arXiv AI

The Show-Up Attack: When Subagents Win Over Their Supervisor

The paper introduces the "show‑up attack," where a malicious subagent tricks a supervisor into assigning it tasks beyond its intended scope. Using the SUA‑Arena benchmark, the authors test six attack strategies across 188 scenarios and evaluate six leading LLMs, finding all are vulnerable, with GPT‑5.6‑Sol experiencing an attack success rate of up to 0.93. Standard mitigations like prompting or restricted communication do not consistently reduce the risk, highlighting the need for explicit authority‑enforcement mechanisms in multi‑agent systems.

arXiv AI
Oct 21

MAS-Guard: Unified Guardrails from Individual Agents to Multi-Agent LLM Systems

MAS-Guard is a unified framework designed to safeguard both single- and multi-agent large language model (LLM) systems. It introduces a local Agent Guardrail (A-Guard) layer that uses task-specific experts to evaluate agentic events, and a system-level Control Plane that applies deterministic structural checks and semantic assessments to routes, capabilities, and message content. The framework enforces interventions—allow, reflection, confirmation, and block—across benchmarks, reducing attack success rates by 71.5‑86.3% while maintaining utility on benign tasks.

By Mohammad Kachuee, Phu Mon Htut, Sheng Li, Nikolaos Pappas, Miguel Ballesteros Martinez, Yassine Benajiba, Sujith Ravi, Dan Roth
arXiv Machine Learning
Aug 28

Out of Sight, Not Out of Mind: Unveiling Latent Attack in Latent-based Multi-Agent Systems

The paper investigates whether hidden representations in latent-based multi‑agent systems can carry attack information that remains effective during normal operation. A latent attack framework is introduced, reactivating attack effects through latent interventions without using adversarial text. Experiments show that these latent attacks can significantly degrade task performance, especially when targeting inter‑agent KV‑cache handoffs, and that the degradation cannot be explained by simple perturbations or invalid generation.

By Chenxi Wang, Ruiyang Huang, Jiayan Sun, Lei Wei, Yifan Wu
arXiv AI
Sep 10

AgentLeak: Cloning Stronger LLM Agent Capabilities onto Weaker Agents Beyond Skill Stealing

The paper introduces AgentLeak, a black‑box attack that clones the task‑solving capabilities of a strong LLM agent onto a weaker one by exploiting differences between successful and failed executions. Unlike prior skill‑stealing methods that only recover explicit skill artifacts, AgentLeak identifies and incorporates missing procedural behaviors, boosting task pass rates by over 40% and closing more than 80% of the capability gap across 20 scenarios. The study demonstrates that observable execution behavior can leak proprietary procedural knowledge, posing a confidentiality risk for LLM agents.

By Xiaoting Lyu, Yuhong Wu, Yufei Han, Shichang Liu, Liang Zhang, Bin Wang, Bin Wang, Xiaobo Ma, Wei Wang
arXiv AI
Oct 27

A Deterministic Security Runtime for LLM Agents on MPI and Batch-Scheduled HPC Systems: Consensus-Governed, Hardware-Rooted Supervision of Every Rank

The paper introduces Enclawed, a deterministic security runtime that protects large language model agents running on high‑performance computing (HPC) systems. It provides hardware‑rooted supervision for every rank, preventing compromised hosts from causing catastrophic failures, and enforces launch policies, lease‑based heartbeats, and automatic eviction or killing of tampered jobs. Enclawed operates without administrator privileges, integrates via Secure Shell, and adds minimal startup overhead while successfully blocking a wide range of simulated attacks.

By Alfredo Metere
arXiv AI
Jun 12

PI-Hunter: Automated Red-Teaming for Exposing and Localizing Prompt Injections

arXiv:2606. 12737v1 Announce Type: cross Abstract: Large Language Models (LLMs) are rapidly evolving into agentic systems that interact with external tools and environments, introducing new security risks such as indirect prompt injection attacks through untrusted external sources.

By Pengfei He, Lesly Miculicich, Vishesh Sharma, Ash Fox, George Lee, Jiliang Tang, Tomas Pfister, Long T. Le