Control: 4.1 Ensure that instances are not configured to use the default service account

Description

It is recommended to configure your instance to not use the default Compute Engine service account because it has the Editor role on the project.

The default Compute Engine service account has the Editor role on the project, which allows read and write access to most Google Cloud Services. To defend against privilege escalations if your VM is compromised and prevent an attacker from gaining access to all of your project, it is recommended to not use the default Compute Engine service account. Instead, you should create a new service account and assigning only the permissions needed by your instance.

The default Compute Engine service account is named [PROJECT_NUMBER]- compute@developer.gserviceaccount.com.

Note: VMs created by GKE should be excluded. These VMs have names that start with gke- and are labeled goog-gke-node.

Remediation

From Console

1. Login to GCP VM Console.
2. Click on the instance name to go to its VM instance details page.
3. Under the section Service Account, ensure that the default Compute Engine service account is not used. This account is named [PROJECT_NUMBER]- compute@developer.gserviceaccount.com.
4. Click STOP to stop the instance and then click EDIT button in top section of the page.
5. Under the section Service Account, select a service account other than the default Compute Engine service account. You may first need to create a new service account.
6. Click Save and then click START.

From Command Line

1. Stop the instance:

gcloud compute instances stop INSTANCE_NAME

2. Update the instance:

gcloud compute instances set-service-account INSTANCE_NAME --serviceaccount=SERVICE_ACCOUNT

3. Restart the instance:

gcloud compute instances start INSTANCE_NAME