cis-oke-v170-3-2-9

name	cis-oke-v170-3.2.9
description	Ensure that the --rotate-certificates argument is not set to false (Automated)
category	cis-oke
version	1.7.0
author	cyberstrike-official
tags	["cis","oke","kubernetes","oci","worker-node","kubelet"]
cis_id	3.2.9
cis_benchmark	CIS Oracle Cloud Infrastructure Container Engine for Kubernetes (OKE) Benchmark v1.7.0
tech_stack	["kubernetes","oci","oke"]
cwe_ids	[]
chains_with	[]
prerequisites	[]
severity_boost	{}

CIS OKE Benchmark v1.7.0 - Control 3.2.9

Profile Applicability

• Level: 1

Description

Enable kubelet client certificate rotation.

Rationale

The --rotate-certificates setting causes the kubelet to rotate its client certificates by creating new CSRs as its existing credentials expire. This automated periodic rotation ensures that the there is no downtime 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.

Note: This feature also require the RotateKubeletClientCertificate feature gate to be enabled (which is the default since Kubernetes v1.7)

Impact

None

Audit Procedure

Audit Method 1

If using a Kubelet configuration file, check that there is an entry for --rotate-certificates set to true.

First, SSH to the relevant node.

Run the following command on each node to find the appropriate Kubelet config file:

find / -name kubelet.service

The output of the above command should return the file and location /etc/systemd/system/kublet.service which is the location of the Kubelet service config file.

Open the Kubelet service config file:

sudo more etc/systemd/system/kubelet.service

Verify that the --rotate-certificates is present.

Audit Method 2

If using the api configz endpoint consider searching for the status of rotateCertificates by extracting the live configuration from the nodes running kubelet.

Set the local proxy port and the following variables and provide proxy port number and node name;

HOSTNAME_PORT="localhost-and-port-number"
NODE_NAME="The-Name-Of-Node-To-Extract-Configuration" # from the output of "kubectl get nodes"

kubectl proxy --port=8001 &

export HOSTNAME_PORT=localhost:8001 (example host and port number)
 NODE_NAME=10.0.10.4 (example node name from )

curl -sSL