[smolsky]

For the ones too lazy to RTFA:

VIII. CONCLUSIONS AND FUTURE WORK

In this paper we presented LightCommands , which is an attack that uses light to inject commands into voice-controllable systems from large distances. To mount the attack, an attacker transmits light modulated with an audio signal, which is converted back to the original audio signal within a microphone. We demonstrated LightCommands on many commercially available voice-controllable systems that use Siri, Portal, Google Assistant, and Alexa, obtaining successful command injections at a maximum distance of more than 100 meters while penetrating clear glass windows. Next, we highlight deficiencies in the security of voice-controllable systems, which leads to additional compromises of third-party hardware such as locks and cars. Better understanding of the physics behind the attack will benefit both new attacks and countermeasures. In particular, we can possibly use the same principle to mount other acoustic injection attacks (e.g., on motion sensors) using light. In addition, heating by laser can also be an effective way of injecting false signals to sensors.