Cracking a CrackMe

Many moons ago, there used to be a website called crackme.de, full of programs designed to be broken into by enthusiasts of the cracking scene (basically, a bunch of people who looked like they ran away form the set of Mr. Robot). Recently, I discovered a mirror of sorts for it, called crackmes.one. So I … Continue reading Cracking a CrackMe →

Stack Frame Prototypes

Zeroing out data in memory costs CPU cycles. It's often avoided, including in the case of malloc() or the callstack. When a function is called, a stack frame is created to house the return address, the frame pointer, function arguments, and local variables. However, when the function returns, that data is not removed. It stays … Continue reading Stack Frame Prototypes →

A Call Without a Call

Using the concepts we looked at in A For Loop Without a For Loop and A Simple Infinite Loop, we can call a different function rather than calling the same one in a loop. In this post, we are going to call a function within main(), by overwriting main()'s return address and replacing it with the … Continue reading A Call Without a Call →