Viruses

Definition

A virus is a program or code that attaches itself to a legitimate, executable program, and then reproduces itself when that program is run.
There are many types of viruses including worms, email, macro and boot-sector.

How to Manage the Threat

Anit-virus programs exist that keep programs with viruses attached to them out of the computer system. However, they don't keep out all viruses because there are always new viruses that counter-act against these anti-virus programs.

Trojans

Definition

A Trojan is a small computer program, usually installed on a computer without the owners knowledge, that allows another person elsewhere on the internet to make use of your computer.

How to Manage the Threat

Don't download anything from insecure web-sites and have a program that keeps out trojans.

Spyware

Definition

Any software that covertly gathers user information through the user's Internet connection without his or her knowledge, usually for advertising purposes. Spyware applications are typically bundled as a hidden component of freeware or shareware programs that can be downloaded from the Internet. Once installed, the spyware monitors user activity on the Internet and transmits that information in the background to someone else.

How to Manage the Threat

Use anti-spyware programs to stop spyware, don't install anything unless you know exactly what it is and keep up to date with new anti-spyware software.

Adware

Definition

Free software that is loaded onto a users computer, with the users permission, to perform some useful task (like automatically filling in their web forms), in exchange for the ability to track the users web activity and show the user targeted contextual ads. Users of Adware have legally opted into the software license.

How to Manage the Threat

It would be a good idea not to download anything from a banner or a pop-up becuase if they paid for the advertisment, they are trying to gain something off of you somehow. (Probably through adware)
Also, don't download anything unless you know exactly what it is.


Link to Anit-virus download

http://www.mcafee.com/au/
http://www.download.com/AVG-Anti-Virus-Free-Edition/3000-2239_4-10320142.html