Security Risks Introduced by Weak Authentication in Smart Home IoT Systems

Smart home IoT systems rely on authentication mechanisms to ensure that only authorized entities can control devices and access sensitive functionality. In practice, these mechanisms must balance security with usability, often favoring persistent connectivity and minimal user interaction. This paper presents an empirical analysis of authentication enforcement in deployed smart home IoT devices, focusing on how authentication state is established, reused, and validated during normal operation and under routine network conditions. A set of widely deployed consumer devices, including smart plugs, lighting devices, cameras, and a hub based ecosystem, was evaluated in a controlled residential environment using passive network measurement and controlled interaction through official mobile applications. Authentication behavior was examined during initial pairing, over extended periods of operation, after common network changes, and under replay attempts from a different local network host. The results show that authentication state established during pairing is consistently reused across control actions, persists for extended periods without explicit expiration, and remains valid after network events such as reconnection, address reassignment, and router reboot. Replay experiments demonstrate that previously observed authentication artifacts can often be reused to issue control commands from another host on the same local network with high success rates. These behaviors were observed across multiple device categories and ecosystems. The findings indicate that current smart home IoT authentication mechanisms rely on long lived trust relationships with limited binding to session freshness, network context, or controller identity.