Cis K8S V1110 4.1.9

4.1.9 If the kubelet config.yaml configuration file is being used validate permissions set to 600 or more restrictive (Automated)

Profile Applicability

• Level 1 - Worker Node

Description

Ensure that if the kubelet refers to a configuration file with the --config argument, that file has permissions of 600 or more restrictive.

Rationale

The kubelet reads various parameters, including security settings, from a config file specified by the --config argument. If this file is specified 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.

Impact

None

Audit

Automated AAC auditing has been modified to allow CIS-CAT to input a variable for the <PATH>/<FILENAME> of the kubelet config yaml file. Please set $kubelet_config_yaml=<PATH> based on the file location on your system for example:

export kubelet_config_yaml=/var/lib/kubelet/config.yaml

To perform the audit manually: Run the below command (based on the file location on your system) on the each worker node. For example,

stat -c %a /var/lib/kubelet/config.yaml

Verify that the permissions are 600 or more restrictive.

Remediation

Run the following command (using the config file location identified in the Audit step)

chmod 600 /var/lib/kubelet/config.yaml

Default Value

By default, the /var/lib/kubelet/config.yaml file as set up by kubeadm has permissions of 600.

References

1. https://kubernetes.io/docs/tasks/administer-cluster/kubelet-config-file/

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