Viruses

According to Computer Economics, Inc., a computer research and analysis group, over $12 billion was spent worldwide in 1999 as a result of computer viruses. A virus, a parasitic program that cannot function independently, is a program or code fragment that is self-propagating. It is called a virus, because like its biological counterpart, it requires a "host" to function. In the case of a computer virus the host is some other program to which the virus attaches itself. A virus is usually spread by executing an infected program or by sending an infected file to someone else, usually in the form of an e-mail attachment.

There are several virus scanning programs available on the market. Most are effective against known viruses. Unfortunately, however, they are incapable of recognizing and adapting to new viruses.

In general, virus scanning programs rely on recognizing the "signature" of known viruses, turning to a database of known virus signatures that they use to compare against scanning results. The program detects a virus when a match is found. If the database is not regularly updated the virus scanner can become obsolete quickly. As one would expect, there is usually some lag time between the introduction of a new virus and a vendor updating its database. Invariably, someone always has the dubious distinction of being one of the early victims of newly released virus.