The Kubernetes kubeadm.conf must have file permissions set to 644 or more restrictive.

STIG ID: CNTR-K8-003220  |  SRG: SRG-APP-000516-CTR-001325 |  Severity: medium |  CCI: CCI-000366 |  Vulnerability Id: V-242455

Vulnerability Discussion

The Kubernetes kubeadm.conf contains sensitive information regarding the cluster nodes configuration. If this file can be modified, the Kubernetes Platform Plane would be degraded or compromised for malicious intent. Many of the security settings within the document are implemented through this file.

Check

Review the kubeadm.conf file :

Get the path for kubeadm.conf by running:
systemctl status kubelet

Note the configuration file installed by the kubeadm is written to
(Default Location: /etc/systemd/system/kubelet.service.d/10-kubeadm.conf)
stat -c %a <kubeadm.conf path>

If the file has permissions more permissive than "644", this is a finding.

Fix

Change the permissions of kubeadm.conf to "644" by executing the command:

chmod 644 <kubeadm.conf path>