Research On Propagation And Control Model Of Internet Worms

In the modern information and network security, internet worms have become one of the most serious security threats to the Internet. Internet worms take the network as a transmission medium and have self-replication capability. In order to effectively defense the internet worm attack and reduce the damage caused by them, the propagation mechanism and control strategies of internet worms have become active research topics. However, with the rapid development of the computer and network technologies, the internet worms have new characteristics such as wide varieties, multiple transmission routes. As a result, only utilizing the disease transmission model simply to analyze the internet worms has no pertinence. Meanwhile, it will be hard to reflect the transmission characteristics of the worms if do not consider the network topology and user behavior. Thus, this dissertation takes the email worms, P2P worms and random scanning worms as the research objects, and study the transmission and control model of the internet worms according to their different network topological structure and possible user behavior. By analyzing the transmission dynamic behaviors of the relative worms, the critical threshold condition which determines whether the worm can survive or not are given. This may contribute to defense and control the propagation of the internet worms. The detailed contents are as follows:Because the special characters of the logical network along which email worms spread,a discrete model of email worms spread are established utilizing the network terminology to abstract and characterize the logical network. By transforming the model to a continuous ordinary differential dynamical system, the dynamical features are analyzed. On the basis of the Liapunov function, the domains of attraction of equilibria are estimated, which provided theoretical guidance for the control of the email worms spread.Due to the scale-free characters of the P2P network and the active defense characters of the benign worms, a complex network model was proposed by analyzing the interactions between benign worms and malicious worms and the network node’s state transition process. Based on the dynamical analysis of the model, the effective reproduction number was obtained, which demonstrate the pivotal role of the network topological structure on the propagation of P2P worms. At the same time, the influences of the related parameters of network topology and worm propagation for the control of malicious worms’ propagation are studied. These results are confirmed by simulation experiment, further more we compared the control effect of different strategies of releasing benign worms and provided feasible control strategies of the worm propagation.In order to study the interactions between the user behaviors and the worm spread, the vulnerable computers were classified according to the corresponding user’s protection behaviors. And then a dynamical model that coupled the user’s adaptive protection behaviors was proposed. By analyzing the dynamics of the model, we obtained the basic reproduction number modified by user protection behaviors. It was shown that the model appears some complex dynamics, such as the backward bifurcation. These show that the user behaviors play an important role on the spread of worms rightly. Further more, reasonable control strategies are provided for different situations.