Cis Ocp V160 2.4

---
name: cis-ocp-v160-2.4
description: "Ensure that the --peer-cert-file and --peer-key-file arguments are set as appropriate (Manual)"
category: cis-openshift
version: "1.6.0"
author: cyberstrike-official
tags: [cis, openshift, kubernetes, redhat, etcd, peer-cert, peer-key, tls, encryption]
cis_id: "2.4"
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 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`:

```bash
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`:

```bash
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

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

## MITRE ATT&CK Mappings

| Techniques / Sub-techniques | Tactics | Mitigations |
| --------------------------- | ------- | ----------- |
| T1552                       | TA0006  | M1022       |

## Profile

**Level 1** (Manual)