The most dangerous Internet viruses are. Computer viruses

Fraudsters continue to use the Internet, and given that not all users use an increased level of security, they manage to successfully commit their “crimes.”


Anti-virus systems fiercely fight viruses and each update of the database allows you to increase the level of security, but, unfortunately, some of them still cannot be detected immediately and users find out about the infection of the system too late.

If you evaluate the volume of antivirus system databases, you can identify a huge number of different viruses, which can be divided not only by type, but also by level of danger.

Experts from the field of antivirus systems have identified the most dangerous Internet viruses, among which the following threats have been identified.

1. Industrial systems that automate production processes faced a dangerous virus in 2010 that disrupted the stability of their development. This virus is called Stuxnet, and it is still unknown who exactly is its developer.

Some experts have suggested that this virus is the development of the US and Israeli intelligence services, but this information has not been confirmed.

This virus spread through various operating room vulnerabilities. Windows systems, which at that time were not yet known to specialists.

The Stuxnet virus gained enormous popularity due to the fact that it infected not only software, but also the hardware of production equipment.

It is difficult to name the exact amount of losses that companies suffered due to this threat, but it is known that developments in the nuclear industry in Israel were “pushed back” by several years.

The Chinese came up with an interesting virus called Code Red in 2001. It spread through infected sites and instead displayed the message “Hacked by the Chinese.” Even the White House website was damaged, and the total damage amounted to $2.6 million.

2. In second place in our list of the most dangerous Internet viruses is Zeus BotNet. This virus was created back in 2007, but gained popularity only in 2009, when a group of scammers modified it and began actively spreading it.

Thanks to this virus, attackers were able to intercept absolutely all entered information, and thereby gained access to various accounts, electronic wallets, Internet banking, etc.

Interception was carried out at the level of input means, i.e. the program remembered every value entered by the user of the infected computer. According to official data, scammers managed to infect more than 3.5 million computers, including 2,500 large companies located in 196 countries.

The exact figure of damage has not been established, but experts say it runs into billions of dollars.

3. A virus called Conficker is also considered one of the most dangerous. The existence of this virus began back in 2008, and in just a few months, hackers managed to spread it to several million computers. This virus is intended to obtain personal data necessary for authorization.

You may have seen files on your computer called autorun.inf, this is one of the signs that your system was infected or is still infected with the Conficker virus.

The negative property of this virus is its additional functionality, which blocks the possibility Windows updates and use of antivirus systems. In addition, Conficker is capable of downloading additional viruses from the server.

4. The I Love you virus received an interesting name, which was distributed via e-mail, indicating the topic, which later became its name. Declarations of love were sent by scammers, and thanks to a file attached to the letter, they managed to infect users’ systems.

In addition to the fact that the virus penetrated the system, the victim’s mailbox was also hacked, from which such letters continued to be sent to all saved contacts. Considering the scale of the spread of this virus, no one will be surprised that the total damage amounted to $15 billion.

5. MyDoom, which was identified in 2004, is recognized as the most dangerous virus. This threat was spread through email and file sharing services. The total damage caused by this virus is $38 billion.

Once it penetrated the system, the victim's computer was used for further distribution. It is also worth noting that all infected computers were used for DOS attacks.

There have been cases when this virus could send up to several million letters a day, which naturally affected its spread. In addition to the fact that the attackers were able to carry out successful DOS attacks on popular resources, they reduced the overall speed of the global network by 10%.

It's hard to believe, but it took the SQL Slammer virus just 10 seconds to infect 75,000 computers, mainly in South Korea (by the end of the day it was already spreading throughout the world). The main feature was its small size, which made it possible to transfer the program in one packet.

Some hackers who make money by creating viruses don’t even think about how much negativity their activities bring into the lives of ordinary people. To avoid becoming a victim, try to use a full range of security programs, as well as systematically update software and antivirus databases.

Other dangerous computer viruses

Viral diseases affect cells that already have abnormalities, which the pathogen takes advantage of. Modern research has proven that this only happens when the immune system is severely weakened and is no longer able to adequately fight the threat.

Features of viral infections

Types of viral diseases

These pathogens are usually distinguished by genetic characteristics:

• DNA – human cold viral diseases, hepatitis B, herpes, papillomatosis, chicken pox, lichen;
• RNA – influenza, hepatitis C, HIV, polio, AIDS.

Viral diseases can also be classified according to the mechanism of their effect on the cell:

• cytopathic - accumulated particles rupture and kill it;
• immune-mediated - the virus integrated into the genome sleeps, and its antigens come to the surface, putting the cell under attack by the immune system, which considers it an aggressor;
• peaceful – the antigen is not produced, the latent state persists for a long time, replication starts when favorable conditions are created;
• degeneration - the cell mutates into a tumor cell.

How is the virus transmitted?

The viral infection spreads:

1. Airborne. Respiratory viral infections are transmitted by drawing in particles of mucus splashed during sneezing.
2. Parenterally. In this case, the disease spreads from mother to child, during medical procedures or sex.
3. Through food. Viral diseases come from water or food. Sometimes they lie dormant for a long time, appearing only under external influence.

Why do viral diseases become epidemics?

Many viruses spread quickly and en masse, which provokes epidemics. The reasons for this are the following:

1. Ease of distribution. Many serious viruses and viral diseases are easily transmitted through droplets of saliva inhaled. In this form, the pathogen can maintain activity for a long time, and therefore is able to find several new carriers.
2. Reproduction rate. After entering the body, the cells are affected one by one, providing the necessary nutrient medium.
3. Difficulty in eliminating. It is not always known how to treat a viral infection, this is due to lack of knowledge, the possibility of mutations and difficulties in diagnosis - at the initial stage it is easy to confuse it with other problems.

Symptoms of a viral infection

The course of viral diseases may differ depending on their type, but there are common points.

1. Fever. Accompanied by a rise in temperature to 38 degrees, only mild forms of ARVI pass without it. If the temperature is higher, this indicates a severe course. It lasts no longer than 2 weeks.
2. Rash. Viral skin diseases are accompanied by these manifestations. They may appear as macules, roseolas, and vesicles. Characteristic of childhood, rashes are less common in adults.
3. Meningitis. Occurs due to enterovirus and is more common in children.
4. Intoxication– loss of appetite, nausea, headache, weakness and lethargy. These signs of a viral disease are caused by toxins released by the pathogen during its activity. The strength of the effect depends on the severity of the disease; it is more difficult for children; adults may not even notice it.
5. Diarrhea. Characteristic of rotaviruses, the stool is watery and does not contain blood.

Human viral diseases - list

It is impossible to name the exact number of viruses - they are constantly changing, adding to the extensive list. Viral diseases, the list of which is presented below, are the most famous.

1. Flu and colds. Their signs are: weakness, fever, sore throat. Antiviral drugs are used, and if bacteria are present, antibiotics are additionally prescribed.
2. Rubella. The eyes, respiratory tract, cervical lymph nodes and skin are affected. It spreads by airborne droplets and is accompanied by high fever and skin rashes.
3. Piggy. The respiratory tract is affected, and in rare cases, the testes are affected in men.
4. Yellow fever. Harmful to the liver and blood vessels.
5. Measles. Dangerous for children, affects the intestines, respiratory tract and skin.
6. . Often occurs against the background of other problems.
7. Polio. Penetrates into the blood through the intestines and breathing; when the brain is damaged, paralysis occurs.
8. Angina. There are several types, characterized by headache, high fever, severe sore throat and chills.
9. Hepatitis. Any variety causes yellowing of the skin, darkening of urine and colorlessness of feces, which indicates a violation of several body functions.
10. Typhus. Rare in the modern world, it affects the circulatory system and can lead to thrombosis.
11. Syphilis. After damage to the genital organs, the pathogen enters the joints and eyes and spreads further. It has no symptoms for a long time, so periodic examinations are important.
12. Encephalitis. The brain is affected, a cure cannot be guaranteed, and the risk of death is high.

The most dangerous viruses in the world for humans

The list of viruses that pose the greatest danger to our body:

1. Hantavirus. The pathogen is transmitted from rodents and causes various fevers, the mortality rate of which ranges from 12 to 36%.
2. Flu. This includes the most dangerous viruses known from the news; different strains can cause a pandemic; severe cases affect the elderly and young children more.
3. Marburg. Discovered in the second half of the 20th century, it is the cause of hemorrhagic fever. Transmitted from animals and infected people.
4. . It causes diarrhea, the treatment is simple, but in underdeveloped countries 450 thousand children die from it every year.
5. Ebola. As of 2015, the mortality rate is 42%, transmitted through contact with the fluids of an infected person. Signs are: a sharp increase in temperature, weakness, muscle and throat pain, rash, diarrhea, vomiting, and possible bleeding.
6. . Mortality is estimated at 50%, characterized by intoxication, rash, fever, and damage to the lymph nodes. Distributed in Asia, Oceania and Africa.
7. Smallpox. Known for a long time, it is dangerous only to people. Characterized by a rash, high fever, vomiting and headache. The last case of infection occurred in 1977.
8. Rabies. Transmitted from warm-blooded animals, it affects the nervous system. Once symptoms appear, treatment success is almost impossible.
9. Lassa. The pathogen is carried by rats and was first discovered in 1969 in Nigeria. The kidneys and nervous system are affected, myocarditis and hemorrhagic syndrome begin. Treatment is difficult, fever claims up to 5 thousand lives annually.
10. HIV. Transmitted through contact with the fluids of an infected person. Without treatment, there is a chance to live 9-11 years; its complexity lies in the constant mutation of strains that kill cells.

Fighting viral diseases

The difficulty of the fight lies in the constant change in known pathogens, making the usual treatment of viral diseases ineffective. This makes it necessary to search for new drugs, but at the present stage of medical development, most measures are developed quickly, before crossing the epidemic threshold. The following approaches have been adopted:

• etiotropic – preventing the reproduction of the pathogen;
• surgical;
• immunomodulatory.

Antibiotics for viral infections

During the course of the disease, the immune system is always suppressed; sometimes it needs to be strengthened to destroy the pathogen. In some cases, for a viral disease, antibiotics are additionally prescribed. This is necessary when a bacterial infection occurs, which can only be killed in this way. In case of a pure viral disease, taking these medications will not bring any benefit and will only worsen the condition.

Prevention of viral diseases

1. Vaccination– effective against a specific pathogen.
2. Strengthening immunity– prevention viral infections This path involves hardening, proper nutrition, and support with plant extracts.
3. Precautionary measures– exclusion of contacts with sick people, exclusion of unprotected casual sex.

Computer viruses are a topic that every programmer should know. Since studying programming also involves studying many details that are closely related to the topic, every IT worker is required to understand the issue at least at a minimum level. In addition, the list of the most common PC threats may be of interest to the average home computer owner.

At the end of last year, the well-known company ESET published detailed statistics that contained the most common viruses. Let's take a quick look at the top ten of the world list:

Win32/Adware.Multiplug

The top 10 is headed by a virus that, unfortunately, is familiar to many of us. It disguises itself as an “.exe” format and inattentive users fall for the bait, launching something completely different from what they planned. After this, the virus begins to multiply on the hard drive, heavily loading the system.

To avoid this problem, be careful about what files you run. To do this, it is best to start from the source - download from trusted sources.

Win32/Bundpil

The Bundpil virus is an ordinary worm that has been known to everyone since ancient times. It is also familiar even to those who have never studied programming. It operates according to a standard scheme known to every modern antivirus. Therefore, as a rule, problems with removal or detection do not arise.

To prevent worms from multiplying on your computer, do not neglect your antivirus. It’s not so easy to keep track of it yourself, but the program will detect and stop the infection without any problems.

HTML/Refresh

Refresh is the culprit of the browser’s incorrect operation. It is because of this that the page often updates itself. In addition, a transition to third-party resources is regularly made.

The “Refresh” virus comes to us from the browser when the user inadvertently agrees to install a plugin or update the player using a fake link. Follow address bar when you are asked for permission to do something. Don’t agree again and check the data.

JS/Kryptik.I

An ordinary Trojan masquerading as a licensed application. To avoid infection, make sure that you download data from trusted sources. After opening the file, the virus reproduces itself and loads HDD. Before running anything, make sure that the source did not give you a virus. In addition, you can scan the file before installation.

Win32/TrojanDownloader.Waski

This Trojan has an even greater impact on the operation of the system, as it manages to download even more viruses from the Internet. Therefore, more dangerous than usual. The best protection against a Trojan is an antivirus.

Win32/Sality

This is a threat that creates a safety net for itself in the form of a driver. The programmer will have no problem finding the source, but regular user You may not be able to figure it out right away. The “Sality” virus affects non-system files and launches only “.exe” and subsequently increases their length. As a rule, this virus comes from downloaded archives or virtual media. Be careful when you are about to unpack an unknown object. It's better to play it safe and check for the threat.

HTML/Scringekt

Aimed at defeating servers. As a rule, antivirus programs block navigation to infected addresses. Therefore, it is enough to have standard protection.

Win32/Ramnit

A worm created to actively send email messages. Learning programming often involves working with by email. Therefore, it will not be a problem for an experienced eye to notice the problem. Monitor processes in Task Manager. If the computer has an unnatural load, then a worm has been missed somewhere. The main source is files from the global network.

INF/Autorun

A threat called “Autorun” is an automatic launch of files in order to load the processor to the limit. Not only the programmer will notice the heavy load, because it significantly interferes with work. More often, this virus is encountered by those who do not consider it necessary to protect their OS.

It's easy to keep track of - don't run unknown files. It can also hide under links.

Win32/Conficker

A worm typically found on removable media. It actively spreads across computers via flash drives, disks and other devices. Check your devices regularly. Especially popular are cases when inexperienced users do not consider it necessary to scan their phones with an antivirus.

As it became clear, all the viruses from the top 10 have long been familiar to us and are unlikely to scare anyone. But in the age information technologies It will not be superfluous for anyone to read it again and fully assimilate the information.

Web development for everyone is a profession "" from GeekBrains.

Hello again.
The topic of today's article. Types of computer viruses, principles of their operation, ways of infection by computer viruses.

What are computer viruses anyway?

A computer virus is a specially written program or assembly of algorithms that are written for the purpose of: making a joke, harming someone’s computer, gaining access to your computer, intercepting passwords or extorting money. Viruses can self-copy and infect your programs and files, as well as boot sectors, with malicious code.

Types of malware.

Malicious programs can be divided into two main types.
Viruses and worms.

Viruses- are distributed through a malicious file that you could download on the Internet, or may end up on a pirated disk, or they are often transmitted via Skype under the guise of useful programs (I noticed that schoolchildren often fall for the latter; they are allegedly given a mod for the game or cheats, but in fact In fact, it may turn out to be a virus that can cause harm).
The virus introduces its code into one of the programs, or disguises itself as a separate program in a place where users usually do not go (folders with the operating system, hidden system folders).
The virus cannot run itself until you run the infected program yourself.
Worms They already infect many files on your computer, for example all exe files, system files, boot sectors, etc.
Worms most often penetrate the system themselves, using vulnerabilities in your OS, your browser, or a specific program.
They can penetrate through chats, communication programs such as skype, icq, and can be distributed through email.
They can also be on websites and use a vulnerability in your browser to penetrate your system.
Worms can spread across local network, if one of the computers on the network is infected, it can spread to other computers, infecting all files along the way.
Worms try to write for the most popular programs. For example, now the most popular browser is “Chrome”, so scammers will try to write for it and create malicious code on sites for it. Because it is often more interesting to infect thousands of users who use a popular program than a hundred with an unpopular program. Although chrome is constantly improving protection.
The best protection against network worms This is to update your programs and your operating system. Many people neglect updates, which they often regret.
Several years ago I noticed the following worm.

But it clearly did not come through the Internet, but most likely through a pirated disk. The essence of his work was this: he allegedly created a copy of each folder on the computer or on a flash drive. But in fact, it did not create a similar folder, but an exe file. When you click on such an exe file, it spreads even more throughout the system. And so, as soon as you got rid of it, you came to a friend with a flash drive, downloaded his music, and you returned with a flash drive infected with such a worm and had to remove it again. I don’t know whether this virus caused any other harm to the system, but soon this virus ceased to exist.

Main types of viruses.

In fact, there are many types and varieties of computer threats. And it’s simply impossible to consider everything. Therefore, we will look at the most common and most unpleasant ones recently.
Viruses are:
— File— are located in an infected file, are activated when the user turns on this program, but cannot be activated themselves.
— Boot- can be loaded when windows loads, getting into startup, when inserting a flash drive or the like.
- Macro viruses - This various scripts which can be located on the site, can be sent to you by mail or in Word and Excel documents, perform certain functions inherent in the computer. They exploit the vulnerabilities of your programs.

Types of viruses.
-Trojans
— Spies
— Extortionists
— Vandals
— Rootkits
— Botnet
— Keyloggers
These are the most basic types of threats that you may encounter. But in reality there are many more.
Some viruses can even be combined and contain several types of these threats at once.
— Trojan programs. The name comes from the Trojan horse. It penetrates your computer under the guise of harmless programs, and then can open access to your computer or send your passwords to the owner.
Recently, Trojans called stealers have become widespread. They can steal saved passwords in your browser and in game email clients. Immediately after launch, it copies your passwords and sends your passwords to the attacker’s email or hosting. All he has to do is collect your data, then either sell it or use it for his own purposes.
— Spies (spyware) track user actions. What sites the user visits or what the user does on his computer.
— Extortionists. These include Winlockers. The program completely or completely blocks access to the computer and demands money for unlocking, for example, to deposit it into an account, etc. Under no circumstances should you send money if you fall into this situation. Your computer will not be unlocked, and you will lose money. You have a direct route to the Drweb company website, where you can find how to unlock many winlockers by entering a certain code or performing certain actions. Some Winlockers may disappear within a day, for example.
— Vandals can block access to antivirus sites and access to antiviruses and many other programs.
— Rootkits(rootkit) are hybrid viruses. May contain various viruses. They can gain access to your PC, and the person will have full access to your computer, and they can merge to the kernel level of your OS. They came from the world of Unix systems. They can disguise various viruses and collect data about the computer and all computer processes.
— Botnet quite an unpleasant thing. Botnets are huge networks of infected “zombie” computers that can be used to DDoS websites and other cyber attacks using infected computers. This type is very common and difficult to detect; even antivirus companies may not know about their existence for a long time. Many people can be infected with them and not even know it. You are no exception, and maybe even me.
— Keyloggers(keylogger) - keyloggers. They intercept everything you enter from the keyboard (websites, passwords) and sends them to the owner.

Ways of infection by computer viruses.

Main routes of infection.
— Operating system vulnerability.

— Browser vulnerability

— The quality of the antivirus is poor

— User stupidity

- Removable media.
OS vulnerability— no matter how hard you try to rivet protection for the OS, security holes appear over time. Most viruses are written for Windows, as this is the most popular operating system. The best protection is to constantly update your operating system and try to use a newer version.
Browsers— This happens due to browser vulnerabilities, especially if they are old. It can also be treated with frequent updates. There may also be problems if you download browser plugins from third-party resources.
Antiviruses — free antiviruses which have less functionality than paid ones. Although paid ones do not give 100 results in defense and misfire. But it is still advisable to have at least a free antivirus. I have already written about free antiviruses in this article.
User stupidity- clicking on banners, following suspicious links from letters, etc., installing software from suspicious places.
Removable media— viruses can be installed automatically from infected and specially prepared flash drives and other removable media. Not long ago the world heard about the BadUSB vulnerability.

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Types of infected objects.

Files— They infect your programs, system and regular files.
Boot sectors- resident viruses. They infect, as the name implies, the boot sectors of the computer, attribute their code to the computer’s startup and are launched at startup operating system. Sometimes they are well camouflaged and difficult to remove from startup.
Macros— Word, Excel and similar documents. I use macros and tool vulnerabilities Microsoft office introduces its malicious code into your operating system.

Signs of computer virus infection.

It is not a fact that the appearance of some of these signs means the presence of a virus in the system. But if they exist, it is recommended to check your computer with an antivirus or contact a specialist.
One of the common signs is This is a severe overload of the computer. When your computer is running slowly, although you don’t seem to have anything turned on, there are programs that can put a lot of stress on your computer. But if you have an antivirus, note that the antiviruses themselves load the computer very well. And if there is no such software that can load, then most likely there are viruses. In general, I advise you to first reduce the number of programs launched in startup.

It may also be one of the signs of infection.
But not all viruses can heavily load the system; some of them are almost difficult to notice changes.
System errors. Drivers stop working, some programs start to work incorrectly or often crash with an error, but let’s say this has never been noticed before. Or programs start to reboot frequently. Of course, this happens due to antiviruses, for example, the antivirus deleted it by mistake, considering the system file to be malicious, or deleted a truly infected file, but it was associated with system files programs and removal resulted in such errors.

The appearance of advertising in browsers or even banners start appearing on the desktop.
The appearance of non-standard sounds when the computer is running (squeaking, clicking for no reason, etc.).
CD/DVD drive opens by itself, or it just starts to read the disk even though there is no disk there.
Turning the computer on or off for a long time.
Stealing your passwords. If you notice that various spam are being sent on your behalf, from your mailbox or pages social network, as there is a possibility that a virus penetrated your computer and transferred passwords to the owner, if you notice this, I recommend that you check with an antivirus without fail (although it is not a fact that this is how the attacker got your password).
Frequent access to the hard drive. Every computer has an indicator that flashes when various programs are used or when you copy, download, or move files. For example, your computer is just turned on but no programs are being used, but the indicator starts blinking frequently, supposedly programs are being used. These are already viruses at the hard drive level.

So we actually looked at computer viruses that you may encounter on the Internet. But in fact, there are many times more of them, and it is not possible to completely protect yourself, except by not using the Internet, not buying disks, and not turning on the computer at all.