System security: I have to know the characteristics of the virus

With the rapid development of computer technology and the increasing popularity of computer applications, computer viruses are constantly evolving. At present, viruses have become an important issue that plagues computer system security and network development. Although there are many kinds of viruses, but they all have the same characteristics, we only need to take precautionary measures on the basis of understanding their characteristics, and believe that it can minimize the harm caused by viruses. Now let's summarize the characteristics of the virus and share it with everyone.

1. Infectiousness

The infectivity of a computer virus means that the virus has the property of copying itself into other programs. A computer virus is a malicious code that is programmed by humans. Once it enters the computer and is executed, it searches for other programs or storage media (such as USB flash drives) that meet its infectious conditions. After determining the target, insert the code into itself. Among them, the purpose of self-reproduction is achieved. As long as a computer is disturbed, if it is not disinfected in time, the virus will spread rapidly on this machine, and a large number of files (usually executable files) will be infected. The infected file becomes a new source of infection, and then exchange data with other machines or transfer data through the network, the virus will continue to spread and interfere with other computers.

Normal computer programs generally do not force their own code into other programs, but viruses can force their own code to be transmitted to all uninfected programs that meet their infectious conditions. in. Computer viruses can infect other computers through a variety of possible channels, such as floppy disks (now being phased out), USB flash drives, and the Internet. When you find a virus on a machine, the U disk that you used to use on this computer may also be infected with the virus, and other computers connected to the machine may be infected. Whether it is contagious is the most important condition for determining whether a program is a computer virus.

2, non-authorized

The normal normal program is called by the user, and then the system allocates resources to complete the tasks assigned by the user. Its purpose is visible and transparent to the user. The virus has all the characteristics of a normal program. It is hidden in the normal program. When the user calls the normal program, the control of the system is stolen. Before the normal program is executed, the action and purpose of the virus are unknown to the user. Allowed.

3, concealed

Virus is generally a program with high programming skills, short and fine. Usually attached to normal programs or where the disk is hidden, and some appear as hidden files, so that users are not easy to find out. If you do not go through code analysis, the virus program is not easily distinguished from the normal program. Generally, in the absence of protective measures, after the computer virus program gains control of the system, it can infect a large number of programs in a short period of time. And after being infected, the computer system usually still works, so that the user does not feel any abnormality. Imagine that if the virus does not function properly after the virus has been transmitted to the computer, it will not be able to continue its infection. It is because of the hidden nature of the virus that it can spread to more computers without the user's awareness.

The code for most viruses is designed to be very short and is also hidden. The virus is usually only a few hundred or 1k bytes, and the computer can access DOS files up to several hundred KB per second, so the virus can be attached to the normal program in a short time. , making the user very difficult to detect.

4, latent

Most viruses infect the system usually do not attack immediately, it can be hidden in the system for a long time, and only when it meets its specific conditions, its performance (destruction) ) module. Only then can it be widely spread. For example, “PETER-2” will raise three questions on February 27th each year. After the error is answered, the hard disk will be encrypted. The famous "Black Friday" s on the Friday of the 13th. The domestic “Shanghai No. 1” will occur on the 13th of each year in March, June and September. Of course, the most memorable one is the CIH that occurred on the 26th. These viruses will hide very well in peacetime, and will only reveal their true colors on the day of the attack.

5, Destructive

Any virus that invades the system will have a different degree of impact on the system and the application. Lighter people can reduce the efficiency of the computer, occupy system resources, and the serious ones can cause the system to collapse. This feature can divide the virus into benign and malignant viruses. A benign virus may only display some pictures or out of music, boring statements, or no disruptive actions at all, but it will consume system resources. There are many such viruses, such as: GENP, small balls, W-BOOT, etc. Vicious viruses have a clear purpose, or destroy data, delete files or encrypt disks, format disks, steal important user information (such as online trading accounts and passwords), and some irreparable damage to data, which also reflects The sinister intentions of the virus compiler.

6, unpredictability

From the perspective of the detection of viruses, the virus is unpredictable. Different kinds of viruses, their code varies widely, but some operations are common (such as resident memory, change interrupt). Some people use the commonality of viruses to create programs that claim to be able to check all viruses. This kind of program can detect some new viruses, but because the current software is extremely rich in types, and some normal programs use virus-like operations and even borrow some viruses, it is inevitable to use this method to detect viruses. Will cause more false positives. Moreover, the production technology of viruses is constantly improving, and viruses are always ahead of anti-virus software.

Although the virus is very powerful but not unpreventable, we need to pay attention to the protection work in the daily use of the computer. Through the basic introduction of the characteristics, types and transmission routes of computer viruses, readers have a rational understanding of them, and on this basis, put forward some effective preventive measures to minimize the harm caused by computer viruses. . I hope everyone has to help.