Life’s a Peach (Fuzzer): How to Build and Use GitLab’s Open-Source Protocol Fuzzer
The Peach protocol fuzzer was a well-known protocol fuzzer whose parent company — Peach Tech — was acquired in 2020 by GitLab. While Peach Tech had previously released a Community Edition of Peach fuzzer, it lacked many key features and updates found in the commercial editions. Fortunately, GitLab has open-sourced the core protocol fuzzing engine of Peach under the name “GitLab Protocol Fuzzer Community Edition,” allowing anyone to build and deploy it. For simplicity, I will refer to the new open-sourced version as Peach Fuzzer.
As expected of an early-stage project, the build process is complicated and not well-documented. In addition, first-time users may have trouble understanding how to use the fuzzer. Moreover, GitLab's open-sourced version still lacks important resources such as fuzzing templates, which means you will have to write them on your own.
To that end, this article aims to demonstrate an end-to-end application of Peach Fuzzer, from build to deployment. Look out for a subsequent article where I will touch on the full workflow of finding and exploiting vulnerabilities using Peach Fuzzer.