What are the types of computer viruses?

Macro virus is a computer virus registered in the macro of a document or template. Once such a document is opened, the macro in it will be executed, and the macro virus will be activated, transferred to the computer and reside on the ordinary template.

From then on, all automatically saved documents will be infected with this macro virus. If other users open the infected documents, the macro virus will be transferred to his computer.

Two. CIH virus.

CIH virus is a kind of malignant viruses that can destroy the hardware of computer system. The virus originated in Taiwan Province province and was produced by Chen Yinghao, chief engineer of Unitalen Communication Company (Gigabyte subsidiary), while studying in Datong Institute of Technology, Taiwan Province Province.

The pirated CDs first sold by two international piracy groups are widely spread in Europe, America and other places, and then further spread to all corners of the world through the Internet.

Third, bugs.

Worm virus is a common computer virus. It uses network replication to spread, and the infection route is through the network and e-mail.

The original definition of worm virus is because in the DOS environment, when the virus breaks out, something similar to a bug will appear on the screen, and the letters on the screen will be swallowed up and randomly reshaped. Worm is a self-contained program (or a set of programs), which can spread copies of its own functions or some parts of itself to other computer systems.

Trojan horse virus.

Trojan, also known as Trojan virus, refers to controlling another computer through a specific program (Trojan program). Trojan horse usually has two executable programs: one is the control terminal and the other is the controlled terminal. . Trojan horse is a popular virus file at present. Unlike ordinary viruses, it does not replicate itself, nor does it "intentionally" infect other files. It attracts users to download and execute by disguising itself, and provides Trojan stallion with an entrance to open the seed host. The stallion can destroy and steal the seed file at will, and even remotely control the seed host. The appearance of Trojan virus has seriously endangered the safe operation of modern networks.

Development history of Trojan virus

Trojan horse technology has developed very rapidly. Mainly because some young people are curious or eager to show their strength, they constantly improve the writing of Trojan horse programs. So far, the Trojan horse program has undergone six generations of improvement:

The first generation is the most primitive Trojan horse program. Mainly simple password stealing, sending information by email, etc. , with the most basic functions of Trojan horse.

The second generation has made great progress in technology. Glacier is one of the typical representatives of Trojans in China.

In the third generation, the main improvement is in data transmission technology, such as ICMP and other types of Trojans, which use malformed messages to transmit data, which increases the difficulty of antivirus software to kill and identify.

The fourth generation has made great changes in process hiding, using kernel plug-in embedding method and remote thread insertion technology to embed DLL threads. Or connect PSAPI to realize Trojan horse hiding, even under Windows NT/2000, it has achieved good hiding effect. Grey pigeons and bee thieves are well-known DLL Trojans.

The fifth generation, driving the Trojan horse. Most driving Trojans use a lot of Rootkit technology to achieve the effect of deep hiding and go deep into the kernel space. After infection, they attack anti-virus software and network firewall, which can initialize the system SSDT, resulting in the loss of anti-virus firewall effect. Some driving Trojans can reside in the BIOS, which is difficult to kill.

In the sixth generation, with the rise of identity authentication UsbKey and anti-virus software active defense, the technical types of armyworm and special anti-display Trojan gradually began to be systematic. The former is mainly aimed at stealing and tampering with user sensitive information, while the latter is mainly aimed at dynamic password and hard certificate attacks. PassCopy and Diablo Spider-Man are the representatives of this kind of Trojans.

The characteristics of computer virus:

(1) parasitic?

(2) infectivity

(3) incubation period

(4) concealment