Cis Eks V160 3.1.2

---
name: cis-eks-v160-3.1.2
description: "Ensure that the kubelet kubeconfig file ownership is set to root:root (Automated)"
category: cis-eks
version: "1.6.0"
author: cyberstrike-official
tags: [cis, eks, kubernetes, aws, worker-node, configuration-files, file-ownership]
cis_id: "3.1.2"
cis_benchmark: "CIS Amazon Elastic Kubernetes Service (EKS) Benchmark v1.6.0"
tech_stack: [kubernetes, aws, eks]
cwe_ids: []
chains_with: []
prerequisites: []
severity_boost: {}
---

# 3.1.2 Ensure that the kubelet kubeconfig file ownership is set to root:root (Automated)

## Profile Applicability

- Level 1

## Description

If kubelet is running, ensure that the file ownership of its kubeconfig file is set to root:root.

## Rationale

The kubeconfig file for kubelet controls various parameters for the kubelet service in the worker node. You should set its file ownership to maintain the integrity of the file. The file should be owned by root:root.

## Audit Procedure

**Method 1 - SSH to the worker nodes:**

To check to see if the Kubelet Service is running:

```bash
sudo systemctl status kubelet
```

The output should return `Active: active (running) since..`.

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

```bash
ps -ef | grep kubelet
```

The output of the above command should return something similar to `--kubeconfig /var/lib/kubelet/kubeconfig` which is the location of the kubeconfig file.

Run this command to obtain the kubeconfig file ownership:

```bash
stat -c %U:%G /var/lib/kubelet/kubeconfig
```

The output of the above command gives you the kubeconfig file's ownership. Verify that the ownership is set to `root:root`.

**Method 2 - Create and Run a Privileged Pod:**

You will need to run a pod that is privileged enough to access the host's file system. This can be achieved by deploying a pod that uses the hostPath volume to mount the node's file system into the pod.

```yaml
apiVersion: v1
kind: Pod
metadata:
  name: file-check
spec:
  volumes:
    - name: host-root
      hostPath:
        path: /
        type: Directory
  containers:
    - name: nsenter
      image: busybox
      command: ["sleep", "3600"]
      volumeMounts:
        - name: host-root
          mountPath: /host
      securityContext:
        privileged: true
```

Save this to a file (e.g., file-check-pod.yaml) and create the pod:

```bash
kubectl apply -f file-check-pod.yaml
```

Once the pod is running, you can exec into it to check file ownership on the node:

```bash
kubectl exec -it file-check -- sh
```

Now you are in a shell inside the pod, but you can access the node's file system through the /host directory and check the ownership of the file:

```bash
ls -l /host/var/lib/kubelet/kubeconfig
```

The output of the above command gives you the kubeconfig file's ownership. Verify that the ownership is set to `root:root`.

## Remediation

Run the below command (based on the file location on your system) on each worker node. For example,

```bash
chown root:root <proxy kubeconfig file>
```

## Default Value

See the AWS EKS documentation for the default value.

## References

1. [https://kubernetes.io/docs/admin/kube-proxy/](https://kubernetes.io/docs/admin/kube-proxy/)

## CIS Controls

| Controls Version | Control                                 | IG 1 | IG 2 | IG 3 |
| ---------------- | --------------------------------------- | ---- | ---- | ---- |
| v8               | 3.3 Configure Data Access Control Lists | X    | X    | X    |
| v7               | 5.2 Maintain Secure Images              |      | X    | X    |