arXiv Machine Learning By Junhoo Lee, Baekseung Kim, Seungyeon Kim, Nojun Kwak

Clean Data Can Still Carry Backdoors: Support-Persistent Backdoors for Model Reuse

Read the original on arXiv Machine Learning →

The paper introduces DAR (Discover-and-Relabel), a support‑persistent backdoor technique that remains effective even after models undergo clean‑data knowledge distillation. DAR discovers naturally occurring patterns in low‑dimensional feature subspaces via subspace clustering and then poisons labels of samples that satisfy these patterns. At inference, the backdoor is triggered by locally modifying the target image’s subspace, achieving attack accuracy comparable to state‑of‑the‑art methods while maintaining over 96% success after clean distillation.

Machine-generated by The Flow from the publisher's headline and feed description — not written or checked by a human. The full article lives at arXiv Machine Learning.

arXiv Computer Vision
Sep 4

Beyond Small Patches: Black-Box Detection and Purification of Diverse Backdoor Triggers

The paper introduces TRIM, a black‑box defense for backdoor attacks in computer vision models. TRIM identifies and removes malicious trigger regions at inference time using region‑based segmentation, adaptive trigger discovery via inpainting and diffusion, and selective purification, without needing model internals, training data, or clean samples. Experiments on various datasets and trigger types show TRIM reduces attack success rates to as low as 1.16% while maintaining high clean accuracy.

By Ahmed Abdelnaby, Mohamed Elmahallawy
arXiv Computer Vision
Aug 28

Checkerboard: Closed-Form and Data-Independent Trigger Design for Clean-Label Backdoor Attacks

The paper introduces Checkerboard, a clean‑label backdoor attack that uses a closed‑form, data‑independent trigger design based on an input‑space Fisher‑separability objective and a ridge four‑neighbor local‑smoothness prior. This approach yields a pixel‑wise checkerboard trigger without requiring data access, surrogate model training, or iterative optimization, and it outperforms existing norm‑bounded clean‑label attacks across four benchmark datasets. On CIFAR‑10, poisoning 20 samples with a 10/255 perturbation achieves a 95.72% attack success rate, while on IN‑100 a 0.4% global poisoning rate yields over 83% ASR without harming clean accuracy, and the attack remains robust against state‑of‑the‑art defenses.

By Yi Yang, Jinyang Huang, Binbin Liu, Feng-Qi Cui, Xiaokang Zhou, Haiming Jin, Zhi Liu, Jie Zhang, Meng Li
arXiv AI
Aug 20

Detecting Backdoors in Object Detection via Pre-NMS Prediction Distribution Shift

The paper introduces DistScan, a backdoor detection framework for object detection models that identifies malicious behavior by detecting shifts in the pre‑NMS prediction class distribution relative to training class frequencies. DistScan operates on clean validation data, requiring no access to model weights, trigger knowledge, or additional training, and it aggregates intermediate predictions to flag backdoored models. Experiments on MS‑COCO and PASCAL VOC across two architectures and three scene‑level attack scenarios show that DistScan outperforms existing methods, improving average detection accuracy by 27.32 percentage points over the best baseline.

By Longtian Wang, Zhengyu Zhao, Chenhao Lin, Le Yang, Shiwei Wang, Yuhan Zhi, Xiaofei Xie, Chao Shen