Malicious and unwanted programs. Malware

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In this article we will get acquainted with main types of malware . There are many different types of these, let's break it all down in order!

And so I will try to describe everything quite simply, I think you will like it! And so let's go!

Viruses

The first type is, as you probably all already know, “viruses” (computer) and “worms” (Well, also computer J) what are they? Surely you have heard many definitions and their classifications? If not yet, now you will definitely know and imagine what they are and how they work!

Viruses are a kind of malicious software that performs various unauthorized actions in your OS (Operating System), it all depends on its purpose. Basically, a virus is a program code that gives your computer certain commands that the computer executes. We’ll talk to you about how this happens and how viruses are written in the article “Virus commands and how it works.” Well, that’s all about viruses for now, let’s move on to the next type: worms.

Worms

What are worms and how does it work? This is also malicious software that contains a slightly different “code”, namely the main difference is self-reproduction (copying itself) each copy of it retains its inherited self-reproduction properties! Which has a very bad effect on your computer speed.

Trojans

Trojan programs are programs designed and written specifically for the specific “needs” of an attacker. For example, a Trojan program can easily copy your data (For example, passwords, or other information from your computer).

I would like to note that such programs can also modify or block information or even an entire system of commands on your computer! Be careful, these are very dangerous and harmful programs that can cause serious consequences. Let me give you an example, let’s say your computer, after visiting the Internet, picked up a “Trojan” and your antivirus detected it, you think, okay, I’ll delete it and that’s it! At first glance, everything is logical: they picked it up and deleted it, it would seem not scary!

And as I already wrote, if you read carefully, such a program can modify information and commands (Change, make changes) and it turns out that the Trojan was removed and it has already done its job by changing a number of commands in your system or its settings. What could this turn out to be? Yes, absolutely everything depends on the code and what changes it brings to the system of your PC.

These are the pies, dear readers! Well, I would like to write how a Trojan differs from a simple virus. The main difference is that such Trojans do not copy “themselves” (they do not create copies of themselves). Well, for now, let's move on with the Trojans!

The next type is quite cunning programs and they are called “Malicious utilities”. This is one of the most complex types of programs since these programs can be both useful and harmful. And of course, like me without an example :)

Malicious utilities

Let me give you an example: such a program is installed on your PC (Personal Computer) and then it may not harm your computer at all, but as always there is a but. Such a program can hack the security system of another computer from yours! Can you imagine? You sit, you drink your tea, watch a movie, and in the meantime, the processor of your machine processes commands with the help of which the protection system of another computer is bypassed, there are few such utilities, but they already exist and I have come across them! And so, as you understand, not everything about this type is clear, but for now let’s finish talking about this and move on to another type.

Adware, Pornware and Riskware

Adware, Pornware and Riskware, well, this is a little more complicated and a little more detailed. So what is this malware? Heh, I'll try to be as clear as possible. Let's begin... This is definitely a conventional series of harmful programs, since they can be both harmful and completely useful programs. Let me give an example again for clarification? With an example, everything will become clearer. Let’s say you are a System Administrator and you need to install a remote system administration program for computers, for those who are not very familiar with this, I will write briefly. This is the ability to control another computer from a distance, via a local network (Special cable) or the Internet. So in this case, everything is fine because you need it to simplify the operation and maintenance of other PCs. But imagine if in the role of a system administrator there is an attacker who wants to get his own idea of ​​using this loophole?

So I briefly described everything, I will write many more articles on this type in more detail, how it all works, and how to implement it all and protect yourself from this kind of threats.

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 a 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 - these are various scripts that can be located on the site, can be sent to you by mail or in Word and Excel documents, and perform certain functions inherent in the computer. They exploit the vulnerabilities of your programs.

Types of viruses.
-Trojan programs
— 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 that 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. As the name implies, they infect the boot sectors of the computer, assign their code to the computer’s startup and are launched when the operating system starts. Sometimes they are well camouflaged and difficult to remove from startup.
Macros— Word, Excel and similar documents. I use macros and vulnerabilities in Microsoft Office tools and introduce 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 the system files of the program and the deletion 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 is being sent on your behalf, from your mailbox or social network page, it is likely that a virus has penetrated your computer and transferred passwords to the owner, if you notice this, I recommend checking with an antivirus without fail (although it is not a fact that this is exactly the case 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.

Malware is intrusive or dangerous programs designed to secretly access a device without the owner's knowledge. There are several types of malware: spyware, adware, phishing, Trojans, ransomware, viruses, worms, rootkits and programs aimed at seizing control of the browser.

Sources of malware

Often, malware reaches a device via the Internet or email. However, it can also come from hacked websites, demo versions of games, music files, toolbars, various software, free subscriptions, and anything that you download from the Internet onto your device that does not have anti-malware protection.

How to recognize malware

Slow performance, pop-up messages, spam or malfunctions often indicate that the device is infected with malware. To check if this is the case, you can use a malware scanner (it is part of all malware removal tools).

How to remove malware

The best way to get rid of the problem is to use a reliable malware removal tool, which can be found in any quality antivirus product. Avast Free Antivirus and its Anti-Malware component can protect you from malware by quickly and easily removing it from your devices. This is not just a tool for removing dangerous programs. It also provides constant, real-time protection against malicious attacks.

How to protect yourself from malware

• Use powerful antivirus products that can also protect against malware.
• Do not download files attached to email messages. mail from senders unknown to you.

So, the topic of our conversation today is malware. We will find out what they are, how they manifest themselves on computers, how one can “catch” this infection, and also classify them all by danger. In addition, let's try to understand how we can remove them from the operating system once and for all. What programs will help us with this? Which ones do the job best? All this will be discussed now.

What are there

Let's start by understanding what types of malware are. After all, computer treatment largely depends on this. Each infection has its own approach that helps eliminate the root of the problem.

In general, a malware is any application created with the purpose of destroying the operating system and obtaining the user’s personal data. Plus, the main feature is to cause harm to your computer. So you will have to work hard to protect yourself from this infection.

Malicious programs, as already mentioned, can be classified. Moreover, using this very classification, you can determine the degree of danger of a particular application. Let's introduce you to all the types.

The first option is spam. The least dangerous, albeit unpleasant, viruses (malware) that can be encountered. Usually aimed at displaying numerous advertisements and cluttering the central processor with their tasks. Sometimes personal data can be stolen.

The second type of viruses are worms. It is also a very “weak” infection. As a rule, it gets onto the computer for the purpose of its own reproduction. Plus, as in the previous case, they load the processor. The consequence is that the computer slows down. Not critical, but still unpleasant.

The following malware are Trojans. They are the most dangerous objects. They destroy the operating system, litter your computer, steal your personal data... In general, a “hodgepodge” of all malicious applications. They must be disposed of immediately.

The last option that may occur is spies. Aimed at identity theft. Sometimes they can destroy the operating system and multiply. Not particularly dangerous for the user and computer, but for data it is a big threat. The system needs good and reliable protection against malware in order to keep all documents safe and sound.

Where do they live?

Well, we have already introduced you to the classification, as well as the degree of danger of all computer infections that a modern user may encounter. Now it’s worth finding out how malware spreads, as well as where you can find it.

The first leader on our list is suspicious advertising on the World Wide Web. For example, offering a free download of a book that will teach you how to earn millions in 2 weeks. Sometimes it’s enough just to follow a link or banner and your computer will already be infected.

Also, viruses and malware are constantly present on prohibited sites, intimate resources, torrents, and so on. As in the previous case, you just need to visit the site - and the infection will already be on your computer. Most often, even the most will not be able to help you prevent infection.

The third place is occupied by various types. They, as a rule, download some document you need onto your computer, and then “wagon” install malicious content. Try not to use such managers very often. It’s better to wait a while and download the document using a browser - at least some kind of protection is already there. Not particularly good, but nevertheless in most cases it really helps us.

Sometimes malware is spread using email campaigns. You go to an unfamiliar letter sent to you - and you're done! It's best to refrain from reading obscure messages unless you know exactly where it came from.

Manifestation

Well, now it’s time to find out how you can understand that your computer is infected. After all, this is what helps us start thinking in time about how to remove a malicious program from a computer. It should be noted that users stopped paying attention to many “signals”. Now we will remind you of them so as not to lose sight of anything.

The first obvious sign is the appearance of brakes on the computer. All this is due to the CPU load. Although this behavior may be caused by a banal system failure. It’s just better to play it safe once again and check your computer for viruses.

The second signal is the appearance of new content on the computer. In this case, we are only talking about software that you did not install. And sometimes we have not even heard of its existence. It’s not worth running these, much less trying to work in them.

Next comes the appearance of spam and advertising on your computer, as well as a change in the start page of your browser. In this case, you should immediately sound the alarm - after all, you definitely have some kind of infection. The anti-malware protection apparently failed and allowed some kind of virus to pass through.

Also, your computer may experience a variety of glitches and problems. There are errors in applications, spontaneous shutdown/reboot and many more similar “surprises”. All this should be paid special attention to.

How to remove: antivirus

Now it's time to find out what malware removal programs are available. The first applications that we will get acquainted with are: This software is aimed at finding and removing infiltrated infections on the computer, as well as providing reliable protection for the operating system.

To be honest, there are a lot of antiviruses out there now. Any user can install the one that he specifically likes. There is no fundamental difference between them. Nevertheless, Dr.Web, Nod32, Avast do their job best. As many users note, it is these antiviruses that quickly detect the infection and then remove it, causing minimal harm to the operating system.

Anti-spies

The second ally in the fight against viruses is an antispyware program. Unlike an antivirus, the action of such content is aimed at detecting and removing computer spyware viruses. They won't find any Trojans. As a rule, they are used after antivirus on the computer.

Malware removal programs are very extensive. Nevertheless, among them there is one leader who is excellent at finding and eliminating spies in the operating system. This is SpyHunter.

Simply download, install and activate the latest version of this software. After that, launch the application, configure the scan and launch it. Next, delete everything that was detected (a special button will appear for this). That's it. The application is freely available and has a simple and intuitive interface.

For the registry

Sometimes viruses and spyware are written into your computer's registry. This makes the healing process much more difficult. What can be done in this situation?

Of course, you can clean the registry of the virus yourself. But it is best to use special utilities for this purpose. For example, CCleaner. With its help, you can easily scan your computer and then clear all “unnecessary” and dangerous data located in the system registry.

To do this, download, install, run and configure the program. After launching, on the left side of the screen you need to check all the hard drive partitions, as well as browsers. After that, click on “analysis” and then on “cleaning”. That's it. Quite easy and simple. Even a novice user can handle this application.

Removing programs

Of course, everything that was described above is an excellent step to eliminate all viruses hanging over the system. True, you shouldn’t limit yourself to them. Let's find out what other steps you should take if you suddenly find some kind of computer infection on your system.

Of course, this means removing all unnecessary programs on the computer. With all this, special attention should be paid to the content that appeared after the system was infected. To get rid of it you will have to use There, find “Add or Remove Programs”, and then wait for the list of all installed content to load. Next, find what was installed “by itself”, highlight the line and click on “delete”. That's it.

We are ending the fight

Today we talked to you about malware, classified it and understood what signs distinguish a healthy computer from an infected one. In addition, we got acquainted with the most popular programs for removing computer infections.

In general, all healing of operating systems comes down to the following algorithm: all installed applications (third-party) are removed, the system is scanned using an antivirus, then scanned with antispyware, and then the registry is cleaned. It all ends with a simple reboot of the computer. Thus, all problems are solved.