Authors: Gunnar Alendal (Norwegian University of Science and Technology (NTNU)), Geir Olav Dyrkolbotn (NTNU), and Stefan Axelsson (NTNU)
DFRWS USA 2021
Abstract
Performing mobile phone acquisition today requires breaking–often hardware assisted–security. In recent years, Embedded Secure Element (eSE) hardware has been introduced in mobile phones, with a view towards increasing the security of critical system features and encrypted user data. The idea being that the eSE should remain secure even if the rest of the system is compromised. The eSE is set to become crucial to modern mobile phone security, challenging Digital Forensics. The eSE is designed to withstand both logical and physical attacks, including side channel attacks, and to keep the attack surface towards the rest of the system/phone small, and complexity low to minimise the risk of implementation errors.
In this paper we adapt current state-of-the-art attacks to the eSE platform and present an attack on an eSE by Samsung, recently introduced in their premium mobile phones. We show how, with limited resources, our approach discovered a vulnerability that could be exploited, leading to a complete compromise of all the eSE security goals and a full loss of future eSE trust, as mitigation of our attack in already fielded devices is challenging. This eSE is Common Criteria EAL 5+ certified and our attack exposes the gap between intended and achieved security, undermining the implied trust in such certifications.
We explain the eSE security design, the details of our attack, and discuss how a single vulnerability can have such devastating security results. The ultimate result of our research facilitates acquisition of affected devices, demonstrating use of offensive methods in advanced Digital Forensic Acquisition.