08. CryptoLocker

The CryptoLocker ransomware attack was a cyber attack using CryptoLocker ransomware that occurred between 5 September 2013 and late May 2014.

FSQL Slammer is a 2003 computer worm that causes a denial of service on some Internet hosts and dramatically slows down general Internet traffic.

07. SQL Slammer

Cloud Banner

Code Red was a computer worm observed on the Internet on July 15, 2001. It attacked computers running Microsoft's IIS web server.

6. CodeRed

5. Gameover ZeuS

GameOverZeus is a peer-to-peer botnet based on elements of the earlier ZeuS Trojan. The malware was created by Russian hacker Evgeny Mikhailovich Bogachev.

4. WannaCry

The WannaCry ransomware attack was a global cyberattack in May 2017 by the WannaCry ransomware cryptoworm, which targeted computers running the Microsoft Windows operating system by 

encrypting data and demanding a ransom in Bitcoin cryptocurrency.


ILOVEYOU, sometimes referred to as Love Bug or Love Letter to You, is a computer worm that infected more than ten million Windows personal computers as of May 5, 2000.

It was first seen on January 26, 2004 It became the fastest-spreading email worm in history, surpassing previous records set by the Sobig worm and ILOVEYOU, a record that was set until 2022.

02. Mydoom

The Sobig worm was a computer worm that infected millions of Internet-connected Microsoft Windows computers in August 2003.

2. Sobig