A Trojan horse virus is a type of malware that disguises itself as legitimate software in order to trick users into installing it on their computers. Once installed, the Trojan horse can then give the attacker remote access to the computer, allowing them to steal data, install additional malware, or even take control of the computer completely.
Trojan horses are one of the most common types of malware, and they can be very difficult to detect. This is because they often use social engineering techniques to trick users into installing them, such as by sending them an email with a link to a malicious website or by attaching a Trojan horse to a legitimate file.