Survey of Transient Execution Attacks and Their Mitigations

Transient execution attacks, also known as speculative execution attacks, have drawn much interest in the last few years as they can cause critical data leakage. Since the first disclosure of Spectre and Meltdown attacks in January 2018, a number of new transient execution attack types have been demonstrated targeting different processors. A transient execution attack consists of two main components: transient execution itself and a covert channel that is used to actually exfiltrate the information.Transient execution is a result of the fundamental features of modern processors that are designed to boost performance and efficiency, while covert channels are unintended information leakage channels that result from temporal and spatial sharing of the micro-architectural components. Given the severity of the transient execution attacks, they have motivated computer architects in both industry and academia to rethink the design of the processors and to propose hardware defenses. To help understand the transient execution attacks, this survey summarizes the phases of the attacks and the security boundaries across which the information is leaked in different attacks.This survey further analyzes the causes of transient execution as well as the different types of covert channels and presents a taxonomy of the attacks based on the causes and types. This survey in addition presents metrics for comparing different aspects of the transient execution attacks and uses them to evaluate the feasibility of the different attacks. This survey especially considers both existing attacks and potential new attacks suggested by our analysis. This survey finishes by discussing different mitigations that have so far been proposed at the micro-architecture level and discusses their benefits and limitations.

Negative Responses to Disclosure of Sexual Victimization and Victims’ Symptoms of PTSD and Depression: The Protective Role of Ethnic Identity

College-aged women experience high rates of sexual victimization. Their postassault symptoms are associated with the types of responses they receive from the people to whom they disclose these experiences. Negative responses are pervasive and associated with poorer outcomes. The current study examined whether a strong sense of ethnic identity and comfort with the mainstream culture moderate the association between negative responses to the first disclosure of sexual victimization and symptoms of posttraumatic stress disorder (PTSD) and depression. A diverse sample (10% Black/African American, 51% White, 39% Other, and 66% Hispanic) of undergraduate women was recruited from two urban, Eastern United States universities for this online study. Participants reported histories of sexual victimization, demographics, responses to sexual assault disclosure (i.e., victim blame, treating the victim differently, taking control, distraction, and egocentric reactions), symptoms of PTSD and depression, and their ethnic identity and mainstream cultural comfort. Thirty-seven percent ( n = 221) endorsed an experience of sexual victimization, and 165 disclosed it to someone. Hierarchical ordinary least squares regressions revealed that a stronger sense of ethnic identity was associated with fewer symptoms of PTSD for those women who experienced higher levels of control, distraction, and egocentric responses from the first disclosure recipient. A strong sense of affiliation with the mainstream culture did not protect survivors who reported receiving negative responses to disclosure against symptoms of PTSD or depression. Ethnic affiliation may protect women against PTSD when they receive high levels of negative messages about sexual victimization experiences.