Evaluating Security Specification Mining for a CISC Architecture

Security specification mining is a relatively new line of research that aims to develop a set of security properties for use during the design validation phase of the hardware life-cycle. Prior work in this field has targeted open-source RISC architectures and relies on access to the register transfer level design, developers' repositories, bug tracker databases, and email archives. We develop Astarte, a tool for security specification mining of closed source, CISC architectures. As with prior work, we target properties written at the instruction set architecture (ISA) level. We use a full-system fast emulator with a lightweight extension to generate trace data, and we partition the space of security properties on security-critical signals in the architecture to manage complexity. We evaluate the approach for the x86-64 ISA. The Astarte framework produces roughly 1300 properties. Our automated approach produces a categorization that aligns with prior manual efforts. We study two known security flaws in shipped x86/x86-64 processor implementations and show that our set of properties could have revealed the flaws. Our analysis provides insight into those properties that are guaranteed by the ISA, those that are required of the operating system, and those that have become de facto properties by virtue of many operating systems assuming the behavior.