GCP Kubernetes Engine Clusters not configured with private nodes feature

Description

Disable public IP addresses for cluster nodes, so that they only have private IP addresses. Private Nodes are nodes with no public IP addresses.
Disabling public IP addresses on cluster nodes restricts access to only internal networks, forcing attackers to obtain local network access before attempting to compromise the underlying Kubernetes hosts.

Fix - Buildtime

Terraform

• Resource: google_container_cluster
• Argument: private_cluster_config

resource "google_container_cluster" "example" {
  name               = var.name
  location           = var.location
  project            = data.google_project.project.name

+ private_cluster_config {
+   enable_private_nodes    = var.private_cluster_config["enable_private_nodes"]
+   enable_private_endpoint = var.private_cluster_config["enable_private_endpoint"]
+   master_ipv4_cidr_block  = var.private_cluster_config["master_ipv4_cidr_block"]
+ }