Checking Information Flow in Cloud-based IoT Access Control Policies (Extended Version)

2026-07-30

AI Summary

This work addresses the challenge of implicit information leakage in cloud-based IoT access control policies, where unintended inter-device information flows can bypass conventional permission checks. To tackle this issue, the authors propose a novel approach that integrates information flow analysis with SMT solving. By formally modeling AWS IoT Core components, they construct policy-driven information flow graphs and leverage an SMT solver to generate finite graph representations, enabling automated verification of cross-device information flows. The resulting tool, IOT:POKER, demonstrates both effectiveness and practicality by successfully uncovering previously unknown security vulnerabilities in real-world deployment scenarios and multiple production-grade policies.

Abstract

Many cloud providers for IoT technologies offer access control mechanisms whose proper configuration is critical for security. However, verifying permissions in isolation is insufficient in a setting where devices have different levels of trust or are compartmentalised in various subsystems. This work analyses IoT access control policies to identify potential security vulnerabilities from unwanted information flow between devices. To this end, we formally model AWS IoT Core's components and define an information flow graph to capture the communication among devices permitted by the access control policies. We build a finite representation of the graph by leveraging an SMT solver, thus enabling the verification of information flow between devices. We implement our approach in a tool called IOT:POKER, and assess it on a realistic scenario and several real-world policies.

Problem

• information flow
• IoT access control
• security vulnerabilities
• cloud-based IoT
• unwanted information flow

Innovation

• information flow
• access control
• IoT security
• SMT solver
• formal verification