You might have read the last chapter on backdoors and thought to yourself,“I’d never run a program named Netcat or VNC on my machine, soI’m safe!” Unfortunately, it isn’t that easy. Attackers with any modestlevel of skill will disguise the nasty backdoors we covered in the last chapteror hide them inside of other programs. That’s the whole idea of a Trojanhorse, which we define as follows:A Trojan horse is a program that appears to have some useful or benign purpose,but really masks some hidden malicious functionality.As you might expect, Trojan horses are called Trojans for short, andthe verb referring to the act of planting a Trojan horse is to Trojanize oreven simply to Trojan. If you recall your ancient Greek history, you’llremember that the original Trojan horse allowed an army to sneak rightthrough a highly fortified gate. Amazingly, the attacking army hid