“Distributed, scalable fuzzing on Windows can be challenging and inefficient. This is especially true for endpoint security products, which use complex interconnected components that span across kernel and user space. This often requires spinning up an entire virtualized Windows environment to fuzz them or collect coverage data.” Porting stuff like Windows antivirus tools to Linux lets Ormandy “run the code I’m testing in minimal containers with very little overhead, and easily scale up testing”. Oh, and “I also think Linux has better tools”. <https://www.theregister.co.uk/2017/05/24/whats_got_a_vast_attack_service_and_runs_on_linux_windows_defender_of_course/>