As one of the most devastating types of Distributed Denial of Service (DDoS) attacks, Domain Name System (DNS) amplification attack represents a big threat and one of the main Internet security problems to nowadays networks. Many protocols that form the Internet infrastructure expose a set of vulnerabilities that can be exploited by attackers to carry out a set of attacks. DNS, one of the most critical elements of the Internet, is among these protocols. It is vulnerable to DDoS attacks mainly because all exchanges in this protocol use User Datagram Protocol (UDP). These attacks are difficult to defeat because attackers spoof the IP address of the victim and flood him with valid DNS responses coming from legitimate DNS servers. In this paper, we propose an efficient and scalable solution, called WisdomSDN, to effectively mitigate DNS amplification attack in the context of software defined networks (SDN). WisdomSDN covers both detection and mitigation of illegitimate DNS requests and responses. WisdomSDN consists of: (1) a novel proactive and stateful scheme (PAS) to perform one-to-one mapping between DNS requests and DNS responses; it operates proactively by sending only legitimate responses, excluding amplified illegitimate DNS responses; (2) a machine learning DDoS detection module to detect, in real-time, illegitimate DNS requests. This module consists of (a) Flow statistics collection scheme (FSC) to gather the features of flows in an efficient and scalable way using sFlow protocol; (b) Entropy calculation scheme (ECS) to measure randomness of network traffic; and (c) Bayes Network based Filtering scheme (BNF) to classify, based on entropy values, illegitimate DNS requests; and (3) DNS Mitigation scheme (DM) to effectively mitigate illegitimate DNS requests. The experimental results show that, compared to state-of-art, WisdomSDN can effectively detect/mitigate DNS amplification attack quickly with high detection rate, less false positive rate, and low overhead making it a promising solution to mitigate DNS amplification attack in a SDN environment.

中文翻译：

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为软件定义网络带来智能：缓解 DDoS 攻击


作为最具破坏性的分布式拒绝服务（DDoS）攻击类型之一，域名系统（DNS）放大攻击对当今的网络构成了巨大的威胁和主要的互联网安全问题之一。构成互联网基础设施的许多协议都暴露了一系列漏洞，攻击者可以利用这些漏洞来实施一系列攻击。 DNS 是互联网最关键的元素之一，也是这些协议之一。它容易受到 DDoS 攻击，主要是因为该协议中的所有交换都使用用户数据报协议 (UDP)。这些攻击很难被击败，因为攻击者会欺骗受害者的 IP 地址，并向受害者发送来自合法 DNS 服务器的有效 DNS 响应。在本文中，我们提出了一种高效且可扩展的解决方案，称为 WisdomSDN，以有效缓解软件定义网络 (SDN) 环境中的 DNS 放大攻击。 WisdomSDN 涵盖非法 DNS 请求和响应的检测和缓解。 WisdomSDN 包括： (1) 一种新颖的主动和有状态方案 (PAS)，用于在 DNS 请求和 DNS 响应之间执行一对一映射；它通过仅发送合法响应来主动运行，排除放大的非法 DNS 响应； (2) 机器学习 DDoS 检测模块，用于实时检测非法 DNS 请求。该模块包括（a）流统计收集方案（FSC），使用 sFlow 协议以高效且可扩展的方式收集流的特征； (b) 熵计算方案（ECS），用于测量网络流量的随机性； (c) 基于贝叶斯网络的过滤方案（BNF），根据熵值对非法 DNS 请求进行分类； (3) DNS 缓解方案 (DM)，有效缓解非法 DNS 请求。 实验结果表明，与现有技术相比，WisdomSDN 能够快速有效地检测/缓解 DNS 放大攻击，且检测率高、误报率低、开销低，使其成为缓解 SDN 中 DNS 放大攻击的有前景的解决方案环境。