Security glossary

Back door

A loophole in a computer's security systems that allows a hacker access to it.

Blog or web log

A blog is a type of web page that serves as a publicly accessible personal journal.


This is effectively how much stuff can you send through a connection. Usually measured in bits-per-second (bps).


Software programs that allow you to view www pages on the internet. E.g. Firefox, Internet Explorer, Safari


Common Gateway Interface is the most common way web programs interact dynamically with users. Used extensively by search programs amongst others.


A message sent from a web server and stored by your browser on your computer. Used to allow the web page to 'remember' your details when you access it next time.

Denial of service attacks

By overloading a network, hackers seek to make it unavailable to legitimate users. For example, by sending millions of spam emails simultaneously to a mail server, ordinary traffic will get clogged up.


Domain Name System used to translate domain names into Internet Protocol numbers.


Digital Subscriber Line – A method for moving data regularly over phone lines.


A common method of connecting computers together in a LAN.


Hardware or software designed to prevent unauthorised access to a computer or network over the Internet.


File Transfer Protocol – Ability to transfer files rapidly from one computer to another.


A hacker is an unauthorised computer user who attempts to gain or gains access to a computer or computer network for malicious purposes.

IP address

Internet Protocol Address (or Number) – a unique address location to identify the computer in use online at a specific moment in time. Usually looks something like

IP spoofing

An attack whereby a system, by using its IP network address, attempts to illicitly impersonate another system.

Network Worm

A program or command file that uses a computer network as a means for adversely affecting a system's integrity, reliability or availability. A network worm may attack from one system to another by establishing a network connection. It is usually a self-contained program that does not need to attach itself to a host file to infiltrate network after network.


An attempt at identity theft in which criminals lead users to a counterfeit website in the hope that they will disclose private information such as user names or passwords.

Rogue program

Any program intended to damage programs or data; encompasses malicious Trojan Horses.

Social engineering

Tricks performed by malicious users offline to gain access to secure systems, for example impersonating a technical support agent.


Unsolicited commercial e-mail. Also known as junk e-mail.


A computer program that contains hidden functions that exploit the user's privileges with a resulting security threat. It can allow intruders easy access to the computer without the user's knowledge, change system configurations and can infect the computer with a virus.


Code written with the express intention of replicating itself. A virus attempts to spread from computer to computer by infecting another file, typically an executable program. Besides spreading, viruses can be used to do harm or for criminal activity.


A personal computer that has been manipulated in such a way to respond to remote orders of a malicious hacker, known as the remote attacker. On command the PC will perform such actions as massive and rapid propagation of computer viruses, the launching of attacks on other PCs and the theft of data, while still hiding the real identity of the culprit.