From a security perspective, one of the most crucial points to understand about the kernel is that it's technically a program made up of code. The real distinction between a flaw in the kernel and a flaw in code on the user side is the privilege; any piece of code running at the kernel level can own the system because the kernel is the system.

Crashing the kernel results in an irrecoverable situation (namely, requires a reboot), whereas crashing a user application just requires restarting the application – so, exploring kernel attacks is more precarious and there is far less room for mistakes. It's still just a computer program, though. I emphasize this because we can understand the kernel attack in this chapter from a programmer's perspective. The kernel is written in a mix of assembly and C (which is useful due to its low-level interface ability), so let's take a look at a basic programming concept from a C and assembly point of view before we dive into exploiting our Windows target.