To crack one system and then use it as a “launching pad” for cracking other systems. University computer systems tend to be a hotbed of compromised systems from which crackers launch DoS attacks. Home computers attached to DSL (Digital Subscriber Lines) and cable modems are frequently exploited by crackers and used to launch Denial of Service (DoS) attacks. The primary reason these exploits occur is that home computers tend to lack key security features and anti-virus software. Given the huge customer base of Internet Service Providers (ISPs) offering cable modems or DSL services, it is very difficult to track the origin of such DoS exploits. Graham, R. Hacking Lexicon. [Online, 2001.] Robert Graham Website. http://www.linuxsecurity.com/resource_files/documentation/hacking-dict.html.