基于入侵容忍技术的监管体系结构研究

【作者】 李韶光；

【导师】 秦志光；

【作者基本信息】 电子科技大学 ， 计算机应用技术， 2004， 硕士

【摘要】 网络攻击的趋势是攻击技术越来越复杂,攻击行为越来越频繁,这些攻击严重威胁着网络使用者的利益。第一代安全系统依靠密码学、可信的计算基础、认证、防火墙、访问控制和其他的外围防卫来抵御入侵行为。虽然这种方法能够满足部分非常保密的用户的需求,但实施成本非常高。在当前网际环境下,此种方法难以支付。并且,它没有提供防止内部人员非法行为的措施。第二代安全系统涉及到用入侵检测技术来标识普遍存在的防卫漏洞。但尽管采取了众多的防护措施,信息系统仍不可避免地受到攻击。为了在面对攻击的情况下,信息系统仍然能持续地为预期的用户提供及时的服务,需要有效的防护措施,入侵容忍技术是一种很有效的保障措施。入侵容忍系统在检测到攻击行为后,应识别已被攻破的系统组件,评估破坏程度,进而触发入侵容忍机制,动态地对软硬件资源进行自我配置来优化性能、功能和安全性,平滑地降低系统的功能和性能,保持尽量多的关键功能模块的正常运行,这在某些应用场合非常必要。本文旨在对入侵容忍技术进行研究,建立一个基于入侵容忍技术的监管体系框架。该系统具有入侵检测,策略分析,策略重配置,服务监控,审计控制等功能;分别从网络级,系统级,服务级对入侵行为进行检测,对服务业务进行保护,通过多样化的网络和服务策略来达到系统对入侵的容忍能力。本文首先分析了国内外同类研究的内容和成果,包括:UIUC的ITUA(Intrusion Tolerance by Unpredictable Adaptation)项目、DUKE 大学的SITAR(A Scalable Intrusion Tolerant Architecture for Distributed Services)项目等。然后根据入侵容忍系统的需求,对入侵检测,策略重配置,服务监控等技术进行了研究,并设计了一个监管体系原型。最后,对该原型系统进行了攻防试验,证明了这种方法的可行性和有效性。课题的最终成果为:设计了一个基于入侵容忍技术的监管系统(包括系统体系结构,程序层次结构),并且实现了监管体系原型。本文的创新性主要体现为,从服务的角度考虑网络安全问题,而不是象普通的安全技术主要侧重于从客户请求的角度来考虑安全防护问题;并且提出了一个融合多种检测方法和多种安全策略的体系框架。更多还原

【Abstract】 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.Due to timeliness or cose,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 servicess even when they are under attack or have been partially compromised; hence the need for intrusion tolerance.An intrusion-tolerant system is capable of self-diagnosis ,repair,and reconstitution,while continuing to provide service to legitimate clients(with possible degradation) in the presence of intrusions.This paper describes the conceptual architecture of such a system,and our experience with its initial implementation.This system consists of IDS subsystem,policy management subsystem and monitoring administration subsystem.It prevents service from being penetrated through networking,system,application level respectively.Two related projects,Intrusion Tolerance by Unpredictable Adaptation(ITUA),A Scalable Intrusion Tolerant Architecture for Distributed Services(SITAR),are analyzed firstly.Then,according to the requirements of Monitoring Administration System(MAS),new techniques such as Adaptive Reconfiguration,Intrusion Detection,policy Analysis are addressed and implemented.The achievements of this research include the design and implementation of a MAS prototype.In the design of the prototype,architecture and program structure are presented.In conclusion, an architecture which integrates many kinds of detection methods and security polices is proposed. And an idea is presented that we need to shift attention from attacks or attacker themselves to the target of protection,which is inherently tied to the functions and services being provided.更多还原