________________ is a program that, unknown to the user, contains instructions that exploit a known vulnerability in some software.

Trojan Horse is a program that, unknown to the user, contains instructions that exploit a known vulnerability in some software. Trojan horse is a program downloaded and installed on a computer that appears harmless, but is, in fact, malicious. 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.