Metadata-Based Detection of Child Sexual Abuse Material

In the last decade, the scale of creation and distribution of child sexual abuse medias (CSAM) has exponentially increased. Technologies that aid law enforcement agencies worldwide to identify such crimes rapidly can potentially result in the mitigation of child victimization, and the apprehending of offenders. Machine learning presents the potential to help law enforcement rapidly identify such material, and even block such content from being distributed digitally. However, collecting and storing CSAM files to train machine learning models has many ethical and legal constraints, creating a barrier to the development of accurate computer vision-based models. With such restrictions in place, the development of accurate machine learning classifiers for CSAM identification based on file metadata becomes crucial. In this work, we propose a system for CSAM identification on file storage systems based solely on metadata – file paths. Our aim is to provide a tool that is material type agnostic (image, video, PDF), and can potentially scans thousands of file storage systems in a short time. Our approach uses convolutional neural networks, and achieves an accuracy of 97% and recall of 94%. Additionally, we address the potential problem of offenders trying to evade detection by this model by evaluating the robustness of our model against adversarial modifications in the file paths.