Weizhong Qiang | Searcharxiv

arXiv2025

$ρ$Hammer: Reviving RowHammer Attacks on New Architectures via Prefetching

Rowhammer is a critical vulnerability in dynamic random access memory (DRAM) that continues to pose a significant threat to various systems. However, we find that conventional load-based attacks are becoming highly ineffective on the most recent architectures such as Intel Alder and Raptor Lake. In this paper, we present $ρ$Hammer, a new Rowhammer framework that systematically overcomes three core challenges impeding attacks on these new architectures. First, we design an efficient and generic DRAM address mapping reverse-engineering method that uses selective pairwise measurements and structured deduction, enabling recovery of complex mappings within seconds on the latest memory controllers. Second, to break through the activation rate bottleneck of load-based hammering, we introduce a novel prefetch-based hammering paradigm that leverages the asynchronous nature of x86 prefetch instructions and is further enhanced by multi-bank parallelism to maximize throughput. Third, recognizing that speculative execution causes more severe disorder issues for prefetching, which cannot be simply mitigated by memory barriers, we develop a counter-speculation hammering technique using control-flow obfuscation and optimized NOP-based pseudo-barriers to maintain prefetch order with minimal overhead. Evaluations across four latest Intel architectures demonstrate $ρ$Hammer's breakthrough effectiveness: it induces up to 200K+ additional bit flips within 2-hour attack pattern fuzzing processes and has a 112x higher flip rate than the load-based hammering baselines on Comet and Rocket Lake. Also, we are the first to revive Rowhammer attacks on the latest Raptor Lake architecture, where baselines completely fail, achieving stable flip rates of 2,291/min and fast end-to-end exploitation.

cs.CR↗

arXiv2022

Contrastive Learning for Robust Android Malware Familial Classification

Due to its open-source nature, Android operating system has been the main target of attackers to exploit. Malware creators always perform different code obfuscations on their apps to hide malicious activities. Features extracted from these obfuscated samples through program analysis contain many useless and disguised features, which leads to many false negatives. To address the issue, in this paper, we demonstrate that obfuscation-resilient malware family analysis can be achieved through contrastive learning. The key insight behind our analysis is that contrastive learning can be used to reduce the difference introduced by obfuscation while amplifying the difference between malware and other types of malware. Based on the proposed analysis, we design a system that can achieve robust and interpretable classification of Android malware. To achieve robust classification, we perform contrastive learning on malware samples to learn an encoder that can automatically extract robust features from malware samples. To achieve interpretable classification, we transform the function call graph of a sample into an image by centrality analysis. Then the corresponding heatmaps can be obtained by visualization techniques. These heatmaps can help users understand why the malware is classified as this family. We implement \emph{IFDroid} and perform extensive evaluations on two datasets. Experimental results show that \emph{IFDroid} is superior to state-of-the-art Android malware familial classification systems. Moreover, \emph{IFDroid} is capable of maintaining a 98.4\% F1 on classifying 69,421 obfuscated malware samples.

cs.CR↗