Any software intended to be malicious to the system (and the system's users) it runs on.
| Type | Description |
|---|---|
| Virus | A program capable of making copies of itself, and inserting those copies into other programs. |
| Worm | A virus can can distribute itself to other systems. |
| Spyware | Software to spy/gather information from a system. |
| Trojan | Software masquerading as legitimate to provide a backdoor to an attacker. |
| Drive by Download | A malware delivery technique triggered when a user accesses a website. |