What are computer viruses classified according to their mode of infection?

According to the infection method of computer viruses, they can be divided into: 1. Boot viruses, which refer to computer viruses that parasitize in the boot area or main boot area of ​​the disk; 2. System viruses, which use its own program to add The operating system or replacing part of the operating system is very destructive and can cause the entire system to paralyze; 3. Application viruses.

Boot-type virus

Boot-type virus refers to a computer virus that parasitizes in the boot area or main boot area of ​​a disk . This kind of virus takes advantage of the shortcoming of not judging whether the contents of the main boot area are correct or not when the system is booted. It invades the system during the boot process, resides in the memory, monitors the system operation, and waits for infection and destruction. According to the parasitic location of boot viruses on the hard disk, they can be subdivided into main boot record viruses and partition boot record viruses. The master boot record virus infects the main boot area of ​​the hard disk, such as marijuana virus, 2708 virus, torch virus, etc.; the partition boot record virus infects the active partition boot record of the hard disk, such as ball virus, Girl virus, etc.

System virus

Operating system virus will use its own program to join the operating system or replace part of the operating system to work. It has strong destructive power and will causing the entire system to collapse. And because it has infected the operating system, this virus will replace the legitimate program modules of the operating system with its own program fragments when it is running. The operating system is destroyed based on the characteristics of the virus itself, the status and role of the legitimate program module in the operating system being replaced, and the way in which the virus replaces the operating system. At the same time, this virus is also highly infective to files in the system.

Application virus

Application virus is also called source code virus. Source code virus attacks programs written in high-level languages. Viruses are compiled in programs written in high-level languages. It was previously inserted into the source program and became part of the legal program after successful compilation.

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