-squared Malware-Info: Trojan-Downloader
A trojan-downloader is a tool that downloads a trojan horse. A trojan, also known as a trojan horse, is simply a program that pretends to be something else.
Why are trojans or trojan horses so dangerous? The basic idea is that you download a program, for example one that you think is some sort a game demo. When you run the demo, to your surprise, nothing happens. Or so you thought.
What may have happened is that you've just unwittingly run some form of program that has planted itself on your hard drive. Perhaps it's going to be a very basic application, and simply delete some files on your system. Perhaps it's an even more sinister tool that will actually give other people full access to your hard drive and system. Sounds ridiculous? It happens literally every single day, to computer users all around the world.
Read more about myths and facts about trojan horses at the a² Knowledgebase: