Information
Disable the read-only port.
Rationale:
The Kubelet process provides a read-only API in addition to the main Kubelet API. Unauthenticated access is provided to this read-only API which could possibly retrieve potentially sensitive information about the cluster.
Solution
Edit the kubelet service file '/etc/systemd/system/kubelet.service.d/10-kubeadm.conf' on each worker node and set the below parameter in 'KUBELET_SYSTEM_PODS_ARGS' variable.
--read-only-port=0
Based on your system, restart the 'kubelet' service. For example:
systemctl daemon-reload
systemctl restart kubelet.service
Impact:
Removal of the read-only port will require that any service which made use of it will need to be re-configured to use the main Kubelet API.