Introduction After learning vulnerabilities like SQL Injection and XSS, the next important concept in web security is Broken Access Control, specifically IDOR (Insecure Direct Object Reference). According to the OWASP Top 10, Broken Access Control is one of the most critical security risks in modern web applications. What is IDOR? IDOR (Insecure Direct Object Reference) happens when a web application uses user-supplied input to directly access objects without proper authorization checks. In simple terms, the application allows access to data by changing an ID without verifying whether the user has permission. Simple Real-World Example Your profile URL might look like: https://example.com/my-account?id=1005 If you change it to: https://example.com/my-account?id=1006 and you can view another user’s private data, then the application is vulnerable to IDOR. Why IDOR is Dangerous Data Exposure Attackers can access sensitive information such as emails, phone numbers, and addresses. Unauthori...