一句话：提出 APT：一种自适应概率 In-DRAM 跟踪器，可防采样遗漏和 RFM 侧信道，缓解 DRAM 读干扰。
DRAM 读干扰加剧使透明 In-DRAM 防御需付出空间与时间开销。已有概率行采样加 RFM 的方案存在动态激活下漏采样，以及 RFM 时序变化被侧/隐蔽信道利用的问题。本文提出 APT：按实时激活计数自适应分配等概率采样机会，避免漏采样；设计 Step Mitigation，利用刷新周期 tRFC 空闲时隙，仅两次受害者刷新即可安全抵御传递性攻击，支持每次 REF 最多三次缓解（APT-3）。作者解析推导全模式下最小 RowHammer 阈值，最坏为 694；采用安全 TB-RFM 可降至 228 且开销可忽略，并显示优于 TPRAC。
With exacerbated DRAM read disturbance, transparent in-DRAM defenses require space (to track the aggressor rows) and time (to perform more mitigations). To reduce storage overhead, recent works have developed probabilistic row-sampling techniques with several entries. To address the time issue, these techniques employ Refresh Management (RFM) commands introduced in DDR5. However, probabilistic defenses with RFM face two critical challenges: (i) fixed-probability sampling under dynamic activation patterns can cause row-sampling misses, allowing attacks to evade mitigation, and (ii) RFM causes timing variations that can be exploited for side and covert channels to leak sensitive information. The goal of this paper is to design a low-cost and secure in-DRAM defense that overcomes these challenges. Our solution, APT (Adaptive Probabilistic In-DRAM Tracker), builds on two key insights. First, by ensuring that mitigation probabilities across activations always sum to 1, row-sampling misses can be prevented and the likelihood of capturing attacked rows can be improved. Second, as RFM is insecure, mitigation should exploit the unutilized slack within the refresh cycle (tRFC) while minimizing per-mitigation latency. APT adaptively allots equal sampling chances to all activations, based on real-time activation counts, avoiding sampling misses. To increase the mitigation rate without relying on RFM, we develop customizable Step Mitigation, which securely protects against transitive attacks with only two victim refreshes. Step Mitigation enables APT to perform up to three mitigations (APT-3) per periodic refresh (REF). We analytically derive the minimum RowHammer threshold tolerated by APT across all patterns. APT achieves a worst-case threshold of 694, which can be reduced to 228 using secure Timing-Based RFM (TB-RFM) at negligible overhead. We also show that APT compares favorably to TPRAC.
@inproceedings{Wu00X026,
title = {APT: Securing Against DRAM Read Disturbance via Adaptive Probabilistic In-DRAM Trackers},
author = {Runjin Wu and Meng Zhang and You Zhou and Changsheng Xie and Fei Wu},
booktitle = {ASPLOS},
year = {2026},
doi = {10.1145/3779212.3790126}
}