Finding Naturally Occurring Physical Backdoors in Image Datasets

Emily Wenger, Roma Bhattacharjee, Arjun Nitin Bhagoji, Josephine Passananti, Emilio Andere, Haitao Zheng, Ben Zhao

Keywords: machine learning, security, backdoors

TL;DR: We discover and validate the existence of natural backdoors in existing image datasets.

Abstract:

Extensive literature on backdoor poison attacks has studied attacks and defenses for backdoors using “digital trigger patterns.” In contrast, “physical backdoors” use physical objects as triggers, have only recently been identified, and are qualitatively different enough to resist most defenses targeting digital trigger backdoors. Research on physical backdoors is limited by access to large datasets containing real images of physical objects co-located with misclassification targets. Building these datasets is time- and labor-intensive.

This work seeks to address the challenge of accessibility for research on physical backdoor attacks. We hypothesize that there may be naturally occurring physically co-located objects already present in popular datasets such as ImageNet. Once identified, a careful relabeling of these data can transform them into training samples for physical backdoor attacks. We propose a method to scalably identify these subsets of potential triggers in existing datasets, along with the specific classes they can poison. We call these naturally occurring trigger-class subsets natural backdoor datasets. Our techniques successfully identify natural backdoors in widely-available datasets, and produce models behaviorally equivalent to those trained on manually curated datasets. We release our code to allow the research community to create their own datasets for research on physical backdoor attacks.

Author Statement: Yes

License: The code accompanying this paper is released under the MIT License.

URL: https://github.com/uchicago-sandlab/naturalbackdoors

Dataset Url: The code to recreate the datasets in this paper can be found at: https://github.com/uchicago-sandlab/naturalbackdoors

Contribution Process Agreement: Yes

In Person Attendance: Yes