建筑智能化系统网络安全体系研究
摘 要
随着 Internet 技术和建筑智能化应用的快速发展以及各种需求的推动,建筑智能化系统网络正趋向于接入 Internet 从而变得更加开放。一些楼宇控制系统、HVAC系统等建筑智能化系统厂商通过Internet进行远程监测和维护以降低服务成本提高售后服务质量;物业管理公司亦通过 Internet 管理处于不同地区的楼盘进行远程监管;国内越来越多城市将主要公共建筑和社区的消防、安防系统均接入 Internet 从而与城市统一远程监控平台联网,以便更加有效地应对突发火灾和安全事故,减少生命财产损失。然而,建筑智能化系统与因特网的互联带来了诸多网络安全威胁,而网络安全防范措施又很缺乏,因此建筑智能化系统的网络安全问题迫切需要加以研究和解决。
本文对网络安全技术理论进行了研究,分析了各种安全技术特点。对常见的三种建筑智能化系统控制网络 LonWorks、BACnet 和 KNX/EIB 的最核心内容进行了阐述,以作为后续研究其安全机制的知识准备。剖析比较了主流的网络模拟软件NS2、OPNET 和 OMNeT++,从组成架构和模拟流程两个方面进行了介绍,选择多个比较点对这三个工具进行了详细的剖析对比,综合考虑各方因素并结合课题需要最终选择 OMNeT++作为本课题的模拟测试工具。建立了建筑智能化系统网络的一般网络架构模型,从而对建筑智能化系统网络有了一个清晰的认识。结合此模型研究了网络安全威胁可能发生的位置和可能遭受威胁且需要安全防护的对象。面对众多的安全威胁,为了准确评价每种威胁对建筑智能化系统网络的影响程度,引入了危害度的概念并给出了计算公式。在分析了建筑智能化系统网络安全防护特点的基础上,构建了一种建筑智能化系统网络安全体系框架,并用形式化的语言予以描述。分别研究 LonWorks、BACnet 和 KNX/EIB 等三种建筑智能化系统网络集成技术的安全机制并分析了存在的安全缺陷,结果显示除了 BACnet的安全性相对较高以外,其他两种技术均较为严重。为了弥补 LonWorks 在安全性方面的缺陷,在建筑智能化系统网络安全体系框架的指导下,设计了 LonWorks 网络技术的安全体系 LonSec,并引入了实施 LonSec 的安全设备安全防护装置(SPU,Security Protection Unit)。最后,为了测试 LonSec 的安全性能,利用从三种主流开源网络模拟软件中优选出的 OMNeT++,在其中添加了 LonTalk 协议与 LonSec 安全体系,并模拟了四类网络攻击,结果显示 LonSec 能起到有效的防护作用。 本课题的研究表明,建筑智能化系统网络安全形势严峻,其面临的安全威胁种类众多,有些是与一般的信息网络所共有的,但大部分是特有的。本文提出的危害度计算公式能够有效评估这些威胁产生的危害,从而为针对性地部署防御措施 提供参考。建立的建筑智能化系统网络安全体系框架区别于信息网络的安全体系,具有建筑智能化系统网络特色,为后续的研究搭建起了整体平台。而构建的以LonWorks 为网络技术基础的建筑智能化系统网络安全体系 LonSec 则是在该框架指导下的具体实践。使用 OMNeT++网络模拟软件模拟了常见四类网络攻击,结果表明 LonSec 能够有效保护 LonWorks 网络安全,同时也证实了通过建立安全体系的途径来解决建筑智能化系统网络安全问题是必要且可行的。
关键词:建筑智能化系统,网络安全,安全体系,LonWorks,网络模拟
ABSTRACT
With the rapid development of Internet technology and building intelligent application, the building intelligent systems tend to be more open and accessable when interconnected with Internet under the impulsion of various novel demands. Out of the willing to reduce service costs and improve service quality, several intelligent building system vendors monitor and maintain their products of building automation and HVAC systems remotely. The property management companies monitor and manage their estate remotely through the Internet. More and more domestic cities interconnect the fire safety and security systems of major urban public buildings and communities with city unified remote monitor platform through the Internet to more effectively deal with sudden incidents of fire and safety, so the loss of life and property could be reduced significantly. Nevertheless, interconnecting building intelligent systems with the Internet brings not only the benefits but also more new network threats. Howerer, the building intelligent systems are short of protections against those threats. So, how to protect the building intelligention systems effectively can be a topic that is worth to be studied and solved. This thesis gives a survey on kinds of network security theories, the three main control network protocols LonWorks, BACnet and KNX/EIB. The network simulator OMNeT++ was chosen as a tool to test the security architecture on the basis of comprehensive comparison with other two mainstream simulators NS2 and OPNET.
After the common structure of the building intelligent system nework was outlined, the positions where network attack may occur and the subjects who may suffer are pointed out. Faced by those attacks a formular especially designed for the building intelligent system is introduced to estimate the influences they could cause. Security architecture was constructed under the guidance of SSE-CMM and described in formal language.
The security defects of the three control network standards are studied and the results show that the BACnet is relatively superior to the other ones in respect of security. The security architecture named LonSec is built under the condition that a new security device named SPU which shorts for security assistant unit is brought in. Finally, the LonSec was tested by simulating four types of network attack in OMNeT++ after the LonTalk protocol was added. The testing result demonstrates that LonSec works well in protecting the whole network.
Through this research we conclude that the building intelligent system networks are
in serious security condition. They are faced with kinds of security threats some of which are shared with traditional IP networks while more are unique. The formula proposed in the thesis can effectively estimate severity of these threats in order to provide reference to the targeted deployment of defensive measures.The established framework of the building intelligent system network security architecture is with
characteristics of the building intelligent system networks and distinguished from IP network security architecture. It constructs a whole platform for the future research. The constructed network security architecture – LonSec for LonWorks network technology based building intelligent systems is a specific practice under the guidance of the framework. LonSec was tested by simulating four typical types of network attack in constructed OMNeT++ simulation enviroment. The results show that it protects LonWorks well. The successful network security architecture proves that it is necessary and feasible to solve most of security problems for the building intelligent system by construting security architecture.
Keywords:Building Intelligent System, Network Security, Security Architecture, LonWorks, Network Simulation- 上一篇: 建筑智能化系统简介 2014/6/2
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