Software that delivers advertising to your PC, perhaps in the form of popups or sidebars with scrolling adverts.


Distributed Denial of Service. A DoS or DDoS attack is an attempt to ?choke up? an internet connection or server, typically by flooding it with junk data. Botnets are often used for DDoS attacks ? hundreds of computers work to shut down an Internet connection or server.

Dumpster diving

The practice of sifting through garbage bins (commercial or domestic) for documents that have been thrown away as ?rubbish?, but which might be useful to the dumpster diver.


Software or hardware that blocks network traffic. A firewall tries to distinguish ?good traffic? from ?bad traffic?. Good traffic is allowed to pass, bad traffic is blocked.


A catch-all term for software that does undesirable things to your computer. Viruses, worms and Trojans are all forms of malware.


A software update designed to fix problems in the shipped versions of products. For example, a security flaw might be found in a piece of software after it has shipped to retailers. So the software developer writes a ?patch? that fixes the flawed parts, and distributes that patch over the internet.


Using email or a fake website to trick people into giving up private information, such as credit card details. The most common example is the email that purports to be from a bank. The email asks the receiver to go to a specific website and log in using their internet banking username and password. The site looks real enough, but in reality all it is doing is harvesting the user?s details. A technique called spear phishing is an evolution of that ? it targets specific individuals to make the phishing attempt sound more plausible.

Script kiddie

A person who uses readily available internet tools to perform basic attacks on computer systems. For instance, a person who uses a downloadable port scanner to find vulnerabilities (such as file shares and open directories on a Windows system), then perhaps uses a downloaded password hacking program to access those vulnerabilities.