| name | cis-gke-v180-3.1.1 |
| description | Ensure that the kubeconfig file permissions are set to 644 or more restrictive (Automated) |
| category | cis-gke |
| version | 1.8.0 |
| author | cyberstrike-official |
| tags | ["cis","gke","kubernetes","gcp","worker-nodes","configuration-files","permissions","kubeconfig","kubelet"] |
| cis_id | 3.1.1 |
| cis_benchmark | CIS Google Kubernetes Engine (GKE) Benchmark v1.8.0 |
| tech_stack | ["kubernetes","gcp","gke"] |
| cwe_ids | [] |
| chains_with | [] |
| prerequisites | [] |
| severity_boost | {} |
3.1.1 Ensure that the kubeconfig file permissions are set to 644 or more restrictive (Automated)
Profile Applicability
Description
If kubelet is running, and if it is configured by a kubeconfig file, ensure that the proxy kubeconfig file has permissions of 644 or more restrictive.
Rationale
The kubelet kubeconfig file controls various parameters of the kubelet service in the worker node. You should restrict its file permissions to maintain the integrity of the file. The file should be writable by only the administrators on the system.
It is possible to run kubelet with the kubeconfig parameters configured as a Kubernetes ConfigMap instead of a file. In this case, there is no proxy kubeconfig file.
Impact
Ensuring that the kubeconfig file permissions are set to 644 or more restrictive significantly strengthens the security posture of the Kubernetes environment by preventing unauthorized modifications. This restricts write access to the kubeconfig file, ensuring only administrators can alter crucial kubelet configurations, thereby reducing the risk of malicious alterations that could compromise the cluster's integrity.
However, this configuration may slightly impact usability, as it limits the ability for non-administrative users to make quick adjustments to the kubelet settings. Administrators will need to balance security needs with operational flexibility, potentially requiring adjustments to workflows for managing kubelet configurations.
Audit
Using Google Cloud Console
- Go to Kubernetes Engine by visiting https://console.cloud.google.com/kubernetes/list
- Click on the desired cluster to open the Details page, then click on the desired Node pool to open the Node pool Details page
- Note the name of the desired node
- Go to VM Instances by visiting https://console.cloud.google.com/compute/instances
- Find the desired node and click on 'SSH' to open an SSH connection to the node.
Using Command Line
Method 1
SSH to the worker nodes.
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
