Google Professional-Cloud-Security-Engineer - Google Cloud Certified - Professional Cloud Security Engineer

For managing and rotating encryption keys in a Compute Engine-based cluster using Managed Instance Groups (MIGs), Customer-Managed Encryption Keys (CMEK) with Cloud KMS is the appropriate solution.

Set Up Cloud KMS:

Go to the Cloud Console and navigate to Security > Cryptographic Keys.

Create a keyring and a key.

Create and Use CMEK:

While creating or updating a Compute Engine instance, specify the CMEK key.

Example command:

gcloud compute instances create example-instance \ --image-family=debian-9 \ --image-project=debian-cloud \ --boot-disk-kms-key=projects/[PROJECT_ID]/locations/global/keyRings/[KEY_RING]/cryptoKeys/[KEY]

Rotate Keys:

Rotate keys periodically using Cloud KMS by creating new key versions and updating the instances to use the new key versions.

Customer-Managed Encryption Keys (CMEK)

Using Customer-Managed Encryption Keys

The most secure and compliant way to manage a policy exception in Google Cloud is through the resource hierarchy using Organization Policies.

Restrictive Baseline: The policy should be applied at the Organization level to enforce the baseline (no external IPs) across the entire company, ensuring minimum policy drift.

Exception and Least Privilege: The regulated unit is placed in its own Folder (isolation). The restrictive policy is then overridden or enforced with an exclusion at this Folder level to grant the exception only where needed. This ensures the exception is applied to the smallest scope necessary, adhering to least privilege.

Extracts:

"Organization Policy is inherited down the resource hierarchy... You can override inherited policies by enforcing a different policy at a lower level." (Source 2.1)

"To implement an exception, the most secure approach is to set the restrictive policy at the highest possible level (e.g., Organization) and override or enforce an exclusion at the lowest possible level (e.g., Project or Folder) where the exception is required." (Source 2.2)

By applying the restriction broadly and granting the exception narrowly at the folder level, you maintain central control and minimize the blast radius of the exception.

The Google Cloud Resource Hierarchy is designed to allow inheritance with the ability to override policies at lower levels (Folders or Projects).2 This is the standard way to handle exceptions for specific business units without weakening the security posture of the entire organization.

According to Google Cloud Documentation (Understanding Hierarchy Evaluation):

"By default, organization policies are inherited by the descendants of the resource on which the policy is enforced. However, you can explicitly override a policy on a child resource (Folder or Project) by setting a new policy that either adds to or replaces the inherited values.3 This allows for granular control and exception handling."

Why this is the correct approach:

Isolation: By moving the workload to a specific folder, you isolate the exception.

Least Privilege: Only the resources within that folder gain the exception; the rest of the organization remains protected by the constraints/compute.vmExternalIpAccess constraint.

No "Bypass" Role: There is no standard IAM role that allows a user to "bypass" an Org Policy (Option A). Policies are enforced at the API level regardless of user roles.

Auditability: Having a specific folder with an override makes it easy for auditors to see exactly where and why an exception exists.

"To support common use cases like setting a Time to Live (TTL) for objects, retaining noncurrent versions of objects, or "downgrading" storage classes of objects to help manage costs, Cloud Storage offers the Object Lifecycle Management feature. This page describes the feature as well as the options available when using it. To learn how to enable Object Lifecycle Management, and for examples of lifecycle policies, see Managing Lifecycles." https://cloud.google.com/storage/docs/lifecycle

To retain security event logs for 2 years while minimizing costs, exporting the logs to Cloud Storage buckets is the most cost-effective solution. Cloud Storage provides scalable and durable storage at a lower cost compared to BigQuery, which is more suited for analytics and querying, or Cloud Pub/Sub, which is designed for messaging and stream processing.

Steps:

Create a Cloud Storage Bucket: Set up a new Cloud Storage bucket configured with appropriate retention policies.

Set Up Log Export: Use the Google Cloud Console or gcloud command-line tool to create a sink that exports the selected log entries to the Cloud Storage bucket.

Configure Retention Policy: Set the retention policy on the Cloud Storage bucket to ensure that logs are retained for the required period of 2 years.

To prepare for migrating Google Cloud projects to a new organization node, it's crucial to ensure that the projects' current configurations and dependencies are appropriately managed. The two necessary preparation steps are:

Identify inherited Identity and Access Management (IAM) roles on projects to be migrated (C):

Projects inherit IAM roles from their parent resources. Identifying these roles is essential to understand the permissions and access levels that users have on the projects. This will help in ensuring that after migration, the appropriate roles and permissions are applied correctly.

Remove the specific migration projects from any VPC Service Controls perimeters and bridges (E):

VPC Service Controls provide security boundaries around your Google Cloud resources to mitigate data exfiltration risks. Before migrating the projects, they need to be removed from any existing VPC Service Controls perimeters and bridges to prevent any disruption in access or network communication. After migration, the projects can be added back to the necessary perimeters.

References

Google Cloud IAM documentation

VPC Service Controls documentation

In Google Cloud's Logging service, log entries are automatically routed to the _Default log bucket unless configured otherwise. When you create a new log bucket and intend to redirect all log entries from the _Default bucket to this new bucket, the most efficient approach is to modify the existing _Default sink to point to the new log bucket.​

Option A: Creating a new user-defined sink with filters replicated from the _Default sink is redundant and may lead to configuration complexities.​

Option B: Implementing exclusion filters on the _Default sink and then creating a new sink introduces unnecessary steps and potential for misconfiguration.​

Option C: Disabling the _Default sink would stop all log routing to it, but creating a new sink to replicate its functionality is inefficient.​

Option D: Editing the _Default sink to change its destination to the new log bucket ensures a seamless transition of log routing without additional configurations.​

Therefore, Option D is the most efficient and straightforward method to achieve the desired log routing.​

The problem has two key requirements:

All applications must send data to a centralized security service.

Developers need high autonomy over firewall rules within their projects.

Prevent accidental blockage of access to the central security service.

This scenario requires a mechanism to enforce critical network policies at a higher level of the resource hierarchy while still allowing project-level flexibility.

Hierarchical Firewall Policies: Google Cloud's Hierarchical Firewall Policies (HFP) are designed precisely for this purpose. They allow administrators to define firewall rules at the organization or folder level, and these rules are inherited by all projects and VPC networks within that hierarchy. Crucially, HFP rules can be prioritized. Rules with higher priority (lower numerical value) are evaluated first. This means you can create high-priority "allow" rules for critical services that cannot be overridden or blocked by project-level firewall rules.Extract Reference: "Hierarchical firewall policies allow you to define and enforce consistent network security policies across your organization. Policies can be applied at the organization or folder level, and they are inherited by all projects and VPC networks within that hierarchy." and "Rules in a hierarchical firewall policy can take precedence over VPC network firewall rules based on priority. A rule with a lower priority value takes precedence over a rule with a higher priority value." (Google Cloud documentation: https://cloud.google.com/vpc/docs/firewall-policies-overview)

Preventing Accidental Blockage while Allowing Autonomy: By setting a high-priority "allow" rule for the central security service in a hierarchical firewall policy, you guarantee that this traffic will always be permitted, regardless of what project-level firewall rules developers might configure. This ensures the critical connectivity while still allowing developers to manage other, less critical firewall rules within their projects with high autonomy.

Let's evaluate the other options:

A. Deploy a central Secure Web Proxy and connect it to all VPC networks. Create a Secure Web Proxy policy to allow traffic to the central security service. A Secure Web Proxy is for HTTP/S outbound traffic to external web services. The central security service might not be an external web service, and this solution is focused on application-layer proxies, not general network connectivity like sending data to an internal service. Also, it doesn't directly address the challenge of developers blocking access with project-level firewall rules.

C. Create a central project to manage Shared VPC networks which will be accessible to all other projects. Administer all firewall rules centrally within this project. While Shared VPC centralizes network management, it means all firewall rules are administered centrally. This directly contradicts the requirement for developers to have "high autonomy to configure firewall rules within their projects." Shared VPC would centralize too much control for this specific scenario.

D. Use Terraform to automate the creation of the required firewall rule in all projects. Restrict rule change permissions solely to the Terraform service account. This approach automates the creation but doesn't prevent developers from creating conflicting or overriding rules in their projects (unless Terraform is used to manage all rules, again removing autonomy). It also relies on restricting IAM permissions for all firewall rules, which is against the "high autonomy" requirement for developers. Hierarchical firewall policies offer a more robust and native solution for overriding and enforcing specific rules.

Therefore, implementing a hierarchical firewall policy is the most effective solution, as it allows for the enforcement of critical security service connectivity at a higher level, while still granting developers the desired autonomy over their project-specific firewall rules.

External HTTP(S) Load Balancer: Deploy an external HTTP(S) load balancer to manage traffic to your VMs. This load balancer will handle incoming traffic from the internet while the VMs themselves do not have public IP addresses.

Host (VPC) Project Deployment: Deploy the load balancer in the host (VPC) project. This allows for centralized management of network resources and maintains the integrity of your shared VPC configuration.

Backend Configuration: Configure the MIG as the backend for the load balancer. This setup ensures that the VMs can still serve external users while reducing their direct exposure to the internet. This solution provides the required access to external users through the load balancer, enhancing security by not exposing individual VM IP addresses. References:

Google Cloud - External HTTP(S) Load Balancer Overview

Google Cloud - Shared VPC Overview

To meet the requirements of encrypted communication over private IP addresses between Compute Engine instances in different Google Cloud organizations, a Cloud VPN connection is appropriate:

Cloud VPN: Cloud VPN creates a secure, encrypted tunnel between your organization's VPC network and the third party's VPC network. This ensures that data transmitted over the network is encrypted and secure.

Private IP Communication: Cloud VPN allows communication over private IP addresses, which helps maintain security by keeping traffic within the Google Cloud network and not exposing it to the public internet.

Firewall Rules: VPC firewall rules can be configured to control the traffic that flows through the VPN, ensuring that only authorized traffic is allowed, further enhancing security.

By setting up a Cloud VPN connection, you can achieve secure, encrypted communication over private IP addresses between different Google Cloud organizations.

References

Cloud VPN Overview