Alert Refresh System for Mitigating RowHammer

Abstract

Modern DRAM cells are known to be vulnerable to RowHammer attacks because they are sensitive to electrical interference between adjacent rows. Most existing approaches to mitigate Rowhammer require complicated hardware structures. This paper proposes an effective protection scheme called Alert Refresh System. The proposed scheme has a low implementation overhead because it utilizes a pin called ALERT_n, which is a part of the standard DRAM interface. In addition, it applies hardware-friendly algorithms to track complicated RowHammer attacks. Experimental results show that the proposed method achieves a high average RowHammer protection rate of 99.81% against maliciously crafted RowHammer attacks, which is 16.94% higher than PRoHIT, one of the state-of-the-art probabilistic RowHammer mitigation methods.