The STMicroelectronics STM32 family of microcontrollers is deployed in billions of embedded systems, making them desirable, high-value targets. In particular, the STM32F2 and STM32F4 have been heavily scrutinized due to their use in popular cryptocurrency hardware wallets like the Trezor One, Trezor Model T, and KeepKey. Previous research has shown that fault injection can bypass protection mechanisms and enable Flash memory extraction. However, those techniques can lead to device corruption or permanent loss of data.

This work refines and extends the attacks against the STM32F2 and STM3F4 into a more repeatable and reliable process, resulting in the security bypass and memory extraction from dozens of devices with a 100% success rate.

Co-developed by Joe Grand of Grand Idea Studio and Lennert Wouters. No technical support will be provided for the information herein.