Image Hijacks: Adversarial Images can Control Generative Models at Runtime

Fuente: arXiv
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Main Authors: Bailey, Luke, Ong, Euan, Russell, Stuart, Emmons, Scott
Format: Preprint
Published: 2023
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author Bailey, Luke
Ong, Euan
Russell, Stuart
Emmons, Scott
author_facet Bailey, Luke
Ong, Euan
Russell, Stuart
Emmons, Scott
contents Are foundation models secure against malicious actors? In this work, we focus on the image input to a vision-language model (VLM). We discover image hijacks, adversarial images that control the behaviour of VLMs at inference time, and introduce the general Behaviour Matching algorithm for training image hijacks. From this, we derive the Prompt Matching method, allowing us to train hijacks matching the behaviour of an arbitrary user-defined text prompt (e.g. 'the Eiffel Tower is now located in Rome') using a generic, off-the-shelf dataset unrelated to our choice of prompt. We use Behaviour Matching to craft hijacks for four types of attack, forcing VLMs to generate outputs of the adversary's choice, leak information from their context window, override their safety training, and believe false statements. We study these attacks against LLaVA, a state-of-the-art VLM based on CLIP and LLaMA-2, and find that all attack types achieve a success rate of over 80%. Moreover, our attacks are automated and require only small image perturbations.
format Preprint
id arxiv_https___arxiv_org_abs_2309_00236
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Image Hijacks: Adversarial Images can Control Generative Models at Runtime
Bailey, Luke
Ong, Euan
Russell, Stuart
Emmons, Scott
Machine Learning
Computation and Language
Cryptography and Security
Are foundation models secure against malicious actors? In this work, we focus on the image input to a vision-language model (VLM). We discover image hijacks, adversarial images that control the behaviour of VLMs at inference time, and introduce the general Behaviour Matching algorithm for training image hijacks. From this, we derive the Prompt Matching method, allowing us to train hijacks matching the behaviour of an arbitrary user-defined text prompt (e.g. 'the Eiffel Tower is now located in Rome') using a generic, off-the-shelf dataset unrelated to our choice of prompt. We use Behaviour Matching to craft hijacks for four types of attack, forcing VLMs to generate outputs of the adversary's choice, leak information from their context window, override their safety training, and believe false statements. We study these attacks against LLaVA, a state-of-the-art VLM based on CLIP and LLaMA-2, and find that all attack types achieve a success rate of over 80%. Moreover, our attacks are automated and require only small image perturbations.
title Image Hijacks: Adversarial Images can Control Generative Models at Runtime
topic Machine Learning
Computation and Language
Cryptography and Security
url https://arxiv.org/abs/2309.00236