Understanding Trojan Horses Like a Guru


Chances are you have heard the term Trojan horse before, maybe in the Greek Mythology, but what about the computers? A Trojan horse is a rather common and dangerous application that’s hidden within software that seem harmless.

Similar to the historic Trojan horse, these work by being installed and opened, infecting the host system, and it can cause chaos for computers. It can collect your information and deliver it to the creator of the Trojan horse via the internet. Depending on the purpose, it could also enable its creator to take control of your system, slow it down, or even crash it altogether.

They are known as “Trojan horse viruses,” “Trojan horses,” “Trojan viruses,” and many just refer to them as Trojans. In reality they’re not actually viruses, and all the terms mean pretty much the same thing. The more important question to ask is how did you allow this nasty thing to get on your computer, and how to avoid it in the future?

The first step is to understand how Trojans can be injected in your PC. The reality is, for Trojan Horses to work, you actually have to do part of the work. You must first install a server-sided program or application, usually done with social engineering, where the Trojan’s creator convinced you to download the file and install the application.

As an alternative, it’s possible they sent you an e-mail with the program in hopes of you opening it, thus the name. You knowingly download, install, or execute the .exe application, without realizing it has an infection hidden inside. Unlike a virus, it requires the user to place it on the computer or open it. Once the infected file has been opened and the Trojan is activated, it automatically runs each time the computer is turned on.

trojans detected

Malwarebytes Anti-Malware detecting a Trojan

Email attachments are the most common method for spreading a Trojan horse, as the creators often resort to spamming methods that deliver hundreds or thousands of emails to those who are not expecting it. Then, the ones who fall for it, open the attachment and save it to their PC are now infected.

Although Trojans can be spread manually, they can also be spread by your computer once it has been infected. There are a few terms used for those who create Trojans. For instance, Crackers are hackers that use their skillset to cause mischief or damage by using Trojans that convert innocent people’s computers into “zombie computers.”

They get this name from the fact that the user usually does not know their system is being controlled. These systems are used by the Crackers to continue sending out more Trojans, until there is an entire network of zombie computers, at that point referred to as botnets.

There are various things you can do to avoid getting Trojans, with the simplest being to only download trusted files and never opening e-mails you do not expect. If you delete those messages and avoid unknown sources, it will lower the chances considerably. Another precaution is to install antivirus software that scans each downloaded file, because even if the file is from a trusted source or a friend, they may not know they’re infected. Better to be safe.

However, if you find that you have an infected computer, there are things you can do, the first being to disconnect the internet. Then, begin to eliminate the threat by removing the infected files using antivirus software, or you can simply reinstall your operating system, which formats the hard drive and wipes all the files (similar to a factory reset on a smartphone). If you need assistance, you can also resort to a computer store’s help.

[Featured image credit: Kaspersky.com / Image scaled and cropped]

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