What are the necessary conditions for computer virus infection?

The necessary conditions for computer virus infection are: "running the virus program in the computer memory" and "performing read/write operations on the disk." The main communication channels are: 1. Network communication, including the Internet and local area network; 2. Mobile media communication, such as U disk, mobile hard disk, etc.

Computer Virus (Computer Virus) is clearly defined in the "Computer Information System Security Protection Regulations of the People's Republic of China". Virus refers to "the compiler's code in the computer program". A set of computer instructions or program code inserted that destroys computer functions or destroys data, affects the use of the computer, and is capable of self-replication."

Different from medical "viruses", computer viruses do not exist naturally. They are a set of instructions or program codes compiled by some people to take advantage of the inherent vulnerabilities of computer software and hardware.

It can lurk in the computer's storage medium (or program) through some means, and is activated when certain conditions are reached. It can create an exact copy of itself or a possible evolved form by modifying other programs. Put it into other programs, thereby infecting other programs and damaging computer resources. The so-called viruses are man-made and are very harmful to other users!

Features

• ##Reproductive
  Computer viruses can reproduce like biological viruses. When normal programs are running, It also replicates itself. Whether it has the characteristics of reproduction and infection is the primary condition for judging a certain program to be a computer virus.

• Destructive
  After computer poisoning, normal programs may not be able to run, and files in the computer may be deleted or damaged to varying degrees. Usually manifested as: add, delete, modify, move.

• Infectiousness
  Computer viruses are not only destructive in themselves, but even more harmful, they are contagious. Once the virus is replicated or mutated, its speed is shocking. Difficult to prevent. Infectiousness is a basic characteristic of viruses.
  In the biological world, viruses spread from one organism to another through infection. Under the right conditions, it can multiply and cause symptoms or even death of infected organisms.
  Similarly, computer viruses will also spread from infected computers to uninfected computers through various channels, causing the infected computers to malfunction or even become paralyzed in some cases.
  Different from biological viruses, computer viruses are a piece of artificially prepared computer program code. Once this program code enters the computer and is executed, it will search for other programs or storage media that meet its infection conditions. After determining the target, insert your own code into it to achieve the purpose of self-reproduction.
  As long as a computer is infected with a virus, if it is not dealt with in time, the virus will spread rapidly on this computer. Computer viruses can be removed through various possible channels, such as floppy disks, hard disks, mobile hard disks, and computer networks. Infect other computers.
  When you find a virus on a machine, the floppy disks that have been used on this computer are often infected with the virus, and other computers connected to this machine may also be infected by the virus. Got infected. Whether it is contagious or not is the most important condition for judging whether a program is a computer virus.

• Latency
  Some viruses are like time bombs, and their timing is pre-designed. For example, the Black Friday virus cannot be detected until the scheduled time. When the conditions are right, it explodes and damages the system.
  A well-written computer virus program generally does not attack immediately after entering the system. Therefore, the virus can quietly hide in the disk or tape for several days or even years. Once the time is right, it can be executed. If there is an opportunity, it will multiply and spread everywhere and continue to cause harm.
  The second manifestation of latentness is that there is often a triggering mechanism inside a computer virus. When the triggering conditions are not met, the computer virus does nothing except infect the virus.
  Once the trigger conditions are met, some will display information, graphics or special logos on the screen, and some will perform operations that damage the system, such as formatting disks, deleting disk files, encrypting and blocking data files. Keyboard and make the system deadlock, etc.

• Concealment
  Computer viruses are highly concealed. Some can be detected through virus software, some cannot be detected at all, and some are sometimes hidden. Emerging and changing, these viruses are often difficult to deal with.

• Triggerability
  The characteristic of a virus that induces the virus to infect or attack due to the occurrence of a certain event or value is called triggerability. In order to hide itself, the virus must lie dormant and make few movements.
  If you don’t move at all and remain latent, the virus will neither be able to infect nor destroy, and will lose its lethality. In order for a virus to be both invisible and lethal, it must be triggerable.
  The triggering mechanism of the virus is used to control the frequency of infection and destructive actions. Viruses have predetermined trigger conditions, which may be time, date, file type, or some specific data.

  When the virus is running, the trigger mechanism checks whether the predetermined conditions are met. If it is met, it starts the infection or destruction action to cause the virus to infect or attack; if it is not met, the virus continues to lurk.

There are roughly two ways of virus transmission:

One is network transmission, including the Internet and LAN, and the other is mobile media transmission , such as U disk, mobile hard disk, etc.

The details are as follows:

(1) Hard disk spread: Because the hard disk with the virus is used locally or moved to other places for maintenance, etc., the virus is infected and spreads.

(2) Disk propagation: Most software is burned on CDs. Since ordinary users rarely buy genuine software, some illegal businessmen put the software on CDs, which will carry viruses during the copying process. Files are burned on it.

(3) U disk propagation: U disk is easy to carry. In order to facilitate the transfer of files between computers, U disks are often used to spread viruses from one computer to another.

(4) Download virus files on the Internet. Today, as computers become increasingly popular, people transfer files and letters to each other through computer networks, which accelerates the spread of viruses. Because of the sharing of resources, people often download and download for free online. Shared software and virus files are inevitably included, and network communication is also the main method of modern virus transmission.

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