Dummy-Aware Weighted Attack (DAWA): Breaking the Safe Sink in Dummy Class Defenses

Fuente: arXiv
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Autori principali: Yu, Yunrui, Feng, Xuxiang, Qin, Pengda, Wang, Pengyang, Wang, Kafeng, Xu, Cheng-zhong, Su, Hang, Zhu, Jun
Natura: Preprint
Pubblicazione: 2026
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author Yu, Yunrui
Feng, Xuxiang
Qin, Pengda
Wang, Pengyang
Wang, Kafeng
Xu, Cheng-zhong
Su, Hang
Zhu, Jun
author_facet Yu, Yunrui
Feng, Xuxiang
Qin, Pengda
Wang, Pengyang
Wang, Kafeng
Xu, Cheng-zhong
Su, Hang
Zhu, Jun
contents Adversarial robustness evaluation faces a critical challenge as new defense paradigms emerge that can exploit limitations in existing assessment methods. This paper reveals that Dummy Classes-based defenses, which introduce an additional "dummy" class as a safety sink for adversarial examples, achieve significantly overestimated robustness under conventional evaluation strategies like AutoAttack. The fundamental limitation stems from these attacks' singular focus on misleading the true class label, which aligns perfectly with the defense mechanism--successful attacks are simply captured by the dummy class. To address this gap, we propose Dummy-Aware Weighted Attack (DAWA), a novel evaluation method that simultaneously targets both the true label and dummy label with adaptive weighting during adversarial example synthesis. Extensive experiments demonstrate that DAWA effectively breaks this defense paradigm, reducing the measured robustness of a leading Dummy Classes-based defense from 58.61% to 29.52% on CIFAR-10 under l_infty perturbation (epsilon=8/255). Our work provides a more reliable benchmark for evaluating this emerging class of defenses and highlights the need for continuous evolution of robustness assessment methodologies.
format Preprint
id arxiv_https___arxiv_org_abs_2603_29182
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Dummy-Aware Weighted Attack (DAWA): Breaking the Safe Sink in Dummy Class Defenses
Yu, Yunrui
Feng, Xuxiang
Qin, Pengda
Wang, Pengyang
Wang, Kafeng
Xu, Cheng-zhong
Su, Hang
Zhu, Jun
Machine Learning
Cryptography and Security
Adversarial robustness evaluation faces a critical challenge as new defense paradigms emerge that can exploit limitations in existing assessment methods. This paper reveals that Dummy Classes-based defenses, which introduce an additional "dummy" class as a safety sink for adversarial examples, achieve significantly overestimated robustness under conventional evaluation strategies like AutoAttack. The fundamental limitation stems from these attacks' singular focus on misleading the true class label, which aligns perfectly with the defense mechanism--successful attacks are simply captured by the dummy class. To address this gap, we propose Dummy-Aware Weighted Attack (DAWA), a novel evaluation method that simultaneously targets both the true label and dummy label with adaptive weighting during adversarial example synthesis. Extensive experiments demonstrate that DAWA effectively breaks this defense paradigm, reducing the measured robustness of a leading Dummy Classes-based defense from 58.61% to 29.52% on CIFAR-10 under l_infty perturbation (epsilon=8/255). Our work provides a more reliable benchmark for evaluating this emerging class of defenses and highlights the need for continuous evolution of robustness assessment methodologies.
title Dummy-Aware Weighted Attack (DAWA): Breaking the Safe Sink in Dummy Class Defenses
topic Machine Learning
Cryptography and Security
url https://arxiv.org/abs/2603.29182