The Coming TEMPEST

Abstract

In this thesis I present a side-channel attack against the Nexus 5, an Android smartphone, that exploits the electromagnetic radiation given off by the phone to identify which app is being run. The attack uses a consumer software-defined radio and homemade antennas tuned to 3.7 MHz and 12.4 MHz and can differentiate between a set of six different apps at a distance of up to 6 cm with an amplifier or 1 cm without. These apps were chosen so that their mere presence on a phone would give information about the political affiliations, religious beliefs, or sexual preferences of the phone’s owner. I also identify two potential sources of the compromising radiation using both the position within the phone that seems to be the source of the radiation and the characteristic radiation patterns of individual functions such as Wi-Fi use and computation. I conclude by noting that this attack is extremely cheap, portable, and easy to assemble, indicating that it a sign of things to come.