Kubernetes API Server must generate audit records that identify what type of event has occurred, identify the source of the event, contain the event results, identify any users, and identify any containers associated with the event.

STIG ID: CNTR-K8-000700  |  SRG: SRG-APP-000026-CTR-000070 |  Severity: medium |  CCI: CCI-000018,CCI-000130,CCI-000131,CCI-000132,CCI-000133,CCI-000134,CCI-000135,CCI-000172,CCI-001403,CCI-001404,CCI-001487,CCI-002264 |  Vulnerability Id: V-242403

Vulnerability Discussion

Within Kubernetes, audit data for all components is generated by the API server. This audit data is important when there are issues, to include security incidents that must be investigated. To make the audit data worthwhile for the investigation of events, it is necessary to have the appropriate and required data logged. To fully understand the event, it is important to identify any users associated with the event.

The API server policy file allows for the following levels of auditing:
None - Do not log events that match the rule.
Metadata - Log request metadata (requesting user, timestamp, resource, verb, etc.) but not request or response body.
Request - Log event metadata and request body but not response body.
RequestResponse - Log event metadata, request, and response bodies.

Satisfies: SRGID:SRG-APP-000092-CTR-000165, SRG-APP-000026-CTR-000070, SRG-APP-000027-CTR-000075, SRG-APP-000028-CTR-000080, SRG-APP-000101-CTR-000205, SRG-APP-000100-CTR-000200, SRG-APP-000100-CTR-000195, SRG-APP-000099-CTR-000190, SRG-APP-000098-CTR-000185, SRG-APP-000095-CTR-000170, SRG-APP-000096-CTR-000175, SRG-APP-000097-CTR-000180, SRG-APP-000507-CTR-001295, SRG-APP-000504-CTR-001280, SRG-APP-000503-CTR-001275, SRG-APP-000501-CTR-001265, SRG-APP-000500-CTR-001260, SRG-APP-000497-CTR-001245, SRG-APP-000496-CTR-001240, SRG-APP-000493-CTR-001225, SRG-APP-000492-CTR-001220, SRG-APP-000343-CTR-000780, SRG-APP-000381-CTR-000905

Check

Change to the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Run the command:
grep -i audit-policy-file

If the audit-policy-file is not set, this is a finding.

The file given is the policy file and defines what is audited and what information is included with each event.

The policy file must look like this:

# Log all requests at the RequestResponse level.
apiVersion: audit.k8s.io/vX (Where X is the latest apiVersion)
kind: Policy
rules:
- level: RequestResponse

If the audit policy file does not look like above, this is a finding.

Fix

Edit the Kubernetes API Server manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane.

Set the value of "--audit-policy-file" to the path of a file with the following content:

# Log all requests at the RequestResponse level.
apiVersion: audit.k8s.io/vX (Where X is the latest apiVersion)
kind: Policy
rules:
- level: RequestResponse

Note: If the API server is running as a Pod, then the manifest will also need to be updated to mount the host system filesystem where the audit policy file resides.
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