Mitigating transient execution attacks: enhancing security through branch predictor defense strategies

In today's digital age, there is a fierce game between the performance pursuit of computer system and information security. However, with the development of technology, various forms of attacks continue to emerge. Transient execution attack, as a subversive hardware architecture vulnerability, can obtain sensitive information of the system by exploiting the internal design vulnerabilities of the processor in the transient execution caused by some errors of the processor, which poses a threat to the credibility and robustness of the overall system. From the perspective of branch predictor, this paper deeply analyzes how transient execution attack exploits branch prediction structure to achieve incorrect program flow execution and illegally steal secret data. Aiming at the structural vulnerabilities of processor branch prediction unit, this paper proposes an improved mechanism of secure branch predictor to resist transient execution attacks through the hardware architecture level. The experimental results show that the performance overhead brought by the proposed improved scheme is less than 6%, and the false prediction rate of the branch predictor is reduced by about 2%, which achieves a better balance between security and processor performance.