In this chapter, we explored Windows kernel attacks. First, we reviewed the theory behind how the kernel works and what attackers try to leverage to pull off these attacks. Included in this theoretical discussion was a review of the low-level management role of the kernel and the security implications of these tasks, including scheduling interrupts. We picked a vulnerability type, the NULL or invalid pointer dereference vulnerability, and studied it in detail to understand how exploiting the kernel in this way gives the attacker full control of the system. We started with a review of pointers in C code and then examined the compiled assembly instructions to understand how the processor deals with the pointer concept. This review prepared us to understand what NULL pointers are and how they can cause problems in software. We then introduced a specific kernel-mode driver, Win32k.sys, and did a low-level review of its pointer flaw. We wrapped up this discussion with a review of the Metasploit exploit module designed to attack this particular kernel-mode driver. Finally, we wrapped up the chapter with a hands-on demonstration of escalating privileges from an initial foothold by leveraging this attack against the vulnerable kernel-mode driver.