中文摘要：

以僵尸网络为载体的各种网络攻击活动是目前互联网所面临的最为严重的安全威胁之一．虽然近年来这方面的研究取得了显著的进展，但是由于僵尸网络不断演化、越来越复杂和隐蔽以及网络和系统体系结构的限制给检测和防御带来的困难，如何有效应对僵尸网络的威胁仍是一项持续而具有挑战性的课题．首先从僵尸网络的传播、攻击以及命令与控制这3个方面介绍了近年来僵尸网络工作机制的发展，然后从监测、工作机制分析、特征分析、检测和主动遏制这5个环节对僵尸网络防御方面的研究进行总结和分析，并对目前的防御方法的局限、僵尸网络的发展趋势和进一步的研究方向进行了讨论．

英文摘要：

Botnets are one of the most serious threats to the Internet. Researchers have done plenty of research and made significant progress. However, botnets keep evolving and have become more and more sophisticated. Due to the underlying security limitation of current system and Internet architecture, and the complexity of botnet itself, how to effectively counter the global threat ofbotnets is still a very challenging issue. This paper first introduces the evolving of botnet＇s propagation, attack, command, and control mechanisms. Then the paper summarizes recent advances of botnet defense research and categorizes into five areas： Botnet monitoring, botnet infiltration, analysis of botnet characteristics, botnet detection and botnet disruption. The limitation of current botnet defense techniques, the evolving trend ofbotnet, and some possible directions for future research are also discussed.