Remote Access Trojan (RAT)

A Remote Access Trojan, or RAT, is a type of malware that, when installed on a computing system, enables a remote attacker to surreptitiously access the system, its resources, and its data.

Remote access trojans are a subset of a larger category of malware known as "trojan horses," so named because they are installed either in secret or under false pretenses or misdirection for the purpose of enabling security protections to be defeated and the system to be taken over.