RemOTA: Remote attestation for detecting use-after-free in low-power microcontrollers

In this paper, we introduce RemOTA, a novel remote attestation protocol to capture dynamic memory allocations and uses in microcontroller embedded systems, enabling detection of use-after-free errors. RemOTA performs a precomputation analysis to identify a minimal set of key points in the control flow graph, called checkpoints, which serve as boundaries enclosing sequences of pointer operations that occur along the same execution path. These checkpoints allow the grouping of multiple pointer usages into larger, semantically meaningful units, enabling efficient and targeted instrumentation. This approach is particularly effective in resource-constrained environments, as it minimizes runtime overhead while offloading verification to a remote server. RemOTA incorporates a remote verifier that receives information from the executing firmware and replicates instructions to dynamically reconstruct pointer usage and emulate memory state, allowing lightweight use-after-free detection. Through the evaluation of real-world firmware on an STM32 microcontroller, RemOTA demonstrates high precision 100% with low overhead, geometric mean 4.47% on the tested dataset. Its scalability and efficiency make RemOTA a practical solution for securing resource-constrained embedded devices in production environments.