GhostBuster: Understanding and overcoming the pitfalls of transient execution vulnerability checkers

Abstract

Transient execution vulnerabilities require system administrators to evaluate whether their systems are vulnerable and whether available mitigations are enabled. They are aided in this task by multiple community-developed tools, transient execution vulnerability checkers. Yet, no analysis of these tools exists, in particular with respect to their shortcomings and whether they might mislead administrators into a false sense of security. In this paper, we provide the first comprehensive analysis of these tools and underpinning methodologies. We run the tools on a large set of combinations of Intel/AMD architectures and Linux kernel versions and report on their efficacy and shortcomings. We also run these tools on 17 of the most prominent cloud providers, report the collected results and present the current status on the preparedness of the IT hosting industry against this class of attacks. Finally, we present a new tool called GhostBuster, that combines methodologies and results gathered by existing tools to provide a more accurate view a system's stance against transient execution attacks for a given use case.