Abstract: Botnet is a novel attack strategy evolved from the traditional malicious softwares. It has become a major threat to Internet security. Propagation model of Botnet has become one of the most efficient methods to research the propagation inherent characteristics of bots. Currently the mainstream propagation model of Botnet is almost based on random network, and the actual Internet is a complex network with scale-free feature, so these mainstream propagation models can not exactly describe how the?bots spread on Internet. In this paper, a new propagation model of Botnet on scale-free network is proposed, which considers carefully about the real situation of Internet with network traffic congestion what is a normal phenomenon on Internet, especially two key factors including growth and preferential attachment. The simulation result indicates that this propagation model of Botnet more exactly confirms with the propagation principle and the inflection feature of bots on actual Internet, and it reflects the infection characteristics of bots when the network congestion occurs.

Key words: scale-free network, network security, Botnet, propagation model, network traffic congestion

摘要： 僵尸网络是一种从传统恶意代码进化而来的新型攻击方式，已成为Internet安全的一个重大威胁。建立僵尸网络的传播模型已成为研究僵尸程序传播特性最有效的一种方法。当前建立的僵尸网络传播模型均是基于随机网络理论的，而实际的Internet是一个具有无尺度特性的复杂网络，因此，这些主流传播模型并不能完全准确反映僵尸程序在Internet的传播特性。提出了一种基于无尺度网络结构的僵尸网络传播模型，根据Internet的实际情况，结合网络流量阻塞这一Internet中的常态现象，重点考虑了真实Internet中节点的增长性和择优连接性。仿真结果表明，该模型不仅符合真实Internet网络中僵尸程序的传播规律和感染特性，而且能够反映出网络中出现拥塞时僵尸程序的感染特性。

关键词: 无尺度网络, 网络安全, 僵尸网络, 传播模型, 网络流量阻塞