The Kubernetes API server must have anonymous authentication disabled.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
high	V-242390	SRG-APP-000033-CTR-000100	CNTR-K8-000360	SV-242390r960792_rule	2025-02-20	2

Description
The Kubernetes API Server controls Kubernetes via an API interface. A user who has access to the API essentially has root access to the entire Kubernetes cluster. To control access, users must be authenticated and authorized. By allowing anonymous connections, the controls put in place to secure the API can be bypassed. Setting "--anonymous-auth" to "false" also disables unauthenticated requests from kubelets. While there are instances where anonymous connections may be needed (e.g., health checks) and Role-Based Access Controls (RBACs) are in place to limit the anonymous access, this access should be disabled, and only enabled when necessary.

Description

The Kubernetes API Server controls Kubernetes via an API interface. A user who has access to the API essentially has root access to the entire Kubernetes cluster. To control access, users must be authenticated and authorized. By allowing anonymous connections, the controls put in place to secure the API can be bypassed. Setting "--anonymous-auth" to "false" also disables unauthenticated requests from kubelets. While there are instances where anonymous connections may be needed (e.g., health checks) and Role-Based Access Controls (RBACs) are in place to limit the anonymous access, this access should be disabled, and only enabled when necessary.

ℹ️ Check
Change to the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Run the command: grep -i anonymous-auth * If the setting "--anonymous-auth" is set to "true" in the Kubernetes API Server manifest file, this is a finding.

✔️ Fix
Edit the Kubernetes API Server manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Set the value of "--anonymous-auth" to "false".