A computer virus is a small program written by a highly skilled programmer, which is capable of multiplying and performing different destructive actions. Now there are over 50,000 computer viruses. They work only as software. Usually, they are attached to the file or penetrate the body of the file. In this case, they say that the file is infected with a virus. The virus gets to the computer through the infected file. To activate the virus, you need to download the infected file, and only after that, can the virus start to act independently. But where do they come from? What are the different sources of computer virus?
Some viruses become resident of your computer as soon as you download the infected file (they are constantly in the computer's RAM) and can infect other downloaded files and programs. Another variety of viruses can cause serious damage, for example, format the hard disk immediately after activation.
The effect of viruses can be manifested in different ways: from different visual effects that interfere with the operation, to the complete destruction of the information. Most viruses infect executables, these are files with the extension .EXE and .COM, although the viruses distributed through the e-mail system are becoming very popular nowadays.
Top 11 sources of computer virus
Floppy disks. The most common infection channel in the 1980-1990's. Now it is practically extinct due to the appearance of more widespread and efficient channels and lack of floppy drives on many modern computers.
Flash-drives. Currently, USB flash drives have replaced floppy disks and are one of the causes of computer virus- a large number of viruses spread through removable drives, including digital cameras, digital video cameras, portable digital drivers, and since the 2000s, mobile phones have also been playing an increasingly important role, especially smartphones. The use of this channel invented as a result of the possibility of creating a special autorun.inf file on the drive, in which you can specify the program that is launched by Windows Explorer when you open such a drive. In Windows 7, the ability to autorun files from portable media was disabled.
Email. Usually, viruses in e-mail letters are masked by innocuous attachments: pictures, documents, music, links to websites and so on. Some of the mails may contain only links, but there may not be malicious code in the messages themselves. It is only when you open such a link that you reach a specially created website containing the virus code.
Instant messaging systems. It is also common to send links to photos, music or programs that are actually viruses, via ICQ, Viber and through other instant messaging programs.
Web pages. It is also possible to get infected via Internet pages due to the presence of various ‘active’ content: scripts, ActiveX components. In this case, the vulnerabilities of the software installed on the user's computer are exploited, or a vulnerability in the site owner's software (which is more dangerous, since good sites with a high flow of visitors are exposed to infection), and unsuspecting users, having visited such a site, risk infecting their computer.
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Internet and local networks (computer worm). Worms are a type of virus that penetrates the victim's computer without the user’s knowledge. Worms use what's called ‘holes’ (vulnerabilities) in the operating system software to penetrate the computer. Vulnerabilities are errors and defects in the software that allow you to download and execute machine code remotely. As a result of which, the worm virus enters the operating system and, typically starts actions to infect other computers via a local network or the Internet. Attackers use infected computers of users to send spam or for DDoS-attacks.
Public file servers and e-conferences also serve as one of the main sources of viruses. Infected files are sent to several conferences simultaneously, and these files are masked for new versions of a software (sometimes under new versions of antiviruses). In the case of mass distribution of the virus, thousands of computers can be affected almost simultaneously.
The third way of rapid infection is local networks. If you do not take the necessary security measures, an infected workstation affects one or more service files on the server when you log on to the network.
Illegal copies of software are one of the main risk areas. Often, pirated copies contain files infected with a wide variety of virus types.
Public computers installed in educational institutions can also fall prey. A student can bring a computer virus on his removable disk and infect the training computer. This virus will spread across all the training computers on the local network. When downloading data from the training computer of the local network, the virus will infect the removable disks of other students who infect their home computers and computers of their colleagues Due to this chain, the computer viruses can get into the computer network of the company where the parent system works.
It is quite possible to infect a computer with a virus during a repaired or preventive examination. Repairers are also people, and some of them tend to disregard the elementary rules of computer security. They might forget to carry out a few actions as protection which mean they will quickly spread the infection on the machines of their clientele.
How to protect yourself?
Various anti-virus programs (antiviruses) are used as software protection tools. Antivirus is a program that detects and neutralizes computer viruses. It should be noted that viruses outstrip antivirus programs in their development, so even in the case of regular use of antivirus, there is no 100% security guarantee.
Antivirus programs can detect and destroy only known viruses. However, many modern anti-virus packages contain a special software module called a heuristic analyzer, which is able to examine the contents of files for the presence of code specific for computer viruses. This makes it possible to identify and warn about the risk of infection with a new virus as soon as possible. Protect your computer and be safe from sources of computer virus infection!
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