Implementing Zero Trust on Google Cloud

Cybersecurity now requires more than just perimeter defences. As you adopt microservices, hybrid workloads, and AI pipelines on Google Cloud, identity becomes your new perimeter. Zero Trust means never trust and always verify. It is no longer optional but essential.

This article guides you on implementing zero trust with Google Cloud Platform. You will learn how to use strong identity and access management strategies. The focus is on practical advice for modern DevSecOps teams using the latest GCP tools.

Zero Trust Principles in the GCP Context

Google Cloud’s infrastructure is built with zero trust in mind, following BeyondCorp principles. However, securing it well means carefully designing IAM to align with zero trust’s five key pillars.

IAM Capabilities in 2025: What's New?

• Principal access boundaries (preview): You can restrict where a user or service account can access resources. Even if they have broad roles, these boundaries limit their access to only specific projects or folders. This helps reduce risk by narrowing permissions.
• IAM deny policies (general availability): These policies let you clearly block certain actions or access. They still apply even if other permissions allow it, helping you stop risky or unwanted behaviour.
• IAM recommender API (version 2): This tool looks at your IAM roles and spots ones that are not being used. It helps you clean up extra permissions so users only have what they need.
• IAM conditions with custom expressions: You can set rules to control access based on time, device, or location. This helps you give access only when needed and keeps your system safe.

Zero Trust IAM Design for GCP

Let’s look at how to design a zero-trust IAM setup for a typical enterprise using GCP. This includes services like GKE, Cloud Run, and BigQuery.

Example Use Case

A data science team uses Cloud Run to run Jupyter notebooks and builds models in BigQuery. Meanwhile, DevOps manages the GKE clusters.

Key IAM Best Practices

1. Segment With Folders and Projects

Organize your resources using folders and projects. This helps you apply permissions more precisely and limits access to only what teams need. It also makes managing policies clearer and safer.

gcloud resource-manager folders create --display-name="ML Team" --organization=ORG_ID
gcloud projects create project-ml --folder=FOLDER_ID

2. Use IAM Conditions to Restrict Access by IP and Time

Use IAM Conditions to limit access based on IP address or time of day. This helps protect your system by letting users connect only from safe locations and during set times.

resource "google_project_iam_member" "conditional_access" {
  project = "project-ml"
  role    = "roles/bigquery.dataViewer"
  member  = "user:[email protected]"

  condition {
    title       = "WorkHoursOnly"
    expression  = "request.time.getHours() >= 9 && request.time.getHours() <= 18"
  }
}

3. Apply Deny Policies to Block Risky Access

Use Deny Policies to explicitly prevent access to sensitive resources. This helps stop dangerous or unintended actions, even if users have broad permissions elsewhere.

denyPolicy:
  rules:
    - denyRule:
        deniedPrincipals:
          - principalSet://goog/group/[email protected]
        deniedPermissions:
          - "iam.serviceAccounts.actAs"

4. Use Principal Access Boundaries to Restrict Wildcards

Set boundaries to limit where users or service accounts can go. This stops them from having too much access and keeps your environment safer.

"principalAccessBoundary": {
  "accessBoundaryRules": [{
    "availableResource": "//cloudresourcemanager.googleapis.com/projects/secure-data",
    "availablePermissions": ["storage.objects.get"],
    "availabilityCondition": {
      "expression": "resource.name.startsWith('projects/secure-data/buckets/restricted')"
    }
  }]
}

5. Automate Drift Detection With Policy Analyzer

Use Policy Analyzer to automatically spot changes in your IAM policies. This helps you catch unintended permission changes quickly and keep your security strong.

gcloud asset analyze-iam-policy \
  --project=project-ml \
  --permissions="bigquery.jobs.create"

Secure GKE and Cloud Run With Identity-Aware IAM GKE

• Use Workload Identity Federation to connect Kubernetes service accounts with GCP IAM.
• Limit permissions by binding roles to specific Kubernetes namespaces.
• Monitor activity using Binary Authorization and Cloud Audit Logs for added security.

gcloud iam service-accounts add-iam-policy-binding \
  [email protected] \
  --role roles/logging.logWriter \
  --member "serviceAccount:project-id.svc.id.goog[namespace/sa-name]"

Cloud Run

• Assign invoker permissions only to specific user groups.
• Cloud Identity-Aware Proxy helps you decide who can use your apps. It looks at who is trying to connect and where they are coming from. This way, only trusted users get access.

IAM Zero Trust Checklist for 2025

Conclusion

Zero trust is not just an idea; it is a must. Google Cloud has new tools that help you limit access and stop risky actions. These tools keep your system safe as things change.

If you work with GCP as a cloud architect, DevSecOps engineer, or security lead, now is the time to use zero trust. It is good for security and good for your work.