HardScope: Hardening Embedded Systems Against Data-Oriented Attacks

Memory-unsafe programming languages like C and C++ leave many (embedded) systems vulnerable to attacks like control-flow hijacking. However, defenses against control-flow attacks, such as (fine-grained) randomization or control-flow integrity are ineffective against data-oriented attacks and more expressive Data-oriented Programming (DOP) attacks that bypass state-of-the-art defenses. We propose run-time scope enforcement (RSE), a novel approach that efficiently mitigates all currently known DOP attacks by enforcing compile-time memory safety constraints like variable visibility rules at run-time. We present Hardscope, a proof-of-concept implementation of hardware-assisted RSE for RISC-V, and show it has a low performance overhead of 3.2% for embedded benchmarks.