Malicious Mobile Code

What Are Trojan Horses and Worms?

The story of the infamous Trojan horse comes from Greek mythology about a battle between the Greeks and the people of Troy (Trojans). For ten years the Greeks had unsuccessfully tried to get into the city of Troy to rescue Helen, queen of Sparta. Troy was surrounded by an impenetrable stone wall. The Greeks decided to play a trick. They built a two-story wooden horse with their best soldiers hidden inside, left it as a gift to the Trojans, and pretended to sail away. Against the warning of a few Trojan wise men, the Trojans hauled the wooden horse inside. The whole city of Troy celebrated their defeat over the Greeks and feel asleep in a drunken stupor. In the wee hours of the morning, the Greek warriors came out of their hiding place and began the slaughter of Troy. The returning Greek army easily overcame the tricked Trojans and gained control of the city. All males were killed and females were enslaved.

A Trojan horse program, shortened to Trojan for simplicity, is any program that intentionally hides its malicious actions while pretending to be something else. Simple Trojans claim to be a game or some sort of program, and when the user runs the program it immediately does something malicious to their system. These types of basic Trojans don’t spread far because they destroy themselves in the process, or are so noticeable that users don’t send them to friends. Today’s sophisticated Trojans are attached to legitimate programs and compromised users ...