A man-in-the-middle attack is a widespread type of WiFi security vulnerability. In this type of attack, an attacker intercepts data passing between two devices but lets them believe that they are still communicating directly (and securely) with each other.
Both parties think that they are communicating securely with a remote server, but in fact, all of this traffic is passing through a “man in the middle.”
Learn more about Man In The Middle Attack.