cis-ocp-v160-4-2-11

name	cis-ocp-v160-4.2.11
description	Verify that the RotateKubeletServerCertificate argument is set to true (Manual)
category	cis-openshift
version	1.6.0
author	cyberstrike-official
tags	["cis","openshift","kubernetes","redhat","worker-nodes","kubelet"]
cis_id	4.2.11
cis_benchmark	CIS Red Hat OpenShift Container Platform Benchmark v1.6.0
tech_stack	["kubernetes","openshift","redhat"]
cwe_ids	[]
chains_with	[]
prerequisites	[]
severity_boost	{}

CIS Red Hat OpenShift Container Platform Benchmark v1.6.0 - Control 4.2.11

Profile Applicability

• Level: 2

Description

Enable kubelet server certificate rotation.

Rationale

RotateKubeletServerCertificate causes the kubelet to both request a serving certificate after bootstrapping its client credentials and rotate the certificate as its existing credentials expire. This automated periodic rotation ensures that the there are no downtimes due to expired certificates and thus addressing availability in the CIA security triad.

Note: This recommendation only applies if you let kubelets get their certificates from the API server. In case your kubelet certificates come from an outside authority/tool (e.g. Vault) then you need to take care of rotation yourself.

Impact

None.

Audit Procedure

Run the following command to check if the RotateKubeletServerCertificate feature gate is enabled on each node:

for node in $(oc get nodes -ojsonpath='{.items[*].metadata.name}'); do
oc get --raw /api/v1/nodes/$node/proxy/configz | jq '.kubeletconfig.featureGates.RotateKubeletServerCertificate'
done

Verify that all nodes return true. Run the following command to check that each node is configured to rotate certificates:

for node in $(oc get nodes -ojsonpath='{.items[*].metadata.name}'); do
oc get --raw /api/v1/nodes/$node/proxy/configz | jq '.kubeletconfig.rotateCertificates'
done

Verify that all nodes return true.

Remediation

None.

Default Value

By default, RotateKubeletServerCertificate is enabled.

References

1. https://github.com/openshift/machine-config-operator/blob/release-4.5/templates/master/01-master-kubelet/_base/files/kubelet.yaml