To identify all principals who can change firewall rules, you need to determine which users or service accounts have permissions that allow them to modify firewall rules in your Google Cloud project. The correct permissions to check for this are compute.firewalls.create and compute.firewalls.delete. These permissions enable a user to create and delete firewall rules, respectively.

The Policy Analyzer tool in Google Cloud allows you to query and analyze IAM policies to identify which principals have specific permissions. By using Policy Analyzer, you can effectively identify all principals with the compute.firewalls.create and compute.firewalls.delete permissions.

Open Policy Analyzer: Go to the Google Cloud Console, navigate to IAM & Admin, and select Policy Analyzer.

Set Up Query: Create a new query specifying the permissions compute.firewalls.create and compute.firewalls.delete.

Run Query: Execute the query to retrieve a list of principals who have these permissions.

Review Results: Analyze the results to identify all users and service accounts with the capability to modify firewall rules.

This method ensures you have a comprehensive list of all principals who can change firewall rules, enhancing your audit and security posture.

Google Cloud Policy Analyzer Documentation

Google Cloud IAM Documentation