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[May-27] Ghost Calls from Operational 4G Call Systems: IMS Vulnerability, Call DoS Attack, and Countermeasure

Institute of Information Systems and Applications

Speaker:

Prof. Chi-Yu Li

Assistant Professor, Computer Science, National Chiao Tung University

Topic:

Ghost Calls from Operational 4G Call Systems: IMS Vulnerability, Call DoS Attack, and Countermeasure

Date:

13:30-15:00 Wednesday 27-May-2020

Locate

Delta 105

QR code:

0527-Online_QRcode

Link:

https://teams.microsoft.com/l/meetup-join/19%3ac66957ce42ce48d1845c9dd63c464b57%40thread.tacv2/1586261565565?context=%7b%22Tid%22%3a%226c3bc511-43c7-4596-baeb-2335c69c41f1%22%2c%22Oid%22%3a%223cb25719-499f-4b52-ba8d-31e6b47c6cab%22%7d

Hosted by:

Prof. Cheng-Hsin Hsu

Abstract

IMS (IP Multimedia Subsystem) is an essential framework for providing 4G/5G multimedia services. It has been deployed worldwide to support two call services: VoLTE (Voice over LTE) and VoWi-Fi (Voice over Wi-Fi). VoWi-Fi enables telephony calls over the Wi-Fi network to complement VoLTE. In this work, we uncover that the VoWi-Fi signaling session can be hijacked to maliciously manipulate the IMS call operation. The adversary can easily make ghost calls to launch a stealthy call DoS (Denial of Service) attack against specific cellular users. Only phone numbers, but not any malware or network information, are required from the victims. This sophisticated attack harnesses a design defect of the IMS call state machine, but not simply flooding or a crash trigger. To stealthily detect attackable phones at run time, we exploit a vulnerability of the 4G network infrastructure, call information leakage, which we explore using machine learning. We validate these vulnerabilities in operational 4G networks of 4 top-tier carriers across Asia and North America countries with 7 phone brands. Our result shows that the call DoS attack can prevent the victims from receiving incoming calls up to 99.0% time without user awareness. We finally propose recommended solutions.

Bio:

Chi-Yu Li is currently an Assistant Professor with the Department of Computer Science, National Chiao Tung University (NCTU). He received his PhD degree in computer science from University of California, Los Angeles (UCLA) in 2015. Before joining UCLA, he received his Master’s and Bachelor’s degrees from the Department of Computer Science, NCTU. His research interests include wireless networking, mobile networks and systems, and network security. He has published many papers in top-tier academic conferences of both networking and security areas, such as ACM MOBICOM, IEEE INFOCOM, and ACM CCS. He received the Award of MTK Young Chair Professor (2016), MOST Young Scholar Research Award (2017-2020), and the Best Paper Award in IEEE CNS 2018.

All faculties and students are welcome to join.

 

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