What are the types of viruses. Computer viruses: names, descriptions, methods of infection and control. Types of viral infections

Questions related to what computer viruses are and their names, what are the ways of their penetration into the system and the impact on computers or user data, ordinary users usually do not care at all until a certain moment. But when the operating system or the programs installed in it begin to behave completely inadequately, many begin to look for answers, but it is often too late. But there are many cases when the OS (most often this refers to Windows systems) is not something that does not work correctly, but it may even be blocked or completely fail. Let's try to figure out what computer viruses are. The names of the main threats will also be given, but it should be said right away that the classification presented below is purely conditional, since today there is no unified structured system for recognizing computer threats and classifying them to a specific class. And this is mainly due to the fact that more and more mixed types of threats are encountered, which are simply impossible to include in any particular class.

The simplest classification of computer threats

So, first, let's consider the simplest division of threats into main types. It is believed that on this moment the main ones are viruses and worms.

The difference between these two large categories is that the former can penetrate computers through malicious files and inject their own codes into programs, while the latter can infect files of a specific type (for example, all EXE-format objects, office documents or multimedia content). This division does not allow us to clearly understand the complete difference between some types of threats, therefore, for a more detailed classification, additional criteria are used, which will be discussed below.

Ways of introducing threats to computers

But let's names computer viruses Let's leave aside for now, and pay special attention to finding out how exactly threats can penetrate user computers. Most often, experts identify several main loopholes here:

  • vulnerability operating system and browsers used to surf the web;
  • removable media;
  • networks;
  • inadequate quality of antivirus software;
  • stupidity or carelessness of the user himself.

As far as operating systems are concerned, it is naive to believe that viruses only affect legacy DOS systems or Windows. Until recently, it was believed that virus threats do not work on Apple and UNIX-like operating systems, including Linux. However, now an absolutely confirmed fact is the impact of viruses and malicious codes with the disabling of the same "iPhones" running on iOS, or Android devices, the operating systems of which are based on the Linux kernel.

With browsers, I think, and so everything is clear, because when visiting unreliable resources, which may contain threats, using the same Internet Explorer you can get viruses quite simply, and not only when downloading some files, but also simply when you enter a site where it can be done automatic execution ActiveX scripting.

The quality of antiviruses can also play a cruel joke on the user, since some of the widely advertised and highly praised antiviruses are unable to fully ensure the protection of the computer and user information from the penetration of threats. In this case, a striking example can be called viral advertising applets, many of which even have security certificates.

On removable media, threats are most often present in the form of autorun files (Autorun.inf), and when connected to a PC or laptop, computer viruses infect the device exactly when it is triggered.

As for the inattention of users, this most often manifests itself when installing programs downloaded from dubious sources (for example, from torrent trackers), when they do not pay attention to the offers to install the accompanying allegedly partner software, which in fact turns out to be an adware or spyware virus. type. Well, and about ignoring the warnings of antiviruses that may appear when trying to go to virus-containing sites on the Internet, we are not talking at all.

In addition, when computers are connected in a network, threats can be transmitted from one infected terminal to all others precisely through gaps in the network, which does not have an antivirus or firewall.

Signs of a computer system infection

Due to the impact, which may not appear immediately, the system starts to slow down with an unreasonably high load on system resources (CPU, RAM or HDD).

Sometimes stop working installed applications, or driver errors occur, which can lead to the appearance of the notorious blue screens... Finally, the browser can be flooded with advertisements, but the saddest thing is that sometimes some files are locked or encrypted, the operating system stops loading, and only helps in this case full formatting disk with OS reinstallation.

Computer viruses: types and their names in the main classes

Now let's move on to a more advanced classification. The main computer viruses are generally as follows:

  • file viruses contained in infected file and activated exclusively when it is launched by the user himself or accessed by the system / program;
  • boot viruses that embed their own codes or startup commands into the autostart of the system or removable media;
  • macro viruses contained on websites on the Internet or sent via e-mail in the form of scripts that are executed exclusively in installed programs ah or superstructures;
  • network viruses.

Again, this distribution can also be called conditional, since today there are also mixed types of threats like file-boot or network macro viruses.

The main types of computer viruses: names and descriptions of their impact

Finally, the most accurate description of threats can be found in the following classification:

  • Trojan horses that penetrate computers under the guise of safe legitimate software that can gain access to installed programs and user data, transfer control of the computer, or "leak" information to cybercriminals;
  • spies stealing extremely important confidential information or tracking user actions on a computer;
  • spy-related keyloggers that monitor keyboard input;
  • extortionists (vinlockers) blocking the system and requiring money transfer for unblocking;
  • encryptors fully encrypting user or system files a certain type;
  • vandals seeking to inflict maximum damage on the operating system in terms of loss of performance;
  • hybrid rootkits that simultaneously track user actions and interfere with the operation of the system according to a specific scenario;
  • botnets that turn a computer into a kind of zombie and use its resources to carry out DDoS attacks or influence other terminals via networks or the Internet.

In general, it should be said that these are only the main names of computer viruses, since they are replenished with new and new copies almost daily, which cannot be attributed to any of the known categories.

Functioning algorithms

We figured out a little about infection with computer viruses and their types. However, it is necessary to dwell on the classification of threats in terms of the algorithms used by them. For this, a division into resident and non-resident viruses has been adopted.

Resident threats are programs that load their executable components directly into RAM and can be constantly active from the moment the operating system boots up until the computer is turned off. Non-resident threats usually have a limited duration of activity, although they can also load their small resident part into RAM, but this usually does not happen.

A striking example of residents are all sorts of macro viruses in the form of executable scripts, and many of them, in addition to everything, also use stealth technology, which allows them to remain unnoticed in the system, replacing the elements that the operating system accesses with its own processes.

Another distribution of the names of computer viruses by class is associated with self-encryption and polymorphism. Encryption in a sense resembles stealth disguise, but it is capable of constantly changing, which makes it very difficult to identify by protective means.

Some of these threats may not contain malicious code signatures at all, by which one could at least with some degree of probability classify them as viruses. But the most dangerous threats very often even use some non-standard camouflage methods that allow them to hide deep in the kernel of the operating system, where no antivirus can reach.

Destructive properties of viruses

Despite their names, computer viruses of different classes are very similar to each other. But in order to classify them according to the degree of impact, it is customary to distinguish four categories:

  • harmless (joke programs);
  • non-hazardous (limited only to consumption system resources);
  • dangerous (leading to very serious failures in the OS);
  • very dangerous (completely disabling the system or destroying the data stored on the computer).

Basic methods of dealing with computer threats

Naturally, it is recommended to use standard antiviruses, which have signature and behavioral analysis modules, as well as Anti-Stealth modules, as the first method for detecting all kinds of known threats or initializing suspicious objects.

Antiviruses with the ability to send suspicious objects for analysis to the "cloud" or "sandbox" also look good in this regard. But you cannot absolutely rely on such tools alone.

Tips for self-removal of some ad viruses

Advertising viruses, which are recent times something too much divorced, you can delete it yourself. As a rule, such threats are not particularly masked in the system, but they can be found either in the list of installed programs, or among panels or browser extensions.

To neutralize these threats, it is enough to delete the main application, clean the registry and residual files in Explorer, change in browsers search engine and start page, and then, finally, correct the path to the executable file of the browser launch in the properties of the shortcut, removing all unnecessary links and postscripts after specifying its name with the extension. Uninstaller programs that automatically clean up leftovers help a lot in terms of removal.

Outcomes

That is, in short, everything related to the names of computer viruses, their distribution into classes, groups and categories, based on different criteria. As additional recommendations, you can advise the following:

  • install only powerful antiviruses, even shareware (many of these programs can be permanently activated for 30 days or more using special free codes);
  • do not ignore the warnings of antiviruses when working with the Internet;
  • do not visit obviously dubious sites and do not download files from them;
  • be attentive to suggestions for installing additional software;
  • check the content removable media before performing any action with them;
  • Perform a preventive check at least once a month using portable utilities.

So, today we will talk to you about how to remove a virus manually from your computer. In addition, let's see what Trojans can be encountered, how they manifest themselves, and from where they can be introduced to the computer. Let's get down to studying our today's topic as soon as possible.

Types of viruses

Well, but before removing the virus manually from the computer, it is worth talking to you about what kind of infection is generally found on the computer. Indeed, in most cases, it depends on this how the treatment should be carried out. So let's get started.

The first virus is a Trojan. Represents itself malicious file, which "lodges" in the operating system, and even harms it. For example, it damages or destroys important documents. Now there are a lot of them.

The second fairly common type of virus is a variety of ransomware. These are files that enter the system and block it. But not destroying, but only encrypting documents. At the end of such a cipher, as a rule, an e-mail of the creator is left, to which it is necessary to transfer a certain amount of money in order to return the documents to their original form.

The third virus that can be caught is, of course, various browser add-ons, or spam. As a rule, they greatly interfere with the work on the Internet. This is due to the fact that the user's start page can change, plus everything in the browser will be located everywhere advertising banners... When users see this picture, they think about how to find viruses on the computer manually, and then remove them. Now we will try to figure it out.

Signs of infection

So, before you manually find viruses and get rid of them once and for all, let's try to figure out what may indicate the presence of a computer infection in the system. After all, if you detect signals in time, you can avoid damage to a large number of files and loss of "operating system".

The first and most obvious sign is nothing more than messages from your antivirus program. It will "swear" at some documents and files, giving you the name of the alleged virus. True, sometimes antivirus behaves this way in relation to various cracks and "pills" to computer games... Nevertheless, this cannot be ignored.

The second scenario is that your computer starts to "slow down". It is then that users begin to actively think about how to remove the virus manually, especially if they do not have antivirus. So, as soon as you notice that your system has become "slow-witted", start sounding the alarm.

Another scenario is that new programs began to appear on the computer that you did not install. Quite a common move among a computer infection.

In addition, advertisements in the browser may also indicate an infection on the computer. Change start page unrecoverable, advertising banners everywhere and everywhere - these are all rather alarming signals. So, let's quickly see how it is done manually from the computer.

Search

Well, the first step is to start by looking for the places where the infection is hidden. This is sometimes very difficult to do. Especially if you don't have antivirus software. In general, let's see what can be done in this situation.

So, when you decide to fight the virus yourself, you will have to find the folder on your computer where it is stored. Sometimes the infection betrays itself by creating its own processes in Open it (Ctrl + Alt + Del), then go to the "Processes" tab. Now find there any suspicious line (it will be somehow strangely called, or even signed with hieroglyphs) and click on the "show file location" button. Done, virus found.

True, not everything is always so easy and simple. If you are thinking how to remove a virus manually from your computer, then you should know that computer infection is often well hidden. In the display of folders, check the box "display and folders". Searching will now be much easier.

Remember also that very often they "settle" in Windows folder... For example, most Trojans are found in System32. Some infection can "register" in the host file. We know the favorite places of viruses. But how do you get rid of them?

Checks

The first scenario is to remove the infection automatically. More precisely, semi-automatically. It is o for viruses using an antivirus program.

In order to ensure yourself reliable data protection, stock up on good antivirus... Dr.Web is great. If you don't like it, you can also try Nod32. He does a pretty good job, too.

Do a deep check. After the program gives you the results, try to cure the documents automatically. Did not work out? Then erase them. However, if you are thinking of how to remove a virus manually from your computer, then most likely the antivirus checks did not help you. Let's see what else you can do.

We erase programs

The second step on the path to healing the system is, of course, the removal of various content that the virus has instructed you. This is a fairly common occurrence. So, take a look at the "control panel", and from there proceed to "add or remove programs". Wait a bit while checking the content on your computer.

When a list of programs appears in front of you, delete everything that you do not use. Pay special attention to content that you haven't installed. Or the one that appeared as a "trailer" after completing the installation of some other "program". Click on the desired line right click mouse, then select the "delete" command. Ready? Then you can think about how to remove the virus manually from your computer.

Total scan

Now let's use some of the services and techniques that will definitely help us. If you know the name of the virus (especially if you are faced with spam), then searching for an infection using a computer registry is suitable for you.

In order to go to the required service, press the key combination Win + R, and then run the command "regedit". See what appears in front of you. On the left side of the window are folders with long and incomprehensible names. It is in them that viruses often hide. But we will make our search task a little easier. It is enough to go to "edit" and then click on "search". Type in the name of the virus and then check it.

After receiving the results, all lines that appear must be erased. To do this, click on each of them in turn, and then select the required command. All is ready? Then restart your computer. Now you know how to remove a virus manually from your computer.

Viruses to a much greater extent than if the computer was working without a connection to information networks... And this is natural, because going out into the external electronic space, the user allows himself to be “seen” by almost all computers in this network. And not all of these systems are “friendly”. It may even happen that an infected machine decides to connect to your computer and if it finds any vulnerability on it, it will immediately share its viruses with you. However, in most cases, the user himself connects to the infected machines when he goes to their sites and downloads files from them. Even having "hung" the most powerful defense on your system, you cannot be sure of complete invulnerability.

Virus writers are cunning enough to catch even experienced users on their hooks. Below I will tell you how to find a virus on your computer if it seems to you that an infection has nevertheless entered your system.

Signs of a computer virus infection

The first thing a user needs to do before starting to “panic” is to carry out a detailed search procedure for a software infection and detect signs of this very virus. How can they be manifested?

  • Login to the system is blocked by a window with messages about money transfer for the possibility of further work.
  • completely, or blocked with the display of a window in which the extortionists demand to transfer money for their further use.
  • You cannot get to your pages in social networks and postal services... The previously valid password is now incorrect.
  • The system periodically begins to react very slowly to user commands: launching programs, connecting to the Internet, copying files, scanning with antivirus, browsing the Internet.
  • The system began to load several times slower, despite the fact that additional programs was not installed by the user.
  • The Internet connection starts on its own, even if the user has disabled automatic start such a connection.
  • Your friends and acquaintances start to complain about spam that comes from you over the Internet.
  • There are unknown messages sent from your accounts in social networks, mail services, messaging services.
  • There is no way to open file disks in the system double click... In this case, usually, opening through context menu right mouse button continues to work.
  • The system detected the disappearance of previously installed programs and created documents.
  • In the documents of the user, inscriptions appear, which he did not leave.
  • Some of the programs on the system have stopped starting or are starting with errors.

Of course, not all of the above explicitly indicates the involvement of viruses in problems in computer system, however, this behavior should already alert you and force you to take a closer look at further scanning your computer.

How to find a virus correctly using an antivirus

Do you think that the presence of an antivirus in your system or its installation will get rid of the software infection or even detect it immediately? I am afraid that you are a little mistaken in placing such hopes on antiviruses, if you do not know the basic rules of their work and the most effective principles for finding and treating viruses with their help.

First, the antivirus should be updated as much as possible. fresh versions in two aspects. One of which means constant renewal anti-virus databases... That is, those data sources that describe the patterns of all known viruses. Without these updated templates, no antivirus will help you, since it simply will not be able to recognize new virus among the already large streams of information that he explores in real time.

The second aspect means the latest version of the antivirus program itself... Since the methods of infection and spread of viruses are constantly changing, as well as the development of operating systems, the antivirus needs constant updating of knowledge about methods of infection, as well as about the behavior of operating systems in which new vulnerabilities are found for the penetration of software infection. That's why old antivirus, even with latest updates virus databases can be useless when searching for viruses already known to him, which, nevertheless, know how to deceive him and make him not pay attention to them.

But let's say that you have latest version any antivirus with updated virus databases. Is it possible to use it to find all the viruses floating in your system? The chance is, of course, much higher, but not sufficient for the maximum efficiency of such work. In this regard, you can imagine a virus as a fraudster who has already gained confidence in your system and is able to manipulate its actions, and therefore the actions of an antivirus program. Viruses that still trying to penetrate to your computer and viruses, already in the system act in completely different living conditions and have incomparable privileges. The former are, as it were, dormant and are easy enough to detect with updated antiviruses. But the second, these are already active independent software enemies who, at their discretion, can do whatever is necessary in order not to be detected. Including a competent bypass of the antivirus check.

As you already understood, it is not enough to reliably search for viruses by running the antivirus from your own operating system. So you need to run it from an external third-party system. For example, removing the hard drive and connecting it to another, obviously harmless computer. If you don't have one at hand, there is a great way to run an antivirus from a third-party system using pre-prepared kits from antivirus companies. For example, such as Kaspersky Rescue Disk or Dr.Web LiveCD.

Environment for launching Kaspersky Anti-Virus from an external CD drive

Launch antivirus scanner from Dr.Web, booting from CD

The above kits are presented as ISO images that can be burned to CD or DVD discs using programs such as Nero Burning ROM, Daemon Tools, CDBurnerXP and the like. After the images are written to the disk, it will be enough to restart the computer and boot from these disks. Now you can manage your antivirus from guaranteed safe system and be sure that no viruses control it. This means maximum efficiency in searching for viruses on your computer.

How to find a virus yourself

Searching for a virus, which is called “manually”, requires the user to have a fairly good knowledge of the processes and resources of the operating system. In some cases, viruses can be recognized almost immediately, sometimes you have to tinker with the study of an unknown process. However, in any case, it should be borne in mind that antiviruses are far from a complete panacea for network infection. If you are lucky enough to "grab" a virtual infection that has just been released into the open global network then most likely antivirus companies don't even know about this type of virus. This means that it will hardly be possible to find it, with their help, even though unknown viruses can still be identified by antivirus programs in a number of cases. How, then, can a user recognize a software enemy in his camp? To do this, I will provide some tips here.

I. Use the "Task Manager".

This simple tool is your first friend and helper in the search for viruses. It is with its help that you can get a list of processes (or, simply put, programs) that are spinning in the memory of your computer at the moment. There are also more advanced versions for process analysis. For example, Process Explorer or System Explorer. However, even with a simple system "task manager", you can carry out all the necessary analysis, and use the extended versions only if this manager is blocked by viruses. You can start the dispatcher with the key combination “ Ctrl +Shift +Esc"Or call by means of the standard" Ctrl +Alt +Del”.

What suspicious processes you need to pay attention to.

Read about symptoms that signal the presence of a virus on the computer... How a computer reacts to viruses, antivirus program or browser. Malware or viruses can plunge your computer into chaos. They can deactivate antivirus software and leave your computer vulnerable to other malware. software, interfere with the normal functioning of the computer, or damage the operating system files.

Ransomware viruses encrypt user data in such a way that it is almost impossible to decrypt or recover it. Viruses can access any data, be it personal files, bank data or user passwords, and create duplicate accounts.

What can you do to protect yourself and your computer from viruses? You need to start by installing an anti-virus program. It also doesn’t hurt to learn the skills to use your PC safely. A common reason for a computer to become infected with viruses or other malware is the lack of computer literacy user, which is also worth pulling up.

New types of viruses and malware appear all the time, so they cannot always be detected by every anti-virus program, at least until they are entered into the virus signature database. Such fresh viruses can enter the system and go through all software protection.

If you accidentally downloaded a suspicious file that contains a virus or clicked on an email attachment, your system may be infected with viruses such as: Trojan, Rootkit, Worm, Backdoor, Junkware or Malware... Therefore, before clicking on an unknown file or link, it is better to think twice and make sure that the antivirus program installed on your computer has the latest antivirus signatures.

So how do you tell if your computer is infected with viruses? Here are some clear signs that signal viruses or other malware on your computer:

And now in detail:


These are just the most common ways to identify viruses, malware or ransomware on your computer and their symptoms. And how quickly the user can deal with such programs on his PC depends on the safety of his data and files.