| name | cis-aks-v180-3.2.9 |
| description | Ensure that the RotateKubeletServerCertificate argument is set to true (Automated) |
| category | cis-aks |
| version | 1.8.0 |
| author | cyberstrike-official |
| tags | ["cis","aks","kubernetes","azure","kubelet","certificate-rotation","server-certificate"] |
| cis_id | 3.2.9 |
| cis_benchmark | CIS Azure Kubernetes Service (AKS) Benchmark v1.8.0 |
| tech_stack | ["kubernetes","azure","aks"] |
| cwe_ids | [] |
| chains_with | [] |
| prerequisites | [] |
| severity_boost | {} |
3.2.9 Ensure that the RotateKubeletServerCertificate argument is set to true (Automated)
Profile Applicability
Description
Enable kubelet server certificate rotation.
Rationale
RotateKubeletServerCertificate causes the kubelet to both request a serving certificate after bootstrapping its client credentials and rotate the certificate as its existing credentials expire. This automated periodic rotation ensures that the there are no downtimes due to expired certificates and thus addressing availability in the CIA security triad.
Note: This recommendation only applies if you let kubelets get their certificates from the API server. In case your kubelet certificates come from an outside authority/tool (e.g. Vault) then you need to take care of rotation yourself.
Impact
None
Audit Procedure
Audit Method 1:
If using a Kubelet configuration file, check that there is an entry for RotateKubeletServerCertificate is set to true.
First, SSH to the relevant node:
Run the following command on each node to find the appropriate Kubelet config file:
ps -ef | grep kubelet
The output of the above command should return something similar to --config /etc/kubernetes/kubelet/kubelet-config.json which is the location of the Kubelet config file.
Open the Kubelet config file:
cat /etc/kubernetes/kubelet/kubelet-config.json
Verify that RotateKubeletServerCertificate argument exists and is set to true.
Audit Method 2:
If using the api configz endpoint consider searching for the status of "RotateKubeletServerCertificate":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.aks.internal (example node name from "kubectl get nodes")
curl -sSL
