What is a computer virus?
Virus – A computer program file capable of attaching to disks or other files and replicating itself repeatedly, typically without user knowledge or permission. Some viruses attach to files so when the infected file executes, the virus also executes. Other viruses sit in a computer’s memory and infect files as the computer opens, modifies or creates the files. Some viruses display symptoms, and some viruses damage files and computer systems, but neither symptoms nor damage is essential in the definition of a virus; a non-damaging virus is still a virus. Protecting Your Computer from Viruses A virus can enter your computer in several ways: • Files downloaded from the Internet • Email messages and attachments • Diskettes, zip disks, and other removable media Steps You Can Take You can protect your computer and personal data in the following ways: • Always restart a public computer before working on it and log off when you end your session. • Save your work frequently • Back up your files
A virus is a program that is attached to other pieces of code, so that when the user tries to run the original program, they also unintentionally run the virus code. The virus code is designed to replicate itself and “infect” other programs, possibly in a modified form, and may also exhibit other behavior as well. In order to be a virus, this program must have the ability to run without the user wanting it to and/or create effects that the programmer wants but that the user did not want or request. It must also have the ability to “infect” or modify other files or disk structures, and replicate itself so it can spread to other files or systems. A virus does not necessarily have to trash your hard drive or exhibit other malicious behavior, in order to be a virus. While many viruses do damage files and disk structures, many are just nuisances or exhibit “prank” behavior such as playing music on the PC speaker or putting funny phrases on the screen when the system is booted. There are thr
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.
Virus Humor What are Computer Viruses? Computer viruses are programs written by “mean” people. These virus programs are placed into a commonly used program so that program will run the attached virus program as it boots, therefore, it is said that the virus “infects” the executable file or program. Executable files include Macintosh “system files” [such as system extensions, INITs and control panels] and application programs [such as word processing programs and spreadsheet programs.] Viruses work the same ways in Windows or DOS machines by infecting zip or exe files. A virus is inactive until you execute an infected program or application OR start your computer from a disk that has infected system files. Once a virus is active, it loads into your computer’s memory and may save itself to your hard drive or copies itself to applications or system files on disks you use. Some viruses are programmed specifically to damage the data on your computer by corrupting programs, deleting files, o
