Exploring Different Types Of Computer Malware: Trojans

A trojan, also referred to as a “trojan horse” or RAT (Remote Access Tool),  is a piece of seemingly harmless software that contains concealed malicious software. You click on it, install it, and everything seems OK. You have no idea that you’ve just installed a piece of malware.

A trojan, once installed, can then allow other programs to download and install. These other programs enable an attacker to do things like upload or download files, turn on your webcam, audio, or install a keylogger or some other type of spyware. This isn’t just about someone getting their kicks watching a live webcam or listening to live audio. Sure, it can be about that, but doesn’t have to be. Attackers can also capture the information contained in audio and video files and then, either periodically or on demand, upload it to a central server at a remote location. The attacker enters, extracts the files, makes his exit, and you didn’t even know he was there.

The name “trojan” comes from Greek mythology and the story of the Trojan Horse contained in book 2 of the Aeneid by Virgil and in Homer’s Odyssey. The Greeks had been involved in a struggle with Troy for 10 years and were, understandably, getting somewhat impatient. They wanted to gain access to walled Troy and thought maybe a little subterfuge would do the trick. With that in mind they constructed a huge, hollow wooden horse on wheels and filled it with Greek soldiers. The Greeks told the gullible Trojans that the horse would make their city impenetrable. Yeah, right. A couple of Troy’s citizens thought the whole thing sounded kind of suspicious and decided that the best course of action would be to reject the “gift”. However, their warnings fell on deaf ears and the horse was allowed inside the gates. Later that night, when everyone in Troy was asleep, the Greeks who had been hiding inside the big, hollow horse emerged and opened Troy’s gates to the Greek army waiting just outside. That was the end of Troy and the Trojan War.

So, you get the idea. It’s all about masking one’s true intent. It looks like a big, wooden horse but it’s actually an entire division of sweaty Greeks. It looks like a fun little game but it’s actually disguised malware.

Will an antivirus catch trojans?

Well, it depends. The attackers who use trojans often alter them slightly so that anti-malware programs won’t detect them as a form of malware. In fact, some trojans actually shut down any installed antivirus software as soon as they’re installed. Therefore, it’s not safe to assume that you’re protected against trojans simply because you have an antivirus program installed. The easiest way to avoid trojans is to keep your anti-malware software up-to-date and to be careful about what you install. If it seems suspicious, it may be a “gift” you’ll want to turn down.

For more information on malware see:

Exploring Different Types Of Computer Malware: Viruses

Exploring Different Types Of Computer Malware: Rootkits & Keyloggers