TROJAN HORSES

What is a Trojan horse program?

Since "Trojan Horses" (or Backdoors) have been in the news a lot recently, the term probably sounds familiar to you. But perhaps you’re not quite sure what a Trojan Horse is and what damage it is capable of doing to your system. Trojan Horses, of which there are now more than one thousand in circulation, are a relatively new and probably the most dangerous strain of viruses that have appeared in recent times. They also threaten to overwhelm systems that only run anti-virus applications and firewalls as a means of combating the threat. Today's Trojans as they are commonly referred to as, have now attained such a degree of sophistication that they pose a real threat to any user who hasn't taken adequate precautions to protect their data.

Trojan Horses act as a means of entering the victim’s computer undetected and then allowing a remote user unrestricted access to any data stored on the user's hard disk drive whenever he or she goes online. The intruder can do anything with the machine that the user can do. An intruder's usual objective is to browse the user's hard drive in order to detemine if there is anything of value stored on it. That could be almost anything such as valuable research papers, credit card details or passwords to restricted web sites for example. If anything of value is found, then the intruder can copy the data to his own hard drive in exactly the same way that the user can copy a file to a floppy disk. Perhaps the worse thing is that all these processes are hidden from the user who might be sitting in front of his own machine working on an entirely different document at the time. Unusual hard drive activity for no apparent reason may be the only indication that something is happening that shouldn't be happening.

The intruder can also cause havoc to the system by deleting (system) files, erasing valuable data or ultimately destroying the hard drive. Simply adding a command to the autoexec.bat file can do that. The next time the unsuspecting victim boots the computer, it will automatically run the format command. Adding a certain flag to that command will also render the hard disk unusable.

Passwords offer no protection at all because today's Trojans are capable of recording the victim’s keystrokes and then transmitting the information back to the intruder. Those passwords can subsequently be deciphered by the Trojan and even changed in order to prevent the user getting access to his own files!

There are links to free Trojan/virus protection software under the "Free Products" heading on the page you just came from.