Check: CNTR-K8-000380
Kubernetes STIG:
CNTR-K8-000380
(in versions v1 r6 through v1 r1)
Title
The Kubernetes kubelet must enable explicit authorization. (Cat I impact)
Discussion
Kubelet is the primary agent on each node. The API server communicates with each kubelet to perform tasks such as starting/stopping pods. By default, kubelets allow all authenticated requests, even anonymous ones, without requiring any authorization checks from the API server. This default behavior bypasses any authorization controls put in place to limit what users may perform within the Kubernetes cluster. To change this behavior, the default setting of AlwaysAllow for the authorization mode must be set to "Webhook".
Check Content
Change to the /etc/sysconfig/ directory on the Kubernetes Master Node. Run the command: grep -i authorization-mode kubelet On each Worker node, change to the /etc/sysconfig/ directory. Run the command: grep -i authorization-mode kubelet If authorization-mode is missing or is set to "AllowAlways" on the Master node or any of the Worker nodes, this is a finding.
Fix Text
Edit the Kubernetes Kubelet file in the/etc/sysconfig/ directory on the Kubernetes Master and Worker nodes. Set the argument --authorization-mode to "Webhook". Restart each kubelet service after the change is made using the command: service kubelet restart
Additional Identifiers
Rule ID: SV-242392r712532_rule
Vulnerability ID: V-242392
Group Title: SRG-APP-000033-CTR-000095
Expert Comments
CCIs
Number | Definition |
---|---|
CCI-000213 |
Enforce approved authorizations for logical access to information and system resources in accordance with applicable access control policies. |
Controls
Number | Title |
---|---|
AC-3 |
Access Enforcement |