Caught in the Act(ivation): Toward Pre-Output and Multi-Turn Detection of Credential Exfiltration by LLM Agents

arXiv:2606.04141v1 Announce Type: cross Abstract: LLM agents often place sensitive credentials in the same context window as untrusted retrieved content, creating a direct path for indirect prompt injection to induce credential exfiltration. We study this failure mode through three complementary defenses. First, we ask whether activation probes can detect credential access before output tokens are emitted. Second, we construct honeytokens from format-specific character models and calibrate detection with split conformal prediction. Third, we treat multi-turn exfiltration as a cumulative inform
The proliferation of LLM agents in sensitive corporate environments is accelerating, making vulnerabilities and defensive measures against credentials exfiltration an immediate concern.
This research addresses a critical security flaw in LLM agent deployments, impacting data integrity and trust in autonomous systems, which is vital for enterprise adoption.
Enterprises can now implement more robust pre-output and multi-turn detection mechanisms to prevent credential exfiltration by LLM agents, enhancing their security posture.
- · Cybersecurity firms
- · Enterprises deploying LLM agents
- · AI agent developers
- · Malicious actors targeting LLMs
- · Companies with weak AI security protocols
Improved security frameworks for LLM agent deployments will emerge, reducing the risk of data breaches.
Increased trust in LLM agents will accelerate their integration into mission-critical business processes.
New regulatory standards for AI system security, specifically addressing agentic vulnerabilities, may be established.
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Read at arXiv cs.AI