Classification of computer viruses: 1. According to the type of media they are attached to, they can be divided into three categories: network viruses, file viruses and boot viruses; 2. According to computer-specific algorithms, they can be divided into incidental viruses and worms Three categories of viruses and variable viruses. Network viruses are computer viruses that infect executable files through a computer network. File viruses are viruses that attack files on your computer. A boot virus is a virus that mainly infects drive sectors and boot sectors of hard disk systems.
The operating environment of this article: Windows 7 system, Dell G3 computer.
Computer virus (Computer Virus) refers to a set of computer instructions or program codes inserted by the programmer into a computer program that destroy computer functions or destroy data, affect the normal use of the computer, and are capable of self-replication.
Computer viruses are artificially created, destructive, contagious and latent programs that damage computer information or systems. It does not exist independently, but is hidden in other executable programs. When a computer is infected with a virus, it may affect the running speed of the machine at first, or crash and damage the system at worst. Therefore, the virus brings great losses to the user. Under normal circumstances, we call this destructive program a computer virus.
Computer viruses are contagious, covert, contagious, latent, excitable, expressive or destructive. The life cycle of a computer virus: development period → infection period → incubation period → attack period → discovery period → digestion period → extinction period.
Computer virus classification:
1. Classification according to attached media type
(1) Network virus: through computer Computer viruses that infect network executable files.
(2) File viruses: viruses that mainly attack files in the computer.
(3) Boot virus: It is a virus that mainly infects drive sectors and hard disk system boot sectors.
2. Classification according to computer-specific algorithm
(1) Accessory virus: usually attached to an EXE file, its name is the same as the EXE file name, but the extension is different, generally not Will destroy the change file itself, but it is this type of virus that is activated first when DOS reads it.
(2) Worm virus: It will not damage computer files and data. Its destructiveness mainly depends on the deployment of the computer network. Computer networks can be used to switch from one computer storage to another computer storage to calculate the network. address to infect the virus.
(3) Variable virus: It can apply complex algorithms on its own and is difficult to detect because the content and length expressed in another place are different.
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