Home Technology 10 Most Famous Computer Viruses Around the World

10 Most Famous Computer Viruses Around the World


If your computer has already been attacked by a virus, you know how devastating it can be. If you have been lucky enough to avoid this kind of catastrophe, reading about these 10 famous computer viruses will convince you to be careful when you are online, and to keep updating your antivirus software frequently.

If you don’t even have anything to defend yourself against computer viruses, what are you waiting for? Contact an IT services and support company to ensure you are protected from the risk of viruses.

Below are the ten most famous computer viruses around the world:

1. Slammer

Slammer was a computer worm that started to be noticed on January 25, 2003. After only 15 minutes, it had managed to infect half of the servers running the internet. It was spreading itself rapidly, and slowing down Internet traffic.

Because of Slammer, 911 services went down, flights were cancelled, and the Bank of America’s ATM service crashed. The cost of the damage caused by this virus was approximately $1 billion.


The name of this dangerous computer virus is misleading. In May 2000, this worm started spreading itself via an email with the subject line “ILOVEYOU”. When curious people would open the email and click on the attachment, their computer became infected and the virus would spread to everyone in their Outlook address book.

ILOVEYOU would then overwrite and destroy many of the files of the infected computers. It cost approximately $15 billion to get rid of it.

3. MyDoom

MyDoom is a worm that was first noticed in January 2004, and different versions of it have appeared in the following years. Just like ILOVEYOU, it spread itself by sending emails containing an attachment, with a subject line such as “Mail Delivery System” or “Mail Transaction Failed”.

It caused a lot of chaos, and cost approximately $38 billion. MyDoom contained the message “andy; I’m just doing my job, nothing personal, sorry”, but no one knows who this Andy was.

4. CryptoLocker

CryptoLocker was a ransomware software that attacked computers between September 5, 2013 and the end of May 2014. It mostly spread through email attachments, and the cost of the damage it caused was more than $30 million.

A ransomware is a type of virus that encrypts the files of a computer user, and holds them hostage until a ransom is paid to the hacker. However, paying the ransom doesn’t always guarantee that the user won’t lose their files.

5. WannaCry

WannaCry was another ransomware virus that attacked several computers during a few days in May 2017. It infected computers running Microsoft Windows, encrypted the files of users, and asked for a payment of up to $600 in Bitcoins.

It is estimated that the damage caused by the WannaCry ransomware attacks cost at least a few hundreds of millions.

6. Storm Worm

Storm Worm is a Trojan horse virus discovered in January 2007. It spread via an email with the subject line “230 dead as storm batters Europe”. Other subject lines were also used to try to hook curious people.

When people would open the email and download the attachment or click on the link inside, their computer would be infected, and start spreading the virus to more computers. No one knows exactly how much money has been lost because of this virus.

7. Sasser

Sasser is a computer worm that started spreading on April 30, 2004. It was created to take advantage of a vulnerability in Windows XP and Windows 2000, so it would spread without any user intervention.

Because of this virus, many flights were cancelled, and the system of a bank in Finland had to be shut down. Sasser caused damage that cost approximately $31 billion.

8. Melissa Virus

The Melissa Virus was a virus that spread itself from one computer to the other by sending infected Word documents via email. It was also corrupting files with the line “22, plus triple-word-score, plus 50 points for using all my letters. Game’s over. I’m outta here”, which comes from an episode of the popular show The Simpsons.

The Melissa Virus was released in March 1999, and caused approximately $80 million of damage.

9. The Morris Worm

The Morris Worm was released on November 2, 1988. It was one of the first computer worms spreading on the Internet. It would infect computers, and slow them down while it was replicating itself.

According to the hacker who created this worm, it was not meant to cause damage, but to highlight security flaws. It did, however, cause around $96 million of damage.

10. Anna Kournikova

Anna Kournikova is the name of a famous tennis player, but it’s also the name of a computer worm that was released on February 11, 2001.

Computer users would receive an email that claimed to contain a photo of tennis player Anna Kournikova, but if they clicked on the attached file, it would infect their computer, slow it down, and spread to their email contacts. The cost of the damage caused was around $166,000.