Virus, Malware, Trojan, Worm, What Does It All Mean? [Part 3: Trojan Horse]

trojan virus

In part 2 of this multi-part article we discussed the worm type of malware. Recall from previous articles that the definition of malware is a type of software designed to take over or damage a computer, without the user’s knowledge or approval. Let’s discus the trojan horse.

A trojan horse is a malicious program that is disguised as legitimate or desirable software. A trojan horse has the following characteristics.

Cannot Replicate Itself

Unlike the worm, the trojan horse cannot self-replicate. The trojan horse requires the user to install it. However, once it is installed, it can download other malicious payloads such as worms and viruses.

Does not need to be attached to a host file

This means that a trojan horse does not require a host to attach to in order to function or spread.

Often contains spying functions

Trojan horse malware often contains spying tools such as such as a packet sniffers (a program used to listen to all data going into and out of your computer). The trojan horse almost always contains backdoor functions that allow a computer to be remotely controlled from the anywhere in the world.

Often is hidden

Trojan horse malware is often found in useful software such as screen savers or games. This is often called a wrapper. A wrapper is a program that is used legitimately, but has a Trojan attached to it that will infiltrate whichever computer runs the wrapper software.

Relies on user

Trojan horse malware relies on the users decisions and actions to spread. What this means is that the trojan horse is only active or activated when the user is using the wrapper program. This depends on how the particular trojan application is programmed.

As we’ve said before, it’s sometimes very difficult to remove these viruses, so the best defense is prevention. Keep your systems updated with the latest patches for all software you run, and ensure you have the latest anti-virus software definition updates. Avoid clicking on links and opening attachments if you did not expect it to be sent.

Stay tuned for our next article where we will cover the ZOMBIE. Or, you can subscribe to our newsletter using the form on the right and have our informative articles delivered to you via email once a week.