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Profile applicability: Level 1 - Master Node
Do not bind the Controller Manager service to non-loopback insecure addresses.
The Controller Manager API service which runs on port 10252/TCP by default is used for health and metrics information and is available without authentication or encryption. As such it should only be bound to a localhost interface, to minimize the cluster's attack surface.
Note
Note
By default, the --bind-address parameter is set to 0.0.0.0.

Audit

Run the following command on the Control Plane node:
ps -ef | grep kube-controller-manager
Verify that the --bind-address argument is set to 127.0.0.1

Remediation

Edit the Controller Manager pod specification file /etc/kubernetes/manifests/kube-controller-manager.yaml on the Control Plane node and ensure the correct value for the --bind-address parameter.
Note
Note
Although the current Kubernetes documentation site says that --address is deprecated in favour of --bind-address Kubeadm 1.11 still makes use of --address.