No, of Course I Can! Deeper Fine-Tuning Attacks That Bypass Token-Level Safety Mechanisms

Fuente: arXiv
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Main Authors: Kazdan, Joshua, Puri, Abhay, Schaeffer, Rylan, Yu, Lisa, Cundy, Chris, Stanley, Jason, Koyejo, Sanmi, Dvijotham, Krishnamurthy
Format: Preprint
Published: 2025
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author Kazdan, Joshua
Puri, Abhay
Schaeffer, Rylan
Yu, Lisa
Cundy, Chris
Stanley, Jason
Koyejo, Sanmi
Dvijotham, Krishnamurthy
author_facet Kazdan, Joshua
Puri, Abhay
Schaeffer, Rylan
Yu, Lisa
Cundy, Chris
Stanley, Jason
Koyejo, Sanmi
Dvijotham, Krishnamurthy
contents Leading language model (LM) providers like OpenAI and Anthropic allow customers to fine-tune frontier LMs for specific use cases. To prevent abuse, these providers apply filters to block fine-tuning on overtly harmful data. In this setting, we make three contributions: First, while past work has shown that safety alignment is "shallow", we correspondingly demonstrate that existing fine-tuning attacks are shallow -- attacks target only the first several tokens of the model response, and consequently can be blocked by generating the first several response tokens with an aligned model. Second, we conceptually illustrate how to make attacks deeper by introducing a new fine-tuning attack that trains models to first refuse harmful requests before answering them; this "refuse-then-comply" strategy bypasses shallow defenses and produces harmful responses that evade output filters. Third, we demonstrate the potency of our new fine-tuning attack by jailbreaking both open-source models equipped with defenses and production models, achieving attack success rates of 57% and 72% against GPT-4o and Claude Haiku, respectively. Our attack received a $2000 bug bounty from OpenAI and was acknowledged as a vulnerability by Anthropic. Our work undermines the notion that models are safe because they initially refuse harmful requests and broadens awareness of the scope of attacks that face production fine-tuning APIs.
format Preprint
id arxiv_https___arxiv_org_abs_2502_19537
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle No, of Course I Can! Deeper Fine-Tuning Attacks That Bypass Token-Level Safety Mechanisms
Kazdan, Joshua
Puri, Abhay
Schaeffer, Rylan
Yu, Lisa
Cundy, Chris
Stanley, Jason
Koyejo, Sanmi
Dvijotham, Krishnamurthy
Cryptography and Security
Artificial Intelligence
Machine Learning
Leading language model (LM) providers like OpenAI and Anthropic allow customers to fine-tune frontier LMs for specific use cases. To prevent abuse, these providers apply filters to block fine-tuning on overtly harmful data. In this setting, we make three contributions: First, while past work has shown that safety alignment is "shallow", we correspondingly demonstrate that existing fine-tuning attacks are shallow -- attacks target only the first several tokens of the model response, and consequently can be blocked by generating the first several response tokens with an aligned model. Second, we conceptually illustrate how to make attacks deeper by introducing a new fine-tuning attack that trains models to first refuse harmful requests before answering them; this "refuse-then-comply" strategy bypasses shallow defenses and produces harmful responses that evade output filters. Third, we demonstrate the potency of our new fine-tuning attack by jailbreaking both open-source models equipped with defenses and production models, achieving attack success rates of 57% and 72% against GPT-4o and Claude Haiku, respectively. Our attack received a $2000 bug bounty from OpenAI and was acknowledged as a vulnerability by Anthropic. Our work undermines the notion that models are safe because they initially refuse harmful requests and broadens awareness of the scope of attacks that face production fine-tuning APIs.
title No, of Course I Can! Deeper Fine-Tuning Attacks That Bypass Token-Level Safety Mechanisms
topic Cryptography and Security
Artificial Intelligence
Machine Learning
url https://arxiv.org/abs/2502.19537