🚨 Broken Function Level Authorization – API5:2023 🔓

Here is the fifth one: Broken Function Level Authorization

APIs expose functions that allow users to interact with systems. But what happens when authorization controls are weak? Attackers can exploit APIs to access admin functions, modify data, or escalate privileges beyond what they should have. 🚨

⚠️ What is Broken Function Level Authorization?

This vulnerability occurs when APIs fail to properly enforce role-based access controls (RBAC), allowing users to:

• Access admin-only endpoints 🛑 – A regular user calls an admin function.
• Perform unauthorized actions 🚫 – Example: A user escalates their own privileges.
• Modify business logic ⚙️ – Example: Changing order prices, bypassing limits.

🔍 How Does It Happen?

🚫 Inconsistent authorization checks – Some endpoints enforce RBAC, others don’t.

🚫 Predictable URL patterns – Example: /admin/deleteUser is accessible with a simple role change.

🚫 Client-side role enforcement – Attackers modify requests to bypass UI restrictions.

🚫 Missing privilege separation – Regular users can access high-privilege functions.

🎯 Real-World Risks:

✅ Data exposure – Unauthorized access to sensitive information 📂

✅ Privilege escalation – Attackers gain admin capabilities 🔑

✅ Business logic abuse – Users modify data without permission 🏦

🛡️ How to Prevent It?

🔸 Enforce RBAC & ABAC 🔐 – Implement strict role-based access at every level.

🔸 Deny by default ❌ – Restrict access unless explicitly permitted.

🔸 Perform server-side authorization checks 🛡️ – Never trust client-side roles.

🔸 Use least privilege principle ⚖️ – Users should only access what they need.

🔸 Monitor API access logs 📊 – Detect and block unauthorized access attempts.

🚀 APIs should respect user roles, not just assume them!

#APISecurity #OWASP #CyberSecurity #RBAC #SecureCoding #Authorization

• CWE-285: Improper Authorization
• Forced Browsing
• "A7: Missing Function Level Access Control", OWASP Top 10 2013
• OWASP Community Guide for Access Control