PostVirus - Code that attaches to a host file and spreads when that file runs.

Virus - Code that attaches to a host file and spreads when that file runs. Keylogger - Records keystrokes to steal passwords, messages, and other typed data. Worm - Self-replicating malware that spreads across networks without a host file. Trojan - Malware disguised as legitimate software that the user installs willingly. Rootkit - Hides itself and other malware by hooking the OS at a deep level. Backdoor - A hidden entry point that lets an attacker bypass normal authentication. Adware - Software that pushes unwanted ads, often bundled with free programs.