This chapter will guide you through the creation of a kernel hook. The kernel of the operating system provides high-level applications with the low-level functionality needed to perform system operations. By hooking the kernel, a rootkit can alter the low-level operations used by high-level applications. This provides a convenient mechanism for control, monitoring, and filtering, and offers many possibilities for concealment.
This chapter includes the following:
The system call table
Memory protection considerations
Kernel hooking macros
Kernel hooking functions
A basic example of kernel hooking
A description of kernel functions by group