A review of endogenous security threats and cross-layer defense mechanisms in integrated sensing and communication system

As a core technology of 6G networks, Integrated Sensing and Communication (ISAC) shows great potential in the field of Space-Air-Ground Integrated Network (SAGIN). However, its integrated nature also introduces complex endogenous security threats. To address the problem that traditional network security mechanisms struggle to balance the dual requirements of communication confidentiality and real-time sensing, this paper systematically studies the endogenous security threats and cross-layer defense of ISAC systems in SAGIN. First, from three fundamental technical dimensions, including waveform and air interface design, spectrum resource sharing, and hardware-software equipment sharing, the endogenous vulnerability mechanisms of the ISAC system at the signal, data, and resource levels are deeply analyzed. Second, considering the highly dynamic spatiotemporal characteristics of space-air-ground application scenarios, the cross-layer security threats and attack paths faced by the system are systematically outlined, revealing the limitations of traditional defense mechanisms. Subsequently, a cross-layer collaborative dynamic defense architecture is proposed, which integrates key mechanisms including the construction of a physical layer trusted foundation, cross-modal data semantic security verification, and network layer resource dynamic elastic scheduling. The results indicate that this system, through the adaptive adjustment of defense strategies, effectively cuts off cross-layer collaborative attack paths, thereby providing significant dynamic resilience for ensuring high system availability. The derived theoretical models and defense framework lay a theoretical foundation for the targeted system research and development of future SAGIN, and provide technical references for the deployment of security services in related highly dynamic aerospace scenarios.