Listen to this Post
Introduction
Insecure Direct Object Reference (IDOR) is a common web vulnerability that occurs when an application exposes internal object references (e.g., user IDs, file paths) without proper authorization checks. Attackers can manipulate these references to access unauthorized data. This article explores IDOR exploitation techniques, mitigation strategies, and practical commands for security professionals.
Learning Objectives
- Identify IDOR vulnerabilities in web applications.
- Exploit IDOR flaws using incremental ID manipulation.
- Implement secure coding practices to prevent IDOR attacks.
You Should Know
1. Detecting IDOR via Incremental ID Manipulation
Command (cURL for API Testing):
curl -X GET "https://example.com/api/user/123" -H "Authorization: Bearer <token>"
Step-by-Step Guide:
- Intercept a legitimate API request (e.g.,
/api/user/100) using Burp Suite or browser dev tools.
2. Increment/decrement the user ID (e.g., `/api/user/101`).
3. Check if unauthorized data is returned.
- If successful, the application is vulnerable to IDOR.
2. Automating IDOR Testing with Python
Python Script Snippet:
import requests
for user_id in range(100, 110):
response = requests.get(f"https://example.com/api/user/{user_id}", headers={"Authorization": "Bearer <token>"})
if response.status_code == 200:
print(f"Data leaked for User ID: {user_id}")
How It Works:
- This script iterates through a range of user IDs.
- If a valid response (HTTP 200) is received, it indicates potential IDOR exposure.
3. Mitigating IDOR with Access Controls
Best Practice:
- Implement server-side authorization checks (e.g., role-based access control).
- Avoid exposing sequential or predictable object IDs.
4. Using Burp Suite for IDOR Testing
Steps:
- Capture a request containing an object reference (e.g.,
user_id=100).
2. Send the request to Burp Repeater.
- Modify the ID and observe responses for unauthorized access.
- Secure Coding: UUIDs Instead of Sequential IDs
Example (Django Model):
from django.db import models import uuid class UserProfile(models.Model): id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
Why It Helps:
- UUIDs are non-sequential, making IDOR attacks harder.
What Undercode Say
- Key Takeaway 1: IDOR is often overlooked but highly exploitable—always test for it in bug bounty programs.
- Key Takeaway 2: Automation (Python, Burp Suite) significantly speeds up IDOR detection.
Analysis:
IDOR remains a critical vulnerability due to poor access control implementations. As APIs grow, manual testing becomes inefficient. Future trends suggest AI-powered scanners will automate IDOR detection, but human verification remains essential for complex logic flaws.
Prediction
With increasing API-driven architectures, IDOR vulnerabilities will rise unless developers adopt strict authorization mechanisms. Bug bounty hunters should focus on API endpoints, as traditional web forms become less common.
IT/Security Reporter URL:
Reported By: David Kamau – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
