Google Updated Professional-Cloud-Security-Engineer Exam Questions and Answers by arley

https://cloud.google.com/resource-manager/docs/organization-policy/org-policy-constraints - constraints/compute.trustedImageProjects

This list constraint defines the set of projects that can be used for image storage and disk instantiation for Compute Engine. If this constraint is active, only images from trusted projects will be allowed as the source for boot disks for new instances.

Multiple network interfaces. The simplest way to connect multiple VPC networks through a virtual appliance is by using multiple network interfaces, with each interface connecting to one of the VPC networks. Internet and on-premises connectivity is provided over one or two separate network interfaces. With many NGFW products, internet connectivity is connected through an interface marked as untrusted in the NGFW software.

https://cloud.google.com/architecture/best-practices-vpc-design#l7

This architecture has multiple VPC networks that are bridged by an L7 next-generation firewall (NGFW) appliance, which functions as a multi-NIC bridge between VPC networks. An untrusted, outside VPC network is introduced to terminate hybrid interconnects and internet-based connections that terminate on the outside leg of the L7 NGFW for inspection. There are many variations on this design, but the key principle is to filter traffic through the firewall before the traffic reaches trusted VPC networks.

VPC Peering is between organizations not between Projects in an organization. That is Shared VPC. In this case, both projects are in same organization so having VPC Service Controls around both projects with necessary rules should be fine.

https://cloud.google.com/vpc-service-controls/docs/overview

Objective: Ensure that a Cloud Storage bucket in Project A can only be readable from Project B and prevent data access or copying to Cloud Storage buckets outside the network, even with correct credentials.

Solution: Use VPC Service Controls to create a security perimeter.

Steps:

Step 1: Open the Google Cloud Console.

Step 2: Navigate to the VPC Service Controls page.

Step 3: Create a new service perimeter.

Step 4: Add Project A and Project B to the service perimeter.

Step 5: Include Cloud Storage service in the perimeter configuration.

Step 6: Define access levels to ensure that only resources within the perimeter can access the Cloud Storage bucket.

By setting up a VPC Service Controls perimeter, you can enforce security boundaries that restrict data access and movement to within defined projects, providing an extra layer of protection beyond IAM permissions.

References:

VPC Service Controls Overview

Configuring VPC Service Controls