Introduction This blog is intended to be a dedicated effort to structure information in relation to Mach Messages in a way that I can remember and use as a reference for the future. Often as a vulnerability researcher, attack-surfaces involving compromising other adjacent processes relative to a preliminar target are increasingly important with today’s enforced mitigations (specially in the SBX realm), and having a good understanding of the internals of the underlying technology which makes this inter-process communication mechanism possible is vital to understand and tackle adjacent attack surfaces.