Quiz Entry - updated: 2026.07.30
What are the three main types of malware and how do they differ?
Virus needs a host file + user action; worm spreads itself across networks; Trojan tricks the user but doesn't self-replicate.
* Virus, worm and trojan — distinguished by how each spreads. *
Viruses, Worms, and Trojans — they differ in how they spread:
| Type | Characteristic |
|---|---|
| Virus | Attaches to programs, requires user action to spread |
| Worm | Self-replicates across networks without user action |
| Trojan | Disguises as legitimate software, doesn't self-replicate |
Key distinction: Viruses need a host program and user interaction; worms are standalone and self-propagating; trojans trick the user but don't spread on their own.
Go deeper:
Computer worm (Wikipedia) — the virus-vs-worm distinction (host + user action vs standalone self-propagation).- Trojan horse (computing) — Wikipedia — social-engineering spread, no self-replication.