Deep Adversarial Defense Against Multilevel-Lp Attacks
Ren Wang, Yuxuan Li, Alfred Hero
TL;DR
This work tackles the vulnerability of deep networks to adversarial perturbations and the limitation of single-$\ell_p$ defenses. It introduces Efficient Robust Mode Connectivity (ERMC), which links two endpoint models trained for $p=\infty$ and $p=1$ via a Quadratic Bezier path $\phi_{\boldsymbol\theta}(t)$ and optimizes a worst-case objective across $\{1,\infty\}$ using a MSD-based solver, followed by ensemble selection along the path. The method yields a computationally efficient multilevel $\ell_p$ defense and demonstrates superior robustness against $\ell_\infty$, $\ell_2$, and $\ell_1$ attacks compared to AT-$\ell_\infty$, E-AT, and MSD on CIFAR-10/100 with architectures including PreResNet110, WideResNet-28-10, and ViT-base; an ensemble (ERMC-5) further boosts performance while reducing training time by about 36%. Overall, ERMC provides a practical route to universal robustness by integrating targeted adversarial training with mode connectivity and model ensembling, enabling robust deployment across diverse perturbation regimes.
Abstract
Deep learning models have shown considerable vulnerability to adversarial attacks, particularly as attacker strategies become more sophisticated. While traditional adversarial training (AT) techniques offer some resilience, they often focus on defending against a single type of attack, e.g., the $\ell_\infty$-norm attack, which can fail for other types. This paper introduces a computationally efficient multilevel $\ell_p$ defense, called the Efficient Robust Mode Connectivity (EMRC) method, which aims to enhance a deep learning model's resilience against multiple $\ell_p$-norm attacks. Similar to analytical continuation approaches used in continuous optimization, the method blends two $p$-specific adversarially optimal models, the $\ell_1$- and $\ell_\infty$-norm AT solutions, to provide good adversarial robustness for a range of $p$. We present experiments demonstrating that our approach performs better on various attacks as compared to AT-$\ell_\infty$, E-AT, and MSD, for datasets/architectures including: CIFAR-10, CIFAR-100 / PreResNet110, WideResNet, ViT-Base.
