Computer Viruses Essay, Research Paper

On March 26, 1999, people everywhere began sending Microsoft and anti-virus companies information about something going wrong with their computers. Those companies figured out that it was a macro virus called “Melissa” hidden into a plain email letter. It would make the infected computer’s email program send an email saying it was an important message from the sender. Thousands of people were infected worldwide.

One commonly asked question about computers is “what

are computer viruses?” Another popular question is “how do I prevent viruses from infecting my computer?” These questions are answered in this essay.

While there is no widely accepted definition of the term ‘computer virus,’ one definition would be executable code that, when run by someone, infects or attaches itself to other executable code in a computer in an effort to reproduce it. Some computer viruses are malicious, erasing files or locking up systems. Others merely present a problem completely through the act of infecting other code (Mansfield 31).

Closely related to computer viruses are Trojan Horses and Worms. A Trojan Horse is a program that performs some unwanted action while pretending to do something else to avoid suspicion. One common class of Trojan Horses is a fake login program that collects accounts and passwords by prompting for this info just like a normal login program does.

Another is a fake disk defragmenter that erases files rather than reorganizing them.

A Trojan Horse differs from a virus because the Trojan Horse does not attempt to reproduce itself like a virus. A Worm is the same as a virus except it also tries to spread itself over the Internet or a network (internet).

Some of the types of viruses and other destructive code are file infectors, cluster infectors, macro viruses, and system infectors (internet).

File infectors are viruses that attach themselves to regular programs, such as .COM or .EXE files under DOS. That means they are put into action each time the infected program runs (internet).

Cluster infectors modify the file system so that they are run prior to other programs. Unlike file infectors, they do not actually attach themselves to programs (internet).

Macro viruses are word processing documents that can use macros like Microsoft’s auto-execution macros to run another type of virus to help it spread.

System infectors are computer operating systems that typically set aside a portion of each disk for code to boot the computer. This section is called a boot sector on floppy disks or a master boot record (MBR) for hard disks. System infectors store themselves in this area and are invoked whenever the disk is used to boot the system.

In all circumstances, someone must execute a virus, usually ignorantly, in order to spread. Two ways in which this occurs include booting from an infected floppy disk or running an infected program.

System infectors are loaded each time an infected disk is used to boot the system. This can happen even if a disk is not equipped with the files needed to truly boot the computer, as is the case with most floppy disks. With Personal Computers (PCs), the first infection typically occurs when someone boots or reboots a computer with an infected floppy accidentally left in the disk drive (Cohen 46-47)

Computer related vandalism will never be stopped altogether, but a computer can be safe with the right precautions.

Cohen, Frederick D. A Short Course on Computer Viruses. New York: John Wiley & Sons, 1994: 46-47

“CSRC Home” Jun. 1998: n, pag. On-line. Internet. 18 Oct. 2000. Available WWW: http://csrc.ncsl.hist.gov/virus

Holland, John. Letter to the author. 28 October, 2000.

“ICSA Anti-Virus Lab” Nov. 2000: n, pag. On-line. Internet. Available WWW: http://www.isca.net/html/communities/antivirus

Mansfield, Richard. Hacker Attack Sybex Sept. 22, 2000: 31

“Trend Micro Security Info” Apr. 1999: n, pag. On-line. Internet. 18 Oct. 2000. Available WWW: http://www.antivirus.com/vinfo/virusencyclo/glossary.asp