Research On DDoS Detection And Mitigation Strategies In Software Defined Network

Distributed Denial of Service(DDoS)attacks have long been a stubborn cybersecurity issue.The emergence of software-defined network(SDN)as a new type of network architecture has been affirmed by the academic and industrial circles and has made great progress in recent years.SDN inherently decouples the control plane and the data plane.The centralized controller has a global view of the whole network.This mode enhances network configuration,improves security performance,and encourages application innovation.However,the centralized thinking of the controller makes the SDN network more vulnerable to DDoS attacks.The inherent decoupling of the network expands the attack area.Single point of failure of the controller will bring serious consequences to the network.As a decentralized distributed platform,blockchain technology has received extensive attention in all circles in recent years.The development and application of blockchain technology has also been strongly supported by our country.This thesis combines Ethereum's smart contract technology and proposes detection and mitigation strategies for DDoS attacks in software-defined networks.The entire SDN is divided into multiple autonomous systems according to the network scope governed by each controller.The method proposed in this thesis consists of three parts: the DDoS attack detection method in the target domain,the DDoS attack mitigation method in the target domain and the cross-domain illegal flow sharing method based on the blockchain.For the intra-domain network,this thesis establishes the intra-domain DDoS attack detection model,which consists of two modules: initial anomaly detection and deep DDoS attack detection.The DDoS attack mitigation method is based on the inherent characteristics of the SDN network.In addition,this thesis proposes a blacklist mechanism to deal with the contradiction between repeated detection and flow entry rule expiration.For the cross-domain illegal flow information sharing strategy,this thesis designs corresponding smart contracts on the Ethereum platform based on blockchain technology,and proposes a safe and distributed illegal flow sharing method.The experimental results prove that the DDoS attack detection method in the SDN network proposed in this thesis has higher detection rate and lower false positive rate.The mitigation strategies of DDoS attack in the target domain can discard the illegal data stream in a timely and efficient manner.Cross-domain information sharing strategies based on the Ethereum blockchain guarantee flexibility and security,while being cost-effective.