Automate service accounts management.
When you create a pod, if you do not specify a service account, it is automatically assigned the 'default' service account in the same namespace. You should create your own service account and let the API server manage its security tokens.
Follow the documentation and create 'ServiceAccount' objects as per your environment. Then, edit the API server pod specification file '/etc/kubernetes/manifests/kube-apiserver.yaml' on the master node and ensure that the '--disable-admission-plugins' parameter is set to a value that does not include 'ServiceAccount'.