cis-oke-v180-3-2-8

name	cis-oke-v180-3.2.8
description	Ensure that the --tls-cert-file and --tls-private-key-file arguments are set as appropriate (Automated)
category	cis-oke
version	1.8.0
author	cyberstrike-official
tags	["cis","oke","kubernetes","oci","worker-node","kubelet"]
cis_id	3.2.8
cis_benchmark	CIS Oracle Cloud Infrastructure Container Engine for Kubernetes (OKE) Benchmark v1.8.0
tech_stack	["kubernetes","oci","oke"]
cwe_ids	[]
chains_with	[]
prerequisites	[]
severity_boost	{}

CIS OKE Benchmark v1.8.0 - Control 3.2.8

Profile Applicability

• Level: 1

Description

Setup TLS connection on the Kubelets.

Rationale

Kubelet communication contains sensitive parameters that should remain encrypted in transit. Configure the Kubelets to serve only HTTPS traffic.

Impact

TLS and client certificate authentication must be configured for your Kubernetes cluster deployment.

Audit Procedure

Audit Method 1

If using a Kubelet configuration file, check that there is an entry for tls-cert-file set to correct pem file and tls-private-key-file is set to correct key file.

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 tls-cert-file=/var/lib/kubelet/pki/tls.pem. Verify that the tls-private-key-file=/var/lib/kubelet/pki/tls.key.

Audit Method 2

If using the api configz endpoint consider searching for the status of tlsCertFile and tlsPrivateKeyFile are set 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:

kubectl proxy --port=8001 &

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

curl -sSL "http://${HOSTNAME_PORT}/api/v1/nodes/${NODE_NAME}/proxy/configz"

Remediation

Remediation Method 1

If modifying the Kubelet service config file, edit the kubelet.service file /etc/systemd/system/kubelet.service and set the below parameter: