Trojan Horse Attacks and preventions

According tolegend, the Greeks won the Trojan war by hiding in a huge, hollow wooden horse to sneak into the fortified city of Troy.
In today’s computer world, a Trojan horse is defined as a “malicious, security-breaking program that is disguised as something benign”. For example, you download what appears to be a movie or music file, but when you click on it, you unleash a dangerous program that erases your disk, sends your credit card numbers and passwords to a stranger, or lets that stranger hijack your computer to commit illegal Denial of Service Attacks like those that have virtually crippled the DALnet IRC network for months on end.The following general information applies to all operating systems, but by far most of the damage is done to/with Windows users due to its vast popularity and many weaknesses.

How pc is infected

Trojans are executable programs, which means that when you open the file, it will perform some action(s). In Windows, executable programs have file extensions like “exe”, “vbs”, “com”, “bat”, etc. Some actual trojan filenames include: “dmsetup.exe” and “LOVE-LETTER-FOR-YOU.TXT.vbs” (when there are multiple extensions, only the last one counts, be sure to unhide your extensions so that you see it).
Trojans can be spread in the guise of literally ANYTHING people find desirable, such as a free game, movie, song, etc. Victims typically downloaded the trojan from a WWW or FTP archive, got it viapeer-to-peer file exchange using IRC/instant messaging/Kazaa etc., or just carelessly opened some email attachment. Trojans usually do their damage silently. The first sign of trouble is often when others tell you that you are attacking them or trying to infect them!

Prevention:

1.NEVER download blindly from people or sites which you aren’t 100% sure about.In other words, as the old saying goes, don’t accept candy from strangers. If you do a lot offile downloading, it’s often just a matter of time before you fall victim to a trojan.

2.Even if the file comes from a friend, you still must be sure what the file is before opening it , because many trojans will automatically try to spread themselves to friends in an email address book or on an IRC channel. There is seldom reason for a friend to send you a file that you didn’t ask for. When in doubt, ask them first, and scan the attachment with a fully updated anti-virus program.

3.Beware of hidden file extensions! Windows by default hides the last extension of a file, so that innocuous-looking “susie.jpg” might really be “susie.jpg.exe” – an executable trojan! To reduce the chances of being tricked,unhide those pesky extensions.

4.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. For example, never turn on “auto DCC get” in mIRC, instead ALWAYS screen every single file you get manually. Likewise, disable the preview mode in Outlook and other email programs. 5.Never blindly type commands that others tell you to type, or go to web addresses mentioned by strangers, or run pre-fabricated programs or scripts

Remove Trojan Horse

To remove trojan horse best way is installing a updated anti virus or trojan remover.
a another way is format hard disk fully and reinstall (install only trusted software )