Computer attackers deceive people into executing programs that enable the intruder to gain control of the system. When an unsuspecting user runs a program planted by an attacker, the result may give the intruder access to the victim's computer system. Other programs record the activities of the computer user and return that information to the attacker. While a social engineer can trick a person into executing computer instructions that may do damage, a technically based attack tricks the computer's operating system into executing computer instructions that may cause the same sort of damage.