arXiv subjects

Shiwen Song

Publications and source records attributed to Shiwen Song.

5 recordsLinked to original sources

arXiv2026

From Signals to Behaviors: Evidence-Based Android Malware Detection

Android malware remains a persistent threat, and detecting it accurately is a long-standing open problem. Whether an app is malicious depends on what it actually does and the context in which it does it, not on the surface signals it happens to exhibit. Existing detectors instead reason about proxies for behavior, such as learned features or local code slices, and flag whatever deviates from these proxies as malicious. But deviation is not maliciousness: benign apps that merely look unusual are over-flagged, evolving malware that looks ordinary slips through. We argue that detection should be behavior-oriented: recover an app's potentially malicious behaviors and judge which are truly malicious. To realize this, we present Praxis, which structures detection as a hypothesize-confirm-judge pipeline: it hypothesizes candidate behaviors from coarse static signals, confirms each by grounding it in code evidence verified with program analysis, and judges the confirmed behaviors in context: the user's awareness, the app's functional context, and how they compose into an attack. For a malicious app, Praxis returns a verdict and the supported behaviors. We evaluate Praxis against seven baselines across three challenging settings. It achieves the best overall detection performance (87.4% F1), outperforming the baselines by 18.6-34.8 percentage points. On high-permission benign apps, it reduces the false-positive rate to 13.0%, a reduction of 41.1-67.0 percentage points compared with the baselines. Beyond binary detection, Praxis recovers fine-grained malicious behaviors at 87.3% F1, outperforming prior behavior-level approaches by 56.5-73.4 percentage points. Ablation studies show that each stage of the pipeline contributes to the final performance.

cs.CR↗

arXiv2026

From Exploration to Specification: LLM-Based Property Generation for Mobile App Testing

Mobile apps often suffer from functional bugs that do not cause crashes but instead manifest as incorrect behaviors under specific user interactions. Such bugs are difficult to detect automatically because they often lack explicit test oracles. Property-based testing can effectively expose them by checking intended behavioral properties under diverse interactions. However, its use largely depends on manually written properties, whose construction is difficult and expensive, limiting its practical use for mobile apps. To address this limitation, we propose PropGen, an automated approach for generating properties for Android apps. However, this task is challenging for two reasons: app functionalities are often hard to systematically uncover and execute, and properties are difficult to derive accurately from observed behaviors. To this end, PropGen performs functionality-guided exploration to collect behavioral evidence from app executions, synthesizes properties from the collected evidence, and refines imprecise properties based on testing feedback. We implemented PropGen and evaluated it on 12 real-world Android apps. The results show that PropGen can effectively identify and execute valid app functionalities, generate valid properties, and repair most imprecise ones. Across all apps, PropGen identified 1,210 valid functionalities and correctly executed 977 of them, compared with 491 and 187 for the baseline. It generated 985 properties, 912 of which were valid, and repaired 118 of 127 imprecise ones exposed during testing. With the resulting properties, we found 25 previously unknown functional bugs in the latest versions of the subject apps, many of which were missed by existing functional testing techniques.

cs.SE↗

arXiv2026

How Effective Are NPM Malicious Package Detectors? A Large-Scale Empirical Study

The NPM ecosystem faces escalating threats from malicious packages that exploit its open publication model. While numerous detection tools have been proposed, they are evaluated on disparate datasets with inconsistent settings, making cross-tool comparison unreliable and leaving practitioners without clear guidance. We present the first large-scale empirical study of NPM malicious package detection, evaluating 11 tools with 16 variants on a unified benchmark of 6,420 malicious and 7,288 benign packages annotated with 11 behavior categories and 8 evasion techniques. Unlike prior work, we inspect each tool's source code to explain why tools succeed or fail, not merely how often. Our key findings: (1) the precision and recall a tool achieves are structurally determined by how it resolves the ambiguity between code capability and malicious intent, with IntelGuard reaching the best F1 at 95.98% by grounding its judgment in retrieved evidence and GuardDog the best among conventional tools at 93.32%; (2) behavioral coupling amplifies detection signals when behaviors co-occur, raising SAP_DT from 3.2% to 79.3% for the collect-and-exfiltrate chain; (3) 80.3% of malware uses no evasion because the ecosystem lacks mandatory pre-publication scanning; (4) ML degradation is driven by concept convergence rather than concept drift, since malware became simpler and every decision boundary fitted to a corpus ages with it; (5) combination effectiveness equals complementarity minus false-positive introduction, not paradigm diversity. Strategic combinations reach up to 97.21% accuracy and 97.02% F1. We release our benchmark and evaluation framework.

cs.SE↗

arXiv2026

Bridging Expert Reasoning and LLM Detection: A Knowledge-Driven Framework for Malicious Packages

Open-source ecosystems such as NPM and PyPI are increasingly targeted by supply chain attacks, yet existing detection methods either depend on fragile handcrafted rules or data-driven features that fail to capture evolving attack semantics. We present IntelGuard, a retrieval-augmented generation (RAG) based framework that integrates expert analytical reasoning into automated malicious package detection. IntelGuard constructs a structured knowledge base from over 8,000 threat intelligence reports, linking malicious code snippets with behavioral descriptions and expert reasoning. When analyzing new packages, it retrieves semantically similar malicious examples and applies LLM-guided reasoning to assess whether code behaviors align with intended functionality. Experiments on 4,027 real-world packages show that IntelGuard achieves 99% accuracy and a 0.50% false positive rate, while maintaining 96.5% accuracy on obfuscated code. Deployed on PyPI.org, it discovered 54 previously unreported malicious packages, demonstrating interpretable and robust detection guided by expert knowledge.

cs.SE↗

arXiv2025

FCGHunter: Towards Evaluating Robustness of Graph-Based Android Malware Detection

Graph-based detection methods leveraging Function Call Graphs (FCGs) have shown promise for Android malware detection (AMD) due to their semantic insights. However, the deployment of malware detectors in dynamic and hostile environments raises significant concerns about their robustness. While recent approaches evaluate the robustness of FCG-based detectors using adversarial attacks, their effectiveness is constrained by the vast perturbation space, particularly across diverse models and features. To address these challenges, we introduce FCGHunter, a novel robustness testing framework for FCG-based AMD systems. Specifically, FCGHunter employs innovative techniques to enhance exploration and exploitation within this huge search space. Initially, it identifies critical areas within the FCG related to malware behaviors to narrow down the perturbation space. We then develop a dependency-aware crossover and mutation method to enhance the validity and diversity of perturbations, generating diverse FCGs. Furthermore, FCGHunter leverages multi-objective feedback to select perturbed FCGs, significantly improving the search process with interpretation-based feature change feedback. Extensive evaluations across 40 scenarios demonstrate that FCGHunter achieves an average attack success rate of 87.9%, significantly outperforming baselines by at least 44.7%. Notably, FCGHunter achieves a 100% success rate on robust models (e.g., AdaBoost with MalScan), where baselines achieve only 11% or are inapplicable.

cs.CR↗