Virus

A computer virus is software code that acts similarly to a biological virus. It infiltrates a system, creates copies of itself, and causes mass infections, first of files on one computer and then on others, up to a global web pandemic.

The functionality of viruses varies, but most often they corrupt or destroy data. In the mildest case, the infection leads to OS “brakes”, which is one of the first signs that a virus has entered the computer.

There are viruses that can damage the “hardware” of a computer as well. In 2015, hackers from the Equation cybergroup created a virus that changed the firmware of a hard disk and actually disabled it. Formatting didn’t help, and re-flashing was so time-consuming that it was easier to replace the disk.

The virus may not manifest itself in the system for a while. The “incubation period” is replaced by an active stage, when the user runs an infected program, which in turn activates the virus code.

Viruses are usually spread over the network – for example, by e-mail, in the format of a mail attachment, via social networks (in messages, links) and malicious websites. The spread via physical media, especially USB drives, is still relevant.

Viruses are often integrated into seemingly legitimate software. This can be avoided by downloading programs only from the manufacturers’ official websites (no torrents).