Input Validation / HTTP Request Smuggling

Description

HTTP Request Smuggling (CWE-113) is a type of web application vulnerability that allows an attacker to exploit an application's trust in a client by sending multiple, overlapping HTTP requests to a web server. This vulnerability occurs when the web server processes overlapping requests as separate requests, allowing the attacker to gain access to sensitive information or execute malicious code on the server. The OWASP Testing Guide identifies HTTP request smuggling as a critical vulnerability, as it can be used to bypass authentication or access control mechanisms, and can allow an attacker to gain remote access to the server.

Risk

HTTP request smuggling can pose a significant risk to an organization, as it can allow an attacker to gain unauthorized access to sensitive data or execute malicious code on the server. An attacker can use this vulnerability to gain access to the server, bypass authentication or authorization mechanisms, or even execute remote code.

Solution

The best way to prevent HTTP request smuggling is to ensure that all requests sent to the web server are properly sanitized and validated. This can be done by ensuring that all input is properly sanitized, and by using a web application firewall to block requests that contain suspicious parameters or headers. Additionally, it is important to update web applications regularly to ensure they are not vulnerable to this type of attack.