Man-in-the-Middle Attack on T-Mobile Wi-Fi Calling
Jethro G. Beekman, Chris P. Thompson · 2013
T-Mobile has a service called ?Wi-Fi Calling?, which lets users make and receive calls even when without cellular service. This service is pre-installed on millions of T-Mobile Android smartphones. We analyze the security aspects of this service from a network perspective, and demonstrate a man-in-the-middle attack caused by a lack of TLS certificate validation, allowing an attacker to eavesdrop and even modify calls and text messages placed using the Wi-Fi Calling feature. We have worked with T-Mobile to fix this issue, and, as of 18 March 2013, they report that all affected customers have received an update fixing this vulnerability.