Know thy enemy is the first tenet of warfare. That being said it is important to understand what a computer virus is. This devious little computer programs attach themselves to legitimate program-hosts and then engage in rampant self-replication. Often, it’s easy to be fooled by their small size but don’t be because they’re never small for long. Computer viruses propagate like rabbits – so by the time you first recognize that they’re present, your data may have already been permanently damaged or erased.
Like biological viruses, computer viruses are not always inherently destructive. Think of it this way, even if you’re not actually sick now, you’re probably harboring a fugitive cold virus in your body right now. Similarly, both biological and computer viruses can infect you without you being “affected”. Oftentimes your computer can be a veritable hive of viruses without exhibiting visible symptoms or actual damage. Viruses can quietly exist, if not instructed to do otherwise, and can unobtrusively and perpetually replicate. They become destructive if and when they are intentionally engineered to be so.
Malicious computer viruses contain what is called a “payload” — a programming element separate from the self-replication code that executes its objectives. For example, a payload might display a personalized message on your monitor or it might erase critical data or program files. It could also reformat your hard drive, or infiltrate your messaging software and overload the local network with authorless e-mails. However, not all computer viruses are created equal. Some are full of sound and fury while being relatively harmless, while others are silent but deadly. In general, there are three main types of computer viruses:
Macro Viruses are the most prevalent type of virus today. Unlike conventional viruses that can attach to virtually any program, macro viruses prey on only specific programs. A macro itself contains instruction code that automatically executes other program commands. In fact, many popular and prominent software applications utilize macros extensively. Essentially, these macro viruses are embedded within a program and they self-replicate.
These macro viruses that run on Microsoft applications like Word and Excel are particularly common — mostly because certain programming strategies employed by these applications make them particularly susceptible. When an infected document is initially opened, the macro virus embeds itself in the application and then proceeds to attach itself to every subsequent document that is created. In this way, the macro virus is unwittingly disseminated whenever the user transfers another document.
Parasitic Viruses are the most infectious type. They attach themselves to executable programs like .com or .exe files. Once an infected file is launched, these viruses freely replicate themselves, embed in primary memory, or release their payload. Furthermore, they can corrupt not just specific programs, but virtually any program that is being processed in RAM.
Boot Sector Viruses represent essential software that resides on hard, floppy or optical disk, and is responsible for loading the operating system into memory at the start of a computing session. Boot sector viruses penetrate the vital boot sector and change and alter the contents. As opposed to macro viruses, boot sector viruses are spread not by sharing diskettes and not documents. Whenever a new diskette is introduced to a previously infected computer, the boot sector virus is transferred to the healthy diskette. This process then conveys the virus to other computers, and so on.
The above are all considered true computer viruses, however, another commonly-observed form of computer pestilence (though not literally a virus) is the worm. Worms differ from viruses in that they can wreak havoc without requiring a host. Other viruses are referred to as Trojans. Trojans are viruses that masquerade as legitimate programs, documents or other software and are often spread through e-mail or online bulletin boards.
Certainly we would not knowingly expose our computer to a virus. However, thousands put their machines in peril every day and ignorance is no excuse. An ounce of prevention is worth a pound of cure so follow some of the common troubleshooting techniques below to keep your computer virus-free:
• Use a reputable anti-virus software applications like Norton or McAfee
• Scan new files, diskettes or software before loading them on your machine
• Back-up critical software or files to avoid permanent loss due to infection or deletion
• Be wary of strange operating tics or unusual graphics
• Ensure vigilance from the other members sharing your computer or network
• Write-protect your system and program disks
• Enable Macro Virus Protection in all Microsoft applications
• Don’t share diskettes or software without assuring their integrity
• Never download e-mail or Internet files/programs without scanning them first
• Don’t act on an e-mail virus alert without confirmation from an IT professional or trustworthy source
• Always use the original diskettes to boot your system.