Almost every modern UAE product — fintech, delivery, proptech, health-tech — is really an API with a thin app on top. That makes the API the real attack surface, and in our testing it's where the most serious vulnerabilities consistently appear. Here are the API flaws we find most often, mapped to the OWASP API Security Top 10, and how to avoid them.

1. Broken Object Level Authorization (BOLA)

The single most common and most damaging API flaw. An endpoint like GET /api/orders/1043 returns order 1043 — but does it check that the requesting user owns that order? Change the ID to 1044 and you may see someone else's data.

Fix: enforce ownership checks on the server for every object access, using the authenticated user's identity — never trust an ID supplied by the client.

2. Broken authentication

Weak or inconsistent authentication across endpoints: unverified JWTs, tokens that never expire, secrets hard-coded in the mobile app, or endpoints that simply forgot to require auth.

Fix: validate tokens properly (signature and expiry), use short-lived access tokens with refresh, and confirm every non-public endpoint actually enforces authentication.

3. Broken Object Property Level Authorization

Two sub-problems: the API returns more fields than it should (leaking internal flags, other users' PII), or it lets clients update fields they shouldn't — mass assignment, where sending "role": "admin" in a profile update quietly escalates privileges.

Fix: explicitly define which fields are readable and writable per role; never bind request bodies straight onto database models.

4. Unrestricted resource consumption

No rate limiting, no pagination caps, no payload-size limits. Attackers abuse this for credential stuffing, scraping, denial of service, or running up your cloud bill.

Fix: rate-limit per user and per IP, cap page sizes and request bodies, and put quotas on expensive operations.

5. Broken function level authorization

Admin-only actions exposed on predictable routes (/api/admin/...) that check the UI but not the API. A regular user who guesses the endpoint can call it.

Fix: enforce role checks at the function level on the server, defaulting to deny.

6. Server-Side Request Forgery (SSRF)

APIs that fetch a user-supplied URL (webhooks, "import from link," image fetchers) can be tricked into calling internal services or cloud metadata endpoints — a serious risk in AWS/Azure environments.

Fix: validate and allow-list outbound destinations; block requests to internal ranges and metadata IPs.

7. Security misconfiguration

Verbose error messages leaking stack traces, permissive CORS (Access-Control-Allow-Origin: * on authenticated APIs), missing security headers, and debug endpoints left in production.

Fix: harden defaults, disable debug in production, and lock CORS to known origins.

Why startups are especially exposed

Speed. APIs get built fast to hit a launch, authorization logic is added per-endpoint under deadline pressure, and the gaps only surface under adversarial testing. It's not carelessness — it's the nature of shipping quickly. The fix is to test the API specifically, not just the app around it.

How to get ahead of it

• Test the API as its own surface, not an afterthought of the web app — see our web application testing checklist for the app side.
• Bake authorization checks into a shared layer, not copy-pasted per endpoint.
• Re-test after major feature releases, since new endpoints are new risk.

TestUnity's API penetration testing is built around the OWASP API Top 10 and the authorization flaws that hurt startups most — with practical, developer-focused remediation guidance. Book an API assessment with our team.