--service-account-lookup is not enabled, the apiserver only verifies that the authentication token is valid, and does not validate that the service account token mentioned in the request is actually present in etcd. This allows using a service account token even after the corresponding service account is deleted. This is an example of time of check to time of use security issue.
Validate service account before validating token.
Run the following command on the Control Plane node:
ps -ef | grep kube-apiserver
Verify that if the
--service-account-lookup argument exists it is set to
Edit the API server pod specification file
/etc/kubernetes/manifests/kube-apiserver.yaml on the Control Plane node and set the below parameter.
Alternatively, you can delete the
--service-account-lookup parameter from this file so that the default takes effect.
--service-account-lookup argument is set to
Updated 12 days ago