RF Leakage in Embedded Devices: Security and Reliability Risks

This paper addresses the growing security challenges associated with RF leakage in embedded devices. As microelectronics systems become more integrated, unintentional electromagnetic emissions can act as side channels, leaking sensitive information even when devices comply with existing Electromagnetic Interference (EMI) and Electromagnetic Compatibility (EMC) standards. While these standards are designed to ensure functional reliability, they fall short in detecting information leakage that exploits side-channel vulnerabilities. We investigate real-world scenarios in which secure data is compromised through RF emissions. Through experimental and simulation-based analysis, we demonstrate how modulated signals from interfaces such as SPI and JTAG in commodity devices (such as TICC2642, ESP32, and AR- TIC R2 ARGOS chipset) can propagate through RF transmission paths, leading to unintended data exposure. Additionally, we mathematically model concretely interesting scenarios such as phase noise leakage in Phase-Locked Loop (PLL) circuits and amplitude-based signal leakage in PCIe3 devices, showing how attackers can exploit these emissions. Despite compliance with FCC and IEEE standards, we illustrate that conventional testing methods fail to detect such threats. Our findings emphasize the need for enhanced RF security measures that account for side-channel risks. We propose practical detection and mitigation strategies to bridge the gap between current EMI regulations and RF security. This work highlights the importance of redefining testing standards to ensure both system reliability and data confidentiality in modern (tiny and tightly coupled) embedded systems.