John has worked in a variety of infosec roles from forensics and consulting to large enterprise security. He was most recently part of the Yahoo! Paranoids red team, operating on a network with over 600,000 systems servicing nearly a billion users. That kind of scale totally alters the security dynamic when designing tools and scoping targets. Previously, he was a consultant and researcher at Accuvant Labs, responsible for executing tightly scoped projects for third party clients and cutting-edge vulnerability research. Before Accuvant, John spent a few years at Matasano Security. This is where his consulting career blossomed. He worked with dozens of clients, finding hundreds of bugs across the entire gambit of programming languages and web services. During his career, education and training were paramount. He routinely volunteered to kickstart training programs and to become a mentor to juniors in the field. John has also spoken at conferences around the world and has given lectures in universities on topics like fuzzing and dynamic program analysis. In his own research, he enjoys exploring complicated code and has reported dozens of security flaws in browsers, kernels, security software, phones and more. He is also known for creating art on the chess board.