7 papers
Loaded Dice: Solving the Non-Selection Problem for Scalable Probabilistic RowHammer Defense
Jeonghyun Woo, Junsu Kim, Aamer Jaleel +1
DRAM scaling has exacerbated the RowHammer vulnerability. To counter this, JEDEC recently introduced Per Row Activation Counting (PRAC) with the Alert Back-Off protocol as an optio…
PrisonBreak: Jailbreaking Large Language Models with at Most Twenty-Five Targeted Bit-flips
Zachary Coalson, Jeonghyun Woo, Chris S. Lin +8
We study a new vulnerability in commercial-scale safety-aligned large language models (LLMs): their refusal to generate harmful responses can be broken by flipping only a few bits…
CnC-PRAC: Coalesce, not Cache, Per Row Activation Counts for an Efficient in-DRAM Rowhammer Mitigation
Chris S. Lin, Jeonghyun Woo, Prashant J. Nair +1
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.…
Taming Wild Branches: Overcoming Hard-to-Predict Branches using the Bullseye Predictor
Emet Behrendt, Shing Wai Pun, Prashant J. Nair
Branch prediction is key to the performance of out-of-order processors. While the CBP-2016 winner TAGE-SC-L combines geometric-history tables, a statistical corrector, and a loop p…
When Mitigations Backfire: Timing Channel Attacks and Defense for PRAC-Based RowHammer Mitigations
Jeonghyun Woo, Joyce Qu, Gururaj Saileshwar +1
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 vulnerabil…
QPRAC: Towards Secure and Practical PRAC-based Rowhammer Mitigation using Priority Queues
Jeonghyun Woo, Chris S. Lin, Prashant J. Nair +2
JEDEC has introduced the Per Row Activation Counting (PRAC) framework for DDR5 and future DRAMs to enable precise counting of DRAM row activations. PRAC enables a holistic mitigati…