How dangerous are computer viruses? The most dangerous computer viruses in the world

The first computer viruses appeared immediately after the creation of computers. Programmers wrote them just for fun; such viruses did not cause any harm. But modern computer viruses are created for completely different purposes and pose a serious danger. What viruses exist and how to fight them?

All existing malware today can be divided into two categories: viruses and Trojans. The first ones simply perform some negative or humorous actions on the infected computer, for example, they can erase files or completely format the hard drive, turn off the computer, make the mouse inaccessible to the user, display some message on the screen, etc.

As a rule, the creators of viruses do not pursue selfish goals; most often such programs are written simply for entertainment. But there are exceptions - for example, viruses that block the operation of Windows.

The user sees a message in which he is asked to transfer a certain amount of money to a specific account, after which he will be sent an unlock code.

Having encountered such a virus, you should remember the features of the message, in particular, the account or phone number (if you are asked to top up your phone balance), then go from another computer to the websites of anti-virus companies and look for the appropriate unlocker. But even if you fail to remove the virus, the worst consequences from it are formatting the PC hard drive.

The biggest danger is Trojans

This type of malware is created with the purpose of stealing a person's confidential data. If the work of a virus on a computer is usually clearly visible, then the Trojan program tries to completely hide its presence. Its task is to collect the necessary information, such as logins, passwords, bank card or online banking data, etc., and then quietly transfer everything to the owner of the Trojan.

High-quality Trojan programs are written by highly skilled programmers and can cost thousands of dollars. A well-made Trojan is absolutely invisible; no anti-virus program can detect it until data about the Trojan gets into anti-virus databases.

Modern spyware easily bypasses firewalls. Having done their dirty deed, many Trojans self-destruct, leaving no traces behind. You can only find out that your computer has been infected with a Trojan after money is lost from your bank card, or mailboxes, admin areas of websites you own, etc. are hacked.

Backdoors

There is also a class of viruses called backdoors. Once the virus infects your computer, it creates a backdoor through which the hacker gains full access to the machine. He can view and copy information from disks, delete or add something. A hacker can use your computer to scan networks and hack other computers to launch attacks on servers. Thousands of hacked computers can be controlled from one center, in which case a botnet is formed - a network of infected computers subordinate to one person.

Viruses and Trojans pose a huge danger, so they are fought in every possible way. The main problem is that the principles of construction and operation of the most common operating system today, Windows, provide hackers with a lot of opportunities to create and introduce malware.

OS developers are trying to close the gaps, but there are still too many of them. The Linux operating system is much more secure in this regard, and it is no coincidence that many hackers use it.

In any case, to protect against viruses and Trojans, your computer must have an up-to-date antivirus and firewall. You should also follow basic security rules - in particular, do not download or open suspicious files.

Computer viruses can significantly reduce the performance of your computer and also destroy all data on your hard drive. They are able to constantly reproduce and propagate themselves. Something reminiscent of human viruses and epidemics. Below is a list of the ten most dangerous computer viruses in the world.

Multi-vector Nimda worm

Nimda is a computer worm/virus that damages files and negatively affects the operation of the computer. First seen on September 18, 2001. The name of the virus comes from the word admin spelled backwards. Due to the fact that the Nimda worm uses several methods of propagation, it became the most widespread virus/worm on the Internet within 22 minutes. It is distributed via email, open network resources, shared folders and file transfers, as well as through browsing malicious websites.

Conficker


Conficker is one of the most dangerous and well-known worms, targeting computers running Microsoft Windows operating systems. Linux and Macintosh systems are completely resistant to it. It was first discovered on the network on November 21, 2008. By February 2009, Conficker had infected 12 million computers around the world, including government, corporate and home computers. On February 13, 2009, Microsoft offered a $250,000 reward for information about the creators of the virus. A special group was even created to combat Conficker, which was unofficially dubbed Conficker Cabal. The damage caused by the malware is estimated at $9.1 billion.


Storm Worm is a backdoor Trojan horse that infects Microsoft Windows operating systems. It was first discovered on January 17, 2007. It is distributed mainly by email with a letter that has the heading “230 dead as storm batters Europe”, and later with other headings. The file attached to the letter contains a virus that creates an information “hole” in the computer system, which is used to receive data or send spam. It is estimated that about 10 million computers were infected with the Storm Worm malware.

Chernobyl


Chernobyl is also known as CIH, a computer virus created by Taiwanese student Chen Ying Hao in June 1998. Works only on computers running Windows 95/98/ME. It is considered one of the most dangerous and destructive viruses, since after activation it is capable of damaging data on BIOS chips and destroying all information from hard drives. In total, about 500,000 personal computers around the world were affected by Chernobyl, losses are estimated at $1 billion. The author of the virus, Chen Ying Hao, was never brought to justice and now works for Gigabyte.

Melissa


Melissa is the first email macro virus, infecting about 20% of all computers worldwide. It was first noticed in March 1999. The malware was sent to the first 50 Outlook Express addresses. The letter had an attached file LIST.DOC (virus), allegedly containing passwords to 80 paid porn sites. The program was invented by David Smith from New Jersey. On December 10, 1999, he was sentenced to 20 months in prison and a fine of $5,000. While the damage caused by the virus amounted to about $80 million.

SQL Slammer


SQL Slammer was a computer worm that generated random IP addresses and sent itself to those addresses. On January 25, 2003, it hit Microsoft servers and another 500,000 servers around the world, which led to a significant decrease in Internet bandwidth, and generally cut off South Korea from the Internet for 12 hours. The slowdown was caused by numerous routers crashing under the burden of extremely high outbound traffic from infected servers. The malware spread with incredible speed; in 10 minutes it infected about 75,000 computers.

Code Red


Code Red is a specific type of computer virus/worm that attacks computers running the Microsoft IIS web server. It was first discovered on July 15, 2001. This malware basically replaced the content of pages on the affected site with the phrase “HELLO! Welcome to http://www.worm.com! Hacked By Chinese! In less than a week, Code Red hit more than 400,000 servers, including the White House server. The total damage caused by the virus is about $2.6 billion.

Sobig F


Sobig F is a computer worm that infected about a million computers running Microsoft Windows operating systems in 24 hours on August 19, 2003, thereby setting a record (although it was later broken by the Mydoom virus). Distributed via email with an attachment. After activation, the virus looked for addresses on the infected computer and sent itself to them. Sobig F itself was deactivated on September 10, 2003, and Microsoft promised $250 thousand for information about the creator of the virus. To date, the criminal has not been caught. The damage caused by the malware is estimated to be $5–10 billion.


Mydoom is an email worm that infects computers running Microsoft Windows. The epidemic began on January 26, 2004. The malware began to spread very quickly using email, a letter with the subject “Hello”, “Test”, “Error”, “Mail Delivery System”, “Delivery Notification”, “Report Server”, which had an attachment. When opened, the worm sent itself to other addresses, and also modified the operating system in such a way that the user could not access the websites of many news feeds, antivirus companies, and some sections of the Microsoft website. The virus has also put a huge strain on internet channels. Mydoom contains the text message "Andy, I'm just doing my job, nothing personal, sorry." Was programmed to stop spreading on February 12, 2004.

ILOVEYOU


ILOVEYOU is a computer virus that has successfully infected more than three million personal computers running Windows. In 2000, it was distributed by email, letter with the subject “ILOVEYOU” and the attachment “LOVE-LETTER-FOR-YOU.TXT.VBS”. After opening the application, the worm sent itself to all addresses in the address book and also made numerous changes to the system. The damage caused by the virus is $10–15 billion, which is why it was listed in the Guinness Book of Records as the most destructive computer virus in the world.

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1) to crashes and freezes during computer operation (+); 2) to the loss of programs and data; 3) to format the hard drive;

15. Dangerous computer viruses can lead...

1) to crashes and freezes during computer operation; 2) to the loss of programs and data (+); 3) to format the hard drive;

4) to reduce the free memory of the computer.

  1. What type of computer viruses are introduced and infect executive files with the extension *.exe, *.com and are activated when they are launched?

1) file viruses; (+)

2) boot viruses;

3) macro viruses;

4) network viruses.

  1. What type of computer viruses are introduced and infect files with the extension *.txt, *.doc?
  1. file viruses;
  2. boot viruses;
  3. macro viruses; (+)
  1. network viruses.
  1. Viruses that are introduced into a document under the guise of macros
  1. Viruses that penetrate a computer block the operation of the network
  1. Malicious programs that penetrate a computer using computer network services (+)
  1. Malicious programs that install other programs secretly from the user.
  1. Hardware.
  1. Software tools.
  1. Hardware and antivirus programs. (+)

22. Antivirus programs are programs for:

  1. Virus detection
  1. Virus removal (+)
  2. Reproduction of viruses
  1. AVP, MS-DOS, MS Word
  2. AVG, DrWeb, Norton AntiVirus (+)
  3. Norton Commander, MS Word, MS Excel.

25. Which programs are not anti-virus programs?

  1. phage programs(+)
  2. scanning programs
  3. audit programs(+)
  4. detector programs
  1. Is it possible to update anti-virus databases on a computer that is not connected to the Internet?
  1. Yes, by calling the technical support service of the antivirus program manufacturer. The specialists of this service will dictate the latest databases that need to be saved on your computer using any text editor
  1. yes, this can be done using mobile media by copying anti-virus databases from another computer on which Internet access is configured and the same anti-virus program is installed, or on it you need to manually copy the databases from the website of the anti-virus program manufacturer (+)