# IDOR & Broken Access Control

> Master the #1 OWASP vulnerability. Learn to map authorization models, exploit IDORs, and bypass broken access controls to achieve total account and privilege escalation.

Canonical: https://codelivly.com/rooms/idor-broken-access-control
Last updated: 2026-07-14

| | |
|---|---|
| Level | Intermediate |
| Category | Cybersecurity |
| Lessons | 5 |
| Estimated time | 30 min |
| XP | 200 |

Broken Access Control (BAC) and Insecure Direct Object References (IDOR) consistently hold the number one spot on the OWASP Top 10. Amateurs think IDOR is just changing user_id=104 to user_id=105 and hoping for a 200 OK. When the application uses UUIDs or returns a generic "403 Forbidden", they assume the access control is secure and move on.

Professionals know that BAC is the most critical and prevalent flaw in modern web applications and APIs. They don't just guess IDs; they map the entire authorization model. They test for indirect object references, exploit HTTP method tampering, leverage parameter pollution, and chain low-severity information leaks into full administrative takeovers.

In this module, we transition from basic ID guessing to systematic authorization bypassing. You will learn to deconstruct complex access control matrices, bypass UUID obfuscation, and exploit the logical gaps between authentication and authorization in modern REST and GraphQL APIs.

## Lessons

1. What is IDOR & Why It's So Common (30 min)
2. Finding IDOR — Manipulating IDs & Parameters (30 min)
3. Broken Access Control Patterns Beyond IDOR (30 min)
4. Real-World IDOR Breach Case Studies (30 min)
5. Guided Lab: Accessing Another User's Private Data (30 min)

## Related

- [Learning path: Exploitation Fundamentals](https://codelivly.com/learning-paths/exploitation-fundamentals)
- [All rooms](https://codelivly.com/rooms)