A Comprehensive Survey of Transient Execution Vulnerabilities: from Meltdown and Specter to Modern Variants

Abstract

Meltdown and Specter exploit hardware vulnerabilities in modern processors. These vulnerabilities allow programs to steal data currently being processed on the computer. Although programs are typically not permitted to read data from other programs, a malicious program can exploit Meltdown and Specter to access secrets stored in the memory of other running programs. This analysis covers distinct attack vectors across multiple processor architectures and provides a systematic taxonomy based on exploitation mechanisms, targeted microarchitectural components, and threat models. Although implementation-specific vulnerabilities like Meltdown have been effectively mitigated, architectural issues exemplified by Specter continue to challenge the security community. This paper also includes explainable machine learning methods for detecting Meltdown and Specter.  The dataset utilized was synthetic and does not represent actual attacks. Genuine attackers may evade detection, as we did not test against real malicious activity. The detector requires further assessment on authentic systems to evaluate its operational overhead and reliability. Future research should concentrate on: (1) designing processors with speculation techniques that leave no detectable traces; (2) developing tools for the preemptive identification of vulnerabilities; (3) establishing formal methodologies to validate security guarantees; and (4) designing architectures, such as RISC-V, with integrated security features.