The Kubernetes Controller Manager must use TLS 1.2, at a minimum, to protect the confidentiality of sensitive data during electronic dissemination.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
medium	V-242376	SRG-APP-000014-CTR-000035	CNTR-K8-000150	SV-242376r960759_rule	2025-02-20	2

Description
The Kubernetes Controller Manager will prohibit the use of SSL and unauthorized versions of TLS protocols to properly secure communication. The use of unsupported protocol exposes vulnerabilities to the Kubernetes by rogue traffic interceptions, man-in-the-middle attacks, and impersonation of users or services from the container platform runtime, registry, and key store. To enable the minimum version of TLS to be used by the Kubernetes Controller Manager, the setting "tls-min-version" must be set.

Description

The Kubernetes Controller Manager will prohibit the use of SSL and unauthorized versions of TLS protocols to properly secure communication. The use of unsupported protocol exposes vulnerabilities to the Kubernetes by rogue traffic interceptions, man-in-the-middle attacks, and impersonation of users or services from the container platform runtime, registry, and key store. To enable the minimum version of TLS to be used by the Kubernetes Controller Manager, the setting "tls-min-version" must be set.

ℹ️ Check
Change to the /etc/kubernetes/manifests/ directory on the Kubernetes Control Plane. Run the command: grep -i tls-min-version * If the setting "tls-min-version" is not configured in the Kubernetes Controller Manager manifest file or it is set to "VersionTLS10" or "VersionTLS11", this is a finding.

✔️ Fix
Edit the Kubernetes Controller Manager manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Set the value of "--tls-min-version" to "VersionTLS12" or higher.