The Kubernetes API Server must enforce ports, protocols, and services (PPS) that adhere to the Ports, Protocols, and Services Management Category Assurance List (PPSM CAL).

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-242410	CNTR-K8-000920	SV-242410r712586_rule		Medium

Description
Kubernetes API Server PPSs must be controlled and conform to the PPSM CAL. Those PPS that fall outside the PPSM CAL must be blocked. Instructions on the PPSM can be found in DoD Instruction 8551.01 Policy.

STIG	Date
Kubernetes Security Technical Implementation Guide	2021-04-14

Details

Check Text ( C-45685r712584_chk )
Change to the /etc/kubernetes/manifests/ directory on the Kubernetes Master Node. Run the command: grep kube-apiserver.manifest -I-insecure-port grep kube-apiserver.manifest -I -secure-port grep kube-apiserver.manifest -I -etcd-servers * -edit manifest file: VIM Review livenessProbe: HttpGet: Port: Review ports: - containerPort: hostPort: - containerPort: hostPort: Run Command: kubectl describe services –all-namespace Search labels for any apiserver names spaces. Port: Any manifest and namespace PPS or services configuration not in compliance with PPSM CAL is a finding. Review the information systems documentation and interview the team, gain an understanding of the API Server architecture, and determine applicable PPS. If there are any ports, protocols, and services in the system documentation not in compliance with the CAL PPSM, this is a finding. Any PPS not set in the system documentation is a finding. Review findings against the most recent PPSM CAL: https://cyber.mil/ppsm/cal/ Verify API Server network boundary with the PPS associated with the CAL Assurance Categories. Any PPS not in compliance with the CAL Assurance Category requirements is a finding.

Check Text ( C-45685r712584_chk )

Change to the /etc/kubernetes/manifests/ directory on the Kubernetes Master Node. Run the command:
grep kube-apiserver.manifest -I-insecure-port
grep kube-apiserver.manifest -I -secure-port
grep kube-apiserver.manifest -I -etcd-servers *
-edit manifest file:
VIM
Review livenessProbe:
HttpGet:
Port:
Review ports:
- containerPort:
hostPort:
- containerPort:
hostPort:
Run Command:
kubectl describe services –all-namespace
Search labels for any apiserver names spaces.
Port:

Any manifest and namespace PPS or services configuration not in compliance with PPSM CAL is a finding.

Review the information systems documentation and interview the team, gain an understanding of the API Server architecture, and determine applicable PPS. If there are any ports, protocols, and services in the system documentation not in compliance with the CAL PPSM, this is a finding. Any PPS not set in the system documentation is a finding.

Review findings against the most recent PPSM CAL:
https://cyber.mil/ppsm/cal/

Verify API Server network boundary with the PPS associated with the CAL Assurance Categories. Any PPS not in compliance with the CAL Assurance Category requirements is a finding.

Fix Text (F-45643r712585_fix)
Amend any system documentation requiring revision. Update Kubernetes API Server manifest and namespace PPS configuration to comply with PPSM CAL.