PDRIMA: A Policy-Driven Runtime Integrity Measurement and Attestation Approach for ARM TrustZone-based TEE

TL;DR

PDRIMA is a novel runtime integrity measurement and attestation framework for ARM TrustZone TEEs, enhancing security by analyzing attack surfaces and providing remote attestation with minimal performance impact.

Contribution

It introduces a policy-driven approach with in-TEE subsystems for measurement, appraisal, and attestation, addressing gaps in runtime integrity verification for TrustZone-based TEEs.

Findings

Prototype implementation on Raspberry Pi 3B+ demonstrates feasibility.

Security analysis confirms robustness against identified attack vectors.

Performance evaluation shows acceptable overhead for practical deployment.

Abstract

Trusted Execution Environments (TEEs) such as ARM TrustZone are widely used in IoT and embedded devices to protect sensitive code and data. However, most existing defenses focus on secure boot or REE-side monitoring and provide little visibility into the runtime integrity of the TEE. This leaves TrustZone-based devices exposed to persistent TEE compromises. We propose Policy-Driven Runtime Integrity Measurement and Attestation (PDRIMA), a runtime integrity protection approach for TrustZone-based TEEs. PDRIMA systematically analyzes TEE attack surfaces and introduces two in-TEE subsystems: a Secure Monitor Agent (SMA) that performs policy-driven measurement, appraisal, logging, and time-based re-measurement over the TEE kernel, static components, user-TAs, and security-critical system calls; and a Remote Attestation Agent (RAA) that aggregates tamper-evident evidence and exposes a remote attestation protocol for verifying. We analyze PDRIMA's security against identified attack surfaces, implement a prototype on OP-TEE for Raspberry Pi 3B+, and evaluate its performance overhead to indicate its practicability.