Portable Executable file infection is a subject I always found to be sketchy. There was always a piece of the puzzle missing in my case... In this article I hope to clarify the matter and hopefully provide a good starting point for those wanting to learn how such tools work.I want to mention that I'm writing this article with an intention of educating others. You may start out with PE infection, but eventually I hope that you'll move onto authoring PE protection tools and exploiting your newly found knowledge in a positive and ethical manner. A lot can be learned during the development and implementation process of such tools.I'll mainly be using C and inline Assembler in this article and I'll assume you've at least a working knowledge of both C and Assembler.Firstly, what is a PE file? You can find out by skimming through this page: