Mitigating Backdoor Attacks using Activation-Guided Model Editing
Felix Hsieh, Huy H. Nguyen, AprilPyone MaungMaung, Dmitrii Usynin, Isao Echizen
TL;DR
Backdoor attacks undermine model integrity by embedding triggers that cause targeted misclassification. The paper introduces activation-guided model editing, a lightweight unlearning approach that uses a small domain-equivalent unseen dataset to guide weight edits on later network layers, without access to the original training data. The method handles two scenarios, with backdoor knowledge (BDK) and without (¬BDK), and includes an optional repair step to preserve target-class utility. Across multiple datasets and architectures, the approach achieves strong forgetting with minimal data and computation, outperforming prior unlearning methods and enabling practical, fast backdoor mitigation.
Abstract
Backdoor attacks compromise the integrity and reliability of machine learning models by embedding a hidden trigger during the training process, which can later be activated to cause unintended misbehavior. We propose a novel backdoor mitigation approach via machine unlearning to counter such backdoor attacks. The proposed method utilizes model activation of domain-equivalent unseen data to guide the editing of the model's weights. Unlike the previous unlearning-based mitigation methods, ours is computationally inexpensive and achieves state-of-the-art performance while only requiring a handful of unseen samples for unlearning. In addition, we also point out that unlearning the backdoor may cause the whole targeted class to be unlearned, thus introducing an additional repair step to preserve the model's utility after editing the model. Experiment results show that the proposed method is effective in unlearning the backdoor on different datasets and trigger patterns.
