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Guangyu Shen

17 accepted papers

2026

From Poisoned to Aware: Fostering Backdoor Self-Awareness in LLMs

ICML 2026spotlight

Backdoor attacks can introduce deceptive behaviors into large language models, causing them to execute prohibited actions only when specific secret triggers appear in the input. Existing safety training methods largely fail to address this vulnerability, due to the inherent difficulty of uncovering …

Cited by 0SourceScholar
2025

JailbreakDiffBench: A Comprehensive Benchmark for Jailbreaking Diffusion Models

ICCV 2025poster

Diffusion models are widely used in real-world applications, but ensuring their safety remains a major challenge. Despite many efforts to enhance the security of diffusion models, jailbreak and adversarial attacks can still bypass these defenses, generating harmful content. However, the lack of stan…

Cited by 0SourcePDFScholar
2025

Profiler: Black-box AI-generated Text Origin Detection via Context-aware Inference Pattern Analysis

EMNLP 2025

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 t

Cited by 0SourcePDFScholar
2025

System Prompt Hijacking via Permutation Triggers in LLM Supply Chains

ACL 2025finding

LLMs are increasingly developed through distributed supply chains, where model providers create base models that deployers customize with system prompts for task-specific applications and safety alignment. We introduce SHIP, a novel post-deployment attack that bypasses system prompts, enabling unres…

2024

BiScope: AI-generated Text Detection by Checking Memorization of Preceding Tokens

NeurIPS 2024poster

Detecting text generated by Large Language Models (LLMs) is a pressing need in order to identify and prevent misuse of these powerful models in a wide range of applications, which have highly undesirable consequences such as misinformation and academic dishonesty. Given a piece of subject text, m…

2024

Elijah: Eliminating Backdoors Injected in Diffusion Models via Distribution Shift

AAAI 2024technical

Diffusion models (DM) have become state-of-the-art generative models because of their capability of generating high-quality images from noises without adversarial training. However, they are vulnerable to backdoor attacks as reported by recent studies. When a data input (e.g., some Gaussian noise)…

2024

LOTUS: Evasive and Resilient Backdoor Attacks through Sub-Partitioning

CVPR 2024poster

Backdoor attack poses a significant security threat to Deep Learning applications. Existing attacks are often not evasive to established backdoor detection techniques. This susceptibility primarily stems from the fact that these attacks typically leverage a universal trigger pattern or transformatio…

2024

UNIT: Backdoor Mitigation via Automated Neural Distribution Tightening

ECCV 2024poster

"Deep neural networks (DNNs) have demonstrated effectiveness in various fields. However, DNNs are vulnerable to backdoor attacks, which inject a unique pattern, called trigger, into the input to cause misclassification to an attack-chosen target label. While existing works have proposed various meth…

2023

Detecting Backdoors in Pre-Trained Encoders

CVPR 2023poster

Self-supervised learning in computer vision trains on unlabeled data, such as images or (image, text) pairs, to obtain an image encoder that learns high-quality embeddings for input data. Emerging backdoor attacks towards encoders expose crucial vulnerabilities of self-supervised learning, since dow…

2023

Django: Detecting Trojans in Object Detection Models via Gaussian Focus Calibration

NeurIPS 2023poster

Object detection models are vulnerable to backdoor or trojan attacks, where an attacker can inject malicious triggers into the model, leading to altered behavior during inference. As a defense mechanism, trigger inversion leverages optimization to reverse-engineer triggers and identify compromised m…

2023

FLIP: A Provable Defense Framework for Backdoor Mitigation in Federated Learning

ICLR 2023poster

Federated Learning (FL) is a distributed learning paradigm that enables different parties to train a model together for high quality and strong privacy protection. In this scenario, individual participants may get compromised and perform backdoor attacks by poisoning the data (or gradients). Existin…

2023

MEDIC: Remove Model Backdoors via Importance Driven Cloning

CVPR 2023poster

We develop a novel method to remove injected backdoors in deep learning models. It works by cloning the benign behaviors of a trojaned model to a new model of the same structure. It trains the clone model from scratch on a very small subset of samples and aims to minimize a cloning loss that denotes…

Cited by 7SourcePDFScholar
2023

ParaFuzz: An Interpretability-Driven Technique for Detecting Poisoned Samples in NLP

NeurIPS 2023poster

Backdoor attacks have emerged as a prominent threat to natural language processing (NLP) models, where the presence of specific triggers in the input can lead poisoned models to misclassify these inputs to predetermined target classes. Current detection mechanisms are limited by their inability to a…

Cited by 21SourcePDFScholar
2022

Better Trigger Inversion Optimization in Backdoor Scanning

CVPR 2022oral

Backdoor attacks aim to cause misclassification of a subject model by stamping a trigger to inputs. Backdoors could be injected through malicious training and naturally exist. Deriving backdoor trigger for a subject model is critical to both attack and defense. A popular trigger inversion method is…

Cited by 104PDFScholar
2022

Complex Backdoor Detection by Symmetric Feature Differencing

CVPR 2022poster

Many existing backdoor scanners work by finding a small and fixed trigger. However, advanced attacks have large and pervasive triggers, rendering existing scanners less effective. We develop a new detection method. It first uses a trigger inversion technique to generate triggers, namely, universal i…

Cited by 64PDFcodeScholar
2022

Constrained Optimization with Dynamic Bound-scaling for Effective NLP Backdoor Defense

ICML 2022spotlight

Modern language models are vulnerable to backdoor attacks. An injected malicious token sequence (i.e., a trigger) can cause the compromised model to misbehave, raising security concerns. Trigger inversion is a widely-used technique for scanning backdoors in vision models. It can- not be directly app…

2021

Backdoor Scanning for Deep Neural Networks through K-Arm Optimization

ICML 2021spotlight

Back-door attack poses a severe threat to deep learning systems. It injects hidden malicious behaviors to a model such that any input stamped with a special pattern can trigger such behaviors. Detecting back-door is hence of pressing need. Many existing defense techniques use optimization to generat…