x86 Software Reverse-Engineering, Cracking, and Counter-Measures

CHAPTER 4Building and Running Assembly Programs

Software reverse engineering is about taking a compiled executable and turning it into human-readable code. However, understanding how to do the opposite, building and running an assembly program, can be invaluable to understanding this process.

This chapter explores some of the key concepts needed to understand how assembly programs are built and run. This includes how these programs interact with the outside world, how to actually build and run them, and how they manage strings.

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In college, I found out it's pretty fun to go to a thrift store and buy a bunch of broken electronics, tear them apart, and rebuild the pieces into something else. Figure 4.1 is one of the first things I ever built. I really like working with impractical things because thinking and designing and building and learning is fun, but as soon as you start to worry about actual applications and usability, it takes away from the enjoyment. So, I go out of my way to try to work on impractical things.

Figure 4.1: Binary wristwatch

I was trying to think of the most impractical thing that I could make here. This is a binary wristwatch that has to be plugged into a power outlet. I never did find a wristband for it, but I was trying to think of the nerdiest thing I could make, and this seemed pretty nerdy.

Assembly and machine code are ...