The trojan horse of Greek literature is a classic. The horse was used to attack Troy, disguised as a gift. Once the gift was in the city, the soldiers attacked and won the city of Troy. The same concept is behind the trojan horse of the computing world. An application is disguised as being something helpful or desired, such as a game. Once it is installed and opened however, any number of things may happen to your computer.
A trojan horse malware can take complete control of your computer. It can also monitor the keystrokes made on your computer with a key logger to steal passwords to your accounts. Other malware can disable security software, download additional malware, or change your computer settings. These are just a few of the things that a trojan horse can do to your computer. A talented programmer can make a trojan do nearly anything.
In order to infect the computer, a trojan horse needs to be installed and run. The most common source of malware is the internet. In most cases, the malware is disguised as an application that you download. It can also be hidden in an email. Some trojans can even copy themselves onto removable devices connected to the computer, infecting other computers when the devices are run. Most trojans of this type install code into the auto run feature of the removable device. This way the malware is run automatically as soon as the device is connected to the computer.
Signs of Infection
There are many signs that your computer has been infected by a trojan horse malware. If you discover that your computer is not operating correctly, there may be a trojan behind the problems. Some of the common signs that your computer has been affected by a trojan are:
- CD ROM closes and opens on its own
- Screen changes such as resolution, flips or color changes
- Change in wallpaper
- Automatic printing of documents without command
- When running an internet browser, pop up ads come up without notice or your browser is automatically redirected to another webpage
- Your mouse moves on its own or the right button becomes the left button
- The task bar disappears or cannot be accessed
- Your computer cannot be shutdown normally
- Suspicious applications are running in the task manager
- The computer restarts or shuts down on its own
- Chat boxes appear that create chat with the developer of the trojan
Removing Trojan Malware
Removing trojan horses are easy with antivirus software. However, some trojans will disable this software and keep it from being reinstalled. When this happens, you may think that you have to reformat your hard drive to get rid of the virus. While this is certainly an option, you should consider other steps first before taking this drastic action.
Check the processes running on your computer through task manager. Task manager can be opened by pressing control, alt, delete all at the same time. You can also right click on the task bar to bring up the task manager. Research the processes that are running on your computer. Make note of anything that comes up as being a trojan. Go into the processes and right click on the suspicious ones. Click Kill Process. This should stop it from running so that you can reinstall your antivirus software.
If you get an access denied message when you click on kill process, you will have to stop the process from running on startup. To do this, you will need to run msconfig by clicking start, run, and typing msconfig. Go to the startup tab and disable the process, then reboot your computer.
Another method is to boot your computer in safe mode. When in safe mode only integral processes are run, so you do not have to worry about the trojan running in that mode. After you have stopped the process from running, locate the file and manually delete it. Check the recycle bin to be certain you completely deleted the file.
Finally, restart your computer to see if you have fixed the problem and gotten rid of the trojan. Check the processing running in task manager again to make sure they are not running. Some trojans regenerate automatically, or hide themselves completely in the computer. When this happens, manual removal is not possible. If you find that this is the case and you have to reformat your hard drive, be sure to back up your important files first, as they will all be deleted with the malware.