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Trojan horse malware can jeopardize your computer’s security, leading to sluggish performance or crashes. But how does it make its way in? Check out more computer images.
Andrey Volodin/iStockphoto.comA prominent tale from the Trojan War, one of Greek mythology's most significant battles, is the story of the Trojan horse. Seeking entry into the city of Troy, the famed warrior Odysseus commanded his troops to construct a giant wooden horse, large enough to conceal several Greek soldiers inside. Once completed, Odysseus and his companions hid within, while the rest of the Greek army sailed away. However, one Greek soldier, Sinon, remained behind to trick the Trojans into believing his comrades had betrayed him and abandoned the city. He claimed the horse would bring the Trojans good fortune, persuading them to bring it into their walls.
After some deliberation, the Trojans agreed to bring the horse through their gates, unwittingly granting the Greeks access to their city. After celebrating their supposed victory and partying late into the night, the Trojans went to sleep. It was then that Odysseus and his warriors emerged from the horse and caused chaos in the city.
You may be familiar with the Trojan horse from Greek myth, but it's also a well-known term in the world of computers. Trojan horses are hazardous programs that disguise themselves within seemingly innocuous software. Just like the legendary Trojan horse, once they’re installed, these programs can spread through your system, damaging files and causing harm to your computer. They can even transmit critical data from your device over the Internet to the virus's creator, granting them control over your machine, slowing it down or causing it to crash.
Although they're not technically viruses, these are often called "Trojan horse viruses," "Trojan viruses," "Trojan horses," or simply "Trojans." No matter the name, they all refer to the same type of threat. But how did this Trojan horse make its way into your computer in the first place? And how can you prevent one from getting through?
How to Protect Yourself from Trojan Horses
What would Laocoon and Cassandra have done? These two Trojans who warned their people about the deceptive wooden horse would likely be the first to identify a suspicious email attachment and dispose of it right away.
Dmitriy Shironosov/iStockphoto.comSo, how do Trojan horses infect computers? Believe it or not, you play a role in it. For a Trojan to infect your system, you need to install the server component of the application yourself. This usually happens through social engineering — the Trojan creator convinces you to download the program. Alternatively, they might send you the file via an email attachment, hoping you’ll run it. This is why it’s called a Trojan horse — you must actively or passively run the .exe file to install the program; it doesn’t spread on its own like a virus (see How Computer Viruses Work for more on Trojans and viruses). Once you run the program, the Trojan server installs and starts up automatically whenever you boot your computer.
The most common way Trojan horses spread is through email attachments. Trojan developers often use spamming tactics, sending out hundreds or even thousands of emails to unsuspecting users. Those who open the emails and download the attachments are at risk of having their systems infected.
Sometimes, it's not even a person directly spreading malware — your own computer might be doing the dirty work if it's already been compromised. Crackers — hackers who intentionally use their skills to create chaos or cause harm — can deploy Trojans that turn unsuspecting web users' computers into zombie computers. These systems are controlled without the owner's knowledge. Crackers then use these zombie computers to distribute even more viruses, eventually forming networks of infected machines called botnets.
To safeguard yourself from Trojan horses, start by avoiding opening emails or downloading attachments from unfamiliar senders. Deleting these messages will often prevent trouble. Installing antivirus software is another key step, as it scans every file you download (even from trusted sources) to keep malicious software at bay. If you discover that your computer has been infected with a Trojan, disconnect from the Internet and remove the harmful files using an antivirus tool or by reinstalling your operating system. If you're unsure, seek help from your computer's manufacturer, a local repair shop, or a tech-savvy friend.
For more detailed information about computer viruses and security, check out the next page.
