What is a Trojan?

A Trojan is one of the many forms of malicious programs that can infiltrate and harm your computer. As with other types of malware like viruses, adware or spyware, it can always help if you know what you’re up against. Read our introduction to Trojans and how you can effectively protect from them.


A Trojan is a type of malware that can come in many different forms and which can do all sorts of damage on your computer. Some Trojans may merely be annoying while others may cause severe damage including financial loss and more.

Trojans got their name from the mythological tale of the warriors who hid inside a giant wooden horse that was given to the Greek town of Troy as a present. At night, the warriors left their hiding place, opened the doors of the city and let their other men in, a trick which allowed them to capture the city.

What all Trojans have in common is that they disguise as a harmless or useful software, hence the name which reminds us of the Greek tale. Once you unsuspectedly start the software, it will begin causing damage.

As compared to viruses, which are yet another type of malware, Trojans are not self-replicating and they don’t spread.


Trojans are a sub-type of malware that comes disguised, trying to trick you to execute them. Many types of programs exist that fall under the Trojan category.

There are banker Trojans or game thieves that try to get to your personal data that cyber criminals can use to steal your money or game account information. There are keyloggers that record anything you do on your computer for malicious purposes. There are clickers which run from your computer and slow it down because they use it to generate website traffic or fraudulent ad clicks. There are more types of Trojans which vary in the way how they are designed along with their purpose.

One of the most common types of Trojans is the backdoor Trojan. These types of programs are designed to open your computer for remote access, which means they can give a cyber-criminal full control over your computer and personal data.


When you are surfing the internet and download files to your computer, you should always be careful. Don’t download files from untrustworthy websites and be especially careful if you use filesharing websites.

Sometimes, criminals use a scheme where they call people claiming there is a problem with the computer or internet which they can fix. The criminals instruct the person to install software on the computer to give them access. Rather than fixing a problem, this software is a Trojan that allows the criminals gain access to the computer. If you get such a call, in particular if you don’t expect it, decline their "help" and simply hang up.

The best way how to protect yourself from Trojans is a reliable and modern anti-virus and anti-malware software program. The anti-virus software runs in the background and alerts you as soon as it comes across something suspicious. It can also scan your computer system and remove any Trojan that it has found.