Malware

Software that serves a malicious purpose, typically installed without the user's consent (or knowledge).

There are multiple types of malware:

Computer Viruses Spyware & Keyloggers Backdoors & Remote Access Trojans (RATs) Rootkits Ransomware Logic Bombs

Viruses

A type of malware designed to be self-replicating and spreads from computer-to-computer automatically. There are four main types of viruses:

Non-resident/file infector Memory resident Boot Scripts and macro viruses

The terms multipartite and polymorphic are used to describe viruses that use multiple attack vectors and that dynamically change and/or obfuscate their code to avoid detection, respectively.