name: cis-ocp-v160-1.3.1 description: "Ensure that controller manager healthz endpoints are protected by RBAC (Manual)" category: cis-openshift version: "1.6.0" author: cyberstrike-official tags: [cis, openshift, kubernetes, redhat, controller-manager, rbac, profiling, healthz] cis_id: "1.3.1" 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 1.3.1

Profile Applicability

• Level: 1

Description

Disable profiling, if not needed.

Rationale

Profiling allows for the identification of specific performance bottlenecks. It generates a significant amount of program data that could potentially be exploited to uncover system and program details. If you are not experiencing any bottlenecks and do not need the profiler for troubleshooting purposes, it is recommended to turn it off to reduce the potential attack surface.

Impact

Profiling information would not be available.

Audit Procedure

By default, the Controller Manager operator exposes metrics via the metrics service. Profiling data is sent to healthzPort, the port of the localhost healthz endpoint. Changing this value may disrupt components that monitor the kubelet health. To ensure the collected data is not exploited, profiling endpoints are secured via RBAC (see cluster-debugger role). By default, the profiling endpoints are accessible only by users bound to cluster-admin or cluster-debugger role. Profiling can not be disabled.

To verify the configuration, run the following command:

Run the following command to check the livenessProbe configuration:

oc -n openshift-kube-controller-manager get cm kube-controller-manager-pod -o json | jq -r '.data."pod.yaml"' | jq '.spec.containers[].livenessProbe'

Verify the output path is set to healthz.

Run the following command to check the readinessProbe configuration:

oc -n openshift-kube-controller-manager get cm kube-controller-manager-pod -o json | jq -r '.data."pod.yaml"' | jq '.spec.containers[].readinessProbe'

Verify the output path is set to healthz.

Verify endpoints exist for the Kubernetes controller manager:

oc -n openshift-kube-controller-manager describe endpoints

Validate that RBAC is enabled and protects controller endpoints. First, switch to the openshift-kube-controller-namespace:

oc project openshift-kube-controller-manager

Next, get the controller manager pod name and port:

export POD=$(oc get pods -l app=kube-controller-manager -o jsonpath='{.items[0].metadata.name}')
export PORT=$(oc get pods -l app=kube-controller-manager -o jsonpath='{.items[0].spec.containers[0].ports[0].hostPort}')

Attempt to make an insecure GET request to the metrics endpoint:

oc rsh $POD curl https://localhost:$PORT/metrics -k

Verify that an HTTP 403 is returned.

Create a test service account:

oc create sa permission-test-sa

Generate a service account token and attempt to access the metrics endpoint:

export SA_TOKEN=$(oc create token permission-test-sa)
oc rsh $POD curl https://localhost:$PORT/metrics -H "Authorization: Bearer $SA_TOKEN" -k

Verify that an HTTP 403 is returned.

Login as a cluster administrator and attempt to access the metrics endpoint:

export CLUSTER_ADMIN_TOKEN=$(oc whoami -t)
oc rsh $POD curl https://localhost:$PORT/metrics -H "Authorization: Bearer $CLUSTER_ADMIN_TOKEN" -k

Verify metrics output is returned. Unset environment variables used in the test and delete the test service account:

unset CLUSTER_ADMIN_TOKEN POD PORT SA_TOKEN
oc delete sa permission-test-sa

Remediation

None.

Default Value

By default, the operator exposes metrics via metrics service. The metrics are collected from the OpenShift Controller Manager and the Kubernetes Controller Manager and protected by RBAC.

References

1. https://docs.openshift.com/container-platform/latest/monitoring/monitoring-overview.html
2. https://github.com/openshift/cluster-kube-controller-manager-operator/tree/master
3. https://github.com/openshift/cluster-kube-controller-manager-operator/blob/release-4.5/bindata/bootkube/bootstrap-manifests/kube-controller-manager-pod.yaml
4. https://github.com/openshift/cluster-kube-controller-manager-operator/blob/release-4.5/bindata/bootkube/manifests/00_openshift-kube-controller-manager-ns.yaml
5. https://github.com/openshift/cluster-kube-controller-manager-operator/blob/release-4.5/bindata/v4.1.0/kube-controller-manager/kubeconfig-cm.yaml
6. https://kubernetes.io/docs/reference/command-line-tools-reference/kube-controller-manager/
7. https://github.com/kubernetes/community/blob/master/contributors/devel/sig-scalability/profiling.md

CIS Controls

MITRE ATT&CK Mappings

Profile

Level 1 (Manual)