1.7 Malicious Coders

Malicious code refers to viruses, worms, Trojan horses, logic bombs , and other "uninvited" software. Sometimes mistakenly associated just with personal computers, such types of malicious code can attack other platforms. The actual costs that have been attributed to the presence of malicious code most often include the cost of system outages and the cost of staff time for those who are involved in finding the malware and repairing the systems. Frequently, these costs are quite significant.

Today, we are subject to a vast number of virus incidents. This has generated much discussion about the issues of organizational liability and must be taken into account. Viruses are the most common case of malicious code. In today's modern computing platform, some form of antivirus software must be included in order to cope with this threat. To do otherwise can be extremely costly. In 1999, a virus named Melissa was released with devastating results. [15] The Melissa virus caused an estimated $80 million in damage and disrupted computer and network operations worldwide.

Melissa was especially damaging as viruses go because its author had deliberately created the virus to evade existing antivirus software and to exploit specific weaknesses in corporate and personal e-mail software, as well as server and desktop operating systems software. Melissa infected e-mail and propagated itself in that infected state to 50 other e-mail addresses it obtained from the existing e-mail address book it found on the victim's machine. It immediately began sending out these infectious e- mails from every machine it touched. The Melissa infection spread across the Internet at an exponential rate. Systems were literally brought down from overload as a result of exponential propagation.