Default VPC Should Not Be Used

More Info:

Determines whether the default VPC is being used for launching new services or artifacts. The default VPC should not be used in order to avoid launching multiple services in the same network which may not require connectivity. Each application, or network tier, should use its own VPC.

Risk Level

High

Address

Security

Compliance Standards

• APRA CPS 234 (Australia)
• BSI C5 (Germany)
• Brazil LGPD
• CCPA / CPRA (California)
• CIS Critical Security Controls v8
• CIS GCP
• CMMC 2.0
• CSA Cloud Controls Matrix v4
• Cloudanix Best Practice
• DPDPA
• Digital Operational Resilience Act (EU)
• GDPR
• ISO 27001
• ISO/IEC 27017
• ISO/IEC 27018
• ISO/IEC 27701
• KSA PDPL
• MAS Technology Risk Management (Singapore)
• MITRE ATT&CK (Cloud)
• NIS2 Directive
• NIST CSF
• NIST SP 800-171
• NYDFS 23 NYCRR 500
• Reserve Bank of India (RBI) Cyber Security Framework
• Reserve Bank of India (RBI) Master Direction – Information Technology Framework
• SOC2
• SWIFT Customer Security Controls Framework
• Sarbanes-Oxley IT General Controls
• UK NCSC Cyber Assessment Framework

Triage and Remediation

Remediation

Remediation

Using Console

To remediate the misconfiguration “Default VPC should not be used” for GCP using the GCP console, follow these steps:

1. Login to the GCP console at https://console.cloud.google.com/
2. Select the project that is using the default VPC.
3. In the left navigation pane, select “VPC network” and then select “VPC network”.
4. Click on the name of the default VPC.
5. Click on “Edit” at the top of the screen.
6. In the “Edit VPC network” screen, uncheck the “Default” checkbox.
7. Click “Save” to apply the changes.

This will remove the default VPC from the project, which is a best practice for security and network segmentation. You can then create custom VPCs with specific configurations to meet your project’s needs.

Using CLI

To remediate the “Default VPC Should Not Be Used” misconfiguration in GCP using GCP CLI, you can follow these steps:

1. Identify all the GCP projects that are using the default VPC. You can use the following command to list all the projects:

gcloud projects list

2. For each project that is using the default VPC, create a new VPC network. You can use the following command to create a new VPC network:

gcloud compute networks create [NETWORK_NAME] --subnet-mode=auto --bgp-routing-mode=regional

3. Once the new VPC network is created, you can move all the existing resources from the default VPC to the new VPC network. You can use the following command to move a resource to a new VPC network:

gcloud compute instances move [INSTANCE_NAME] --zone [ZONE] --network [NETWORK_NAME]

4. Once all the resources are moved to the new VPC network, you can delete the default VPC network. You can use the following command to delete the default VPC network:

gcloud compute networks delete default

5. Finally, you should update your organization’s policies to prevent the use of default VPCs in the future.

Note: Before making any changes to your GCP environment, it is recommended to test the changes in a non-production environment to ensure that there are no unintended consequences.

Using Python

To remediate the “Default VPC Should Not Be Used” misconfiguration in GCP using Python, you can follow the below steps:

1. Install the necessary Python packages:

pip install google-cloud-compute

2. Authenticate to GCP:

from google.oauth2 import service_account
from google.cloud import compute_v1

credentials = service_account.Credentials.from_service_account_file('<path_to_service_account_key_file>')
compute_client = compute_v1.ComputeClient(credentials=credentials)

3. Get the list of all VPCs:

vpcs = compute_client.networks().list(project='<project_id>').execute()

4. Check if any of the VPCs are default:

for vpc in vpcs['items']:
    if vpc['autoCreateSubnetworks'] == True:
        print(f"{vpc['name']} is a default VPC and should be deleted.")

5. Delete the default VPC:

compute_client.networks().delete(project='<project_id>', network='<default_vpc_name>').execute()

Note: Replace <path_to_service_account_key_file>, <project_id>, and <default_vpc_name> with the appropriate values for your GCP environment. Also, make sure to test the script in a non-production environment before running it in production.

Using Terraform

# New application-specific VPC network (replace placeholders)
resource "google_compute_network" "APP_VPC" {
  name                    = "APP_VPC_NAME"          # e.g. "orders-app-vpc"
  project                 = "GCP_PROJECT_ID"        # your GCP project ID
  auto_create_subnetworks = false                   # use custom subnets only
}

resource "google_compute_subnetwork" "APP_SUBNET" {
  name          = "APP_SUBNET_NAME"                # e.g. "orders-app-subnet-a"
  project       = "GCP_PROJECT_ID"
  region        = "GCP_REGION"                     # e.g. "us-central1"
  network       = google_compute_network.APP_VPC.id
  ip_cidr_range = "APP_SUBNET_CIDR"                # e.g. "10.10.0.0/24"
}

# Example: move a VM instance off the default network onto the new VPC
# WARNING: changing the `network_interface` forces replacement of the instance
# and will cause downtime for this VM.
resource "google_compute_instance" "APP_VM" {
  name         = "APP_VM_NAME"
  project      = "GCP_PROJECT_ID"
  zone         = "GCP_ZONE"
  machine_type = "e2-medium"

  boot_disk {
    initialize_params {
      image = "BOOT_IMAGE"
    }
  }

  # Previously this might have used:
  # network_interface {
  #   network = "default"
  # }
  #
  # Now explicitly use the new VPC/subnet instead of the default VPC.
  network_interface {
    subnetwork = google_compute_subnetwork.APP_SUBNET.id
    # optional: access_config {} for external IP
  }

  # ... other arguments ...
}

Terraform cannot delete the default VPC in-place; to remove it entirely you must delete it via the GCP Console or gcloud compute networks delete default after all resources have been moved off it.

terraform plan should show:

• + creation of google_compute_network.APP_VPC and google_compute_subnetwork.APP_SUBNET.
• ~ update (typically -/+ replacement) of each resource moved off the default VPC, with network_interface.network/subnetwork changing from "default" (or the default subnet) to the new VPC/subnet.

Additional Reading:

• https://cloud.google.com/vpc/docs/vpc