Who’s Calling? Characterizing Robocalls through Audio and Metadata Analysis Sathvik Prasad, Elijah Bouma-Sims, Athishay Kiran Mylappan, and Bradley Reaves, North Carolina State University https://www.usenix.org/conference/usenixsecurity20/presentation/prasad This paper is included in the Proceedings of the 29th USENIX Security Symposium. August 12–14, 2020 978-1-939133-17-5 Open access to the Proceedings of the 29th USENIX Security Symposium is sponsored by USENIX. Who’s Calling? Characterizing Robocalls through Audio and Metadata Analysis Sathvik Prasad Elijah Bouma-Sims North Carolina State University North Carolina State University
[email protected] [email protected] Athishay Kiran Mylappan Bradley Reaves North Carolina State University North Carolina State University
[email protected] [email protected] Abstract Despite the clear importance of the problem, much of what Unsolicited calls are one of the most prominent security is known about the unsolicited calling epidemic is anecdotal issues facing individuals today. Despite wide-spread anec- in nature. Despite early work on the problem [6–10], the re- dotal discussion of the problem, many important questions search community still lacks techniques that enable rigorous remain unanswered. In this paper, we present the first large- analysis of the scope of the problem and the factors that drive scale, longitudinal analysis of unsolicited calls to a honeypot it. There are several challenges that we seek to overcome. of up to 66,606 lines over 11 months. From call metadata we First, we note that most measurements to date of unsolicited characterize the long-term trends of unsolicited calls, develop volumes, trends, and motivations (e.g., sales, scams, etc.) have the first techniques to measure voicemail spam, wangiri at- been based on reports from end users.