PCI DSS 4.0 is now mandatory (as of March 31, 2025) and requires an automated technical solution that detects and prevents web attacks. For Google Cloud applications, that solution is Cloud Armor WAF.

Always confirm specific requirements with your QSA (Qualified Security Assessor).

Ref: PCI SSC FAQ (now in effect)

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Your 5-Step Google Cloud Armor Compliance Checklist

1) Deploy Cloud Armor with OWASP Rules

Set up your baseline Web Application Firewall protection:

• Attach a Cloud Armor security policy to your external HTTP(S) Load Balancer

• Enable preconfigured OWASP Core Rule Set (CRS 3.3.x) at moderate sensitivity

• Start with broad protection; fine-tune using preview mode

PCI requirement: Automated solution that continually detects and prevents web application attacks (requirement 6.4.2).

Common mistake: Many teams disable entire rulesets when they hit false positives instead of using surgical exclusions.

📖 Setup Guide: Cloud Armor OWASP rules

2) Enable Request Logging for Audit Evidence

Configure logging to capture all Cloud Armor decisions:

• Turn on per-request logging for your Load Balancer

• Ensure logs include `enforcedSecurityPolicy` and `statusDetails` fields

• Set retention period to match your audit cycle (typically 12 months)

Why auditors care: You need evidence that your WAF is actively blocking attacks and that legitimate traffic flows normally.

Pro tip: Cloud Armor events appear in Load Balancer logs and follow the LB's sampling configuration, so verify your sampling rate captures security events.

📖 Documentation: Cloud Armor request logging

3) Implement Safe Tuning Workflow

Avoid the #1 WAF mistake - making blind production changes:

• Always test in preview mode before applying rule changes

• Use exclusions for noisy parameters instead of disabling rules

• Document all changes with business justification

• Never disable OWASP rules without understanding the security impact

Real-world problem: 73% of companies discover Cloud Armor configuration drift only during annual audits, often finding either blocked legitimate traffic or ineffective security policies.

📖 Guide: Cloud Armor rule tuning

4) Set Up Monthly Compliance Monitoring

Track these key metrics for leadership and audit readiness:

Security metrics:

- Attack block rate and trends

- Top triggered OWASP rules

- Policy drift alerts

Operational metrics:

- False positive incidents

- Time-to-resolve WAF issues

- Percentage of changes tested in preview

Audit metrics:

- Policy change history with approvers

- Evidence of continuous monitoring

Start with Google Cloud's [built-in Cloud Armor monitoring](https://cloud.google.com/armor/docs/monitoring), then expand based on your needs.

5) Your Implementation Action Plan

Complete these steps in your next sprint:

- ✅ Week 1: Deploy Cloud Armor policy with OWASP CRS enabled

- ✅ Week 1: Configure request logging with proper retention

- ✅ Week 2: Establish preview-first change management process

- ✅ Week 3: Set up automated monthly compliance reporting

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Automate Your Cloud Armor Compliance Management

Manual WAF management doesn't scale. Security teams spend 40+ hours per compliance cycle analyzing logs, tracking false positives, and preparing audit evidence.

CloudPort automates Google Cloud Armor management with AI-powered analysis:

✨ Instant compliance posture scoring against PCI DSS 4.0 requirements

✨ Automated false positive detection with plain English explanations

✨ Safe tuning recommendations that prioritize exclusions over rule disabling

✨ Audit-ready compliance reporting with trend analysis and change tracking

100% agentless and read-only - connects via least-privilege service account, never touches your production traffic.

Get your Cloud Armor compliance score in under 10 minutes → Join the Private Beta

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Frequently Asked Questions

Q: Can I use a different WAF solution for PCI compliance on Google Cloud?

A: While PCI doesn't specify Cloud Armor by name, it must be an automated solution that integrates with your Google Cloud architecture. Cloud Armor is the native GCP solution that best meets the requirements.

Q: What's the difference between Cloud Armor Standard and Plus?

A: Cloud Armor Plus includes advanced features like bot management and adaptive protection. For basic PCI compliance, Cloud Armor Standard with OWASP rules is sufficient.

Q: How do I handle false positives without breaking compliance?

A: Use exclusions to skip rule inspection for specific parameters, headers, or cookies. This maintains security coverage while allowing legitimate traffic. Avoid disabling entire rules.

Q: What happens during a PCI audit?

A: Auditors will review your Cloud Armor configuration, request logs showing blocked attacks, and verify your change management process. Having automated reporting makes this much easier.

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