computer virus
Computer virus is not caused by sudden or accidental factors, it is a program created by humans. Computer viruses can destroy computer functions or data, affect computer use, and can replicate themselves.
Classification of viruses:
- Classified by operating system
Viruses that attack Windows systems: viruses that infect files, macro viruses that infect office, and concept attacks word viruses.
Viruses that attack Unix and Linux systems: Bliss virus, Ramen virus , Lion.worm, etc.
2. Classification of communication media
Stand-alone virus: The carrier is a disk, an early virus.
Network virus: The medium is the internet, which causes network congestion, modification of web pages, and modification or destruction of files in combination with other viruses.
3. Classified according to link form
Computer viruses must enter the system before they can infect and destroy operations. Therefore, computer viruses must establish links with files that may be executed in the operating system. These files may be system files, or application programs and data files used.
Executable files are infected with viruses: These viruses can infect executable programs, linking virus code with executable files.
Operating system virus: The virus program replaces part of the legitimate program modules of the operating system with its own logic part, thereby parasitic in the system partition.
4. Classified according to virus damage
Benign viruses: refer to those viruses that only express themselves and do not damage the operating system. They are pranks and are not destructive, but they will affect the operation of the operating system.
Vicious virus: Compared with benign viruses, it destroys system resources, deletes data and files stored in the operating system, writes to disks, and modifies files and data; formats disks and specific sectors.
Characteristics of the virus:
- Destructive: After the computer is invaded, normal programs may not run. The virus deletes and modifies the computer files according to the built-in instructions.
- Infectiousness: Once the virus is replicated or mutated, it spreads quickly.
- Concealment: After the virus invades the system, it will automatically hide in the system. Only when the trigger condition is met, the virus will destroy the operating system or files according to the instructions.
- Latentness: (1) Users cannot detect potential computer viruses in the system without using professional detection programs. (2) The computer virus is preset with a trigger mechanism. When the trigger condition is not met, the computer virus will not cause any damage except infection until the trigger condition is met.
5. Unpredictability: With the development of science and technology, virus production technology continues to improve.
Symptoms after computer poisoning: CPU usage has always remained above 95%, IE browser creation database is continuously opened, anti-virus software is blocked, system file icons become unified icons, and system time is changed.
Computer protection:
(1) Install the latest anti-virus software , upgrade the anti-virus software virus database every day, check and kill viruses on the computer regularly, and turn on all the anti-virus software monitoring when surfing the Internet. Develop good online habits.
(2) Do not execute software that has been downloaded from the Internet without anti-virus processing; do not browse or log in to unfamiliar websites casually, strengthen self-protection. There are many illegal websites now, and malicious codes are sneaked into. Once opened by users, they will be Planting Trojan horses or other viruses.
(3) Cultivate a conscious information security awareness. When using mobile storage devices, try not to share these devices as much as possible, because mobile storage is also the main way for computers to spread and the main target of computer virus attacks.
(4) Use the Windows Update function to patch the whole system , and at the same time, upgrade the application software to the latest version.