A computer virus is a specially written, usually small-sized program that can write (embed) copies of itself (possibly modified) into computer programs.
The Computer Virus and Its Development Stages
Computer viruses are programs that can “multiply” and secretly inject copies of themselves into files, disk boot sectors, and documents. An indispensable property of a computer virus is the ability to replicate (self-copy) and be invisible to the user to penetrate into files, boot sectors of disks, and documents. The name “virus” in relation to computer programs came from biology precisely because of its ability to reproduce itself.
A computer virus is a program capable of creating copies of itself, introducing them into various objects or resources of computer systems, networks and performing certain actions without the user’s knowledge. A computer virus got its name for some resemblance to a biological virus (for example, another program – a virus – reproduces itself in an infected program, and an infected program can work for a long time without errors, as in the incubation stage).
Virus development stages:
- latent stage – the effect of the virus does not manifest itself and remains unnoticed;
- avalanche-like breeding, but its actions are not yet activated;
- active actions – harmful actions laid down by its author are performed.
When an infected program starts running, the virus first takes control. The virus infects other programs and performs planned destructive actions. To mask its actions, the virus is not always activated, but only when certain conditions are met (the expiration of a certain time, the execution of a certain number of operations, the onset of a certain date or day of the week, etc.).
After the virus performs the actions it needs, it transfers control to the program in which it is located. An externally infected program can operate in the same way as a regular program. Like real viruses, computer viruses hide, multiply and look for an opportunity to switch to other computers.
The Widespread Prevalence of Viruses
The virus cannot spread in complete isolation from other programs. Obviously, the user will not specifically launch a lonely virus program. Therefore, viruses attach themselves to the body of other useful programs.
Despite the widespread prevalence of antivirus programs designed to combat viruses, viruses continue to proliferate. On average, about 300 new varieties appear per month. Naturally, viruses do not appear on their own, but they are created by crackers – vandals (techno – rats). All users hate crackers with fierce hatred.
Different viruses do different things and there are some options how to prevent computer virus:
- Display interfering text messages (congratulations, political slogans, phrases with a claim to humor, expressions of resentment from unrequited love, obscene expressions, advertising, glorification of favorite singers, names of cities);
- Create sound effects (play anthem, scale or popular melody);
- Create video effects (flip or shift the screen, simulate an earthquake, cause letters to fall in the text or simulate snowfall, imitate a jumping ball, a jumping point, display drawings. and pictures);
- Slow down the operation of the computer, gradually reduce the amount of free RAM;
- Increases wear and tear on equipment (for example, drive heads);
- They cause the failure of individual devices, freeze or restart of the computer, and the crash of the entire computer;
- Simulate repeated errors in the operation of the operating system (for example, in order to conclude a contract for guaranteed computer maintenance);
- They carry out scientific, technical, industrial, and financial espionage.