Thermal Covert Channels on Multi-core Platforms

Side channels remain a challenge to information flow control and security in modern computing platforms. Resource partitioning techniques that minimise the number of shared resources among processes are often used to address this challenge. In this work, we focus on multicore platforms and we demonstrate that even seemingly strong isolation techniques based on dedicated cores and memory can be circumvented through the use of thermal side channels. Specifically, we show that the processor core temperature can be used both as a side channel as well as a covert communication channel even when the system implements strong spatial and temporal partitioning. Our experiments on an x86-based platform demonstrate covert thermal channels that achieve up to 12.5 bps and a weak side channel that can detect processes executed on neighbouring cores. This work therefore shows a limitation in the isolation that can be achieved on existing multi-core systems.