How to do a security audit of a Wix Harmony app?

Why a Wix Harmony-specific audit (not a generic web audit)

A generic OWASP audit will tell you your Wix Harmony app "needs CSP headers." A Wix Harmony-aware audit tells you that your specific Wix Harmony app has an RPC function callable without auth or a service key in a client bundle — the issues that actually appear when Wix Harmony apps get compromised. The difference in output value is why the audit should be scoped to Wix Harmony's real failure modes.

Step 1 — Fingerprint the deployment

Confirm the Wix Harmony stack components: database (firebase, postgres), hosting, auth provider, third-party integrations. For Wix Harmony apps this is often visible in the Firebase endpoint URL in network requests. Document every component — each is an independent audit target.

Step 2 — Automated scan with Wix Harmony-aware rules

Run VAS against the deployed URL. The scan probes the specific issue classes found in Wix Harmony apps: data exposure, permissions audit, secrets scan, access control. This is the 80/20 — most critical and high findings surface here. Fix anything critical before continuing to manual steps.

Step 3 — Manual Firestore Security Rules review

Open the Firebase Console → Firestore → Rules. Every match path needs explicit `allow read/write: if request.auth.uid == resource.data.userId` (or similar ownership check). Storage rules require the same. Use the Firebase Emulator to test: a `firebase emulators:exec` with a write attempt as an anonymous user must fail.

Step 4 — Authentication & authorization probing

Test every endpoint with no session (expect 401), with a valid session for a different user (expect 403 on user-owned resources), and with session tokens that have been tampered with (expect 401 if signatures are enforced). Rate limiting on login/password-reset is a pass/fail check here, not a nuance.

Step 5 — Re-scan to verify

Fix findings in severity order (critical → high → medium → low), re-scan after each batch of fixes. "I applied the fix" is not evidence — the fix might not have been deployed, might have been partial, or might have been reverted. Only the scan output proves the gap is closed. Log each finding + fix + verification scan for compliance records.

Wix Harmony-specific checks often missed

• Exposed Wix Data Collections
• Misconfigured Wix Permissions
• Insecure Third-Party Integrations
• Broken Access Control in Custom Pages