TCO Blog

5 most dangerous computer viruses

by Ksajikyan
5 most dangerous computer viruses

Friends computers can also be infected with viruses. However, their “anger” is assessed not by the degree of aggressiveness, but by the size of the damage that they are planning to inflict. We have compiled for you the Top 5 most dangerous viruses of all time. As criteria, we chose the size of the damage caused and the number of injured persons. We hope you are familiar with these viruses only through the news.

5th place: SLAMMER

Slammer: initiated such a large volume of traffic that “the entire Internet” slowed down

Slammer is a worm that appeared in 2003. Like many other viruses, Slammer had several names. He also became known as SQL Slammer, Saphire, WORM_SQLP1434.A, SQL Hell or Helkern.

Slammer infected about 200,000 computers. The damage he caused is estimated at 1.2 billion US dollars.

The target was the database servers on which Microsoft SQL Server 2000 was installed. Actually, the spread of this pest could be avoided. Microsoft has already released a patch to fix the vulnerability – only many did not install it.

Slammer sent a continuous stream of data and thereby significantly slowed down access to the Internet. Because of this, some hosts have completely stalled. Also, the server of one of the American nuclear power plants was damaged – the security system was paralyzed.

4th place: CODE RED

This is also a worm, the mere name of which looks threatening. In 2001, he sneaked through a vulnerability in Microsoft’s Internet Information Server and began to spread from one web server to another.

The purpose of the worm was to modify the contents of web pages.

In addition, in the direction of certain IP addresses, he launched a so-called DDoS attack. DDoS attacks should make servers inaccessible. The most famous victim of such an attack by CODE RED was the White House server.

Code Red infected 400,000 servers in just one week. A total of about 1 million PCs were affected by the worm, and the damage caused was approximately $ 2.6 billion.

3rd place: ILOVEYOU

I love you

Under the microscope: Symantec generated this graph based on the I Love You virus source code.

ILOVEYOU, also known as Loveletter, is, unfortunately, not a declaration of love, but also a computer worm. In May 2000, many Internet users received an e-mail with a declaration of love “contained” in the attached file. However, the joy was short-lived – as soon as the user opened the mail, the virus sat firmly in the mail program and on the hard drive.

Then the virus proceeded to self-distribution: it sent itself by mail to the contacts from the address book.

Loveletter overwritten image files and stole passwords from computers.

The only good thing about ILOVEYOU was that it was with the advent of this worm that users for the first time massively turned really serious attention to malware and realized the importance of using antivirus software.

This worm infected more than 3 million computers, it managed to cause damage, estimated at as much as 15 billion US dollars. The alleged origin of ILOVEYOU is considered to be the Philippines. Even three specific people were suspected there. However, for the alleged authors of the virus, there were no consequences in any case: in those days, the Philippines simply did not have laws requiring liability for the spread of malware.

2nd place: SOBIG.F

SOBIG.F is both a self-copying worm and a Trojan, and it appeared in August 2003.

With 2 million infected computers and damages in excess of $ 37 billion, Sobig.F takes its place just behind our “Number 1” in the ranking of the most dangerous viruses of all time.

It was fast, admittedly Sobig.F: within 24 hours, the pest managed to send about a million of its copies.

Not only mail services were overloaded with a gigantic stream of data, even entire systems “fell”. In Washington, sending emails and exchanging data for a short time was not possible at all. Many computers of various enterprises worked extremely slowly. Air Canada was forced to cancel some flights due to Sobig.F.

Microsoft has even announced a reward for the capture of the author of the worm – $ 250,000. To no avail – to date, the name of the developer Sobig.F is not known.

In September 10, 2003, Sobig.F again disappeared from computer screens.

1st place: MYDOOM


MyDoom opened Notepad files and filled them with arbitrary lines

And the winner is … MyDoom, in a negative sense, of course. MyDoom is also a worm that crawled free from January to February 2004. After that, MyDoom disappeared.

Mydoom was distributed through the so-called Bounce Message. These are “Non Delivery Notification” notifications that the mail server generates if the message cannot be delivered. As soon as the user opened such a notification, the computer became infected. Then the worm sent itself to all the contacts that it could detect.

Mydoom slowed the Internet overall by about 10 percent, and page loading time increased by 50 percent. The peak activity of the virus was observed on January 26, 2004: for several hours, the effects were noticeable aroundA the world.

2 million computers were infected. The damage Mydoom inflicted over several weeks is estimated at an incredible $ 38 billion.

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