🚨 Broken Access Control: The Critical Security Failure You Can't Ignore

Broken Access Control remains the #1 security risk in the OWASP Top 10, responsible for countless data breaches. This vulnerability occurs when applications fail to properly restrict what authenticated users can do.

⚠️ Why This Matters

Successful exploitation allows attackers to:

• Access other users' accounts and sensitive data
• Perform privileged operations without authorization
• View or modify restricted resources
• Escalate privileges to admin levels

🔍 How Broken Access Control Works

1. Vertical Privilege Escalation

When a regular user gains admin privileges by:

• Accessing admin URLs directly
• Modifying role parameters in requests
• Exploiting missing permission checks

2. Horizontal Privilege Escalation

When a user accesses another user's data of the same privilege level:

• Changing IDs in API requests (?user_id=123 → ?user_id=456)
• Bypassing ownership checks
• Exploiting direct object references

💻 Real-World Example

Vulnerable Code:

// No permission check before accessing user profile
app.get('/profile/:userId', (req, res) => {
    const user = getUserById(req.params.userId);
    res.send(user);
});

Attack: Any authenticated user can view any profile by changing the userId parameter.

🛑 Common Attack Vectors

• Insecure Direct Object References (IDOR): Manipulating parameters to access unauthorized resources
• Missing Function-Level Access Control: Accessing privileged functions via forced browsing
• API Security Misconfigurations: Improperly configured CORS or missing authorization headers
• Metadata Manipulation: Modifying JWT tokens or cookies to elevate privileges

🛡️ Prevention Strategies

✅ Best Practices for Developers

• Implement proper authorization checks on every request
• Use indirect object references instead of exposing database IDs
• Apply the principle of least privilege for all accounts
• Validate permissions server-side (client-side checks aren't enough)
• Use standardized frameworks for access control (RBAC, ABAC)

Technical Safeguards

• Role-Based Access Control (RBAC): Define clear roles and permissions
• Attribute-Based Access Control (ABAC): More granular control based on attributes
• JWT Validation: Verify tokens and check claims for each request
• Log and monitor access control failures

🔎 Recent High-Profile Cases

• 2023 Healthcare Breach: IDOR vulnerability exposed 2.3 million patient records
• 2024 Banking App Exploit: Parameter tampering allowed balance manipulation
• 2023 Social Media Scandal: API endpoint without authorization leaked private messages

🚨 Immediate Action Items

1. Conduct thorough access control testing in your applications
2. Implement automated scanning for IDOR vulnerabilities
3. Train developers on secure coding practices
4. Review all API endpoints for proper authorization
5. Monitor logs for failed permission checks

🔐 Security is a process, not a product. Regular audits and staying updated on vulnerabilities are crucial for maintaining robust access controls.

📢 Pro Tip: Use OWASP's Access Control Cheat Sheet as a developer reference.

🛡️ Stay Secure!
— Art Of Vector Lab