Arm Cortex-M Microcontrollers (MCUs) are widely used in IoT devices, and the introduction of TrustZone-M brought about a new security landscape. However, the TrustZone-M technology primarily focuses on CPU-level security controls, overlooking the need for system-wide isolation mechanisms that include various peripherals. This oversight can lead to vulnerabilities in TrustZone-M systems
The presentation discussed the assessment of an MCU-based TEE, highlighting the limitations in achieving isolation within the secure world and the potential exploits that could bypass existing isolation measures. The talk emphasized the importance of understanding PSA isolation levels and developing mechanisms to offer comprehensive protection in MCU environments. Through a live demo, the speakers showcased how a Secure Partition could breach hardware and software TEE isolation boundaries, underscoring the critical need for a holistic security approach in MCU systems. ```https://www.youtube.com/watch?v=o_-a-_oqCgU