What are Backdoor Trojans?

Trojans are pieces of software created by black hat hackers or crackers. Their name is inspired in the famous Trojan horse. According to the epic poem, The Aeneid, the army of Greece was laying siege to the city of Troy for ten years, with no result. Tired of their efforts, they decided to use a new approach.

Instead of using brute force, they decided to give to the Torjans a giant wooden horse. Their intention was to make them believe that the siege had ended. First, the Trojans though that it was a ruse. After a careful inspection, they didn't find anything wrong with the horse, so they took it into their city.

Once inside, the Trojans decided to celebrate the end of the siege. However, during the night, a group of hidden Greek soldiers went out of the Horse and opened the gates of the city to their fellow soldiers. The city was destroyed, all the men were killed and thousands of women and children were taken into slavery.

There are two types of backdoor Trojans. The first one is a useful program that has been altered by a cracker. That way, the black hat hacker can disguise his attack. Once the program is executed, the altered code is activated. What this new code may do is unknown. Only it can be known once it is running.

The second type of backdoor Trojan is a program that masks itself as another program. For example, a cracker may replace a free game from a website and hang his "hidden Trojan". Since this is unnoticed by a regular computer user, he will download the program without even suspecting its potential danger.




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