operating system to restrict access to the kernel message buffer.

Set the system to the required kernel parameter by adding or modifying the following line in /etc/sysctl.conf or a config file in the /etc/sysctl.d/ directory:

     kernel.dmesg_restrict = 1

Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/ /etc/sysctl.d/ /usr/local/lib/sysctl.d/ /usr/lib/sysctl.d/ /lib/sysctl.d/ /etc/sysctl.conf

Reload settings from all system configuration files with the following command:

     $ sudo sysctl --system

Identifiers

Group ID
V-255915
Group title
SRG-OS-000138-GPOS-00069
Rule ID
SV-255915r1137695_rule
Check ID
C-59592r880926_chk
Fix ID
F-59535r880927_fix