Title

Kubernetes etcd must enable client authentication to secure service. (Cat II impact)

Discussion

Kubernetes container and pod configuration are maintained by Kubelet. Kubelet agents register nodes with the API Server, mount volume storage, and perform health checks for containers and pods. Anyone who gains access to Kubelet agents can effectively control applications within the pods and containers. Using authenticity protection, the communication can be protected against man-in-the-middle attacks/session hijacking and the insertion of false information into sessions. The communication session is protected by utilizing transport encryption protocols, such as TLS. TLS provides the Kubernetes API Server with a means to be able to authenticate sessions and encrypt traffic. To enable encrypted communication for Kubelet, the parameter client-cert-auth must be set. This parameter gives the location of the SSL Certificate Authority file used to secure Kubelet communication.

Check Content

Change to the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Run the command: grep -i client-cert-auth * If the setting client-cert-auth is not configured in the Kubernetes etcd manifest file or set to "false", this is a finding.

Fix Text

Edit the Kubernetes etcd manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Set the value of "--client-cert-auth" to "true" for the etcd.

Additional Identifiers

Rule ID: SV-242423r879636_rule

Vulnerability ID: V-242423

Group Title: SRG-APP-000219-CTR-000550

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.