Updated 6/30/2020 from
Viruses come in many forms and are created for different purposes. Some corrupt or delete computer files, while others are designed to replicate themselves until they consume your RAM and render your computer inoperable. There are even viruses, like Ping Pong, which are created as a hoax and do no real harm.
To date, there are over a million computer viruses, but only a small percentage of them are in circulation. Few have wreaked havoc and tax bills on these viruses listed on this page.
Ten of the most prolific viruses of all time
Here are some of the viruses that have caused widespread computer infections:
1. stormworm (also called Peacomm etc Nuvar) – As of January 19, 2007, more than 200 million emails contained links to download the Stormworm, contributing to the overall attack. Most people think that the worm got its name from the fact that one of the emails containing the virus had the subject line “230 dead in storm that hit Europe”.
- Unlike the W32_Storm_Worm released in 2001, this virus was released and identified in late 2007.
- Allow hackers to remotely control the computer and use it for malicious activities such as bulk email (spam).
- Distribution through fake links to videos and news reports.
2. Netsky and Sasser – Netsky spread through email and Windows networks, causing massive web traffic and causing Denial of Service (DDoS) attacks. At the time, it was estimated that Netsky and its variants were responsible for up to 25% of all viral infections. Sasser reproduced itself by finding other systems with vulnerabilities and forcing them to download the virus. Once on a new computer, it modified the operating system to make it difficult for users to shut down their computers.
- Released in February and April 2004 respectively.
- Created by Sven Jaschan, 17 years old.
- One of the few viruses that can be traced back to its creator.
3. My destiny – This worm was unique in that it had some sort of timer. The virus launched denial of service attacks and stopped spreading 11 days later. These attacks targeted various internet servers, including attacks on search engines, causing many of them to crash and search results to return much more slowly than normal.
- Released February 1, 2004.
- Reproduced over email and peer-to-peer networks.
- It created a backdoor that stayed open even after the worm stopped spreading.
4. Earthworm Blaster – Once this worm entered a network, it spread faster because firewalls often did not prevent internal computers from using a port that the worm was using. It was stopped by ISP filtering and public awareness.
- Released August 2003, original creator unknown.
- Infecting millions of computers worldwide.
- Launching Denial of Service (DoS) attacks against Microsoft servers.
5. SQL slammer – Slammer (aka Sapphire), a prolific web server virus, infected almost half of the servers that power the Internet 15 minutes after its initial attack.
- Released January 2003.
- The affected computer networks and systems caused shutdowns and a series of damages estimated at more than a billion dollars.
- Caused disruption to Bank of America ATM service and Seattle emergency services.
6. you know – Spreading via emails and websites, this worm targeted Internet servers and slowed Internet performance almost to a standstill. It also opened a backdoor to the computer’s operating system and allowed a hacker to gain access to the computer. However, access has been restricted by user account permissions.
- Released in 2001.
- The name is the word “admin” spelled backwards.
- The fastest spreading computer virus in history.
7. Code Rouge / Coderouge II – These viruses exploited a vulnerability in Microsoft Windows 2000 and NT and caused a buffer overflow. Code Red launched denial-of-service attacks against White House web servers, while Code Red II provided a backdoor for hackers to gain access to Windows 2000 systems.
- Released in summer 2001.
- Later, Microsoft’s patch prevented the release.
8th. klez – This virus was unique in that hackers reproduced it in many forms. He was also able to spoof himself to help spread the virus, as recipients thought it came from a friend.
- Released late 2001.
- Distributed via email.
- Can disable antivirus programs and render a computer unusable.
9. I LOVE YOU – Traveled via email as a message from a secret admirer. When users downloaded the attachment called WIN-BUGSFIX.EXE, the virus copied and embedded itself in key files including registry keys.
- Probably created by Onel de Guzman (Philippines) in 2000.
- Originally distributed via email and later by IRC clients.
- The damage caused by the virus is estimated at around US$10 billion.
10 Melissa – Once activated, the virus replicates and then sends itself to the first 50 people in the recipient’s address book.
- Created by David Smith in 1999.
- It has created a mess for government and public sector networks.
- Some email providers had to shut down their email services until the virus was contained.