Basically, the computer virus is a computer program that has the ability to reproduce themselves with the program, insert a file into another. Similar viruses, such as biological, computer viruses can spread quickly in the files in a computer, or even infect other files on the computer, either over a network or through the exchange of files.
Previously we recognize the target based on spreading the virus, the virus boot sector viruses and file. Boot sector viruses designed by the author to menginfeksi boot sector, which is part of a storage media (floppy disks, hard disk) that was first read by the operating system while the media is accessed. Once the media is infected by the virus of this type is used to make booting, the virus live in the memory is ready menginfeksi and other storage media used in the same computer. Later, boot sector virus developed into a more violent type of virus known as the partition (partition table). The partition table is on the hard disk that store the data CHS (cylinder / head / sector) that become guidelines for the operating system to do the reading process. Once this section be-leburkan by the virus, the hard disk would no longer be able to read and all the data on any drift.
Meanwhile, the virus file to work with the program insert in a file. Previously, when the DOS or. operating system is still widespread, the target is a virus of this type of executable files, namely the ending with the extension. COMEXE. In addition to transmission, the virus file often add commands on a program code that ditularinya. Generally, the virus of this kind have a "time bomb", where the virus program will do aksinya at certain times which have been determined by the programmer. "Action" can be diverse, ranging from mild, such as display messages and blast the speakers, to do with the destruction delete data, or even formatting the hard disk!
Later, when the use of Windows-based program began with a flare various features, then we return to a new type of virus, the macro virus. Macro is a series of command in the command-like programming language, which is provided by software that allows users to set up a series of specific work. A series of command will be run simultaneously by software when running macros. Macros useful facilities to ease the user in these steps and the sequence repeated. Unfortunately, this facility eventually disalah use by ignorant hands to make macro that contains the commandments of destruction and even!
Type of macro virus is a virus that is famous WordMacro specifically made for menginfeksi data files from word processing software Microsoft Word (berekstensi. DOC). This type of virus to have thousands of variants with the various types of interference. Start from the display messages only at certain times, to make the file destruction. WordMacro have classified the virus variants because most code-code that is easy to be modified. In addition, learn on the MS Word macros not as Assembly language or C (programming language that is often used to create a virus program).
Trojan Horse and worms
In addition to the virus in the sense as mentioned above, we also recognize that the program called Trojan Horse (Horse TROYA). Trojan Horse is not a virus in the sense indeed, because this program does not have the ability to reproduce itself to other programs. However, this program is no less dangerous when compared with the computer virus program.
Trojan Horse is generally packed in the form of a program of interest. But behind the attractiveness of the software, hidden functions of others to do destruction. Computer users who get this file will generally terpancing to run it. As a result of fatal, because with so the user has meenjalankan routine routine-ready menebar destructive disaster in the computer.
Other sources of catastrophe similar to the virus (but not as dikatagorikan virus) is a worm. Ordinary worm spreads through e-mail, in the form of a small program that diattachkan in an e-mail message. Users will be interested in running the program. Next, be to guess, the program will make a direct aksinya. Worm will reproduce itself by automatically sending the file via the attachment to every address in the address book software on the e-mail victim. Worms are generally not harmful, but in addition to causing irritation on the part of the victim, worm attacks can be very harmful to the Mailserver. Berjangkitnya worm Mailserver the work load can be increased drastically to affect performance.
Worm generally shaped executable file (berekstensi. EXE datau. SCR), which is attached (attach) in the email. However, there are several types of worms in the script written in Visual Basic (VBScript). Target worm attacks of this type of software is especially e-mail Microsoft Outlook Express.
Nowadays, the software has been available in the market as a prophylactic against the virus. This program usually works with a scan (scan) and mencocokkannya a file with the characteristics of the virus in its database. Part of anti-virus program is a program within the (resident) in the computer memory. This section serves to monitor the activities of read-write on the media against the "anomalies" that may be caused by the virus. Not all viruses can be removed by anti-virus. Some types of viruses do penimpaan (overwrite) the file that ditularinya. File with the virus of this type is impossible to be fixed.
Some types of the virus to trick diracang programs that have anti-virus at this time. This type of virus are stealth and polymorphic types. Stealth virus type (invisible) work with a sophisticated system seems to be in a normal condition so that the virus is not detected by anti-virus program, even though in fact the file has been infected. Meanwhile bertipe polymorphic viruses are able to change the characteristics of each character-time infect a file. With the change itself, the virus programmers hope to make the anti-virus in characteristics to identify the virus buatannya. Some types of the virus using a combination of both of these techniques are then classified as a type of virus hybrid (mixture).
However, the war between the virus with the antinya will continue. Creator of the virus is always clear step ahead, while the anti-virus also does not want to continue to examine the lag and make a virus for prophylactic-new virus. Nowadays at least 200 new viruses appear each month. There are suspicions that computer users be circulating that the actual anti-virus justeru "in cahoots" with the programmer of the virus to increase the sale of its products, but so far these allegations have not been proven correct.
Avoid the threat VIRUS
For computer users, there are several steps we can do to prevent our system from the threat of viruses and bad consequences that ditimbulkannya:
1. Install Anti Virus on your system
For protection in the front line, the use of anti-virus is mandatory. There are many anti-virus circulating in the market at this time. Some of them are powerful enough McAfree VirusScan (http://www.mcafee.com/) and Norton Anti Virus (http://www.symantec.com/).
2. Update anti-virus database program regularly
Hundreds of new viruses appear each month. Always try to keep to update the database of anti-virus program you use. Latest database can be viewed on the website of the company anti-virus program you use.
3. Be careful before running the new files
Make scanning first with anti-virus before running a file obtained from the Internet or download a copy from other people. If you are using regular e-mail, take care to receive any form of attachment in the executable file. Waspadai files berekstensi: *. COM, *. EXE, *. vbs, *. SCR, *. VB. Do not open it directly to terkecoh before scanning with anti-virus software.
4. Singularity occurs when the suspect on your system
Decreasing system performance dramatically, especially when performing operations reading / writing files on the disk, and the emergence of problems in the software can be operated at an indication that the system has been infected by the virus. Be careful!
5. Backup your data regularly
Tips may not directly save your data from the threat of viruses, however, will be very useful if a virus when exactly the attack and damage the data on the computer you use. At least in the case, you will not lose all the data that you have backups before.