Cis Ocp V160 2.2

CIS Red Hat OpenShift Container Platform Benchmark v1.6.0 - Control 2.2

Profile Applicability

• Level: 1

Description

Enable client authentication on etcd service.

Rationale

etcd is a highly-available key value store used by Kubernetes deployments for persistent storage of all of its REST API objects. These objects are sensitive in nature and should not be available to unauthenticated clients. You should enable the client authentication via valid certificates to secure the access to the etcd service.

Impact

All clients attempting to access the etcd server will require a valid client certificate.

Audit Procedure

OpenShift uses X.509 certificates to provide secure communication to etcd. OpenShift installation generates these files and sets the arguments appropriately. The following certificates are generated and used by etcd and other processes that communicate with etcd:

• Client certificates: Client certificates are currently used by the API server only, and no other service should connect to etcd directly except for the proxy. Client secrets (etcd-client, etcd-metric-client, etcd-metric-signer, and etcd-signer) are added to the openshift-config, openshift-monitoring, and openshift-kube-apiserver namespaces.
• Server certificates: Used by the etcd server for authenticating client requests.

Run the following command on the etcd server node:

for i in $(oc get pods -oname -n openshift-etcd)
do
    oc exec -n openshift-etcd -c etcd $i -- \
      ps -o command= -C etcd | sed 's/.*\(--client-cert-auth=[^ ]*\).*/\1/'
done

Verify that the --client-cert-auth argument is set to true for each etcd member.

Remediation

This setting is managed by the cluster etcd operator. No remediation required.

Default Value

By default, client-cert-auth is set to true.

References

1. https://docs.openshift.com/container-platform/latest/security/certificate_types_descriptions/etcd-certificates.html
2. https://github.com/openshift/cluster-etcd-operator
3. https://github.com/openshift/cluster-etcd-operator/blob/release-4.5/bindata/etcd/pod.yaml#L154-L167
4. https://github.com/openshift/cluster-etcd-operator/blob/master/bindata/etcd/pod.yaml#L154-L167
5. https://etcd.io/
6. https://kubernetes.io/docs/tasks/administer-cluster/configure-upgrade-etcd/
7. https://etcd.io/#client-cert-auth

CIS Controls

MITRE ATT&CK Mappings

Profile

Level 1 (Manual)