Mastering Reverse Engineering

Keylogger

A keylogger is a program that logs what keys have been pressed by a user. The log is usually stored in a file. The core API used here is GetAsyncKeyState. Every button that can be pressed from the keyboard or the mouse has an assigned ID called a virtual key code. Specifying a virtual key code, the GetAsyncKeyState gives information about whether the key has been pressed or not. 

The source code for this program can be found at https://github.com/PacktPublishing/Mastering-Reverse-Engineering/blob/master/ch7/keylogger.cpp.

For keylogging to work, we will need to check the state of each virtual key code and run them in a loop. Once a key has been identified as pressed, the virtual key code gets stored into a file. The following code ...