What computer viruses have

One, according to the virus transmission way, we can divide into the resident virus and the non-resident virus.

Resident virus: A computer that is infected by this virus, releasing its own memory into the computer's memory, and then hooking up the system to merge with the system, which will continue to shut down or reboot after activation.

Non-resident virus: The virus does not infect the computer's memory when it is activated, and only a small portion of it is left in memory.

Second, according to the virus existing media can be divided into:

1, guide the area computer virus

The boot area virus is the first virus that appears on PC, and it is also the earliest virus species found in China. This type of virus mainly infects the boot sector of the floppy disk and the boot sector of the hard disk or the master boot record. A normal computer boot process is when the computer reads the boot sector or the master boot record loads it into memory and then directs the appropriate system. A machine that has a boot zone virus will load the virus into memory before it is properly booted.

2. File type computer virus

File-type computer viruses, also known as parasitic viruses, typically infect execution files (. EXE), but some can infect other executable files, such as DLL,SCR, etc. ... Every time an infected file is executed, a computer virus occurs: The computer virus copies itself to other executables and continues to execute the original program to avoid being perceived by the user.

3. Complex computer virus

Complex computer virus has the dual characteristics of boot area virus and file viruses.

4, Macro virus

A macro virus is a computer virus in a macro that exists in a document or template. Once you open such a document, the macros are executed, and the macro virus is activated, transferred to your computer, and resides on the Normal template. Since then, all automatically saved documents will "infect" the macro virus, and if other users open the infected document, the macro virus will be transferred to his computer.

5. Trojan Horse

Trojan or Trojan Horse is a seemingly legitimate procedure, but in fact it carries out some vicious and improper activities when executed. Trojan can be used as a hacker tool to steal user's password information or damage the program or data on the hard drive. The difference with computer viruses is that Troy does not replicate itself. Its communication techniques are often used to trick computer users into putting Trojan horses into computers, such as the attachment of games on email.

6. Worm virus

Worm virus is a common computer virus. It is used to replicate and spread through the network, via network and email. The original worm was defined as a bug-like thing appearing on the screen in a DOS environment, devouring the letters on the screen and changing them. A worm is a self-contained program (or set of programs) that propagates copies of its functions or portions of itself (worms) to other computer systems (usually through network connections).

7, other types of virus/malicious program code

A malicious program usually refers to a program written with the intent of the attack. These threats can be grouped into two categories: threats that require host programs and threats that are independent of each other. The former is essentially a program fragment that is not independent of a real application, utility, or System program, which is a self-contained program that can be scheduled and run by the operating system. You can also divide these software threats into tasks that do not replicate and replicate.