pretend
Computer viruses generally have the following characteristics: ① Unauthorized execution: Computer viruses are destructive computer programs. In general, no one will actively execute virus programs, and being activated without the permission of the operator is a feature of computer viruses. ② Concealment: In order to ensure its own safety, computer viruses will take some measures to disguise themselves and avoid detection by anti-virus systems. ③ Infectious: Reproduction is the only way to ensure the sustainable survival of all races, and computer viruses are no exception. In order to survive, it is necessary to constantly reproduce and infect yourself to other "healthy" computers. Incubation period: Most viruses do not move immediately after infection. They can be hidden in the system for a long time, and only when their specific conditions are met can they start and show destructiveness. Only in this way can they spread widely. Like the famous CIH virus, it attacks on the 26th of every month. ⑤ Destructiveness: Destructiveness is the essence of computer viruses. They all have a clear purpose, either to destroy data or to delete files. So destructiveness is a typical feature of viruses. ⑥ Triggerability: Computer virus is a program that destroys computer system. If this program doesn't run, the computer system won't be destroyed. So computer viruses will do everything possible to give themselves a chance to be run. Parasitic on other normal computer programs is the main means of viruses, and the process of computer viruses parasitizing themselves on other normal computer programs is called "infection". When an unsuspecting operator runs an infected computer program, the virus is triggered, which is also called "activation".