Web Browsers are one of the most used and critical software in the world. Using millions of lines of code, they are in charge of handling, sanitizing, and interpreting all kinds of (untrusted) data coming from the web. To be honest, It’s just impossible for developers to write such complex pieces of software (involving compilers, interpreters, and parsing libraries) without introducing any bugs.

As shown in the last years, fuzz testing is by far the most efficient and scalable testing technique to find software bugs. In this training, we will apply fuzzing to find critical vulnerabilities in different web browser implementations.

First, this course will give you all the prerequisites to understand the architecture and major components of modern web browsers. Then, you will create and set up a testing environment allowing you to easily replay, debug, minimize and analyze existing issues, CVEs, and PoCs. Over dedicated modules, you will discover and fuzz the main browser components such as DOM, JS engines, JIT compilers, WebAssembly, and IPC. You will learn how to use famous tools (Domato, Dharma, Fuzzilli, Frida) and create your custom fuzzers to apply different fuzzing techniques (coverage-guided, grammar-based, in-process fuzzing) to find vulnerabilities/bugs.

A lot of hands-on exercises will allow you to internalize concepts and techniques taught in class. This course will mainly focus on Google Chrome, Firefox, and WebKit/JSC.