Cis K8S V1110 1.2.1

1.2.1 Ensure that the --anonymous-auth argument is set to false (Manual)

Profile Applicability

• Level 1 - Master Node

Description

Disable anonymous requests to the API server.

Rationale

When enabled, requests that are not rejected by other configured authentication methods are treated as anonymous requests. These requests are then served by the API server. You should rely on authentication to authorize access and disallow anonymous requests.

If you are using RBAC authorization, it is generally considered reasonable to allow anonymous access to the API Server for health checks and discovery purposes, and hence this recommendation is not scored. However, you should consider whether anonymous discovery is an acceptable risk for your purposes.

Impact

Anonymous requests will be rejected.

Audit

Run the following command on the Control Plane node:

ps -ef | grep kube-apiserver

Verify that the --anonymous-auth argument is set to false.

Alternative Audit:

kubectl get pod -nkube-system -lcomponent=kube-apiserver -o=jsonpath='{range .items[*]}{.spec.containers[*].command} {"\n"}{end}' | grep '\--anonymous-auth' | grep -i false

If the exit code is '1', then the control isn't present / failed.

Remediation

Edit the API server pod specification file /etc/kubernetes/manifests/kube-apiserver.yaml on the Control Plane node and set the below parameter.

--anonymous-auth=false

Default Value

By default, anonymous access is enabled.

References

1. https://kubernetes.io/docs/admin/kube-apiserver/
2. https://kubernetes.io/docs/admin/authentication/#anonymous-requests

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