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3.1.1 Ensure that the kubeconfig file permissions are set to 644 or more restrictive

Information

If kubelet is running, and if it is configured by a kubeconfig file, ensure that the proxy kubeconfig file has permissions of 644 or more restrictive.

The kubelet kubeconfig file controls various parameters of the kubelet service in the worker node. You should restrict its file permissions to maintain the integrity of the file. The file should be writable by only the administrators on the system.

It is possible to run kubelet with the kubeconfig parameters configured as a Kubernetes ConfigMap instead of a file. In this case, there is no proxy kubeconfig file.

Solution

Run the below command (based on the file location on your system) on the each worker
node. For example,

chmod 644 <kubeconfig file>

Impact:

Ensuring that the kubeconfig file permissions are set to 644 or more restrictive significantly strengthens the security posture of the Kubernetes environment by preventing unauthorized modifications. This restricts write access to the kubeconfig file, ensuring only administrators can alter crucial kubelet configurations, thereby reducing the risk of malicious alterations that could compromise the cluster's integrity.

However, this configuration may slightly impact usability, as it limits the ability for non-administrative users to make quick adjustments to the kubelet settings. Administrators will need to balance security needs with operational flexibility, potentially requiring adjustments to workflows for managing kubelet configurations.

See Also

https://workbench.cisecurity.org/benchmarks/24956

Item Details

Category: ACCESS CONTROL, SECURITY ASSESSMENT AND AUTHORIZATION, MEDIA PROTECTION, SYSTEM AND COMMUNICATIONS PROTECTION, SYSTEM AND INFORMATION INTEGRITY

References: 800-53|AC-3, 800-53|AC-5, 800-53|AC-6, 800-53|CA-9, 800-53|MP-2, 800-53|SC-7, 800-53|SI-4, 800-53|SI-4(4), CSCv7|5.2

Plugin: Unix

Control ID: cf4c1c9c45657929251c5459d58a81848660842e6c7b705dbff5672b0368809a