Deobfuscation: recovering an OLLVM-protected program

We recently looked at the Obfuscator-LLVM project in order to test its different protections. Here are our results, and explanations on how we deal with obfuscation.

Introduction
As we sometimes have to deal with heavily obfuscated code, we wanted to have a look at the Obfuscator-LLVM project to check the strengths and weaknesses of the generated obfuscated code. We looked at the latest version available (based on LLVM 3.5). We will show how it is possible to break all the protections using the Miasm reverse engineering framework.