Introduction

As we ve discussed in earlier chapters, there are many different types of cybercrime, committed by all kinds of cybercriminals some of whom have very little technical knowledge or skill. However, thanks to the news media and a few popular movies, most people associate the term cybercrime with a particular type of offense: hacking into a system or network from outside an organization. Included in this narrow definition are malicious attacks designed to crash computers and congest networks, even when no actual illegal entry takes place. In either case, the criminal is presumed to have a high level of knowledge about computers and networking.

Unlike the cyberscam artist who needs to know only enough about computers to send mass e-mailings, or the child pornographer whose technical know-how is limited to uploading and downloading files, the network intruder or attacker has traditionally been able to boast of a certain amount of skill. It takes knowledge (and sometimes talent) to circumvent security measures and slip through the holes programmers leave in applications and operating systems to gain access to someone else s servers. It takes a thorough understanding of how network protocols work to exploit their characteristics and bring down systems or entire networks. Or at least, it once did.

Dedicated hackers spend hundreds or even thousands of hours perfecting intrusion techniques and attacks. Today, however, many hackers who break into or bring down networks aren t really hackers at all at least, not in the original sense of the word (which referred to computer...