How dangerous is a virus on a computer? Computer viruses

In search of protecting our data, we begin to think about how to protect our computer from third-party attacks with the aim of taking over our information. We will talk below about the types of malware and viruses that attack our PCs.

Let's start with perhaps the most common habitat of viruses and malware - the Internet. Only at first glance it may seem that the Internet is a big, kind “world”, very friendly and diverse with many paths and roads into its depths. But it is precisely in this “Internet world” that millions of different dangers live, including Internet viruses.

The Internet today is not only millions of pages on a variety of topics, it is also an insidious place with viruses, malware, and spyware. And even if you limit your use of the Internet, viruses still have a good chance of getting in and infecting your data on your computer.

According to the history of PC development, viruses did not “lag behind” electronics in their development. “Virtual diseases” began to be developed back in the 80s of the last century. Back then, viruses were mechanical structures that could self-repair, activate, and capture new types of information. But over the past half century, viruses have come very far in their development and types; many malicious programs and individual dangerous viruses have appeared. In order to understand what viruses exist today and what threats they pose if they get onto your computer, we list them below by group:

Classic computer viruses – a type of viruses that begin their activity only when they are directly activated, i.e. when, for example, a user starts watching a movie or a photo or a song on the computer, then at that moment the hidden virus is activated and adds its code and begins to operate . This type of virus can enter or be transferred from one computer to another only when we copy a media file or program infected with it from one PC to another, or transfer the infected file on some medium (disk, flash drive, etc.).

The next type of viruses are Trojans . This is a very insidious type of virus, which carries a number of functions: failure of the PC operating system and all equipment in general; taking over PC resources for purposes contrary to yours; infection and destruction of data stored on a computer; capture and transfer of information stored on a computer to other persons.

Another type of virus is network worms. . Their task is to distribute their malicious copies to other PCs, as well as infect running programs with a virus. In addition, network worms can sometimes be characterized by the properties of Trojan programs

Once we have decided on the types of dangerous viruses, it is worth thinking about how you can protect yourself from malicious attacks on your computer. Again, the question is not simple, but there are always options. For example, when purchasing anti-virus programs, you can rely on the advice of the software seller, become more familiar with existing ratings of security programs and reviews about them, and communicate with professionals in protecting your PC from virus attacks. And only after that should you choose a specific antivirus program. And even if later you are not satisfied with something in it, you can always replace it with another one.

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.

I LOVE YOU


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 amounts 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.

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 embedded in 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.
  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 (+)

The concept of a computer virus is familiar to any user. Many people heard about certain “Trojans” and “worms” even before they had their first PC. And seasoned computer scientists always install an anti-virus program first, so that the system is maximally protected from malicious files that enter the machine from the outside. And if earlier, when the Internet was not yet so developed, the same viruses infected computer after computer, but they knew how to fight them. Now, with the development of the network, the range of malware is growing not by the hour, but by the minute, and it is becoming more and more difficult to fight them. No wonder antivirus databases are updated every day

What is a computer virus? Consequences of virus infection

But still, what is a computer virus? And is it transmitted by airborne droplets? If you look at various thematic encyclopedias, they have a clear concept.

A virus is malicious software that can reproduce in any operating system, destroying some important files, making changes to existing programs.

In a word, they “mess up” users’ computers. Ultimately, it becomes impossible to work with such a machine, the PC begins to slow down, behave strangely, upsetting its user in every possible way. Viruses work like surgeons - they penetrate the source codes of files and carry out their malicious operations there.

The virus creation industry began to actively develop with the advent of the Internet, since the World Wide Web is the easiest place for hackers to carry out their “dirty deeds.” The goals pursued by malware creators are very different. Some people do it just for fun, to practice writing programs. Most often, such “worms” do not pose a particular threat to the system, however, the creator himself does not always understand what his virus is capable of, so a harmless “worm” can sometimes become a real monster that devours system resources. The second category of people, engaged in the production of malware, pursues completely different goals, more specific - the theft of personal information from computers. Such viruses pose the greatest danger, as they are capable of stealing logins and passwords from some services, social networks, or, what is much worse, from payment systems. The result is a hacked account, stolen money from electronic wallets and other unpleasant consequences.

The most famous viruses

Despite the huge number of viruses, among them there are the most famous ones that have infected a significant number of computers. The most “romantic”, but also one of the most dangerous “worms” was written by some Filipino guy. The hacker called his creation “I love you.” The essence of the virus was that, using the mail service, it sent letters to everyone, in the subject line of which it was written “I love you”, and the attached file contained the “worm” itself, which was stealing passwords. The “love plague” swept almost the entire computer world in 2008. According to various sources, the damage caused by the Trojan amounted to several hundred million dollars.

Many users consider computer viruses to be either a completely useless, empty application that does nothing, or a program that “explodes monitors,” disables power supplies and removes all the money from the balance in the current bank account.

In this article we will try to figure out what to expect from a computer virus and what not to.

Let's start with what viruses now definitely cannot do:

  • Disable any hardware component of your PC directly.

Despite the fact that viruses cannot currently exploit PC components deeper than operating systems, there is a non-zero chance that one day such viruses may still appear. They will know how to communicate directly with devices in order to put them into technological modes or change something directly in the firmware or settings. The most vulnerable link in this regard at the moment is your hard drive.

What viruses can do:

  • Block access to the operating system or program
  • Irreversibly modify, delete and encrypt your data
  • Using social engineering methods to extract financial benefit from the user
  • Monitor user actions: record passwords entered, resources visited, documents opened
  • Transform an infected operating system into a Botnet network participant who, on command, can create DDos attacks, send spam, or perform any other actions dictated by a special Botnet server
  • Scan notebooks, documents, extracting mailing addresses from them, sending the latter to spammers or making your own mailings, inserting a virus into the body of the letter
  • Disturb the operation of banking and other financial programs, obtain personal data from them, and forward this data to attackers
  • Reproduce through email, local network, Internet network, hard drives, flash media, any information media, through infected files, p2p clients, online games, instant messaging services (ICQ, MSN, Yahoo!), VoIP programs (Skype) and etc.
  • Download new viruses, turning your computer into a breeding ground for viruses
  • Significantly slow down the operating system and programs
  • Disable the operating system and programs

Problems caused by viruses can be very diverse: some can be eliminated, some cannot. Almost all of these difficulties can be avoided, or at least the likelihood of their occurrence can be minimized. To do this, it is enough to have a working antivirus with up-to-date databases on the system.

Alexey Gavrilenko

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