Static analysis of binary code is challenging for several reasons. In particular, standard static analysis techniques operate over control flow graphs, which are not available when dealing with self-modifying programs which can modify their own code at runtime. We formalize in the Coq proof assistant some key abstract interpretation techniques that automatically extract memory safety properties from binary code. Our analyzer is formally proved correct and has been run on several self modifying challenges, provided by Cai et al. in their PLDI 2007 paper.