Remote Fault Injection Attack against Cryptographic Modules via Intentional Electromagnetic Interference from an Antenna

Fault injection attacks on cryptographic modules pose significant threats, yet conventional fault injection methods require physical access to the target device. This paper introduces a novel fault injection method using Intentional Electromagnetic Interference (IEMI) to induce temporary faults in cryptographic modules without intrusion, proximity, or synchronization with the encryption process. The proposed method selects a frequency that can cause faults only in the target cryptographic modules without disrupting other modules in the device. Additionally, faults suitable for secret key analysis are efficiently generated even when EM waves are injected asynchronously into the cryptographic operation. To demonstrate the effectiveness of the proposed method, an experiment was conducted where EM waves were irradiated from an antenna positioned 2 meters away from a cryptographic device with an Advanced Encryption Standard (AES) implementation, inducing faults. The secret key was successfully retrieved by applying Differential Fault Analysis (DFA) to the obtained faulty ciphertexts. The proposed method holds the potential to be applied to devices that have previously been considered outside the scope of fault injection attack threats, owing to the difficulty in implementing conventional fault scenarios. This suggests a broader range of applicability for addressing security concerns in such devices. Consequently, there exists a possibility that even devices already in circulation could become susceptible to these threats, necessitating the implementation of measures to protect such equipment against potential attacks. In the countermeasure approach against this kind of threat, we propose and demonstrate the ability to significantly reduce the transmission efficiency of EM waves utilized for attacks by expanding upon the concept of EM shielding. Consequently, it significantly decreased the occurrence rate of faults. This is achieved by merely positioning conductive materials close to cryptographic devices rather than completely enclosing them in a conductive enclosure.