Research On Chaotic Dynamics Of Worm Propagation Among Unpatched Hosts

With the development of the network, the security problem of the network is increasingly outstanding. The flowage of the network worm causes great damage for the network users. The research of worm propagation model is very significant to reveal the propagation characteristics and propose effective control method. Because the traditional worm propagation models are described by linear equations and the parameters in these models are constant, it’s improper to apply them to describe the complex process of worm propagation. And if these models are adopted to predict the worm propagation, it will lead that the propagation behaviors of worm can not be controlled well. Moreover, this will affect the Internet security. Therefore, the research of nonlinear propagation dynamics of worm is an important advanced topic.In this thesis, the propagation characteristic of Conficker worm is analyzed from the propagation data set of Conficker worm. Then, based on the research productions of epidemiology and nonlinear dynamics, the repeated infection of unpatched hosts which is reflected by the propagation data set of Conficker worm is modeled and the worm chaotic propagation model CSI (Chaotic Susceptible-Infected) is proposed. Afterwards, the numerical results of the CSI model are analyzed. Besides, the influence of the parameters in CSI model to the worm propagation is investigated and the evolution theory that Conficker worm spread from the bifurcation to chaos is also discussed.Some basic principles of Internet worm and chaos are introduced at the beginning of this thesis. The propagation data set of Conficker worm is analyzed in detail to find the propagation characteristic of Conficker worm. Based on several classical worm propagation models, combining the repeated infection characteristic of Conficker worm to unpatched hosts, the worm chaotic propagation model CSI is proposed. Then, the stability analysis and chaos analysis of CSI model is given, and the time sequence of infected hosts is also studied. From the numerical results, it is concluded that there exist three threshold values of a control parameter depending on the ratio of infection rate to removal rate share the behavior of worm propagation in four types:no infection, increase of infection, bifurcation and then chaos. At last, NS-2simulation environment is selected to simulate worm chaotic propagation model CSI. The simulation results also prove that the above control parameter plays an important role in the bifurcation and chaos of worm. Besides, they prove that the propagation state of worm can be controlled well by adjusting the value of the parameter with containment Strategies. Therefore, the worm chaotic propagation model CSI for the future research work of worm propagation and worm restraint among unpatched hosts provides a theoretical basis.