An Embarrassingly Simple Detector for Model Extraction Attacks in Large Language Model API Traffic

arXiv:2606.05725v1 Announce Type: cross Abstract: Large language models (LLMs) are increasingly deployed through hosted APIs, making model extraction a practical threat to model ownership and service security. However, individual extraction queries often resemble benign requests, and existing evaluations often focus on single-query anomaly scoring or pure benign-versus-attacker user settings. We formulate model extraction monitoring as benign-calibrated traffic-window distribution testing and show that an embarrassingly simple detector is effective: embed incoming queries into a semantic space
As LLM APIs become ubiquitous, the practical threats of model extraction necessitate immediate detection mechanisms to protect intellectual property and service integrity.
This development offers a simple yet effective defense against a growing threat to proprietary AI models, safeguarding investments and competitive advantages for API providers.
The ability to monitor and detect model extraction attacks in real-time within LLM API traffic improves security posture for AI service providers.
- · LLM API providers
- · AI Intellectual Property holders
- · Cybersecurity sector
- · Malicious actors attempting model extraction
- · Competitors relying on illicit model replication
Increased security for Large Language Models deployed via APIs.
Reduced incentive for illicit model extraction, fostering more legitimate AI development.
Potential for new business models around AI model security and intellectual property protection.
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Read at arXiv cs.CL