Your Neighbor Knows What You're Doing: Defending Smart Home IoT Device Traffic from Privacy LAN Attacks

Internet of Things (IoT) devices introduce unprecedented security challenges for protecting the privacy of users inside the home. Despite encrypting wireless communication traffic by standard security protocols (e.g., WPA2), an attacker near the smart home can still extract packet header information (e.g., MAC address, packet length) from the available unencrypted contents to make predictions about the user’s behavior. To prevent this severe breach on privacy, in this paper, we propose a bandwidth efficient defense method through the introduction of changing padding durations for traffic shaping to reduce the confidence of a nearby attacker in the LAN from identifying genuine user activities for WiFi-enabled IoT devices. From our performance evaluation, we decreased bandwidth usage by over 20% at low attacker confidence with our proposal compared to the conventional method of fixed padding.