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Convolutional Transformer based Dual Discriminator Generative Adversarial Networks for Video Anomaly Detection

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Detecting abnormal activities in real-world surveillance videos is an important yet challenging task as the prior knowledge about video anomalies is usually limited or unavailable. Despite that many approaches have been developed to resolve this problem, few of them can capture the normal spatio-temporal patterns effectively and efficiently. Moreover, existing works seldom explicitly consider the local consistency at frame level and global coherence of temporal dynamics in video sequences. To this end, we propose Convolutional Transformer based Dual Discriminator Generative Adversarial Networks (CT-D2GAN) to perform unsupervised video anomaly detection. Specifically, we first present a convolutional transformer to perform future frame prediction. It contains three key components, i.e., a convolutional encoder to capture the spatial information of the input video clips, a temporal self-attention module to encode the temporal dynamics, and a convolutional decoder to integrate spatio-temporal features and predict the future frame. Next, a dual discriminator based adversarial training procedure, which jointly considers an image discriminator that can maintain the local consistency at frame-level and a video discriminator that can enforce the global coherence of temporal dynamics, is employed to enhance the future frame prediction. Finally, the prediction error is used to identify abnormal video frames. Thoroughly empirical studies on three public video anomaly detection datasets, i.e., UCSD Ped2, CUHK Avenue, and Shanghai Tech Campus, demonstrate the effectiveness of the proposed adversarial spatio-temporal modeling framework.

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Countering Malicious Processes with Process-DNS Association

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Modern malware and cyber attacks depend heavily on DNS services to make their campaigns reliable and difficult to track. Monitoring network DNS activities and blocking suspicious domains have been proven an effective technique in countering such attacks. However, recent successful campaigns reveal that at- tackers adapt by using seemingly benign domains and public web storage services to hide malicious activity. Also, the recent support for encrypted DNS queries provides attacker easier means to hide malicious traffic from network-based DNS monitoring.We propose PDNS, an end-point DNS monitoring system based on DNS sensor deployed at each host in a network, along with a centralized backend analysis server. To detect such attacks, PDNS expands the monitored DNS activity context and examines process context which triggered that activity. Specifically, each deployed PDNS sensor matches domain name and the IP address related to the DNS query with process ID, binary signature, loaded DLLs, and code signing information of the program that initiated it. We evaluate PDNS on a DNS activity dataset collected from 126 enterprise hosts and with data from multiple malware sources. Using ML Classifiers including DNN, our results outperform most previous works with high detection accuracy: a true positive rate at 98.55% and a low false positive rate at 0.03%.

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