What Is a Trojan Virus?

by Zakiya Lathan

A Trojan is malicious software disguised as something else. Executing a file hidden in a Trojan may reveal an annoying but relatively harmless computer prank--if you're lucky. If you are unlucky, you may find that your entire system is wiped out.


A Trojan is a vehicle by which unsuspecting people are tricked into executing or downloading software onto their computer. A Trojan may be disguised as anything that will entice a user to click on it, such as an innocent-looking link, a picture or a video player. Once the user opens a Trojan, malicious software can get to work, often in the computer's background.

Viruses and Malware

Viruses destroy data--sometimes specific data, sometimes whole directories. A virus is a type of malware. Malware, as the name suggests, is malicious software. Malware may be used to do any number of things. A common use of malware is to log keystrokes and steal passwords and other personal data.


A worm is a type of malware that replicates. It is not content to infect only your computer--it wants to infect the computers of all of your friends. Worms most often use the address book in your email program to send copies of themselves out.

Data Loss

You should make a habit of backing up your computer's important files. Data loss is an inherent risk of computer use. Your data could just as easily be at risk from a power surge as it is from malware. It is always a good practice to save often and back up files to a location other than your computer. Removable hard drives, flash drives and DVDs are good backup solutions.

Reducing Trojan Risk

There are several ways that you can reduce your risk of becoming a victim of Trojan software. Don't open suspicious-looking email. Don't click on links in emails unless you know it is from a reputable source. Don't download software from unknown sites. Download software from reputable sources only. Don't click on video players or links unless you are on a reputable site. Don't use third-party sites for software updates. If you need to update multimedia software, go directly to the software's site. Most importantly, keep your antivirus and anti-spyware software updated.

About the Author

Zakiya Lathan began her professional media career in 2002. Prior to Lathan's freelance career she worked in broadcast news as a Web producer and online journalist for the CBS affiliate in Anchorage, Ala. She also produced newscasts for the Anchorage FOX affiliate and has written for local and national media outlets. Lathan earned a Bachelor of Arts in English from Lake Forest College.

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