Abstract:Denoising probabilistic diffusion models have shown breakthrough performance that can generate more photo-realistic images or human-level illustrations than the prior models such as GANs. This high image-generation capability has stimulated the creation of many downstream applications in various areas. However, we find that this technology is indeed a double-edged sword: We identify a new type of attack, called the Natural Denoising Diffusion (NDD) attack based on the finding that state-of-the-art deep neural network (DNN) models still hold their prediction even if we intentionally remove their robust features, which are essential to the human visual system (HVS), by text prompts. The NDD attack can generate low-cost, model-agnostic, and transferrable adversarial attacks by exploiting the natural attack capability in diffusion models. Motivated by the finding, we construct a large-scale dataset, Natural Denoising Diffusion Attack (NDDA) dataset, to systematically evaluate the risk of the natural attack capability of diffusion models with state-of-the-art text-to-image diffusion models. We evaluate the natural attack capability by answering 6 research questions. Through a user study to confirm the validity of the NDD attack, we find that the NDD attack can achieve an 88% detection rate while being stealthy to 93% of human subjects. We also find that the non-robust features embedded by diffusion models contribute to the natural attack capability. To confirm the model-agnostic and transferrable attack capability, we perform the NDD attack against an AD vehicle and find that 73% of the physically printed attacks can be detected as a stop sign. We hope that our study and dataset can help our community to be aware of the risk of diffusion models and facilitate further research toward robust DNN models.