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

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

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.

Note

See the AWS EKS documentation for the default value.

Audit

Method 1

SSH to the worker nodes.
Enter the following command to check to see if the Kubelet Service is running:
```
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:
```
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:
```
stat -c %U:%G /var/lib/kubelet/kubeconfig
```
Verify that the ownership is set to root:root.

Method 2

Create and Run a Privileged Pod

Run a pod that is privileged enough to access the host's file system. To do this, deploy a pod that uses the hostPath volume to mount the node's file system into the pod.
An example of a simple pod definition that mounts the root of the host to /host within the pod:
```
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:
```
kubectl apply -f file-check-pod.yaml
```
Once the pod is running, exec into it to check file permissions on the node:
```
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 permission level of the file:
```
ls -l /host/var/lib/kubelet/kubeconfig
```
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:

chown root:root <proxy kubeconfig file>