PRACtical: Subarray-Level Counter Update and Bank-Level Recovery Isolation for Efficient PRAC Rowhammer Mitigation

As DRAM density increases, Rowhammer becomes more severe due to heightened charge leakage, reducing the number of activations needed to induce bit flips. The DDR5 standard addresses this threat with in-DRAM per-row activation counters PRAC and the Alert Back-Off ABO signal to trigger mitigation...

CnC-PRAC: Coalesce, Not Cache, Per Row Activation Counts for an Efficient In-DRAM Rowhammer Mitigation

JEDEC has introduced the Per Row Activation Counting PRAC framework for DDR5 and future DRAMs to enable precise counting of DRAM row activations using per-row activation counts. While recent PRAC implementations enable holistic mitigation of Rowhammer attacks, they impose slowdowns of up to 10% d...

When Mitigations Backfire: Timing Channel Attacks and Defense for PRAC-Based RowHammer Mitigations

Per Row Activation Counting PRAC has emerged as a robust framework for mitigating RowHammer RH vulnerabilities in modern DRAM systems. However, we uncover a critical vulnerability: a timing channel introduced by the Alert Back-Off ABO protocol and Refresh Management RFM commands. We present...