arXiv AI

AlignPoison: Conditional Targeted Poisoning of Generative Recommenders via Decoding-Aligned Prefixes

arXiv Machine Learning
Oct 2

VirusCascade: Hijacking Collaborative Reflection in LLM-Powered Recommender Agents

The paper introduces VirusCascade, a black‑box attack that exploits the collaborative reflection mechanism in LLM‑powered recommender agents. By leveraging reflective persistence and cross‑agent propagation, the attack promotes a target item through semantic rationalisation and structural positioning, achieving state‑of‑the‑art targeted exposure on four real‑world datasets. The study demonstrates that existing static‑pipeline attacks cannot exploit this recurrent, multi‑agent amplification pathway.

By Yurong Hao, Wen Zhou, Guowei Guan, Tiantong Wu, Fuyao Zhang, Wei Yang Bryan Lim
arXiv AI
Jun 3

Inference Cost Attacks for Retrieval-Augmented Large Language Models

arXiv:2606. 02643v1 Announce Type: cross Abstract: Retrieval-Augmented Generation (RAG)-enhanced LLM systems, while powerful, introduce substantial inference costs due to the inclusion of an extra multi-stage pipeline that dynamically retrieves and synthesizes information from external knowledge sources.

By Chengliang Liu, Liangbo Ning, Yujuan Ding, Wenqi Fan
arXiv Machine Learning
Oct 16

Poisoning the corpora of protein design systems during pre-training and retrieval

The paper reports two data‑only poisoning attacks on protein design systems. In the first, poisoned sequences were added to the pre‑training corpus of large autoregressive language models, causing the models to reliably generate sequences triggered by specific patterns after as few as 200 contaminated examples. The second attack inserted malicious records into a retrieval corpus, enabling a single query‑aware record to dominate retrieval results and, in many cases, alter the generated protein sequence or transfer a new domain via homology.

By Charalampos Koilakos, Kimon-Antonios Provatas, Michail Patsakis, Candace SY Chan, Georgios A. Pavlopoulos, Ilias Georgakopoulos-Soares
arXiv AI
Oct 9

Token by Token, Compromised: Backdoor Vulnerabilities in Unified Autoregressive Models

Unified autoregressive models (UAMs) generate both text and image tokens in a single pass, simplifying multimodal generation but introducing new vulnerabilities. The authors present the Token by Token Backdoor Attack (ToBAC), the first backdoor attack targeting UAMs, which can be executed via data-based or model-based poisoning. ToBAC can manipulate both visual outputs and accompanying text, enabling subtle triggers such as the word "cool" to induce brand promotion or ideological influence in a majority of generations, with success rates up to 63.1% against JanusPro.

By Tobias Braun, Jonas Henry Grebe, Hossein Shakibania, Anna Rohrbach, Marcus Rohrbach
arXiv Computation and Language
Sep 2

VerTox: Verifiable Reward-Guided Corpus Poisoning Against Neural Ranking Models

VerTox is a framework that turns corpus poisoning of neural ranking models into a verifiable reward‑guided reinforcement learning problem. By fine‑tuning compact large language models with reward shaping that couples ranking distortion and factual corruption, VerTox generates fluent, low‑perplexity adversarial documents that frequently outrank target items across multiple ranking architectures, including a commercial embedding model. Experiments show near‑perfect attack success and significant degradation of downstream retrieval‑augmented generation performance.

By Zhiqi Huang, Vivek Datla, Zhichao Xu, Puxuan Yu, Vivek Srikumar, Alfy Samuel