One Exploit to Rule them All? On the Security of Drop-in Replacement and Counterfeit Microcontrollers

Authors: 

Johannes Obermaier, Marc Schink, and Kosma Moczek

Abstract: 

With the increasing complexity of embedded systems, the firmware has become a valuable asset. At the same time, pressure for cost reductions in hardware is imminent. These two aspects are united at the heart of the system, i.e., the microcontroller. It runs and protects its firmware, but simultaneously has to prevail against cheaper alternatives. For the very popular STM32F1 microcontroller series, this has caused the emergence of many competitors in the last few years who offer drop-in replacements or even sell counterfeit devices at a fraction of the original price. Thus, the question emerges whether the replacements are silicon-level clones and, if not, whether they provide better, equal, or less security. In this paper, we analyze a total of six devices by four manufacturers, including the original device, in depth. Via a low-level analysis, we identify all of them as being individually developed devices. We further put the focus on debug and hardware security, discovering several novel vulnerabilities in all devices, causing the exposure of the entire firmware. All of the presented vulnerabilities, including invasive ones, are on a Do it Yourself (DiY) level without the demand for a sophisticated lab -- thereby underlining the urgency for hardware fixes. To facilitate further research, reproduction, and testing of other devices, we provide a comprehensive description of all vulnerabilities in this paper and code for proofs-of-concepts online.

Open Access Media

USENIX is committed to Open Access to the research presented at our events. Papers and proceedings are freely available to everyone once the event begins. Any video, audio, and/or slides that are posted after the event are also free and open to everyone. Support USENIX and our commitment to Open Access.

This content is available to:

BibTeX
@inproceedings {257192,
author = {Johannes Obermaier and Marc Schink and Kosma Moczek},
title = {One Exploit to Rule them All? On the Security of Drop-in Replacement and Counterfeit Microcontrollers},
booktitle = {14th {USENIX} Workshop on Offensive Technologies ({WOOT} 20)},
year = {2020},
url = {https://www.usenix.org/conference/woot20/presentation/obermaier},
publisher = {{USENIX} Association},
month = aug,
}
Obermaier PDF
View the slides