What are the four types of Rootkit?

The four types of rootkits are:

1. User-mode Rootkits: These operate at the application layer, modifying user-level applications and system calls to hide malicious activities.
2. Kernel-mode Rootkits: These have deeper system access, modifying the operating system's kernel to hide their presence and manipulate system operations.
3. Bootkits: These target the system's boot process, infecting the bootloader to gain control before the operating system loads.
4. Firmware Rootkits: These reside in firmware, such as BiOS or UEFI, allowing them to maintain persistence and control over the hardware, even after the operating system is reinstalled.