Labeling Malicious Communication Samples Based on Semi-Supervised Deep Neural Network

The limited labeled sample data in the field of advanced security threats detection seriously restricts the effective development of research work.Learning the sample labels from the labeled and unlabeled data has received a lot of research attention and various universal labeling methods have been proposed.However,the labeling task of malicious communication samples targeted at advanced threats has to face the two practical challenges:the difficulty of extracting effective features in advance and the complexity of the actual sample types.To address these problems,we proposed a sample labeling method for malicious communication based on semi-supervised deep neural network.This method supports continuous learning and optimization feature representation while labeling sample,and can handle uncertain samples that are outside the concerned sample types.According to the experimental results,our proposed deep neural network can automatically learn effective feature representation,and the validity of features is close to or even higher than that of features which extracted based on expert knowledge.Furthermore,our proposed method can achieve the labeling accuracy of 97.64%~98.50%,which is more accurate than the train-then-detect,kNN and LPA methodsin any labeled-sample proportion condition.The problem of insufficient labeled samples in many network attack detecting scenarios,and our proposed work can function as a reference for the sample labeling tasks in the similar real-world scenarios.

Research and Practice of Dynamic Network Security Architecture for IaaS Platforms

Network security requirements based on virtual network technologies in laaS platforms and corresponding solutions were reviewed. A dynamic network security architecture was proposed, which was built on the technologies of software defined networking, Virtual Machine （VM） traffic redirection, network policy unified management, software defined isolation networks, vulnerability scanning, and software updates. The proposed architecture was able to obtain the capacity for detection and access control for VM traffic by redirecting it to configurable security appliances, and ensured the effectiveness of network policies in the total life cycle of the VM by configuring the policies to the right place at the appropriate time, according to the impacts of VM state transitions. The virtual isolation domains for tenants＇ VMs could be built flexibly based on VLAN policies or Netfilter/Iptables firewall appliances, and vulnerability scanning as a service and software update as a service were both provided as security supports. Through cooperation with IDS appliances and automatic alarm mechanisms, the proposed architecture could dynamically mitigate a wide range of network-based attacks. The experimental results demonstrate the effectiveness of the proposed architecture.

An Anomalous Behavior Detection Model in Cloud Computing

This paper proposes an anomalous behavior detection model based on cloud computing. Virtual Machines （VMs） are one of the key components of cloud Infrastructure as a Service （laaS）. The security of such VMs is critical to laaS security. Many studies have been done on cloud computing security issues, but research into VM security issues, especially regarding VM network traffic anomalous behavior detection, remains inadequate. More and more studies show that communication among internal nodes exhibits complex patterns. Communication among VMs in cloud computing is invisible. Researchers find such issues challenging, and few solutions have been proposed--leaving cloud computing vulnerable to network attacks. This paper proposes a model that uses Software-Defined Networks （SDN） to implement traffic redirection. Our model can capture inter-VM traffic, detect known and unknown anomalous network behaviors, adopt hybrid techniques to analyze VM network behaviors, and control network systems. The experimental results indicate that the effectiveness of our approach is greater than 90%, and prove the feasibility of the model.

DGA-Based Botnet Detection Toward Imbalanced Multiclass Learning

Botnets based on the Domain Generation Algorithm(DGA) mechanism pose great challenges to the main current detection methods because of their strong concealment and robustness. However, the complexity of the DGA family and the imbalance of samples continue to impede research on DGA detection. In the existing work, the sample size of each DGA family is regarded as the most important determinant of the resampling proportion;thus,differences in the characteristics of various samples are ignored, and the optimal resampling effect is not achieved.In this paper, a Long Short-Term Memory-based Property and Quantity Dependent Optimization(LSTM.PQDO)method is proposed. This method takes advantage of LSTM to automatically mine the comprehensive features of DGA domain names. It iterates the resampling proportion with the optimal solution based on a comprehensive consideration of the original number and characteristics of the samples to heuristically search for a better solution around the initial solution in the right direction;thus, dynamic optimization of the resampling proportion is realized.The experimental results show that the LSTM.PQDO method can achieve better performance compared with existing models to overcome the difficulties of unbalanced datasets;moreover, it can function as a reference for sample resampling tasks in similar scenarios.

DTA-HOC:Online HTTPS Traffic Service Identification Using DNS in Large-Scale Networks

An increasing number of websites are making use of HTTPS encryption to enhance security and privacy for their users.However,HTTPS encryption makes it very difficult to identify the service over HTTPS flows,which poses challenges to network security management.In this paper we present DTA-HOC,a novel DNS-based two-level association HTTPS traffic online service identification method for large-scale networks,which correlates HTTPS flows with DNS flows using big data stream processing and association technologies to label the service in an HTTPS flow with a specific associated domain name.DTA-HOC has been specifically designed to address three practical challenges in the service identification process:domain name ambiguity,domain name query invisibility,and data association time window size contradictions.Several experiments on datasets collected from a 10-Gbps campus network are conducted alongside offline and online testing.Results show that DTA-HOC can achieve an average online association rate on HTTPS traffic of 83%and a generic accuracy of 86.16%.Its processing time for one minute of data is less than 20 seconds.These results indicate that DTA-HOC is an efficient method for online identification of services in HTTPS flows for large-scale networks.Moreover,our proposed method can contribute to the identification of other applications which make a Domain Name System(DNS)communication before establishing a connection.

Efficient Feature Extraction Using Apache Spark for Network Behavior Anomaly Detection

Extracting and analyzing network traffic feature is fundamental in the design and implementation of network behavior anomaly detection methods. The traditional network traffic feature method focuses on the statistical features of traffic volume. However, this approach is not sufficient to reflect the communication pattern features. A different approach is required to detect anomalous behaviors that do not exhibit traffic volume changes, such as low-intensity anomalous behaviors caused by Denial of Service/Distributed Denial of Service （DoS/DDoS） attacks, Internet worms and scanning, and BotNets. We propose an efficient traffic feature extraction architecture based on our proposed approach, which combines the benefit of traffic volume features and network communication pattern features. This method can detect low-intensity anomalous network behaviors and conventional traffic volume anomalies. We implemented our approach on Spark Streaming and validated our feature set using labelled real-world dataset collected from the Sichuan University campus network. Our results demonstrate that the traffic feature extraction approach is efficient in detecting both traffic variations and communication structure changes. Based on our evaluation of the MIT-DRAPA dataset, the same detection approach utilizes traffic volume features with detection precision of 82.3% and communication pattern features with detection precision of 89.9%. Our proposed feature set improves precision by 94%.