Cis Ocp V160 2.4

CIS Red Hat OpenShift Container Platform Benchmark v1.6.0 - Control 2.4

Profile Applicability

• Level: 1

Description

etcd should be configured to make use of TLS encryption for peer connections.

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 be encrypted in transit and also amongst peers in the etcd clusters.

Impact

etcd cluster peers are set up TLS for their communication.

Audit Procedure

OpenShift uses X.509 certificates to provide secure communication to etcd. OpenShift generates these files and sets the arguments appropriately. etcd certificates are used for encrypted communication between etcd member peers, as well as encrypted client traffic. Peer certificates are generated and used for communication between etcd members.

Openshift installs etcd as static pods on control plane nodes, and mounts the configuration files from /etc/etcd/ on the host. The etcd.conf file includes peer-cert-file and peer-key-file configurations as referenced in /etc/etcd/etcd.conf.

Run the following command to check the value of --peer-cert-file:

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/.*\(--peer-cert-file=[^ ]*\).*/\1/'
done

Run the following command to check the value of --peer-key-file:

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/.*\(--peer-key-file=[^ ]*\).*/\1/'
done

Verify that the following is returned for each etcd member:

--peer-cert-file=/etc/kubernetes/static-pod-certs/secrets/etcd-all-peer/etcd-peer-${ETCD_DNS_NAME}.crt
--peer-key-file=/etc/kubernetes/static-pod-certs/secrets/etcd-all-peer/etcd-peer-${ETCD_DNS_NAME}.key

For example:

--peer-cert-file=/etc/kubernetes/static-pod-certs/secrets/etcd-all-peer/etcd-peer-ip-10-0-158-52.us-east-2.compute.internal.crt
--peer-key-file=/etc/kubernetes/static-pod-certs/secrets/etcd-all-peer/etcd-peer-ip-10-0-158-52.us-east-2.compute.internal.key

Remediation

None. This configuration is managed by the etcd operator.

Default Value

By default, peer communication over TLS is configured.

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/

CIS Controls

MITRE ATT&CK Mappings

Profile

Level 1 (Manual)