In computer-ese, the term “Trojan Horse” means one thing — a “malicious, security-breaking program that is disguised as something benign.” This type of computer hack has been dubbed “Trojan Horse,” because the virus tends to hide in something safe and then unleashes itself on your computer when you least expect it.
According to legend, the Greeks won the Trojan War by hiding in a huge, hollow wooden horse to sneak into the fortified city of Troy. On a computer, you may download a fun screensaver or open an attachment not realizing that what’s hidden inside is a small file prepared to attack your computer.
Trojans come in many shapes and sizes. Some create annoying, unending pop-up advertisements; some get into your email and send out spam; some claim to clean viruses off your computer; and others may actually implant in your computer and track your keystrokes in an attempt to steal a credit card number or password. The basic rule is, just as you would be wary of anyone coming to your door or calling you on the phone to sell you something, you should be extra cautious of things you come across on the internet, especially when they do not have a reputable company name behind them. You should also take caution when opening attachments in email. You may know the person that sent it to you, but who sent it to them? And who sent it to that person?
Trojans can be spread in the guise of literally ANYTHING people find on the internet: a free game, movie, song, etc. They get to victims’ computers through downloads from an un-reputable website via a peer-to-peer file exchange or by just carelessly and simply opening an email attachment.
How to get rid of Trojan Horses
Your computer should also be equipped with up-to-date virus software and firewalls, such as Norton or McAfee. "Up-to-date" is the key word here. New viruses are created daily, so expect virus software updates just as often. With virus protection you may be notified if a file you are downloading has a virus attached. With a firewall, it would notify you if a program on your computer is trying to access the internet. The two work hand-in-hand.
You should also obtain spyware software. Adware is a free spyware program that catches most of the Trojans out there. If you couple it with another spyware program like Spysweeper or Spybot, your computer will have extra protection to catch Trojans that one program might not. Again, be sure to keep your spyware up to date.
Finally, take precautions when browsing the internet by following these guidelines:
NEVER download blindly from people or sites which you aren't 100% sure about.
ALWAYS be sure what the file is before opening, even if it comes from a friend. Many Trojans will automatically try to spread themselves through your email address book. When in doubt, ask the sender first and scan the attachment with a fully updated anti-virus program.
BEWARE of hidden file extensions. Windows, by default, hides the last extension of a file so that innocuous-looking "Mountains.jpg" might really be "Mountains.jpg.exe" — an executable Trojan. To reduce the chances of being tricked, unhide those pesky extensions.
NEVER use features in your programs that automatically “get” or “preview” files. Those features may seem convenient, but they let anybody send you anything which is extremely reckless. Disable the preview mode in Outlook and other email programs.
Other Trojan Horses Solutions
Clean Re-installation: This is the only sure way to completely get rid of a Trojan or virus. However, it also means that you must be sure all of your personal files are backed up on disk or CD and that you have all of the disks available to reinstall software programs. If you are sure you want to go this route, you can either do it yourself or you can pay a professional.
Anti-Virus Software: Some anti-virus programs can handle most of the well-known Trojans, but none are truly perfect, which is why you should not rely on anti-virus programs alone for protection. You can download free trials of most anti-virus software and they usually come with an annual fee. When you are done, make sure you've updated Windows with all security patches. Download this free here.
Anti-Trojan Programs: These programs specialize in Trojans instead of general viruses. You can purchase programs online or at a local computer store. Again, when you are done, make sure you've updated Windows with all security patches.