Goal

Detect when multiple external connections are made to the port for the Kubernetes API (6443) or Kubelet API (10250).

Strategy

Kubernetes should not be publicly-accessible. This poses a risk of an attacker gaining access to the entire container platform. Incoming connections from multiple public IP addresses indicate an exposed instance.

Triage and response

1. Determine if the service running on the port is Kubernetes.
2. Review all events for connections from unexpected IP addresses.
3. Review running containers and audit logs for malicious activity.
4. Move the API to an interface that is not publicly-accessible. If you must expose Kubernetes to external hosts, configure secure authentication and restrict access with a security group.

This detection is based on data from Cloud Network Monitoring.