10 place – Nimda

The multi-vector computer worm Nimda was first spotted a week after attacks on the World Trade Center buildings in New York, on September 18, 2001.

Within 22 minutes, it spread via the Internet through email, open network resources, shared folders and file transfer, as well as through browsing malicious websites. The virus significantly slowed the speed of the Internet connection and sent emails with an infected read-me file to all email contacts of users, causing damage of $635 million.

Nimda got its name from the word admin, written in reverse. Since then, several modifications of the virus have appeared, differing only in text lines of copyright.

9 place – Conficker

The Conficker worm, first discovered on the network on November 21, 2008, infected 12 million computers running Microsoft Windows in three months. The damage caused to state, corporate and home PCs exceeded $9 billion.

Microsoft, searching for the creators of the virus, put out a reward of $250 thousand for any information about them. A special broad industry alliance, Conficker Cabal, was also created to combat the virus.

8 place – Storm Worm

A year earlier, on January 17, 2007, Microsoft Windows operating systems were attacked by the Storm Worm, a trojan horse of the backdoor type.

In the e-mail with the title “230 dead as storm batters Europe”, a file with a virus was attached, which infected about 10 million computers worldwide.

The informational breach formed in the computer system was used to receive data or send spam.

7 place – Chernobyl

CIH, better known as “Chernobyl”, attacked computers running Windows 95/98 / ME in June 1998. After activation, it damaged BIOS data chips of 500 thousand computers around the world, destroying all the information from their hard drives.

Despite the serious damage inflicted by Chernobyl (more than $1 billion), its creator, a Taiwanese student Chen Ying Hao, was not punished and now works at Gigabyte. They say that he created the CIH to demonstrate how vulnerable the computers of Tatung University are but did not assess the possible consequences.

6 place – Melissa

Melissa was the first macro virus to have a devastating effect by mailing malware. So, about 20 percent of all computers worldwide were infected, and the damage amounted to about $80 million.

Infection began in March 1999, when the first 50 addresses of Microsoft Outlook Express received a letter with an attached virus list.doc file that allegedly contained passwords to 80 paid porn sites. The malicious message also contained the words: "Here is that document you asked for...don't show anyone else ;-)."

The author of the program, American David Smith from New Jersey, named his creation in honor of a stripper from Florida. Soon he was sentenced to 20 months in prison and a symbolic fine of $5,000.

5 place – SQL Slammer

The SQL Slammer worm began to generate random IP addresses and send itself out to those addresses on January 25, 2003. Mainly automated systems of banking institutions were attacked. In total, more than 200 thousand computers worldwide were infected which resulted in a loss of $750 million.

As a result, the internet connection slowed down because of the collapse of numerous routers under the burden of extremely high bombardment traffic from infected servers. South Korea suffered the most, where there was no Internet for 12 hours.

4 place – Code Red

On July 15, 2001, computers running a Microsoft IIS web server were hit by a specific Code Red computer worm, named after one of the varieties of the Mountain Dew drink.

During the week of its “work,” it infected more than 400,000 servers (including the White House server), replacing the contents of the pages on the affected sites with the phrase “Hello! Welcome to http://www.worm.com! Hacked By Chinese!" The amount of total damage is estimated at $2.6 billion.

3 place – Sobig F

Sobig F is another worm that infected 1 million computers running Microsoft Windows within 24 hours. It paralyzed Air Canada and caused a slowdown in computer networks around the world.

The principle of the virus was similar to its predecessors: after a user opened an e-mail with an attachment, the virus found the addresses on the infected computer and sent itself out to them.

The damage caused by the malware from August 19 to September 10, 2003, exceeded $37 billion. Despite the announced remuneration of $250 thousand, the name of the creator of the virus remained unknown.

2 place – Mydoom

The record for the number of infected computers running Microsoft Windows was broken by the Mydoom mail worm which caused damage of a whopping $38 billion.

The computer "epidemic" began on January 26, 2004, with emails with the topics "Hello", "Test", "Error", "Mail Delivery System", and so on, containing virus attachments and a text message "Andy; I'm just doing my job, nothing personal, sorry.” In addition to sending the worm to other addresses, the operating system was modified in such a way that the websites of most news feeds and anti-virus companies, as well as some sections of the Microsoft website, were blocked for the user.

A couple of weeks later, on February 12, the virus was programmed and ceased to operate.

1 place – Iloveyou

The Iloveyou computer worm became the most destructive virus in the entire history. In 2000, it successfully hit more than 3 million personal computers due to a skillful disguise as a letter from a fan.

The attached letter with the Iloveyou theme and the Love-letter-for-you.txt.vbs attachment contained a virus that, after opening the attachment, sent itself out to all addresses from contacts and also performed numerous changes in the system.

The damage caused by the virus to the Windows servers amounted to $10-15 billion, which is why it was listed in the Guinness Book of Records as the most destructive computer virus in the world.