Basically, a computer virus is a computer program that has the ability to reproduce itself by inserting a program into another file. Much like a biological virus, computer viruses can spread quickly on the files in a computer, or even infect other files on your computer, either through a network or through the activities of file exchange. In the past we know the target distribution based on spreading the virus, which boot sector viruses and file viruses. Boot sector virus is designed by the manufacturer to infect the boot sector, which is part of a storage media (floppy disks, hard disks) who first read by the operating system while the media is accessed. Once the storage media are infected by the virus of this type is used for booting, the virus had settled in memory and ready to infect other storage media used in the same computer. Later, the boot sector virus developing into a more virulent type, which is known as viral partition (partition table). Is part of the partition table on the hard disk that stores data CHS (cylinder / head / sector) which serve as guidelines for the operating system to perform the reading process. Once this section leburkan destroyed by the virus, then the disk would no longer be read and all the data in it was floating. Meanwhile, the virus files works by inserting the program in a file. Previously, when using the DOS operating system is still widespread, this type of target viruses are executable files, ie, whose name ends with the extension. COM or. EXE. In addition to transmission, the virus files often add certain commands to the source code of ditularinya. These viruses generally have a character as a "time bomb", where the virus program will do the action at certain times which have been determined by the programmer. "Action" this can vary, ranging from mild such as displaying a message and sounds the speakers, to perform destruction by deleting data, or even reformat your hard disk! Later, when the use of Windows-based programs began to bloom with a wide variety of features, then we go back to know a new virus types, macro viruses ie. Macro is a series of orders - orders in similar programming language - which provides software that allows users to construct a series of specific jobs. Series of commands will be executed at once by the software when the macro is run. Macro facility is useful for enabling users to do the steps sequentially and repeatedly. Unfortunately, this facility eventually misused by ignorant hands to create a macro that contains the transmission of commands and even the destruction! Type famous macro virus is a virus that WordMacro specially made to infect the data files from word processing software Microsoft Word (berekstensi. DOC). The virus of this type have up to thousands of variants with various kinds of interference. Starting from the only display a message at certain times, to make the destruction of files. Viruses classified as a variant WordMacro most
much as the code-the code that is easy to modify. In addition, learn macros in MS Word is not that difficult to learn Assembly language or C (programming language often used to create a virus program).
TROJAN HORSE AND WORM
addition in terms of viruses such as noted above, we also know the program called Trojan Horse (Trojan Horse). Trojan Horse is not a virus in real terms, because the program does not have the ability to reproduce itself into other programs. However, this program is no less dangerous when compared to a computer virus program. Trojan Horse is generally packaged in the form of an interesting program. But the appeal behind the software, other hidden functions to do the destruction. Computer users who get these files are going to come in to run it. As a result of fatal, because then the users have the routines meenjalankan ready to spread destructive disaster in the computer. Another source of disaster similar to the virus (but not dikatagorikan as viruses) are worms. Common worm spreads via e-mail, the form of a small program that diattachkan on an e-mail message. Users who are interested will run the program. Furthermore, predictably, the program will perform the action. Worms will multiply by sending the file automatically via attachment to every address in the address book in an e-mail software victims. Generally not a destructive worm, however, resulted in aggravation in addition to the victim, the worm attacks can be very dangerous for the mailserver. Worm outbreak caused mailserver workload soared up can affect performance. Generally shaped worm executable file (berekstensi. EXE datau. SCR), which is attached (attach) to the email. However, there are several types of worms in the form of scripts written in Visual Basic (VBScript). Worm attack this type of software in particular is an e-mail Microsoft Outlook Express.
ANTI VIRUS
Today, a variety of software already available in the market as an antidote to a virus attack. These programs typically work by scanning (scan) a file and match it to the characteristics of existing viruses in its database. Another part of the anti-virus program is a permanent program (resident) in the computer memory. This section serves to monitor the activity on the read-write storage media for the presence of "anomalies" that may be caused by a virus. Not all viruses can be removed by the anti-virus. Some types of viruses do overwriting (overwrite) the file ditularinya. Virus infected files of this type is impossible to be repaired.
Some types of viruses diracang to defraud the programs that have anti-virus today. The virus of this type include the type of stealth and polymorphic. Virus type stealth (stealth) to trick the system works as if a file is in normal condition so that the virus was not detected by antivirus programs, despite the fact that the file has been infected. Meanwhile, polymorphic-type virus capable to change the character every time infecting a file. With the always changing itself, the virus programmers hope to complicate anti-virus makers to recognize the characteristics of the virus product. Some types of viruses use a combination of both these techniques are then classified as type virus hybrid (mixture). However the war between the virus makers with antinya makers will continue. Clear the virus makers are always one step ahead, while anti-virus makers do not want to be left to continue researching and making antidotes for new viruses. Today at least 200 new viruses appear each month. There are suspicions that circulated among computer users that the actual anti-virus makers are precisely "conspired" with the virus programmers to increase sales of its products, but so far these allegations have not been proven true.
AVOID THE THREAT OF VIRUSES
As a computer user, there are several steps we can do to prevent our systems from virus threats as well as adverse effects that cause:
1. Install Anti Virus on your system as front-line protection, use of anti-virus is mandatory. There are many anti-virus that circulated in the market today. Some of them are reliable enough McAfree VirusScan (www.mcafee.com) and Norton Anti Virus (www.symantec.com).
2. Database update anti-virus program regularly Hundreds of new viruses appear each month. Always try to update the database of anti-virus program you use. Latest database can be viewed on the company website maker anti-virus program you use.
3. Be careful before starting a new file Perform first scan with anti virus before running a file obtained from the download on the Internet or copy from others. If you are accustomed to using e-mail facilities, take care of each receive an attachment in the form of executable files. Be aware that files berekstensi: *. COM, *. EXE, *. VBS, *. SCR, *. VB. Do not be fooled to directly open it before scanning with anti-virus software.
4. Suspect in case of anomaly in your system
Decline in system performance dramatically, especially during the reading operation / writing files on the disk, and the emergence of problems in the software can be operated as an indication that the system has been infected by the virus. Be careful!
5. Backup your data regularly these tips may not directly save your data from virus threats, but it would be very useful if a virus when actually attack and destroy the data on your computer you use. At least in these conditions, you will not lose all the data you have previous backups.
6. Avoid sharing files or folders if you do not need to really, also do not ever share your hard drive C: or that there is the system.
