Getting Ready for the Next Attack

A careful intruder never likes to leave a trail to his own network. The preferred method is to launch an attack from a system that has already been compromised. Some hackers operate through a chain of several remote systems. This strategy makes it almost impossible to determine where the hacker is actually located.

After a hacker has established a foothold, he might upload tools to assist with infiltrating other systems on the network. He also might use the compromised system to attack other computers elsewhere on the Internet. Intruders are constantly engaged in building their webs of connections.

The recent popularity of denial-of-service (DOS) attacks creates yet another role for the compromised system. You'll learn more about denial-of-service attacks in a later section.