arXiv AI

Same Operation, Different Permission: Evaluating Whether Guardrails Honor Authorization

arXiv AI
Sep 23

ActGov: Governing LLM Agent Actions via Policy-Constrained Validation

ActGov is a runtime enforcement framework that validates each action proposed by a large language model (LLM) agent before it interacts with external tools, ensuring that actions stay within task‑scoped authorization boundaries and comply with dynamically constructed policies. It builds policies from tool specifications, benign tasks, and failure traces, verifying updates via SMT‑based counterexample checking. In evaluations on AgentDojo and AgentDyn benchmarks, ActGov consistently reduces indirect prompt‑injection attack success while maintaining task utility, outperforming existing defenses.

By Kaiyuan Zhang, Yuke Peng, Ke Jiang, Yinqian Zhang
arXiv AI
Oct 12

VEPA: Verified Evolving Formal Policy for Lifelong LLM Agent Guardrails

VEPA is a framework that enables the verified evolution of formal guardrails for lifelong large language model agents. It represents guardrails as formal policies of symbolic rules over typed agent events, and during deployment uses LLM‑guided feedback to propose policy patches that fix new failures while preserving correct behavior. A deterministic verifier accepts only structurally valid, conflict‑free policies, and an evidence‑aware authority layer activates verified rules only when sufficient supporting evidence exists, ensuring that uncertain updates do not directly affect guardrail decisions.

By Duy Nguyen, Lesly Miculicich, Bhavana Dalvi Mishra, Shuo Li, Krishnamurthy Dj Dvijotham, Mohit Bansal, Tomas Pfister, Long T. Le
arXiv AI
6d ago

From Approval to Abuse: Privilege Escalation Attacks on Harness-Protected Coding Agents

The paper "From Approval to Abuse: Privilege Escalation Attacks on Harness-Protected Coding Agents" examines how coding agents that use execution harnesses to enforce permission boundaries can be tricked into granting overly broad allow-rules. By planting adversarial context in a repository, attackers can steer an agent into requesting a plausibly justified yet dangerously wide permission, which, if approved, lets the agent bypass the harness and execute malicious actions without further human oversight. Experiments on platforms such as Claude Code and Codex CLI show that 58% of trials succeed in eliciting such rules, which then cover 56.9% of category-specific capability tests and enable silent goal completion in 81% of approved cases, thereby undermining the safety promise of human-in-the-loop oversight.

By Xianglin Yang, Yechao Zhang, Jiahao Liu, Yulin Chen, Yuxin Cao, Bryan Hooi, Jiaheng Zhang