What is HTTP Parameter Pollution (HPP)…!!

Hello Hackers..!!!

I’m Divya today’s topic is HTTP Parameter Pollution

What is HTTP Parameter Pollution (HPP)

An attacker can use HTTP Parameter Pollution (HPP), an attack evasion technique, to build an HTTP request with the intention of manipulating or retrieving secret data.

The basic concept of this method is the division of an attack vector among several occurrences of a parameter with the same name. The concepts of HTTP parameter manipulation are not defined by any of the pertinent HTTP RFCs, so different web application delivery platforms may handle it in different ways.

Certain environments handle these types of requests by combining the values obtained from every instance of a parameter name in the request. This behavior is exploited by the attacker to get beyond pattern-based safeguards.

How does HTTP Parameter Pollution Work?

When handling HTTP requests with several parameters that have the same name, HPP takes advantage of the mismatch. An HTTP request with duplicate parameter names that each include a little bit of malicious code is sent by the attacker. The particular web application framework and the server’s configuration determine how the server responds to these requests.

On the server side, some servers reassemble the malicious code by combining parameter values with the same name. It’s possible for other servers to just use the first or last occurrence of a duplicated parameter, which can be used to cover up dangerous parameter values with safe ones.

Because HPP may split and conceal harmful code within parameters that appear harmless, it’s an especially covert attack approach. It is able to get over standard security measures,such as intrusion detection systems and web application firewalls (WAF) that depend on spotting recognized harmful patterns. By manipulating the behavior of the program, the HPP approach can result in information exposure, illegal data access, or even remote code execution.

Example of HTTP Parameter Pollution

HTTP Parameter Pollution (HPP) vulnerabilities can occur in various ways. Let’s explore each type of vulnerability and provide examples for better understanding:

1. Parameter Value Merging:

Certainly! Let’s consider a scenario where an online shopping website allows users to search for products by specifying multiple search terms in the URL parameters. Here’s a simplified example:

Suppose the website’s search functionality works by constructing a URL with parameters for each search term, like this:

https://shop.example.com/search?keyword=shoes&keyword=red

In this example, the user is searching for products containing both “shoes” and “red” keywords.

Now, let’s say an attacker exploits the HPP vulnerability by injecting multiple instances of the keyword parameter with different values:

https://shop.example.com/search?keyword=shoes&keyword=red&keyword=sale

Here, the attacker has added an additional keyword=sale parameter alongside the original ones.

Vulnerability: The application fails to handle multiple values for a parameter, allowing an attacker to merge values and potentially exploit vulnerabilities.

2. Parameter Name Manipulation

Consider a scenario where a web application has a feature that allows users to specify their preferred language using a lang parameter in the URL. The server processes this parameter to display content in the user's chosen language.

https://example.com/page?lang=en

Now, an attacker exploits the HPP vulnerability by manipulating the parameter names:

https://example.com/page?lang=en&lang=fr

In this manipulated URL, the attacker has injected two lang parameters, one specifying English (en) and the other specifying French (fr).

Vulnerability: The application doesn’t properly validate or sanitize parameter names, making it susceptible to parameter name manipulation attacks.

3. Parameter Order Manipulation:

Imagine a scenario where a web application uses parameters in a URL to authenticate users. The application expects the username parameter to come before the password parameter for authentication.

https://example.com/login?username=user123&password=pass456

Now, an attacker exploits the HPP vulnerability by manipulating the order of parameters:

https://example.com/login?password=pass456&username=admin

In this manipulated URL, the attacker has switched the order of the username and password parameters, placing the password parameter before the username.

Vulnerability: The application relies on a specific order of parameters, which can be manipulated by an attacker to disrupt intended behavior.

How to prevent HPP attacks and secure your web application effectively.

1. Validate Inputs: Check all user-supplied data to make sure it’s what you expect, rejecting anything suspicious.
2. Encode Parameters: Use URL encoding to handle special characters in parameter values properly.
3. Avoid Duplicates: Don’t allow duplicate parameters in your requests to prevent confusion.
4. Protect Sessions: Implement strong session management to keep user sessions safe from hijacking.
5. Control Access: Only give users access to what they need and nothing more, with strict access controls.
6. Use Security Headers: Add security headers to your responses to help protect against various web threats.
7. Test Regularly: Conduct security audits and testing to catch vulnerabilities early and fix them fast.
8. Stay Updated: Keep your software and libraries up to date to patch any known security holes.

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