Rootkit

A rootkit is a type of malware ✕ Malware (from "malicious software") is the umbrella term for any harmful software — viruses, trojans, ransomware, spyware — that damages, spies on, or hijacks devices. More in the glossary → designed to hide in the deepest layers of the operating system and grant the attacker privileged control over the machine without being detected. Its name comes from the "root" (administrator) user: once inside, it can conceal other malicious programs, intercept what you do and manipulate the system itself so the antivirus ✕ An antivirus is a program that detects, blocks and removes malicious software. Modern ones combine known signatures with behavior analysis. More in the glossary → cannot see it. Precisely because it operates at such a low level, it is among the hardest malware to find and remove; sometimes it is only cleaned by reinstalling the system. Prevention is key: do not install software of dubious origin, keep everything updated and use an antivirus with specific rootkit detection. More in the best antivirus comparison.