The Research Of An Intrusion Tolerant System Based On Code Access Control

The attack techniques are getting more and more sophisticated. And attack events are becoming more and more frequent. These attacks impact the network security seriously. Despite efforts over many years to provide defenses against computer and network attacks, attacks still succeed with painful frequency. Many of the techniques devised to build more secure systems, such as, access control and IDS etc. These techniques are not appropriate for most applications. A growing recognition is that a variety of mission critical applications need to continue to operate or provide a minimal level of services even when they are under attack or have been partially compromised; hence the need for intrusion tolerance. That is core of the third generation in secure technology.This paper describes the conceptual architecture of an intrusion-tolerant system, which is capable of self-diagnosis, repair, and reconfiguration, while continuing to provide service to legitimate clients (with possible degradation) in the presence of intrusions. The system is built on the mechanism of Code Access Control and Role Based Access Control.We do the following creative work in this paper:1. Classify existing intrusion tolerant systems with different standards and make an overview of existing intrusion tolerant technologies.2. Generalize few kinds of intrusion tolerant model and analyse the disadvantage of these model. An evidence-based code access control(EBCAC) model,which can provide the lower access control of system security, is generalized from code access control of Microsoft. Then we give a formalized description of it and descript a improved system architecture based on it. We also discussed how to implement it and give an instance of EBCAC Model.3. Presents a new intrusion-tolerant architecture which combines the code access control and role-based access control. The system consists of intrusion detection subsystem, policy management subsystem and audit control subsystem. Then we discuss the design of the key component of the intrusion-tolerant system,that is, the design of intrusion tolerant triggers.