Google CloudOverview
To prevent use of default network, a project should not have a default network.
Rationale
The default network has a preconfigured network configuration and automatically generates the following insecure firewall rules:
- default-allow-internal: Allows ingress connections for all protocols and ports among instances in the network.
- default-allow-ssh: Allows ingress connections on TCP port 22(SSH) from any source to any instance in the network.
- default-allow-rdp: Allows ingress connections on TCP port 3389(RDP) from any source to any instance in the network.
- default-allow-icmp: Allows ingress ICMP traffic from any source to any instance in the network.
These automatically created firewall rules do not get audit logged and cannot be configured to enable firewall rule logging.
Furthermore, the default network is an auto mode network, which means that its subnets use the same predefined range of IP addresses, and as a result, it's not possible to use Cloud VPN or VPC Network Peering with the default network.
Based on organization security and networking requirements, the organization should create a new network and delete the default network.
Remediation guidance
From Console
- Login to the
VPC networkspage by visiting: https://console.cloud.google.com/networking/networks/list - Click the network named
default. - On the network detail page, click
EDIT. - Click
DELETE VPC NETWORK. - If needed, create a new network to replace the default network.
From Command Line
For each Google Cloud Platform project,
- Delete the default network:
gcloud compute networks delete default
- If needed, create a new network to replace it:
gcloud compute networks create NETWORK_NAME
Prevention
The user can prevent the default network and its insecure default firewall rules from being created by setting up an Organization Policy to Skip default network creation at https://console.cloud.google.com/iam-admin/orgpolicies/compute-skipDefaultNetworkCreation.
Default Value
By default, for each project, a default network is created.
Service-wide remediation
Recommended when many resources are affected: fix the platform baseline first so new resources inherit the secure setting, then remediate the existing flagged resources in batches.
Google Cloud
Use organization or folder policies where available, shared project templates, logs and alerting baselines, and IaC modules so new resources inherit the secure setting.
Operational rollout
- Fix the baseline first at the account, subscription, project, cluster, or tenant scope that owns this control.
- Remediate the currently affected resources in batches, starting with internet-exposed and production assets.
- Re-scan and track approved exceptions with an owner and expiry date.
Query logic
These are the stored checks tied to this control.
The default network does not exist in a project
Connectors
Covered asset types
Expected check: eq []
vpcs(where:{name:"default"}){...AssetFragment}
