Second Order Soft-TEMPEST in RF Front-Ends: Design and Detection of Polyglot Modulations

Many studies have focused on threats induced by electromagnetic compatibility for information security. A potential correlation between the information processed by an electronic device and its emanations represents a real threat for the confidentiality of the information. Studies have also shown that the susceptibility of electronic devices represents a nonnegligible risk for its integrity and its availability. In particular, several Soft-TEMPEST attacks have been proposed recently in order to create electromagnetic physical covert channels. These however focus on a direct correlation between the processed data and the electromagnetic emanations. In this paper we propose to investigate indirect attacks involving a local impact of the electromagnetic compatibility of a device, such as a crosstalk, modifying the behavior of a component which in turn will contribute to establish the covert channel. To introduce such second order Soft-TEMPEST attack, the case of an attacker-controlled communication line inducing perturbations on the local oscillator of a radio frequency front-end and creating a polyglot modulation-based covert channel is proposed.