Adware - A form of spyware that enters your computer from an Internet download, launching numerous pop-up ads in your browser.

Anti-Virus Software - Anti-virus software will protect your computer from viruses encountered on the web.

Backdoor - A backdoor is a tool installed after a compromise to give an attacker easier access to the compromised system around any security mechanisms that are in place.

Black Hat Hacker - Is a hacker who "violates computer security for little reason beyond maliciousness or for personal gain."

Botnet - A botnet is a large number of compromised computers that are used to create and send spam or viruses or flood a network with messages as a denial of service attack.

Cookie - A small data file that a web site installs on your computer's hard drive to collect information about your activities on  the site or to allow other capabilities on the site.  Web sites use cookies to identify returning visitors and profile their preferences on the site.

Dumpster Diving - Dumpster Diving is obtaining passwords and corporate directories by searching through discarded media.

Firewall - A security tool that protects an individuall computer or even an entire network from unauthorized attempts to access your system.

Grey Hat Hacker - Is a hacker refers to a computer hacker or computer security expert who may sometimes violate laws or typcial ethical standards, but does not have the malicious intent typical of a black hat hacker.

Hacker -  A hacker is someone who has the techinical know-how to intetionally break or "hack" into a computer system to steal confidential information or to cause damage to a computer or whole network.  

IP Forwarding - IP forwarding is an Operating System option that allows a host to act as a router.  A system that has more than 1 network interface card must have IP forwarding turned on in order for the system to be able to act as a router.

IP Spoofing - The techinique of supplying a false IP address.

Keylogger - A key logger is any piece of software or hardware that has the capability to intercept and record input from the keyboard of a compromised machine.

Logic Bombs - Logic bombs are programs or snippets of code that execute when a certain predefined event occurs.  Logic bombs may also be set to go off on a certain date or when a specificed set of circumstances occurs.

Malicious Code - Software that appears to perform a useful or desirable function, but actually gains unauthorized access to system resources or tricks a user into executing other malicious logic.

Malware - Malware refers to any "malicious software" created to damage or illegally access a computer or network. 

Password Cracking - Password cracking is the process of attempting to guess passwords, given the password file information.

Password Sniffing - Passive wiretapping, usually on a local area network, to gain knowledge of passwords.

Phishing -The use of e-mails that appear to originate from a trusted source to trick a user into entering valid credentials at a fake website.  Typically the e-mail and the web site looks like they are part of a bank the user is doing business with.

Rootkit - A collection of tools (programs) that a hacker uses to mask intrusion and obtain administrator-level access to a computer or computer network.

Social Engineering - This refers to a direct communication, either in person, by phone, by fax or cover the internet, designed to trick you into providing your personal information.  

Spam - Unsolicited, commerical e-mail message that are sent out in a bulk, often to millions of users in hopes that one person may actually reply.  

Spim - A new term for spam messages being sent to instant message addresses.

Spoofing -  Forging an e-mail or instant message address to make it appear as if it came from someone or somewhere other than the true source.  Whole web sites can also be spoofed, tricking users into providing their passwords or other personal information.

Spyware - Spyware refers to a software program that slips into your computer without your consent to track your online activity.

SQL Injection - SQL injection is a type of input validation attack specific to database-driven applications where SQL code code is inserted into application queries to manipulate the database.

Trojan Horse - A trojan horse refers to a malicious program that enters a computer or system disguised or embedded with legitimate software.

Virus - A program that attaches itself to an executable file or vulnerable application and delivers a payload that ranges from annoying to extremely destructive. 

White Hat Hacker - Is a hacker refers to an ethical computer hacker, or a computer security expert, who specializes in penetration testing and in other testing methodologies to ensure the security of an organization's information systems.

Worm - A computer worm is a program built to reproduct itself and spread across a network, rendering it ineffective.  A worm can harm a network by consuming large amounts of bandwidth, potentially shutting the network down.

Zombie - A computer overtaken by a hacker and used to perform malicious tasks.  Commonly, zombie computers are used to send large amounts of spams or host fraudulent web sites.