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1 min read Advanced Web

Insufficient Security Controls

Insufficient Security Controls

AspectDetails
DescriptionSecurity defenses that should be present are missing, weak, or only partially applied, such as absent authorization checks, no rate limiting, missing input validation, or inconsistent enforcement across endpoints. Attackers exploit the gaps.
Conditions to be Vulnerable- Controls enforced on some endpoints but not others.
- Client-side-only validation or authorization.
- Missing rate limiting, logging, or anomaly detection.
Where to Find- New, legacy, or undocumented API endpoints.
- Admin functions reachable without server-side authorization.
- Bulk/automation-prone actions lacking throttling.
Common Exploits- Accessing privileged actions by calling unprotected endpoints directly.
- Bypassing client-side validation by editing requests.
- Abusing missing rate limits for enumeration or brute force.
ExampleThe UI hides an admin button, but POST /api/admin/users/delete has no server-side role check, so any authenticated user can delete accounts directly.
How to Test1. Map all endpoints (including those not linked in the UI).
2. Replay privileged requests as a low-privilege or anonymous user.
3. Tamper with client-side validation and probe for missing rate limits.
ToolsBurp Suite, OWASP ZAP, ffuf, nuclei, Postman
Mitigation- Enforce authentication, authorization, and validation server-side on every endpoint.
- Apply controls consistently and deny by default.
- Add rate limiting, logging, and monitoring.

Resources

CreditURL
OWASP Top 10 - Broken Access Controlhttps://owasp.org/Top10/A01_2021-Broken_Access_Control/
OWASP WSTG - Authorization Testinghttps://owasp.org/www-project-web-security-testing-guide/latest/4-Web_Application_Security_Testing/05-Authorization_Testing/
OWASP ASVShttps://owasp.org/www-project-application-security-verification-standard/