Types of Malware: Virus vs Worm vs Trojan vs Rootkit

Which malware type is this?

Malware cheat sheet

Virus

Attaches to a file or program. Needs the user to RUN something to spread. Most often spread by sharing infected files.

Worm

Self-replicates and spreads on its own across a network. Does NOT need a user to do anything.

Trojan

Disguised as something legitimate, like a free game or a software update. Tricks the user into running it.

Ransomware

Encrypts or locks files and demands payment to unlock them. Attacks AVAILABILITY.

Spyware

Secretly monitors what the user does: keystrokes, screenshots, browsing, sometimes the camera or microphone. Attacks CONFIDENTIALITY.

Rootkit

Hides malicious activity from the operating system. Designed so antivirus and the user cannot see it is there. Hard to detect, hard to remove.