• 👉 Overview
• 👀 What ?
• 🧐 Why ?
• ⛏️ How ?
• ⏳ When ?
• ⚙️ Technical Explanations
• 🖇️ References

👉 Overview

👀 What ?

Browser HTTP Request Smuggling (BHR Smuggling) is a technique used in cyber attacks to exploit the discrepancies in processing HTTP requests between web servers, proxies, and web application firewalls. In essence, it allows an attacker to inject malicious HTTP requests into the TCP stream being sent from a victim's browser to the web server. The fundamental concept behind BHR smuggling is the manipulation of the HTTP protocol to carry out malicious activities.

🧐 Why ?

Understanding BHR smuggling is crucial because it's a potent cyber security threat that can lead to serious data breaches. It exploits the inconsistencies in how different web servers handle HTTP requests, thereby bypassing security mechanisms and providing a stealthy attack vector. BHR smuggling can lead to a range of security issues, such as session hijacking, unauthorized actions, and disclosure of sensitive information.

⛏️ How ?

To use BHR smuggling to your advantage for defensive purposes, firstly, you must have a deep understanding of the HTTP protocol and the behaviour of your web servers and proxies. Regularly updating and patching your systems can help prevent known vulnerabilities. Also, using tools to test for HTTP Request Smuggling vulnerabilities can help you discover if your systems are at risk. Lastly, implementing strict rules and checks on the HTTP request methods and headers can prevent BHR smuggling.

⏳ When ?

The practice of BHR smuggling started becoming prominent in the mid-2000s when the inconsistencies in HTTP protocol implementations were discovered. It has since become a significant security concern with the increasing complexity of web architectures.

⚙️ Technical Explanations

BHR smuggling works by taking advantage of the inconsistencies in how different systems parse HTTP requests. This is typically due to the presence of ambiguous headers or methods in the HTTP request. For example, if a front-end server interprets a request differently from a back-end server, an attacker can smuggle a malicious request into the stream of legitimate requests. This smuggled request can then be processed by the back-end server, potentially leading to unauthorized actions.

🖇️ References