What is HTTP Parameter Pollution? How to detect and prevent it?

HTTP Parameter Pollution (HPP)

HTTP Parameter Pollution (HPP) is a type of web application vulnerability that occurs when an attacker is able to inject multiple values into a single HTTP parameter. This can lead to various security issues such as cross-site scripting (XSS), SQL injection, and other types of injection attacks.

Detection

To detect HPP vulnerabilities, you can use tools such as scanners and fuzzers to test your application for potential vulnerabilities. You can also manually test your application by attempting to inject multiple values into HTTP parameters and observing the application's behavior.

Prevention

To prevent HPP vulnerabilities, you can use the following methods:

1. Input validation: Validate all user input to ensure that it is of the expected type and format.
2. Output encoding: Use proper output encoding techniques to prevent user input from being interpreted as code by the browser.
3. Parameter filtering: Filter out any unexpected or malicious parameters before they are processed by the application.
4. HTTP parameter binding: Use HTTP parameter binding frameworks to bind HTTP parameters to application objects, which can help prevent HPP attacks.