The problem with a Trojan virus can be summed up in its name-it looks harmless, but, once you click on it, the trouble starts. Just like the Greek soldiers who snuck into Troy with a wooden horse and destroyed it, hackers hide their weapons in a seemingly innocuous package.
What A Trojan Virus Can Do
You might click on the link, and you won't notice any problems. However, a Trojan virus can wipe out your data or even lurk in the background, capturing your activities and reporting them back to another computer. Here are some examples of damage done by past Trojan viruses:
Data Destruction: Some of the less sophisticated Trojan horses can reformat your hard drive the next time you restart your computer.
Data Stealing: If the Trojan virus is kind enough to leave your hard drive intact, that doesn't mean they're not playing with your information. The virus could install a keylogger that captures your passwords and transmits that information elsewhere.
Site And Server Crashing: These viruses can use your e-mail program to spread itself and send data to other Web sites and servers, thereby clogging the site and causing it to crash.
Backdoor Vulnerabilities: One of the most clever Trojan horse viruses appears to leave your computer alone. However, it has opened up your computer, exposing it to attack so a hacker can get into your computer without your knowledge.
How To Protect Yourself
Since a Trojan virus can hide out, you need to scan your computer regularly using antivirus and anti-malware software. Plus, Trojan-fighting software won't do you much good if you don't have the latest information, so be sure to update it regularly.
And don't forget the firewall. A good firewall blocks questionable programs from accessing your computer. An even better firewall makes sure programs aren't sending out your information unless you approve it.
Most important of all, do not click on any unusual downloads. If you signed up for automatic updates from Microsoft or common programs like iTunes prompt you to download an update, then you are most likely fine. However, if a site you've never heard of asks you to install software for "security reasons" or to see a video you can't get anywhere else, be suspicious, and always think before you click on a link or attachment sent out via e-mail or instant messenger.