1,325 research outputs found

    Intrusion Detection System using Bayesian Network Modeling

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    Computer Network Security has become a critical and important issue due to ever increasing cyber-crimes. Cybercrimes are spanning from simple piracy crimes to information theft in international terrorism. Defence security agencies and other militarily related organizations are highly concerned about the confidentiality and access control of the stored data. Therefore, it is really important to investigate on Intrusion Detection System (IDS) to detect and prevent cybercrimes to protect these systems. This research proposes a novel distributed IDS to detect and prevent attacks such as denial service, probes, user to root and remote to user attacks. In this work, we propose an IDS based on Bayesian network classification modelling technique. Bayesian networks are popular for adaptive learning, modelling diversity network traffic data for meaningful classification details. The proposed model has an anomaly based IDS with an adaptive learning process. Therefore, Bayesian networks have been applied to build a robust and accurate IDS. The proposed IDS has been evaluated against the KDD DAPRA dataset which was designed for network IDS evaluation. The research methodology consists of four different Bayesian networks as classification models, where each of these classifier models are interconnected and communicated to predict on incoming network traffic data. Each designed Bayesian network model is capable of detecting a major category of attack such as denial of service (DoS). However, all four Bayesian networks work together to pass the information of the classification model to calibrate the IDS system. The proposed IDS shows the ability of detecting novel attacks by continuing learning with different datasets. The testing dataset constructed by sampling the original KDD dataset to contain balance number of attacks and normal connections. The experiments show that the proposed system is effective in detecting attacks in the test dataset and is highly accurate in detecting all major attacks recorded in DARPA dataset. The proposed IDS consists with a promising approach for anomaly based intrusion detection in distributed systems. Furthermore, the practical implementation of the proposed IDS system can be utilized to train and detect attacks in live network traffi

    An SDN-based Approach For Defending Against Reflective DDoS Attacks

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    Distributed Reflective Denial of Service (DRDoS) attacks are an immanent threat to Internet services. The potential scale of such attacks became apparent in March 2018 when a memcached-based attack peaked at 1.7 Tbps. Novel services built upon UDP increase the need for automated mitigation mechanisms that react to attacks without prior knowledge of the actual application protocols used. With the flexibility that software-defined networks offer, we developed a new approach for defending against DRDoS attacks; it not only protects against arbitrary DRDoS attacks but is also transparent for the attack target and can be used without assistance of the target host operator. The approach provides a robust mitigation system which is protocol-agnostic and effective in the defense against DRDoS attacks

    On Application Layer DDoS Attack Detection in High-Speed Encrypted Networks

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    Application-layer denial-of-service attacks have become a serious threat to modern high-speed computer networks and systems. Unlike network-layer attacks, application-layer attacks can be performed by using legitimate requests from legitimately connected network machines which makes these attacks undetectable for signature-based intrusion detection systems. Moreover, the attacks may utilize protocols that encrypt the data of network connections in the application layer making it even harder to detect attacker’s activity without decrypting users network traffic and violating their privacy. In this paper, we present a method which allows us to timely detect various applicationlayer attacks against a computer network. We focus on detection of the attacks that utilize encrypted protocols by applying an anomaly-detection-based approach to statistics extracted from network packets. Since network traffic decryption can violate ethical norms and regulations on privacy, the detection method proposed analyzes network traffic without decryption. The method involves construction of a model of normal user behavior by analyzing conversations between a server and clients. The algorithm is self-adaptive and allows one to update the model every time when a new portion of network traffic data is available. Once the model has been built, it can be applied to detect various types of application-layer denial-of- service attacks. The proposed technique is evaluated with realistic end user network traffic generated in our virtual network environment. Evaluation results show that these attacks can be properly detected, while the number of false alarms remains very low

    Distributed reflection denial of service attack: A critical review

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    As the world becomes increasingly connected and the number of users grows exponentially and “things” go online, the prospect of cyberspace becoming a significant target for cybercriminals is a reality. Any host or device that is exposed on the internet is a prime target for cyberattacks. A denial-of-service (DoS) attack is accountable for the majority of these cyberattacks. Although various solutions have been proposed by researchers to mitigate this issue, cybercriminals always adapt their attack approach to circumvent countermeasures. One of the modified DoS attacks is known as distributed reflection denial-of-service attack (DRDoS). This type of attack is considered to be a more severe variant of the DoS attack and can be conducted in transmission control protocol (TCP) and user datagram protocol (UDP). However, this attack is not effective in the TCP protocol due to the three-way handshake approach that prevents this type of attack from passing through the network layer to the upper layers in the network stack. On the other hand, UDP is a connectionless protocol, so most of these DRDoS attacks pass through UDP. This study aims to examine and identify the differences between TCP-based and UDP-based DRDoS attacks

    Graph-based feature enrichment for online intrusion detection in virtual networks

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    The increasing number of connected devices to provide the required ubiquitousness of Internet of Things paves the way for distributed network attacks at an unprecedented scale. Graph theory, strengthened by machine learning techniques, improves an automatic discovery of group behavior patterns of network threats often omitted by traditional security systems. Furthermore, Network Function Virtualization is an emergent technology that accelerates the provisioning of on-demand security function chains tailored to an application. Therefore, repeatable compliance tests and performance comparison of such function chains are mandatory. The contributions of this dissertation are divided in two parts. First, we propose an intrusion detection system for online threat detection enriched by a graph-learning analysis. We develop a feature enrichment algorithm that infers metrics from a graph analysis. By using different machine learning techniques, we evaluated our algorithm for three network traffic datasets. We show that the proposed graph-based enrichment improves the threat detection accuracy up to 15.7% and significantly reduces the false positives rate. Second, we aim to evaluate intrusion detection systems deployed as virtual network functions. Therefore, we propose and develop SFCPerf, a framework for an automatic performance evaluation of service function chaining. To demonstrate SFCPerf functionality, we design and implement a prototype of a security service function chain, composed of our intrusion detection system and a firewall. We show the results of a SFCPerf experiment that evaluates the chain prototype on top of the open platform for network function virtualization (OPNFV).O crescente número de dispositivos IoT conectados contribui para a ocorrência de ataques distribuídos de negação de serviço a uma escala sem precedentes. A Teoria de Grafos, reforçada por técnicas de aprendizado de máquina, melhora a descoberta automática de padrões de comportamento de grupos de ameaças de rede, muitas vezes omitidas pelos sistemas tradicionais de segurança. Nesse sentido, a virtualização da função de rede é uma tecnologia emergente que pode acelerar o provisionamento de cadeias de funções de segurança sob demanda para uma aplicação. Portanto, a repetição de testes de conformidade e a comparação de desempenho de tais cadeias de funções são obrigatórios. As contribuições desta dissertação são separadas em duas partes. Primeiro, é proposto um sistema de detecção de intrusão que utiliza um enriquecimento baseado em grafos para aprimorar a detecção de ameaças online. Um algoritmo de enriquecimento de características é desenvolvido e avaliado através de diferentes técnicas de aprendizado de máquina. Os resultados mostram que o enriquecimento baseado em grafos melhora a acurácia da detecção de ameaças até 15,7 % e reduz significativamente o número de falsos positivos. Em seguida, para avaliar sistemas de detecção de intrusões implantados como funções virtuais de rede, este trabalho propõe e desenvolve o SFCPerf, um framework para avaliação automática de desempenho do encadeamento de funções de rede. Para demonstrar a funcionalidade do SFCPerf, ´e implementado e avaliado um protótipo de uma cadeia de funções de rede de segurança, composta por um sistema de detecção de intrusão (IDS) e um firewall sobre a plataforma aberta para virtualização de função de rede (OPNFV)
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