What is a Trojan?
When you think of Trojans, you would normally think of the Wooden Horse, that had soldiers hidden in it, and attached Troy by surprise. Computer Trojans are based on the same idea; what can appear as a useful program or a harmless site can be hiding a small Trojan program that once it has infected your computer, it opens a backdoor that will allow and intruder to remotely gain access to your computer.
A simple example of a Trojan horse would be a program named "waterfalls.scr" where its author claims it is a free waterfall screensaver. When run, it instead unloads hidden programs, commands, scripts, or any number of commands with or without the user's knowledge or consent.
Some Examples of Trojan Horse damages:
- Erasing or overwriting data on a computer
- Logging keystrokes to steal information such as passwords and credit card numbers
- Corrupting computer files in a subtle way
- Upload and download files (could cost you lots in excess data charges if you are not on a price-capped plan)
- Spying on the user of a computer and covertly reporting data like browsing habits to other people
Methods of deletion
Since Trojan horses have a variety of forms, there is no single method to delete them. The simplest responses involve clearing the temporary internet files on a computer, or finding the file and deleting it manually (safe mode is recommended). Normally, anti-virus software is able to detect and remove the Trojan automatically. If the antivirus cannot find it, booting the computer from alternate media (CD) may allow an antivirus program to find a Trojan and delete it. Updated anti-spy ware programs are also very efficient against this threat.
What do I do if I have become a victim?
Disconnect your computer from the internet immediately, to prevent further spreading of the virus and contact a technician to have it removed properly.