Malware

Adware

Spyware

Virus

Worm

Trojan

Rootkit

Backdoors

Keyloggers

Rogue Security Software

Ransomware

10. Melissa

9. ILOVEYOU

8. The Klez Virus

7. Code Red & Code Red II

6. Nimda

5. SQL Slammer / Saphire

4. MyDoom

3. Sasser & Netsky

2. Leap-A / Oompa-A

1. Storm Worm