User ID controlled by request parameter with data leakage in redirect

Access Control Vulnerability

In the vast landscape of cybersecurity, access control vulnerabilities are a critical risk that can lead to severe breaches of privacy and security. One particularly dangerous flaw occurs when User ID is controlled by request parameters, combined with data leakage in redirects. This creates a perfect storm for attackers to exploit, potentially gaining unauthorized access to sensitive data and wreaking havoc across your application.

We’ll explore how this vulnerability works, the dangers of data leakage in redirects, and the best ways to protect your system against it.

In many web applications, user IDs are passed through URL parameters to identify and retrieve user-specific data. For instance, a URL might look like this:

https://example.com/profile?user_id=12345

Here, the user_id is used by the server to load the correct user’s profile. The problem arises when applications trust this user_id blindly, allowing attackers to manipulate the value to access other users’ data…