What is a virus in a computer?

Perhaps there is no such person who does not know what a virus is. Spongy autumn and frosty winter are the usual time for viral diseases. High body temperature, loss of vitality - all this is quite familiar and familiar. Physicians have long figured out the question of what a virus is. It is the simplest living organism that makes the cell infected by it reproduce its copies. In fact, the cell, unwittingly, starts producing new and new generations of the original virus. Studying what a virus is, often pay attention to the fact that its structure is so primitive that a similar living organism can be compared with ... a computer program. Indeed, the analogy is clearly traced. Any running program "forces" the computer components to work in accordance with the wishes of the programmer who created it. It was this similarity that served as the reason why a small section of the digital code was called a computer virus.

Often you can hear the phrase "the laptop picked up the virus." What does this mean? Let's look at one very common situation. One day a friend came to the laptop owner and brought some information downloaded from the Internet to a flash drive. It can be a program, a driver, a system library. At the same time, a person does not even suspect that a small section of executable code was added by someone to the binary application code. Running such a modified file, the user sends the processor to execute at once two programs - the main and unnoticeable extra. A computer virus is that additive. An important point: its functioning does not appear in any way. First, the added code is executed and then the main code is executed. Once in memory, the virus, as a rule, begins to clone itself, assigning its copy to other files on all available media. Very soon all files are infected. Such reproduction is necessary to reduce the risk of being destroyed and increase the likelihood of further spread. This stage occurs very quickly and completely unnoticed.

The further fate of this additional program depends on the purpose pursued by the person who created it. A complete list of opportunities to list is meaningless, because tasks can be very diverse. In general, you can specify the main directions that a virus can implement:

- violation of the computer's performance: the processor load with infinite calculations, which causes the braking, heating, failures; Destruction of important system files, without which you need to reinstall the operating system, etc .;

- initiate the sending of network packets: the computer becomes part of the botnet;

- theft of personal data: access codes to certain sites, bank accounts;

- distribution of emails of an advertising nature.

After the reboot, the virus already runs itself and starts its work. Obviously, for the user these actions are undesirable, therefore they are classified as malicious.

The above example looks at file viruses. Besides them there are others, with excellent ways of distribution. So, recently there is a real epidemic of viruses that infect computers through the autorun mechanism. In any case, a user whose computer is infected with a virus risks not only losing time to reinstall all programs, but also losing their own money, which the attacker can transfer to their accounts, knowing the codes and passwords for access.

Summing up, we will answer the question about what a virus is. This is the most common computer program that runs without the user's knowledge and performs unwanted actions on the computer. To prevent infection, you must install special programs on your computer - antivirus software.