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arXiv · 2010.01799

Understanding Catastrophic Overfitting in Single-step Adversarial Training

Hoki Kim·Woojin Lee·Jaewook Lee
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Abstract

Although fast adversarial training has demonstrated both robustness and efficiency, the problem of "catastrophic overfitting" has been observed. This is a phenomenon in which, during single-step adversarial training, the robust accuracy against projected gradient descent (PGD) suddenly decreases to 0% after a few epochs, whereas the robust accuracy against fast gradient sign method (FGSM) increases to 100%. In this paper, we demonstrate that catastrophic overfitting is very closely related to the characteristic of single-step adversarial training which uses only adversarial examples with the maximum perturbation, and not all adversarial examples in the adversarial direction, which leads to decision boundary distortion and a highly curved loss surface. Based on this observation, we propose a simple method that not only prevents catastrophic overfitting, but also overrides the belief that it is difficult to prevent multi-step adversarial attacks with single-step adversarial training.

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BibTeXRIS

Hoki Kim, Woojin Lee, Jaewook Lee. 2020-10-05. Understanding Catastrophic Overfitting in Single-step Adversarial Training. https://arxiv.org/abs/2010.01799

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