cis-eks-v160-3-2-6

name	cis-eks-v160-3.2.6
description	Ensure that the --make-iptables-util-chains argument is set to true (Automated)
category	cis-eks
version	1.6.0
author	cyberstrike-official
tags	["cis","eks","kubernetes","aws","worker-node","kubelet","iptables","networking"]
cis_id	3.2.6
cis_benchmark	CIS Amazon Elastic Kubernetes Service (EKS) Benchmark v1.6.0
tech_stack	["kubernetes","aws","eks"]
cwe_ids	[]
chains_with	[]
prerequisites	[]
severity_boost	{}

3.2.6 Ensure that the --make-iptables-util-chains argument is set to true (Automated)

Profile Applicability

• Level 1

Description

Allow Kubelet to manage iptables.

Rationale

Kubelets can automatically manage the required changes to iptables based on how you choose your networking options for the pods. It is recommended to let kubelets manage the changes to iptables. This ensures that the iptables configuration remains in sync with pods networking configuration. Manually configuring iptables with dynamic pod network configuration changes might hamper the communication between pods/containers and to the outside world. You might have iptables rules too restrictive or too open.

Kubelet would manage the iptables on the system and keep it in sync. If you are using any other iptables management solution, then there might be some conflicts.

Audit Procedure

Audit Method 1:

First, SSH to each node. Run the following command on each node to find the Kubelet process:

ps -ef | grep kubelet

If the output of the above command includes the argument --make-iptables-util-chains then verify it is set to true.

If the --make-iptables-util-chains argument does not exist, and there is a Kubelet config file specified by --config, verify that the file does not set makeIPTablesUtilChains to false.

Audit Method 2:

If using the api configz endpoint consider searching for the status of authentication... "makeIPTablesUtilChains.:true 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)
export NODE_NAME=ip-192.168.31.226.ec2.internal (example node name from "kubectl get nodes")

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