The Kubernetes Kubelet certificate authority file must have file permissions set to 644 or more restrictive.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-242449	CNTR-K8-003160	SV-242449r919324_rule		Medium

Description

The Kubernetes kubelet certificate authority file contains settings for the Kubernetes Node TLS certificate authority. Any request presenting a client certificate signed by one of the authorities in the client-ca-file is authenticated with an identity corresponding to the CommonName of the client certificate. If this file can be changed, the Kubernetes architecture could be compromised. The scheduler will implement the changes immediately. Many of the security settings within the document are implemented through this file.

STIG	Date
Kubernetes Security Technical Implementation Guide	2023-08-29

Details

Check Text ( C-45724r919321_chk )
On the Control Plane, run the command: ps -ef | grep kubelet If the "--client-ca-file" option exists, this is a finding. Note the path to the config file (identified by --config). Run the command: grep -i clientCAFile Note the path to the client ca file. Run the command: stat -c %a If the client ca file has permissions more permissive than "644", this is a finding.

Fix Text (F-45682r919324_fix)
On the Control Plane, run the command: ps -ef | grep kubelet Remove the "--client-ca-file" option. Note the path to the config file (identified by --config). Run the command: grep -i clientCAFile Note the path to the client ca file. Run the command: chmod 644