MIT CSAIL researcher Joseph Ravichandran has built Fractal, a custom OS written from scratch in assembly, C, and C++ designed to strip away conventional OS defenses and expose raw CPU behavior for security research. Fractal's three key features — multi-privilege concurrency, cooperative multitasking, and a custom memory system called gmap — eliminate variables that normally obscure hardware behavior during testing. Using Fractal on an Apple M1, Ravichandran discovered the first evidence of Phantom speculation on Apple Silicon, a vulnerability previously known only in AMD and Intel chips. While the practical impact appears limited (instructions are never executed), the finding was disclosed to Apple. Fractal runs on Apple Silicon, Intel/AMD PCs, and Raspberry Pis, and is freely available as open source under the MIT license on GitHub.
