Fundamentals
- A Virus is a program which attaches itself to other programs.
- A Worm is a program which tries to spread to other systems.
- A Trojan is a program which fakes to be harmless, but it isn’t.
Comparison
| Malware | Virus | Worm | Trojan |
|---|---|---|---|
| Spreads within the machine? | Yes | No | No |
| Spreads over the network? | No | Yes | No |
| What is it primarily used for? | Destruction | Botnet | Backdoor |
Disclaimer
Theses are pure forms of malware, but in reality they are often combinations.