STIGQter STIGQter: STIG Summary: Red Hat OpenShift Container Platform 4.x Security Technical Implementation Guide Version: 2 Release: 6 Benchmark Date: 01 Jul 2026:

OpenShift must restrict access to the kernel buffer.

DISA Rule

SV-257552r1137645_rule

Vulnerability Number

V-257552

Group Title

SRG-APP-000243-CTR-000600

Rule Version

CNTR-OS-000600

Severity

CAT II

CCI(s)

Weight

10

Fix Recommendation

Apply the machine config to restrict access to the kernel message buffer by executing the following:

for mcpool in $(oc get mcp -oname | sed "s:.*/::" ); do
echo "apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
metadata:
name: 75-sysctl-kernel-dmesg-restrict-$mcpool
labels:
machineconfiguration.openshift.io/role: $mcpool
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,kernel.dmesg_restrict%3D1%0A
mode: 0644
path: /etc/sysctl.d/75-sysctl_kernel_dmesg_restrict.conf
overwrite: true
" | oc apply -f -
done

Check Contents

Verify the Red Hat Enterprise Linux CoreOS (RHCOS) is configured to restrict access to the kernel message buffer.

Check the status of the kernel.dmesg_restrict kernel parameter by executing the following:

for node in $(oc get node -oname); do oc debug $node -- chroot /host /bin/bash -c 'echo -n "$HOSTNAME "; sysctl kernel.dmesg_restrict' 2>/dev/null; done

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

Vulnerability Number

V-257552

Documentable

False

Rule Version

CNTR-OS-000600

Severity Override Guidance

Verify the Red Hat Enterprise Linux CoreOS (RHCOS) is configured to restrict access to the kernel message buffer.

Check the status of the kernel.dmesg_restrict kernel parameter by executing the following:

for node in $(oc get node -oname); do oc debug $node -- chroot /host /bin/bash -c 'echo -n "$HOSTNAME "; sysctl kernel.dmesg_restrict' 2>/dev/null; done

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

Check Content Reference

M

Target Key

5547