A kernel driver is a low-level software module that runs in <a href="https://en.wikipedia.org/wiki/Kernel_(operating_system)" target="_blank">Kernel</a> mode on the level 0 of the <a href="https://en.wikipedia.org/wiki/Protection_ring" target="_blank">Protection ring</a> responsible for managing or interfacing with hardware, Operating System’s core functions or low-level system resources such as CPU instructions.