Classification of computer viruses and the characteristics of various types of viruses Urgently need

A computer virus refers to a set of computer instructions or programs that are compiled or inserted into a computer program that destroys computer functions or destroys data, affects the use of the computer, and can replicate itself. Bi Ju Chun.

Computer viruses can be divided into the following types: File viruses: Spread and infect other computers by infecting files.

Computer viruses are transmissible, hidden, infectious, latent, excitable, expressive, or destructive. The life cycle of a computer virus: development stage, infectious period, incubation period, attack period, discovery period, digestion period, and death period.

A computer virus is a kind of program that is artificially created and has a destructive effect on computer information or systems during computer operation. This kind of program does not exist independently, it is hidden in other executable programs, and it is both destructive and infectious. It will affect the running speed of the machine and make the machine unable to operate normally; At worst, the machine is paralyzed, which will bring immeasurable losses to users.

This destructive program is often referred to as a computer virus.

Computer viruses have the following characteristics:

1. Parasitism: Computer viruses are parasitic in other programs, and when the program is executed, the virus plays a destructive role, and before the program is started, it.

It is not easily noticed;

2. Infectious: Computer viruses are not only destructive in themselves, but also more harmful in terms of infectiousness.

Difficult to prevent; 3. Latent: Some viruses are like time bombs, and it is pre-designed when it will attack. For example, the Black Friday virus, which is less than the scheduled time.

I can't detect it, and when the source attack is ready, it will suddenly open up and destroy the system.

1. Latentity.

In general, after a computer virus infects a system, it does not attack the computer immediately, but has an incubation period for a period of time. The length of the incubation period is generally determined by the trigger conditions set by the virus programmer.

2. Infectious.

After the computer virus invades the system, under certain conditions, it destroys the defense function of the system itself, quickly replicates itself, spreads from the infected storage location to the uninfected storage location, and can carry out virus infection between computers through the network.

3. Destructive.

Once a computer system is infected with a virus program, the stability of the system will be affected to varying degrees. In general, computer viruses attack due to their continuous self-replication.

Most of the system resources are occupied, which slows down the computer and makes it impossible for the user to use it normally. In severe cases, the entire system can be paralyzed and cannot be repaired, resulting in losses.

4. Concealment.

Computer viruses usually exist in the form of programs that people are familiar with. Some virus names tend to be named similar to system file names, such as the fake IE icon Internnet Explorer, where one "n" of the Internet word is changed to two "n" by the fake icon

It is difficult for users to spot, and once you click on the ** pointed to by these icons, you are likely to face a phishing or trojan threat; Another example is the folder EXE virus, its icon is the same as the default folder icon of Windows XP, which is very confusing, and the virus will be activated when the user double-clicks to open this folder.