【摘要】 基于处理器微架构的隐蔽信道能够绕过现有安全检测进行秘密信息传输或泄漏,已成为现代处理器面临的主要威胁.本文从隐蔽信道的工作原理入手,根据秘密信息在隐蔽信道中存储时间的长短将基于微架构的隐蔽信道分为持续型和瞬时型两类,详细介绍两类隐蔽信道的泄露原理、运行特征、典型攻击、攻击条件等,利用已有的隐蔽信道评估指标对现有隐蔽信道进行横向评估,给出了微处理器资源中潜在隐蔽信道挖掘的分析思路,对未被现有隐蔽信道覆盖的微架构资源进行分析.分析发现Intel处理器中的前端总线符合构建新型瞬时隐蔽信道的条件.对已有防护和检测策略按原理进行分类,详细介绍每类防护和检测策略的工作原理、现有策略、适用范围,对未来出现新型微架构隐蔽信道威胁提出合理可行的防护建议.更多还原

【Abstract】 Covert channels based on processor microarchitecture have become a major threat to modern processors by bypassing existing security detection to transmit or leak secrets. Based on the storage time of covert channels, this paper divides microarchitecture-based covert channels into two types: persistent covert channels and volatile covert channels. The principle of the attack, runtime characteristics, typical attacks and attack conditions of the two types of covert channels are introduced and the existing covert channels are evaluated by the existing metrics. Based on the analysis of the attack conditions, a new analysis method on how to find the potential covert channel in microprocessor resources is proposed, and the microprocessor resources that are not used by existing covert channels are analyzed. The analysis shows that, the front-end bus in the Intel processors meets the conditions for creating a new transient covert channel. Based on the working principle of microarchitecture-based covert channel, many strategies of protection and detection methods have been proposed, and they are classified according to the working principles. The working principle, existing strategies and application scope of each type are introduced in detail. Moreover, reasonable and feasible protection suggestions are proposed for potential microarchitecture-based covert channels that may exist in the future.更多还原