Ensure that the --authorization-mode argument is not set to AlwaysAllow

Description:

Do not allow all requests. Enable explicit authorization.

Rationale:

Kubelets, by default, allow all authenticated requests (even anonymous ones) without needing explicit authorization checks from the apiserver. You should restrict this behavior and only allow explicitly authorized requests.

Unauthorized requests will be denied.

Remediation Method 1:

If modifying the Kubelet config file, edit the kubelet-config.json file '/etc/kubernetes/kubelet/kubelet-config.json' and set the below parameter to false

"authentication"... "webhook.*{"enabled":true

Remediation Method 2:

If using executable arguments, edit the kubelet service file '/etc/systemd/system/kubelet.service.d/10-kubelet-args.conf' on each worker node and add the below parameter at the end of the 'KUBELET_ARGS' variable string.

--authorization-mode=Webhook

Remediation Method 3:

If using the api configz endpoint consider searching for the status of '"authentication.webhook.{"enabled":true"' by extracting the live configuration from the nodes running kubelet.

**See detailed step-by-step configmap procedures in Reconfigure a Node's Kubelet in a Live Cluster, and then rerun the curl statement from audit process to check for kubelet configuration changes

kubectl proxy --port=8001 &

export HOSTNAME_PORT=localhost:8001 (example host and port number)
export NODE_NAME=ip-192.168.31.226.ec2.internal (example node name from "kubectl get nodes")

curl -sSL "http://${HOSTNAME_PORT}/api/v1/nodes/${NODE_NAME}/proxy/configz"

For all three remediations:
Based on your system, restart the 'kubelet' service and check status

systemctl daemon-reload
systemctl restart kubelet.service
systemctl status kubelet -l
.