Cis Ocp V190 4.2.11

---
name: cis-ocp-v190-4.2.11
description: "Verify that the RotateKubeletServerCertificate argument is set to true (Manual)"
category: cis-openshift
version: "1.9.0"
author: cyberstrike-official
tags: [cis, openshift, kubernetes, redhat, worker-nodes, kubelet]
cis_id: "4.2.11"
cis_benchmark: "CIS Red Hat OpenShift Container Platform Benchmark v1.9.0"
tech_stack: [kubernetes, openshift, redhat]
cwe_ids: []
chains_with: []
prerequisites: []
severity_boost: {}
---

# CIS Red Hat OpenShift Container Platform Benchmark v1.9.0 - Control 4.2.11

## Profile Applicability

- **Level:** 2

## 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

Run the following command to check if the `RotateKubeletServerCertificate` feature gate is enabled on each node:

```bash
for node in $(oc get nodes -ojsonpath='{.items[*].metadata.name}'); do
oc get --raw /api/v1/nodes/$node/proxy/configz | jq '.kubeletconfig.featureGates.RotateKubeletServerCertificate'
done
```

Verify that all nodes return `true`.

Run the following command to check that each node is configured to rotate certificates:

```bash
for node in $(oc get nodes -ojsonpath='{.items[*].metadata.name}'); do
oc get --raw /api/v1/nodes/$node/proxy/configz | jq '.kubeletconfig.rotateCertificates'
done
```

Verify that all nodes return `true`.

## Remediation

None.

## Default Value

By default, `RotateKubeletServerCertificate` is enabled.

## References

1. https://github.com/openshift/machine-config-operator/blob/release-4.5/templates/master/01-master-kubelet/_base/files/kubelet.yaml
2. https://github.com/openshift/machine-config-operator/blob/release-4.5/templates/worker/01-worker-kubelet/_base/files/kubelet.yaml
3. https://github.com/kubernetes/kubernetes/pull/45059
4. https://kubernetes.io/docs/reference/command-line-tools-reference/kubelet-tls-bootstrapping/#kubelet-configuration

## CIS Controls

| Controls Version | Control                                           | IG 1 | IG 2 | IG 3 |
| ---------------- | ------------------------------------------------- | ---- | ---- | ---- |
| v8               | 3.10 Encrypt Sensitive Data in Transit            |      | \*   | \*   |
| v7               | 14.4 Encrypt All Sensitive Information in Transit |      | \*   | \*   |

## MITRE ATT&CK Mappings

| Techniques / Sub-techniques | Tactics | Mitigations |
| --------------------------- | ------- | ----------- |

## Profile

**Level 2** (Manual)