cis-ocp-v160-4-2-3

name	cis-ocp-v160-4.2.3
description	Ensure that the --authorization-mode argument is not set to AlwaysAllow (Automated)
category	cis-openshift
version	1.6.0
author	cyberstrike-official
tags	["cis","openshift","kubernetes","redhat","worker-nodes","kubelet"]
cis_id	4.2.3
cis_benchmark	CIS Red Hat OpenShift Container Platform Benchmark v1.6.0
tech_stack	["kubernetes","openshift","redhat"]
cwe_ids	[]
chains_with	[]
prerequisites	[]
severity_boost	{}

CIS Red Hat OpenShift Container Platform Benchmark v1.6.0 - Control 4.2.3

Profile Applicability

• Level: 1

Description

Do not allow all requests. Enable explicit authorization.

Rationale

Kubelets, by default, allow all authenticated requests (even anonymous ones) without needing explicit authorization checks from the apiserver. You should restrict this behavior and only allow explicitly authorized requests.

Impact

Unauthorized requests will be denied.

Audit Procedure

In OpenShift 4, the Kubernetes configuration file is managed by the Machine Config Operator. By default, OpenShift rejects unauthenticated and unauthorized users. You can verify that each node in the cluster is configured to only accept authenticated users with the following command:

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

Verify none of the nodes return AlwaysAllow for the authorization mode.

Remediation

None.

Default Value

By default, OpenShift uses Webhook authorization.

References

1. https://docs.openshift.com/container-platform/4.5/architecture/control-plane.html#understanding-machine-config-operator_control-plane
2. https://docs.openshift.com/container-platform/4.5/scalability_and_performance/recommended-host-practices.html#create-a-kubeletconfig-crd-to-edit-kubelet-parameters_
3. https://github.com/openshift/machine-config-operator/blob/release-4.5/docs/KubeletConfigDesign.md
4. https://kubernetes.io/docs/reference/command-line-tools-reference/kubelet/
5. https://kubernetes.io/docs/reference/command-line-tools-reference/kubelet-authentication-authorization/#kubelet-authentication