The Kubernetes API server must use approved cipher suites.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-242418	CNTR-K8-001400	SV-242418r712610_rule		Medium

Description
The Kubernetes API server communicates to the kubelet service on the nodes to deploy, update, and delete resources. If an attacker were able to get between this communication and modify the request, the Kubernetes cluster could be compromised. Using approved cypher suites for the communication ensures the protection of the transmitted information, confidentiality, and integrity so that the attacker cannot read or alter this communication.

Description

The Kubernetes API server communicates to the kubelet service on the nodes to deploy, update, and delete resources. If an attacker were able to get between this communication and modify the request, the Kubernetes cluster could be compromised. Using approved cypher suites for the communication ensures the protection of the transmitted information, confidentiality, and integrity so that the attacker cannot read or alter this communication.

STIG	Date
Kubernetes Security Technical Implementation Guide	2021-06-17

Details

Check Text ( C-45693r712608_chk )
Change to the /etc/kubernetes/manifests/ directory on the Kubernetes Master Node. Run the command: grep -i tls-cipher-suites * If the setting feature tls-cipher-suites is not set in the Kubernetes API server manifest file or contains no value or does not contain TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_RSA_WITH_AES_128_GCM _SHA256,TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305,TLS_ECDHE_RSA_WITH_AES_256_GCM _SHA384,TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,TLS_ECDHE_ECDSA_WITH_AES_256_GCM _SHA384, this is a finding.

Check Text ( C-45693r712608_chk )

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

grep -i tls-cipher-suites *

If the setting feature tls-cipher-suites is not set in the Kubernetes API server manifest file or contains no value or does not contain TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_RSA_WITH_AES_128_GCM _SHA256,TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305,TLS_ECDHE_RSA_WITH_AES_256_GCM _SHA384,TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,TLS_ECDHE_ECDSA_WITH_AES_256_GCM _SHA384, this is a finding.

Fix Text (F-45651r717025_fix)
Edit the Kubernetes API Server manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Master Node. Set the value of tls-cipher-suites to: TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_RSA_WITH_AES_128_GCM _SHA256,TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305,TLS_ECDHE_RSA_WITH_AES_256_GCM _SHA384,TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,TLS_ECDHE_ECDSA_WITH_AES_256_GCM _SHA384