2021/08/27 by Reza Soosahabi, Soosahabi, Reza, Bayoumi, Magdy
Computer Science · Engineering · #Cryptography and Security (cs.CR) #FOS: Computer and information sciences #Information Theory (cs.IT) #Internet Traffic Analysis and Secure E-voting #Networking and Internet Architecture (cs.NI) #Privacy-Preserving Technologies in Data #Wireless Communication Security Techniques
paper · pdf · doi:10.48550/arxiv.2108.12161
openalex publication_date 2021/08/27 · openalex created_date 2022/10/01 · openalex updated_date 2026/08/01
In this work, we propose a novel framework to identify and mitigate a recently disclosed covert channel scheme exploiting unprotected broadcast messages in cellular MAC layer protocols. Examples of covert channel are used in data exfiltration, remote command-and-control (CnC) and espionage. Responsibly disclosed to GSMA (CVD-2021-0045), the SPARROW covert channel scheme exploits the downlink power of LTE/5G base-stations that broadcast contention resolution identity (CRI) from any anonymous device according to the 3GPP standards. Thus, the SPARROW devices can covertly relay short messages across long-distance which can be potentially harmful to critical infrastructure. The SPARROW schemes can also complement the solutions for long-range M2M applications. This work investigates the security vs. performance trade-off in CRI-based contention resolution mechanisms. Then it offers a rigorously designed method to randomly obfuscate CRI broadcast in future 5G/6G standards. Compared to CRI length reduction, the proposed method achieves considerable protection against SPARROW exploitation with less impact on the random-access performance as shown in the numerical results.