Enhancing Fraud Transaction Detection via Unlabeled Suspicious Records

Ye Wang, Yunpeng Liu, Ningtao Wang, Peiyang Li, Jiahao Hu, Xing Fu, Weiqiang Wang, Kun Sun, Qi Li, Ke Xu

Abstract: Deep learning-based classifiers have been widely used in the field of financial fraud transaction detection. However, training a high-performance classifier for fraud detection is challenging due to the lack of sufficient labeled fraud data. Particularly, it is difficult to detect stealthy fraud transactions that closely mimic benign user behaviors. We observe that the suspicious transactions identified by the online detection system can augment the feature space to improve the detection performance of machine learning-based models. In this paper, we propose a new framework GIANTESS to leverage suspicious transactions to augment the feature space and thus enhance the detection of stealthy fraud transactions. Our semi-supervised approach combines both labeled transactions and unlabeled suspicious transactions to train a detection model. Specifically, it first estimates pseudo labels of suspicious transactions and then combines the pseudo labels with ground truth labels to train the detection model. We conduct experiments on two real-world datasets to demonstrate the effectiveness of our proposed method on detecting stealthy fraud transactions. The experimental results show that GIANTESS successfully improves the recall by up to 6.3% at the fixed low false positive rate of 1%. We also perform a 9-week deployment test of our system in a real-world online payment platform to demonstrate the performance of GIANTESS.