Control-flow Integrity for Real-time Embedded Systems

• Main Author: Brown, Nicholas
• Other Authors: Craig E. Wills, Department Head
• Format: Others
• Published: Digital WPI 2017
• Subjects: real-time; embedded; CFI; ARM; cybersecurity
• Online Access: https://digitalcommons.wpi.edu/etd-theses/402; https://digitalcommons.wpi.edu/cgi/viewcontent.cgi?article=1401&context=etd-theses

As embedded systems become more connected and more ubiquitous in mission- and safety-critical systems, embedded devices have become a high- value target for hackers and security researchers. Attacks on real-time embedded systems software can put lives in danger and put our critical infrastructure at risk. Despite this, security techniques for embedded systems have not been widely studied. Many existing software security techniques for general purpose computers rely on assumptions that do not hold in the embedded case. This thesis focuses on one such technique, control-flow integrity (CFI), that has been vetted as an effective countermeasure against control-flow hijacking attacks on general purpose computing systems. Without the process isolation and fine-grained memory protections provided by a general purpose computer with a rich operating system, CFI cannot provide any security guarantees. This thesis explores a way to use CFI on ARM Cortex-R devices running minimal real-time operating systems. We provide techniques for protecting runtime structures, isolating processes, and instrumenting compiled ARM binaries with CFI protection.