Mia has discovered that a process that looks like a system driver is running commands on the server, the process has super user access.

The commands appear to be coming from operating system low level driver code that interacts with the disk subsystem. Further analysis shows this rogue process is trying to open the password file which a driver does not require. What is the most likely type of malware that has infected Mia's system and is trying to do things only the Operating System can do$?$

Phishing

Rootkit

Kernel Flood

Ransomware