IDOR (Insecure Direct Object Reference)

Introduction

IDOR vulnerabilities occur when direct object references (like IDs) are exposed without proper authorization checks. These weaknesses often provide access to other users’ data in CTF web challenges.

Example

https://example.com/profile?id=123

Change the parameter:

https://example.com/profile?id=456

Tips

Enumerate sequential IDs and UUIDs.
Look for exposed numeric parameters (id, uid, order_id).
Combine with authorization tokens or cookies to confirm privilege checks.
Monitor API responses and status codes for unauthorized access hints.