Graduation thesis-How to prevent the computer network virus _ Graduation Thesis

Summary of computer viruses in the network, such as mail viruses, worms and Trojans and other types of viruses and the characteristics of the relationship between the common message virus and the example. At the same time, according to the current computer virus development trend, put forward some prevention suggestions.

Keywords Network virus program


With the rapid development of Internet, e-Mail has become the most common tool for people to communicate with each other, so it is also an important carrier of e-mail virus. In recent years, many of the most harmful mail-type viruses, such as "Love You" virus, "Kournikova" Virus, "homepage" virus and "cover letter" virus, and so on, these viruses are mainly using e-mail as a means of transmission, and are generally selected Microsoft Outlook invades, using Outlook's programmable features to complete the seizure and destruction. When the recipient uses OUTLOOKRS to open a virus message or attachment, the virus inside will automatically activate and send a message with a virus attachment to the person in the "directory", similar to the worm "squirming", infecting multiple machines from one machine to another. This type of virus is very contagious and destructive, in a very short period of time, virus mail will be replicated and spread, which may cause the mail server exhausted resources and paralysis, and seriously affect the network operation. Some viruses may even damage data and files on the user's local hard drive. "Mao Xia" website
Mail viruses have typical characteristics of viruses: the "I loveyou" (AI) virus can understand the general characteristics of the mail virus, self-replication and dissemination, which is characterized by the dissemination of media or channels through e-mail, so called "Mail virus." Since the attachment of an e-mail message allows any file to be packed in any format, most viruses are secretly sent in disguised form as mail attachments. When a user opens a poison attachment, the virus is activated and infected with the user's system. It sends a message with Microsoft Outlook to all addresses in the user's address book, "I Love You," which reads "kindly check the attached lovelet2ter coming from me" and takes a name called "Love letter Foryoutxt." VBS "with poison attachment. Once the user has opened the attachment, it activates the hidden virus program, so they start the mail client out look will be sent with poison mail, causing a ripple effect.
You can also pass. HTM file or a mIRC script to propagate. After infecting this virus, it automatically looks for local drives and mapped network drives, searches all directories and subdirectories for infectious targets, such as JSE, Csswsh, SCT, HTA, JPEG, MP2, MP3 files with extensions, overwrites the original content with virus code, and changes the extension to VBS. Slows the user's mail system and then destroys the original file. By analyzing the special computer program of "Worm" and "Trojan" virus, we can understand the characteristics of "mail virus" deeply so as to take preventive measures actively. Worms are a program that can propagate across different hosts on a network without having to modify other files on the target host. Its propagation relies on the operation of the host or the network, and only relies on itself without the need of other object programs to reproduce, and constantly replicate between the host system resources and network bandwidth. Computer viruses are parasitic, often using other programs to spread, affect the normal operation of computer systems, and finally make the network system overloaded and paralyzed. The removal of worms is also troublesome. Www.st35.com
Because in the network environment, as long as a host of Worms did not kill, it will be revived. There is no distinction between "computer worms" and "Virus viruses". This is because, despite their different implementations, the two functions are similar, especially now that some viruses also use worm technology, which can damage the network. A Trojan horse is a generic term for hacking tools. It performs normal actions on the surface, but performs certain functions without the user's knowledge, and is often used by hackers to steal information on the user's machine. It is characterized by at least some function, which is often used by hackers to steal information on the user's machine. It is characterized by at least two programs: one is the client program, the other is the server program. Once the server-side program is running on a computer on the Internet, the hacker can manipulate the host through the client program. Trojan Horse itself is unable to reproduce itself must rely on the implementation of other programs to install their own. This is also the difference between it and computer viruses. Hackers often put Trojan programs on the Internet in some file servers, let people to download, or hidden in the e-mail attachment, sent to the user, and some tempting reasons to entice users to execute the resulting program. Make some novice fooled. Trojan Horse program based on TCP/IP protocol and the use of "client/server" mode of work.
First, the hacker must install the Trojan server program to the user's machine, by means of luring the user to execute the program including Trojan Horse. When the server-side program is installed on the user's machine, the installer usually modifies the system settings file to ensure that the Trojan is automatically restarted on the computer. Since then, hackers can use client-side programs to search the network, find the host running the server program, and monitor the host, you can implement the program has all the functions, steal data, monitor user behavior, remote control and so on. The damage the hacker can do will depend on the functionality of the tool it uses, which is very covert, and it is hard to find it as a general user in the absence of a hacker attack. The Common Trojan Horse program is hacker tool Bo (back Orfice2000). Its host-side program is Bogui. EXE, the client program is Bogui. EXE, the operating environment is WIN98, can monitor any Internet computer under the TCP/IP protocol. Server-side programs run automatically through the registry. With the continuous development of network technology, the global network quickly realized. Based on the characteristics and harm of network virus, the software that does not have the real-time anti-virus of network is very dangerous for our computer. That would have devastating consequences for our computers. Therefore, we must take effective management measures and technical means to prevent the virus infection and destruction, and strive to minimize the loss. Of course, the prevention of computer viruses should also improve the legal system, strengthen management and find measures, according to the characteristics of network viruses, the major sites should strengthen the prevention and control of the virus, the use of the latest technical means, the fight against computer viruses to the end. The protection of the Mail virus example of the Trojan prevention, understand the Trojan horse program, the prevention is relatively simple.
First of all, do not casually download software from your personal website. Download software to the well-known, reputable sites, usually these site software is relatively safe. Second, do not believe too much and casually run the software that others give. Often check their own system files, registry, port, etc., pay more attention to security information, and then get rid of Windows about hidden file extensions default settings, so that we can see the real file name extension. Many anti-virus software currently has the function of killing "Trojan" or "backdoor" program, but still need to update and adopt advanced anti-virus software. The last thing to remind: if you suddenly find your computer hard drive inexplicably work, or in the absence of any connection in the case of the modem still "blink" immediately disconnect the network, a Trojan search. Mail virus mainly through the transmission of e-mail, and mostly through the attachment entrainment, understand this, for this kind of virus prevention is more clear and easy:
(1) Do not easily open the attachment of strangers letter, especially some EXE-class executable files.
(2) For more familiar friends of the mail, if the letter with an attachment but not in the body of the description, also do not open the attachment, because its system may have been infected. Www.st35.com
(3) Do not blindly forward mail. Send the program files to others and even electronic greeting cards, you can first in their own computer to try to confirm that there is no problem after the hair, lest inadvertently become a virus propagator.
(4) If you receive the theme "I Love You" immediately after the deletion of the message, not to open the attachment.
(5) At any time to pay attention to anti-virus alerts, timely update anti-virus software virus code base. From the technical means, can be installed with a monitoring mail system anti-virus real-time monitoring program, at any time to monitor system behavior, such as the use of the latest version of anti-virus real-time software to kill the file in the attachment