Faster and Better: Detecting Vulnerabilities in Linux-based IoT Firmware with Optimized Reaching Definition Analysis

Abstract

IoT devices are often found vulnerable, i.e., untrusted inputs may trigger potential vulnerabilities and flow to sensitive operations in the firmware, which could cause severe damage. As such vulnerabilities are in general taint-style, a promising solution to find them is static taint analysis. However, existing solutions have limited efficiency and effectiveness. In this paper, we propose a new efficient and effective taint analysis solution, namely HermeScan, to discover such vulnerabilities, which utilizes reaching definition analysis (RDA) to conduct taint analysis and gets much fewer false negatives, false positives, and time costs. We have implemented a prototype of HermeScan and conducted a thorough evaluation on two datasets, i.e., one 0-day dataset with 30 latest firmware and one N-day dataset with 98 older firmware, and compared with two state-of-theart (SOTA) solutions, i.e., KARONTE and SaTC. In terms of effectiveness, HermeScan, SaTC, and KARONTE find 163, 32, and 0 vulnerabilities in the 0-day dataset respectively. In terms of accuracy, the true positive rates of HermeScan, SaTC, and KARONTE are 81%, 42%, and 0% in the 0-day dataset. In terms of efficiency, HermeScan is 7.5X and 3.8X faster than SaTC and KARONTE on average in finding 0-day vulnerabilities.