DDoSPedia is a glossary that focuses on network and
application security terms with many distributed
definitions. It provides a central place for hard to find web-scattered
definitions on this topic.
A Man-in-the-Middle (MitM) Attack involves an attacker intruding on an existing connection, establishing himself or herself as a “man-in-the-middle”, or someone able to intercept and selectively modify all network traffic between two communicating devices.
If Alice is attempting to communicate with Bob, a MitM attack on Alice (by attacker Charlie) would occur as follows:
Alice receives Bob’s message encrypted with Charlie’s public key (unaware that it isn’t Bob’s key), and this process continues, with Charlie able to read and potentially modify any messages sent between Alice and Bob without either one of them knowing.