Assault and Battery: Evaluating the Security of Power Conversion Systems Against Electromagnetic Injection Attacks

Many modern devices, including critical infrastructure, depend on the reliable operation of electrical power conversion systems. The small size and versatility of switched-mode power converters has led to their widespread use. While transformer-based systems passively convert voltage, switched-mode power converters have an actively controlled feedback loop that relies on accurate sensor measurements. Previous academic work has shown that many types of sensors are vulnerable to Intentional Electromagnetic Interference (IEMI) attacks, and it has been speculated that power converters are also susceptible.In this paper, we present the first detailed and practical evaluation of IEMI attacks against switched-mode power converters as a whole by manipulating the voltage and current sensors in their feedback loops. We develop a novel multi-frequency IEMI attack technique to effectively target devices with multiple sensors. We experimentally validate our theoretical predictions by analyzing multiple AC-DC and DC-DC converters, automotive-grade current sensors, dedicated battery chargers, and a real-world electric vehicle charger. Our attack is reliably effective at overcharging and permanently damaging Li-ion cells, and causing the EV charger to output 50 V more than it reports.