【作者】 戴诏；

【导师】 胡志刚；

【作者基本信息】 中南大学 ， 计算机软件与理论， 2007， 硕士

【摘要】 随着网络技术和网络应用的发展，网络安全问题显得越来越重要。拒绝服务(DoS)攻击由于发动容易、难于防御和追踪，成为当前网络中最常见也最具威胁的一种攻击方式，给网络带来了极大的危害。因此，研究拒绝服务攻击及其对策是极为重要的，如何快速、有效的确定攻击源，并及时采取相应的防御措施，就成了DoS攻击防御研究中的最具挑战性也是最关键课题之一。本文首先对拒绝服务攻击的攻击机制、方法及其对策作了介绍，然后研究了当前IP追踪方案现状以及主要的几种数据包标记追踪方案，并在此基础上提出对现有数据包标记方案的改进，以期在攻击路径重构时达到较高的追踪收敛率和较低的误报率。本文研究并提出了基于密钥集序列消息认证码的认证机制，防止攻击者对标记信息进行修改和伪造，达到较高的安全性和抗干扰性；通过在标记算法中采用新的动态标记概率序列，使路径重构算法的收敛率和算法效率得到提高；本文还对分布式反射拒绝服务攻击进行研究，提出反射标记算法，使追踪方案能够有效发现出反射服务器背后真正的攻击者。本文最后对追踪方案的兼容性、收敛率和安全性进行了实验对比，实验结果表明本文提出的IP追踪方案相对其他方案达到了较高的收敛率和较低的误报率。更多还原

【Abstract】 With the development of network technology and application, network security becomes more and more important. Denial of service attack is among the hardest security problems to address because it is easy to launch, difficult to defend and trace. So, doing research on DoS attack and its countermeasures is not only challenging but also very important. And IP Traceback is the key thesis in the research.In this paper, the mechanism, methods of and countermeasures to denial of services attacks are discussed. After that, several IP Traceback schemes, especially the Packet Marking scheme are reviewed and some improvements to the current packet marking schemes are given, which improve the astringency and false positive rate in the attacking tree reconstruction.Based on the research on HMAC (Keyed-Hashing for Message Authentication) with Key Collection Exposure, the marking information is authenticated by using HMAC to achieve high security and robustness. The reconstruction algorithm can also achieve great astringency and high efficiency by adopting a new dynamic probability marking value sequence in the marking algorithm. And a reflection marking algorithm is improved to trace the real attackers beyond the reflector server in DRDoS attacks.Compared with the results of other schemes, it shows comparatively lower false positive rate and higher astringency.更多还原