  Recent work shows that deep neural networks are vulnerable to adversarial
examples. Much work studies adversarial example generation, while very little
work focuses on more critical adversarial defense. Existing adversarial
detection methods usually make assumptions about the adversarial example and
attack method (e.g., the word frequency of the adversarial example, the
perturbation level of the attack method). However, this limits the
applicability of the detection method. To this end, we propose TREATED, a
universal adversarial detection method that can defend against attacks of
various perturbation levels without making any assumptions. TREATED identifies
adversarial examples through a set of well-designed reference models. Extensive
experiments on three competitive neural networks and two widely used datasets
show that our method achieves better detection performance than baselines. We
finally conduct ablation studies to verify the effectiveness of our method.
