Biblio

Discovering the potential vulnerabilities in software plays a crucial role in ensuring the security of computer system. This paper proposes a method that can assist security auditors with the analysis of source code. When security auditors identify new vulnerabilities, our method can be adopted to make a list of recommendations that may have the same vulnerabilities for the security auditors. Our method relies on graph representation to automatically extract the mode of PDG(program dependence graph, a structure composed of control dependence and data dependence). Besides, it can be applied to the vulnerability extrapolation scenario, thus reducing the amount of audit code. We worked on an open-source vulnerability test set called Juliet. According to the evaluation results, the clustering effect produced is satisfactory, so that the feature vectors extracted by the Graph2Vec model are applied to labeling and supervised learning indicators are adopted to assess the model for its ability to extract features. On a total of 12,000 small data sets, the training score of the model can reach up to 99.2%, and the test score can reach a maximum of 85.2%. Finally, the recommendation effect of our work is verified as satisfactory.

Network communication data are high-dimensional and spatiotemporal, and their information content is often degraded by common traffic analysis methods. For long-term network attack detection based on network flows, it is important to extract a discriminative, high-dimensional intrinsic representation of such flows. This work focuses on a hybrid deep neural network design using a combination of a convolutional neural network (CNN) and long short-term memory (LSTM) with graph similarity measures to learn high-dimensional representations from the network traffic. In particular, examining a set of network flows, we commence by constructing a temporal communication graph and then computing graph kernel matrices. Having obtained the kernel matrices, for each graph, we use the kernel value between graphs and calculate graph characterization vectors by graph signal processing. This vector can be regarded as a kernel-based similarity embedding vector of the graph that integrates structural similarity information and leverages efficient graph kernel using the graph Laplacian matrix. Our approach exploits graph structures as the additional prior information, the graph Laplacian matrix for feature extraction and hybrid deep learning models for long-term information learning on communication graphs. Experiments on two real-world network attack datasets show that our approach can extract more discriminative representations, leading to an improved accuracy in a supervised classification task. The experimental results show that our method increases the overall accuracy by approximately 10%-15%.

Flow-based network attack detection technology is able to identify many threats in network traffic. Existing techniques have several drawbacks: i) rule-based approaches are vulnerable because it needs all the signatures defined for the possible attacks, ii) anomaly-based approaches are not efficient because it is easy to find ways to launch attacks that bypass detection, and iii) both rule-based and anomaly-based approaches heavily rely on domain knowledge of networked system and cyber security. The major challenge to existing methods is to understand novel attack scenarios and design a model to detect novel and more serious attacks. In this paper, we investigate network attacks and unveil the key activities and the relationships between these activities. For that reason, we propose methods to understand the network security practices using theoretic concepts such as graph kernels. In addition, we integrate graph kernels over deep learning architecture to exploit the relationship expressiveness among network flows and combine ability of deep neural networks (DNNs) with deep architectures to learn hidden representations, based on the communication representation graph of each network flow in a specific time interval, then the flow-based network attack detection can be done effectively by measuring the similarity between the graphs to two flows. The proposed study provides the effectiveness to obtain insights about network attacks and detect network attacks. Using two real-world datasets which contain several new types of network attacks, we achieve significant improvements in accuracies over existing network attack detection tasks.

Machine learning techniques were extensively applied to learn and detect malware. However, these techniques use often rough abstractions of programs. We propose in this work to use a more precise model for programs, namely extended API call graphs, where nodes correspond to API function calls, edges specify the execution order between the API functions, and edge labels indicate the dependence relation between API functions parameters. To learn such graphs, we propose to use Generalized Random Walk Graph Kernels (combined with Support Vector Machines). We implemented our techniques and obtained encouraging results for malware detection: 96.73% of detection rate with 0.73% of false alarms.