A Trojan horse is a type of malware that disguises itself as legitimate code or software. It is a program downloaded and installed on a computer that appears harmless but is, in fact, malicious. Unlike viruses or worms, Trojan malware cannot replicate itself or self-execute, and it requires specific and deliberate action from the user. Trojans are designed to damage files, redirect internet traffic, monitor the user’s activity, steal sensitive data, or set up backdoor access points to the system. They may delete, block, modify, leak, or copy data, which can then be sold back to the user for ransom or on the dark web.
The name "Trojan horse" comes from the Greek myth in which the Greeks used a wooden horse to enter the city of Troy and win the Trojan War. Similarly, a Trojan virus looks like legitimate software and appears to be a legitimate gift. Once inside the network, attackers are able to carry out any task the attacker designed it to carry out. The delivery method typically sees an attacker use social engineering tactics to trick unsuspecting users into downloading and installing the malware.
Trojans can infect a computer in several ways, including opening infected attachments, visiting shady websites, or downloading cracked software. Once inside, some Trojans sit idly on the computer and wait for further instructions from its host hacker, while others begin their malicious activity right from the start. Unexpected changes to computer settings and unusual activity, even when the computer should be idle, are strong indications that a Trojan is residing on a computer.
