What is a man-in-the-middle (MitM) attack?
A man-in-the-middle (MitM) attack is an exploit in which an intruder intercepts communications between two parties, usually an end user and a website. The attacker can use the information accessed to commit identity theft or other types of fraud.
Users can protect themselves from a traditional man-in-the-middle attack by refraining from logging into sites where sensitive data is maintaned while on a public network. However, a variation on that exploit, called an "active man-in-the-middle attack" makes it possible for an intruder to access information for any site that the user logs into at other times.
This was last updated in January 2010
Editorial Director: Margaret Rouse