Zhuo Zhang
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2026
Environment Steering: Using Data Flow Control to Improve Agent Utility and Safety
Charlie Summers | Prajwal Raghunath | Aaditya Pai | Mayur Kulkarni | Zhuo Zhang | Oliver Kennedy | Eugene Wu
Proceedings of the Second Workshop for REsearch on Agent Language Models (REALM 2026)
Charlie Summers | Prajwal Raghunath | Aaditya Pai | Mayur Kulkarni | Zhuo Zhang | Oliver Kennedy | Eugene Wu
Proceedings of the Second Workshop for REsearch on Agent Language Models (REALM 2026)
LLM agents can make unsafe tool calls even when instructed to behave safely. Existing defenses constrain agents before execution, modify tool inputs/outputs, or rely on LLM judges; these approaches may depend on model behavior or block unsafe actions without helping the agent recover. We argue that the execution environment should instead enforce safety as the agent runs and steer it toward safe alternatives when violations occur—we call this Environment Steering. We implement this by modeling the agent and harness execution state as database tables, track the record-level data flows, and check these data flows against declarative policies during runtime. When violations are detected, policy- and context-specific feedback steers the agent toward safe trajectories. On AgentDyn, this enables the agent to improve task success rate over no-defense while achieving 0% attack success rate.
2025
Profiler: Black-box AI-generated Text Origin Detection via Context-aware Inference Pattern Analysis
Hanxi Guo | Siyuan Cheng | Xiaolong Jin | Zhuo Zhang | Guangyu Shen | Kaiyuan Zhang | Shengwei An | Guanhong Tao | Xiangyu Zhang
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Hanxi Guo | Siyuan Cheng | Xiaolong Jin | Zhuo Zhang | Guangyu Shen | Kaiyuan Zhang | Shengwei An | Guanhong Tao | Xiangyu Zhang
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
With the increasing capabilities of Large Language Models (LLMs), the proliferation of AI-generated texts has become a serious concern. Given the diverse range of organizations providing LLMs, it is crucial for governments and third-party entities to identify the origin LLM of a given AI-generated text to enable accurate mitigation of potential misuse and infringement. However, existing detection methods, primarily designed to distinguish between human-generated and LLM-generated texts, often fail to accurately identify the origin LLM due to the high similarity of AI-generated texts from different LLMs. In this paper, we propose a novel black-box AI-generated text origin detection method, dubbed Profiler, which accurately predicts the origin of an input text by extracting distinct context inference patterns through calculating and analyzing novel context losses between the surrogate model’s output logits and the adjacent input context. Extensive experimental results show that Profiler outperforms 10 state-of-the-art baselines, achieving more than a 25% increase in AUC score on average across both natural language and code datasets when evaluated against five of the latest commercial LLMs under both in-distribution and out-of-distribution settings.
Exploiting the Shadows: Unveiling Privacy Leaks through Lower-Ranked Tokens in Large Language Models
Yuan Zhou | Zhuo Zhang | Xiangyu Zhang
Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Yuan Zhou | Zhuo Zhang | Xiangyu Zhang
Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Large language models (LLMs) play a crucial role in modern applications but face vulnerabilities related to the extraction of sensitive information. This includes unauthorized accesses to internal prompts and retrieval of personally identifiable information (PII) (e.g., in Retrieval-Augmented Generation based agentic applications). We examine these vulnerabilities in a question-answering (QA) setting where LLMs use retrieved documents or training knowledge as few-shot prompts. Although these documents remain confidential under normal use, adversaries can manipulate input queries to extract private content. In this paper, we propose a novel attack method by exploiting the model’s lower-ranked output tokens to leak sensitive information. We systematically evaluate our method, demonstrating its effectiveness in both the agentic application privacy extraction setting and the direct training data extraction. These findings reveal critical privacy risks in LLMs and emphasize the urgent need for enhanced safeguards against information leakage.
2024
Threat Behavior Textual Search by Attention Graph Isomorphism
Chanwoo Bae | Guanhong Tao | Zhuo Zhang | Xiangyu Zhang
Proceedings of the 18th Conference of the European Chapter of the Association for Computational Linguistics (Volume 1: Long Papers)
Chanwoo Bae | Guanhong Tao | Zhuo Zhang | Xiangyu Zhang
Proceedings of the 18th Conference of the European Chapter of the Association for Computational Linguistics (Volume 1: Long Papers)
Cyber attacks cause over $1 trillion loss every year. An important task for cyber security analysts is attack forensics. It entails understanding malware behaviors and attack origins. However, existing automated or manual malware analysis can only disclose a subset of behaviors due to inherent difficulties (e.g., malware cloaking and obfuscation). As such, analysts often resort to text search techniques to identify existing malware reports based on the symptoms they observe, exploiting the fact that malware samples share a lot of similarity, especially those from the same origin. In this paper, we propose a novel malware behavior search technique that is based on graph isomorphism at the attention layers of Transformer models. We also compose a large dataset collected from various agencies to facilitate such research.Our technique outperforms state-of-the-art methods, such as those based on sentence embeddings and keywords by 6-14%. In the case study of 10 real-world malwares, our technique can correctly attribute 8 of them to their ground truth origins while using Google only works for 3 cases.