An attack in which a cracker intercepts data and replies to it, making it look as though the reply came from the intended recipient. A victim thus attacked might expose private data—such as credit card or bank account information—that can later be used to defraud the victim.
Schell, B.H. and Martin, C. Contemporary World Issues Series: Cybercrime: A Reference Handbook. Santa Barbara, CA: ABC-CLIO, 2004.