IDOR in the Wild: A Comprehensive Analysis of 200+ Real-World Vulnerabilities

🔍 Executive Summary

Insecure Direct Object Reference (IDOR) vulnerabilities continue to plague modern web applications, representing one of the most persistent and damaging security flaws in today's digital landscape. Through analysis of over 200 disclosed IDOR reports from HackerOne spanning 2017-2025, this study reveals alarming trends in application security and provides critical insights for developers, security professionals, and organizations.

Our analysis reveals that IDOR vulnerabilities have resulted in $127,500+ in disclosed bounties, with individual reports reaching as high as $20,000. More concerning is the breadth of impact: from complete account takeovers affecting millions of users to unauthorized access to sensitive healthcare data and financial information.

🎯 What is IDOR?

Insecure Direct Object Reference occurs when applications expose direct references to internal objects (database IDs, file paths, user identifiers) without proper access controls. Unlike complex vulnerabilities requiring sophisticated exploitation techniques, IDOR vulnerabilities are often trivially exploitable through simple parameter manipulation.

GET /api/users/12345/profile HTTP/1.1
# Attacker changes user ID to access another user's data
GET /api/users/67890/profile HTTP/1.1

📊 Analysis Methodology

This study examines 200+ disclosed IDOR reports from HackerOne's Hacktivity, focusing on:

🔥 Key Findings

1. Persistent and Growing Threat

Despite increased security awareness, IDOR vulnerabilities show no signs of declining:

2. Critical Business Impact

Notable High-Impact Cases:

3. Common Exploitation Patterns

# Original request
GET /api/orders/1234/details

# Attacker manipulation  
GET /api/orders/1235/details
GET /api/orders/1236/details

POST /v1/account/destroy HTTP/1.1
Authorization: Bearer [ATTACKER_TOKEN]
Content-Type: application/json

{
  "email": "victim@example.com",
  "authPW": "victim_password_hash"
}

mutation AddTagToAssets {
  addTagToAssets(input: {
    tag_id: "base64_encoded_victim_tag"
    asset_ids: ["attacker_asset_id"]
  }) {
    tag { name }
  }
}

GET /Download.aspx?id=4675 HTTP/1.1
# Enumerate through document IDs
GET /Download.aspx?id=4676 HTTP/1.1
# Result: Military personnel docs

🏭 Industry Impact Analysis

🔬 Technical Deep Dive: Root Causes

# Vulnerable code pattern
def get_user_profile(user_id):
    # Authentication check present
    if not current_user.is_authenticated():
        return unauthorized()
    
    # Missing: ownership validation
    # Should check: current_user.id == user_id
    return database.get_user(user_id)

// Vulnerable: Sequential IDs
const orderId = 1001; // Easily enumerable

// Secure: UUID or cryptographically random
const orderId = "a1b2c3d4-e5f6-7890-abcd-ef1234567890";

# Secure endpoint
GET /api/users/profile (validates ownership)

# Vulnerable endpoint  
GET /api/users/{id}/orders (missing validation)

🚀 The Evolution of IDOR: Modern Attack Vectors

# Traditional REST IDOR
GET /api/users/123/posts

# GraphQL IDOR - Multiple resources in single request
query {
  user(id: "123") {
    posts { title, content }
    profile { email, phone }
    orders { total, items }
  }
}

# API Gateway route - Missing authorization
/api/v1/users/{userId}/data:
  backend: user-service
  # Missing: authorization validation

# Mobile API - Often less protected
POST /mobile/api/v1/user/update
{
  "userId": "attacker_controlled",
  "data": {...}
}

🛡️ Prevention Strategies

# Secure implementation
@require_authentication
def get_user_resource(resource_id):
    resource = get_resource(resource_id)
    
    # Critical: Verify ownership
    if resource.owner_id != current_user.id:
        raise PermissionDenied()
    
    return resource

# Instead of direct database IDs
GET /api/orders/12345

# Use session-based references
GET /api/orders/current_user_orders

# Resource-based access control
class OrderPermission:
    def has_permission(self, user, order):
        return (
            order.customer_id == user.id or
            user.has_role('admin') or
            user.has_permission('view_all_orders')
        )

🧪 Tools and Testing Methodologies

user_id, id, uid, user, profile_id, account_id
booking_id, order_id, transaction_id, payment_id
document_id, file_id, attachment_id, media_id

# Sequential ID enumeration
for user_id in range(1, 10000):
    response = requests.get(f"/api/profile/{user_id}", 
                          headers={"Authorization": f"Bearer {token}"})
    if response.status_code == 200:
        print(f"Accessible profile: {user_id}")

💰 Business Impact and Financial Consequences

🌍 Geographic and Researcher Patterns

👨‍💻 Lessons for Development Teams

# Design-time consideration
class UserResource:
    def __init__(self):
        self.access_control = ResourceAccessControl()
    
    def get(self, resource_id, requesting_user):
        if not self.access_control.can_access(requesting_user, resource_id):
            raise PermissionDenied()
        return self.fetch_resource(resource_id)

// Centralized authorization middleware
const authMiddleware = (req, res, next) => {
    const resourceId = req.params.id;
    const userId = req.user.id;
    
    if (!canAccessResource(userId, resourceId)) {
        return res.status(403).json({error: 'Forbidden'});
    }
    next();
};

# CI/CD Pipeline Test
security_tests:
  - name: "IDOR Detection"
    script: |
      python scripts/idor_scanner.py --endpoints api_endpoints.txt
      if [ $? -ne 0 ]; then exit 1; fi

🔮 Future Trends and Emerging Threats

# Modern API patterns vulnerable to IDOR
GET /api/v2/resources/{resource_id}/relationships/{relationship_type}

# Service mesh authorization
apiVersion: security.istio.io/v1beta1
kind: AuthorizationPolicy
metadata:
  name: user-service-policy
spec:
  selector:
    matchLabels:
      app: user-service
  rules:
  - when:
    - key: source.service_account
      values: ["trusted-service"]

# Serverless function with proper authorization
def lambda_handler(event, context):
    user_id = event['requestContext']['authorizer']['userId']
    resource_id = event['pathParameters']['resourceId']
    
    # Critical: Validate resource ownership
    if not user_owns_resource(user_id, resource_id):
        return {
            'statusCode': 403,
            'body': json.dumps({'error': 'Forbidden'})
        }

🏢 Recommendations for Organizations

🎯 Conclusion