Flush+Time: A High Accuracy and High Resolution Cache Attack On ARM-FPGA Embedded SoC

Flush based cache attacks have become a practical threat to data privacy and information security due to their advantages such as high accuracy and resolution. However, their accuracy and resolution still has room for improvement. In addition, although most of the attacks have been demonstrated on x86 processors, few of them have been executed on ARM devices. We propose a high accuracy, high resolution flush based cache attack, Flush+Time. This technique solves two important challenges for cache attacks on ARM: how to flush cache lines and how to achieve precise timing. Experiments show that Flush+Time increases accuracy from 95.1% of Flush+Reload, the most powerful general cache attack so far, to 99.3%. Flush+Time has a 30.5% higher resolution than Flush+Reload, but its execution time is only 0.59 times that of Spectre.