Presented at
DEF CON 29 (2021),
Aug. 8, 2021, noon
(45 minutes)
The concept of Trusted Execution Environments has been broadly introduced to microcontrollers with ARM's TrustZone-M. While much experience with TrustZone-A can be applied, architectural differences with ARMv8-M lead to a very different approach to configuration and transitions between secure and non-secure worlds. This talk will deep dive into how TrustZone-M works, where to look for weaknesses in implementations, and a detailed look into NXP LPC55S69's implementation including discovering an undocumented peripheral that leads to a priviledge escalation vulnerability exploitable with TrustedFirmware-M. Finally, NXP PSIRT will be used as a case study in how _not_ to respond to a vulnerability report.
REFERENCES:
TrustZone technology for the ARMv8-M architecture Version 2.0; ARM; https://developer.arm.com/documentation/100690/0200
Your Peripheral Has Planted Malware -- An Exploit of NXP SOCs Vulnerability; Yuwei Zheng, Shaokun Cao, Yunding Jian, Mingchuang Qin; DEFCON 26; https://media.defcon.org/DEF CON 26/DEF CON 26 presentations/DEFCON-26-Yuwei-Zheng-Shaokun-Cao-Bypass-the-SecureBoot-and-etc-on-NXP-SOCs-Updated.pdf
Presenters:
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Rick Altherr
- Oxide Computer Company
Rick Altherr has a career ranging from ASICs to UX with a focus on the intersection of hardware and software, especially in server systems. His past work includes USBAnywhere, leading the unification of OpenBMC as a project under Linux Foundation, co-authoring a whitepaper on Google's Titan, and reverse engineering Xilinx 7 Series FPGA bitstreams as part of prjxray.
@kc8apf
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Laura Abbott
- Oxide Computer Company
Laura Abbott is a software engineer who focuses on low level software. Her background includes Linux kernel development with work in the memory management and security areas as well as ARM enablement.
@openlabbott
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