Cybersecurity Malware Types: Definitions and Functions

Virus

Malicious code that attaches to legitimate files and spreads when executed; requires user action.

Worm

Self-replicating malware that spreads across networks without user interaction.

Trojan Horse

Disguises itself as a legitimate program; often creates backdoors for attackers.

Rootkit

Hides deep in the OS to avoid detection and maintain privileged access; disables security tools.

Spyware

Secretly monitors user activity and sends data to attackers; often used for credential theft.

Adware

Displays unwanted ads and may track user behavior; sometimes bundled with free software.

Ransomware

Encrypts files and demands payment for decryption; often spread via phishing or exploits.

Keylogger

Records keystrokes to steal sensitive information; can be software or hardware-based.

Botnet

Network of infected devices controlled remotely; used for DDoS, spam, or crypto mining.

Logic Bomb

Malicious code triggered by specific conditions like dates or events; hidden until activated.

Backdoor

Bypasses normal authentication to allow remote access; often installed by Trojans.