Jeremiah Grossman: Forging HTTP request headers with Flash

Tuesday, July 25, 2006

Forging HTTP request headers with Flash

Amit Klein, a top webappsec expert, published "Forging HTTP request headers with Flash". Essentially Amit found a way using Flash to force a users browser to send HTTP requests to any location and alter the Referer header in the process. This discovery has wide-ranging implications for web application security, not the least of which impact the ability to do anti-CSRF using Referers. In an odd conicidence, I was working on a solution to do easy anti-CSRF using ModSecurity (Amit had prior knowledge of) based on using Referers. Was set to be released through WASC. I know what your thinking, "don't ever ever ever trust the client". But I felt there could be an exception in this case and had the proof to back it up. But Amit being the nice guy that he is let me know what he was working on ahead of time. So, the article I had planned is being moth balled. Every week is something new.

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BIO

Jeremiah Grossman brings 20+ years of experience in Computer Security and has become one of the most recognizable and world-renowned cybersecurity experts in the industry, coining several of the original hacking terms commonly used around the world today. Early in his career, Jeremiah was known as “The Hacker Yahoo” which led to his role as the company’s Information Security Officer. Jeremiah founded WhiteHat Security (now Synopsis), and served as Chief of Security Strategy for SentinelOne which was the highest-valued cybersecurity IPO in history. Most recently, Jeremiah was the founder & CEO of Bit Discovery, which was acquired by Tenable in 2022. He also serves as a company advisor and board member to several tech startups. In his spare time, Jeremiah does Brazilian Jiu-Jitsu and is passionate about classic cars. He recently opened Toybox, a luxury car club in Boise, Idaho.