What is a computer virus?
A computer virus is a malicious computer program that infects the computer memory or hard disk. Some are comical and will simply change the display on your monitor while most are designed to do damage to the data on the computer. Boot sector viruses are especially damaging since they rewrite the information needed to start up and access your computer s hard disk. Trojan horses are destructive programs disguised as something harmless like a game. Worms are programs written to replicate themselves until the computer s memory or hard drive is completely used up at which time the computer crashes and becomes inoperable. A good place to learn more about computer viruses is CERT s web site (http://www.cert.
A computer virus is a program that spreads itself by infecting files. When it runs, a virus will essentially wrap a file’s data in its own code. When the file is opened, the virus runs its program first and then opens the file as initially requested. Some computer viruses are malicious, erasing files or locking up systems; others merely present a problem solely through the act of infecting other code. Standard viruses will spread only when an infected file is transferred from one computer to another. Computer worms are self-propagating and can not be considered ordinary viruses. Worms, unlike other viruses, don’t infect files, but entire disks or computer systems. Because worms can’t rely on file-to-file transfers to spread their code, they need to have a way of sending themselves to other computer systems and the most common way is via e-mail. Known as mass mailers due to the technique of spamming themselves to every address in the e-mail address book, such worms generally require a p
A computer virus is not a disease. Rather, a computer virus is a computer program that happens to operate in a fashion similar to the way a real virus attacks the human body. Consequently, people call the program a “computer virus”. Some malicious programs may also be labeled “computer worm” or “Trojan horse”. The exact classification is based on how it attacks your computer. However, the general goal of all such programs is always the same, to take over your computer without your knowledge. When a real virus enters the human body it breaks into a cell and takes over the operation. The cell is forced to become a virus factory, making many copies of the virus. The newly-created viruses are released to find other cells, and the cycle starts, again. The body eventually detects the problem and creates antibodies that capture the viruses before they are able to attack new cells. The most common computer virus today is sent as an program attachment in email (see the Email section for questio
