Ubuntu 24.04 LTS must restrict access to the kernel message buffer.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-270749 | UBTU-24-600140 | SV-270749r1067179_rule | CCI-001090 | low |
| Description | ||||
| Restricting access to the kernel message buffer limits access only to root. This prevents attackers from gaining additional system information as a nonprivileged user. | ||||
| STIG | Date | |||
| Canonical Ubuntu 24.04 LTS Security Technical Implementation Guide | 2025-05-16 | |||
Related Frameworks
3 paths across 3 frameworks
Related Frameworks
NIST 800-531 mapping
SC-4
1.00
- DISA · 1 · disa_xccdf · related
- DISA · 2025-01-23 · disa_cci_list · equivalent
NIST 800-1711 mapping
3.13.4
1.00
- DISA · 1 · disa_xccdf · related
- DISA · 2025-01-23 · disa_cci_list · equivalent
- NIST · Rev 2 (Feb 2020, errata Jan 2021) · nist_800_171_app_d · equivalent
CCI1 mapping
CCI-001090
1.00
- DISA · 1 · disa_xccdf · related
Details
Check Text (C-270749r1067179_chk)
Verify Ubuntu 24.04 LTS is configured to restrict access to the kernel message buffer with the following command:
$ sysctl kernel.dmesg_restrict
kernel.dmesg_restrict = 1
If "kernel.dmesg_restrict" is not set to "1" or is missing, this is a finding.
Verify there are no configurations that enable the kernel dmesg function:
$ 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.d/10-kernel-hardening.conf:kernel.dmesg_restrict = 1
If any instance of "kernel.dmesg_restrict" is uncommented and set to "0", or if conflicting results are returned, this is a finding.
Fix Text (F-74683r1066735_fix)
Configure Ubuntu 24.04 LTS 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