Kubernetes endpoints must use approved organizational certificate and key pair to protect information in transit.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-245544	CNTR-K8-002640	SV-245544r754897_rule		Medium

Description
Kubernetes control plane and external communication is managed by API Server. The main implementation of the API Server is to manage hardware resources for pods and container using horizontal or vertical scaling. Anyone who can gain access to the API Server can effectively control your Kubernetes architecture. 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. By default, the API Server does not authenticate to the kubelet HTTPs endpoint. To enable secure communication for API Server, the parameter -kubelet-client-certificate and kubelet-client-key must be set. This parameter gives the location of the certificate and key pair used to secure API Server communication.

Description

Kubernetes control plane and external communication is managed by API Server. The main implementation of the API Server is to manage hardware resources for pods and container using horizontal or vertical scaling. Anyone who can gain access to the API Server can effectively control your Kubernetes architecture. 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. By default, the API Server does not authenticate to the kubelet HTTPs endpoint. To enable secure communication for API Server, the parameter -kubelet-client-certificate and kubelet-client-key must be set. This parameter gives the location of the certificate and key pair used to secure API Server communication.

STIG	Date
Kubernetes Security Technical Implementation Guide	2021-11-22

Details

Check Text ( C-48819r754895_chk )
Change to the /etc/kubernetes/manifests/ directory on the Kubernetes Master Node. Run the command: grep -i kubelet-client-certificate * grep -I kubelet-client-key * If the setting "--kubelet-client-certificate" is not configured in the Kubernetes API server manifest file or contains no value, this is a finding. If the setting "--kubelet-client-key" is not configured in the Kubernetes API server manifest file or contains no value, this is a finding.

Check Text ( C-48819r754895_chk )

Change to the /etc/kubernetes/manifests/ directory on the Kubernetes Master Node. Run the command:

grep -i kubelet-client-certificate *
grep -I kubelet-client-key *

If the setting "--kubelet-client-certificate" is not configured in the Kubernetes API server manifest file or contains no value, this is a finding.

If the setting "--kubelet-client-key" is not configured in the Kubernetes API server manifest file or contains no value, this is a finding.

Fix Text (F-48774r754896_fix)
Edit the Kubernetes API Server manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Master Node. Set the value of "--kubelet-client-certificate" and "--kubelet-client-key" to an Approved Organizational Certificate and key pair.