A Rule Mining-Based Advanced Persistent Threats Detection System

Advanced persistent threats (APT) are stealthy cyber-attacks that are aimed at stealing valuable information from target organizations and tend to extend in time. Blocking all APTs is impossible, security experts caution, hence the importance of research on early detection and damage limitation. Whole-system provenance-tracking and provenance trace mining are considered promising as they can help find causal relationships between activities and flag suspicious event sequences as they occur. We introduce an unsupervised method that exploits OS-independent features reflecting process activity to detect realistic APT-like attacks from provenance traces. Anomalous processes are ranked using both frequent and rare event associations learned from traces. Results are then presented as implications which, since interpretable, help leverage causality in explaining the detected anomalies. When evaluated on Transparent Computing program datasets (DARPA), our method outperformed competing approaches.

Categorical anomaly detection in heterogeneous data using minimum description length clustering

Fast and effective unsupervised anomaly detection algorithms have been proposed for categorical data based on the minimum description length (MDL) principle. However, they can be ineffective when detecting anomalies in heterogeneous datasets representing a mixture of different sources, such as security scenarios in which system and user processes have distinct behavior patterns. We propose a meta-algorithm for enhancing any MDL-based anomaly detection model to deal with heterogeneous data by fitting a mixture model to the data, via a variant of k-means clustering. Our experimental results show that using a discrete mixture model provides competitive performance relative to two previous anomaly detection algorithms, while mixtures of more sophisticated models yield further gains, on both synthetic datasets and realistic datasets from a security scenario.