back door A hidden pathway for gaining entry to a computer system.
buffer overflow An attack method that lets the attacker deliver malicious commands to a system by overrunning an application buffer.
denial-of-service attack An attack design to cripple the victim's system by consuming system resources.
email worm A malicious script or program transmitted through an email message.
hacker A user who trespasses on computer systems for fun or profit. To some, a hacker is any high-end user who is obsessed with and devoted to working with computers.
root access The highest level of access to a computer system. Root access offers nearly unlimited control of the system.
root kit A set of tools used by an intruder to expand and disguise his control of a system.
script kiddie A young, usually adolescent hacker who works mostly with ready-made scripts and tools available on the Internet.
session hijacking An attack method that lets the attacker insert malicious packets into an existing TCP session.
Trojan horse A program that purports to do one thing but actually takes other unseen and malicious actions behind the scenes.