are impostor files that claim to be something desirable but are actually malicious. Trojan horse programs do not replicate themselves. They contain malicious code that causes loss, or even theft, of data when triggered
A Trojan horse is a program that performs unauthorized actions within a system, which are usually malicious. They can erase files, reformat a disk, or display certain messages. It is a program looks as if it's legitimate but is actually malicious. Trojans are most effective at gaining backdoor access into a system. It will not infect other files, so cleaning of the system is not necessary. To get rid of a Trojan, you just need to delete the Trojan program. Trojans do not replicate or make copies of themselves, however they are often combined with viruses and worms which do.
Trojan horses slip into an individual's system and run without the user's knowledge. They can have many functions. For example, some use a computer's modem to dial long-distance, generating huge phone bills for the computer owner. Unlike viruses and worms, Trojan horses do not make copies of themselves.
This program could be used to find some information such as a password or it could destroy your computer. It is similar to a virus, except it doesn't replicate itself. It could destroy most things on you hard disk. http://www.techweb.com/encyclepedia/defineterm?term=TROJANHORSE&exact=1
A nasty computer program cleverly hidden inside a legitimate program. It comes from a strategy used in the Trojan War. Sneaky computer programs that pretend to one thing while disguising a more nefarious deed are called Trojan horses. You are more likely to find a Trojan horse packaged inside shareware or forewarn than in off-the-shelf commercial software.
program that enables the user to gain entry to the system that it penetrates. Unlike a virus which multiplies itself thousands of times, as in its original sense a Trojan horse is designed to gain access to systems without detection. A Trojan horse concealed in a random game program downloaded from your favourite newsgroup can read any file you have read access to, and mail it anywhere in the world. It can erase, or just shuffle around a few bytes in, any file you can write to. It can send obscene messages to the White House, or post embarrassing things to random newsgroups.