Cis Ocp V180 1.2.30

CIS Red Hat OpenShift Container Platform Benchmark v1.8.0 - Control 1.2.30

Profile Applicability

• Level: 1

Description

Ensure that the API server is configured to only use strong cryptographic ciphers.

Rationale

TLS ciphers have had a number of known vulnerabilities and weaknesses, which can reduce the protection provided by them. By default Kubernetes supports a number of TLS ciphersuites including some that have security concerns, weakening the protection provided.

Impact

API server clients that cannot support the custom cryptographic ciphers will not be able to make connections to the API server.

Audit Procedure

Ciphers for the API servers, authentication operator, and ingress controller can be configured using the tlsSecurityProfile parameter. The ingress controller provides external access to the API server. There are four TLS security profile types:

• Old
• Intermediate
• Modern
• Custom

Only the Old, Intermediate and Custom profiles are supported at this time. Custom provides the ability to specify individual TLS security profile parameters. Follow the steps in the documentation to configure the cipher suite for Ingress and the API server.

Run the following command to obtain the TLS cipher suites used by the authentication operator:

oc get cm -n openshift-authentication v4-0-config-system-cliconfig -o jsonpath='{.data.v4\-0\-config\-system\-cliconfig}' | jq .servingInfo

Run the following command to obtain the TLS cipher suites used by the Kubernetes API server operator:

oc get kubeapiservers.operator.openshift.io cluster -o json | jq .spec.observedConfig.servingInfo

Run the following command to obtain the TLS cipher suites used by the OpenShift API server operator:

oc get openshiftapiservers.operator.openshift.io cluster -o json | jq .spec.observedConfig.servingInfo

Run the following command to obtain the TLS cipher suites used by the OpenShift ingress operator:

oc get -n openshift-ingress-operator ingresscontroller/default -o json | jq .status.tlsProfile

Make sure that tlsSecurityProfile is not set to Old and if set to Custom, make sure that the minTLSVersion is not set to VersionTLS10 or VersionTLS11. Verify the minTLSVersion is at least VersionTLS12.

Note: The HAProxy Ingress controller image does not support TLS 1.3 and because the Modern profile requires TLS 1.3, it is not supported. The Ingress Operator converts the Modern profile to Intermediate. The Ingress Operator also converts the TLS 1.0 of an Old or Custom profile to 1.1, and TLS 1.3 of a Custom profile to 1.2.

Remediation

None.

Default Value

By default, OpenShift uses the Intermediate TLS profile, which requires a minimum of TLS 1.2.

You can configure TLS security profiles by following the OpenShift TLS documentation.

References

1. https://docs.openshift.com/container-platform/latest/security/tls-security-profiles.html
2. https://docs.openshift.com/container-platform/4.13/rest_api/config_apis/apiserver-config-openshift-io-v1.html
3. https://github.com/ssllabs/research/wiki/SSL-and-TLS-Deployment-Best-Practices#23-use-secure-cipher-suites

CIS Controls

MITRE ATT&CK Mappings

Profile

Level 1 (Manual)