Parallel Fuzzing of IoT Messaging Protocols Through Collaborative Packet Generation

Internet of Things (IoT) messaging protocols play an important role in facilitating communications between users and IoT devices. Mainstream IoT platforms employ brokers, server-side implementations of IoT messaging protocols, to enable and mediate this user-device communication. Due to the complex nature of managing communications among devices with diverse roles and functionalities, comprehensive testing of the protocol brokers necessitates collaborative parallel fuzzing. However, being unaware of the relationship between test packets generated by different parties, existing parallel fuzzing methods fail to explore the brokers’ diverse processing logic effectively. This article introduces MPF uzz , a parallel fuzzing tool designed to secure IoT messaging protocols through collaborative packet generation. The approach leverages the critical role of certain fields within IoT messaging protocols that specify the logic for message forwarding and processing by protocol brokers. MPF uzz employs an information synchronization mechanism to synchronize these key fields across different fuzzing instances and introduces a semantic-aware refinement module that optimizes generated test packets by utilizing the shared information and field semantics. This strategy facilitates a collaborative refinement of test packets across otherwise isolated fuzzing instances, thereby boosting the efficiency of parallel fuzzing. We evaluated MPF uzz on six widely used IoT messaging protocol implementations. Compared to two state-of-the-art protocol fuzzers with parallel capabilities, Peach and AFLNet, as well as two representative parallel fuzzers, SPFuzz and AFLTeam, MPF uzz achieves (6.1%, $174.5\times $ ), (20.2%, $607.2\times $ ), (1.9%, $4.1\times $ ), and (17.4%, $570.2\times $ ) higher branch coverage and fuzzing speed under the same computing resource. Furthermore, MPF uzz exposed seven previously unknown vulnerabilities in these extensively tested projects, all of which have been assigned with CVE identifiers.