In this gist I show how to disassemble and modify a Linux executable binary to change the body of a function. This will allow you to control how a binary behaves, even when you don't have access to the source code and you can't recompile it.
In my case, I was asked to try and bypass the protection mechanism implemented. The protection mechanism implemented was meant to only allow a binary to be run in presence of a valid license.
So basically my activity involved:
- Finding the function which performs the protection check
- Disassembling the binary