Spam is simply junk e-mail. It is unsolicited e-mail sent to you by an individual or company with which you have had no previous dealings. Often many copies of the same commercial message are posted like bulk e-mail to multiple online forums and newsgroups without regard to the relevance of the message to the members of that forum. Because bulk e-mail is inexpensive to send compared to traditional junk mail, spam is popular among some businesses that send out unsolicited mass e-mail messages. Spam is considered a serious breech of netiquette. Spam creates many problems for universities, schools, and businesses. Increased volumes of e-mail messages can overload servers and cause interruption of network and e-mail services. Spam forces e-mail systems and computer networks to scale systems to accommodate all of this unsolicited e-mail traffic. Spam often contains offensive materials or solicitations for pornographic material or websites.

Viruses are self-replicating pieces of computer code that can partially or fully attach themselves to files or applications. A computer virus is designed to hide in the background and replicate itself from one computer to another by attaching itself to existing programs or parts of the operating system. Viruses usually cause a computer to do something that can cause damage to the data stored on the computer. Viruses are commonly and usually unknowingly spread from one computer to another as an attachment to an e-mail message. A worm is a virus that copies itself from one disk drive to another and is often spread by e-mail. It may do damage and compromise computer/network security.

Spyware – Software that covertly gathers user information through a user's Internet connection without the user’s knowledge is spyware. Spyware exists as independent executable program that has the ability to monitor keystrokes, scan files on the hard drive, spy on other applications such as chat programs or word processors, install other spyware programs, read cookies, and change the default home page on the Web browser. Spyware relays this information back to the spyware author who usually uses it for advertising purposes or sells the information to another party. Spyware is usually downloaded from the Internet as a hidden component of freeware or shareware programs rather than being distributed through e-mail. Spyware is used to monitor user activity on the Internet and then transmit that information in the background to someone else. Spyware can also gather information about e-mail addresses, passwords, and credit card numbers. A common way to become a victim of spyware is to download certain peer-to-peer file swapping appplications.

Anti-Spam and Anti-Virus Measures – Measures to prevent or control spam or viruses can be either client- or server-based. For example, spam blocking programs may scan an e-mail message to see if it is from a familiar address based on a contact list and makes the sender confirm they are a real person and not a bulk e-mail spammer. E-mail antivirus programs scan e-mail attachments and when a virus is detected, the e-mail message is stripped of the virus and a message is sent to the e-mail recipient (and sometimes to the originating sender) of the message with a detailed description of the virus. Some antivirus programs scan both inbound and outbound e-mail messages. Antivirus programs should be installed on every computer and kept up-to-date. To reduce the risk of infecting a computer with an e-mail virus, do not open or save attachments from strangers and do not open or save attachments that were not expected or that seem suspicious.

Copyright © 1995-2008, Pearson Education, Inc., publishing as Pearson Prentice Hall Legal and Privacy Terms