即时通信软件协议分析技术的研究与实现

发布时间：2018-01-24 19:34

本文关键词： 即时通信软件动态污点分析技术 Pin 密码函数定位协议分析技术　出处：《电子科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：伴随着人们对即时通信软件的依赖程度越来越高,即时通信软件的通信内容安全越来越引起安全研究人员的重视。协议分析技术在网络应用程序内容安全方面具有重要的作用,但由于越来越多的即时通信软件使用了加密通信协议,加密技术隐藏了网络数据原有的格式信息和语义信息,阻碍了协议分析工作,因此如何高效的对加密协议进行协议分析是一项重要且极具探索性的研究课题。论文首先介绍了协议分析的研究现状、技术背景以及常用方法,并对已有的研究成果进行了论述。在此基础上,本文提出了一种针对即时通信软件进行协议分析的方法:通过定位二进制软件中的密码函数,以提取解密后的明文协议消息,并使用协议格式提取方法对获取到的协议数据进行分析,以得到该协议消息的格式信息。本文的工作主要包括:1.密码函数定位技术的研究。通过对密码算法实现中指令特征以及I/O参数信息熵变化的研究,提出基于特征的密码函数定位方法;通过对密钥、密文/明文以及密码算法三者之间依赖关系的研究,提出基于循环数据流的密码函数定位方法,并从适用范围、时间开销以及实现复杂度等方面对两种方法进行了比较。2.协议格式提取技术的研究。通过动态跟踪被分析软件解析例程的执行轨迹,归纳总结了解析例程对协议消息中各个主要协议字段解析过程,提出了针对各个主要协议字段及其语义信息的提取方法,并将提取到的字段及其语义信息添加到协议字段树中,以完成协议分析工作。3.设计并实现了基于Pin的原型系统IMPA。首先,通过对动态污点分析技术在协议分析领域的研究,本文设计并实现了一种高效的污点传播跟踪方法;之后,本文详细论述了IMPA系统中各个模块的设计和实现细节,并从功能测试和比较测试两个方面对系统进行了评估。功能测试结果说明了本文提出方法的有效性,与已有的方法相比较,本文提出的方法能更加准确的定位密码函数的位置,并有效的提取协议消息的格式信息。
[Abstract]:Along with people's dependence on instant messaging software is becoming more and more high. Security researchers pay more and more attention to the content security of instant messaging software. Protocol analysis plays an important role in the security of network applications. However, because more and more instant messaging software use encrypted communication protocol, encryption technology hides the original format information and semantic information of network data, which hinders the protocol analysis. Therefore, how to efficiently analyze the protocol of encryption protocol is an important and very exploratory research topic. Firstly, this paper introduces the research status, technical background and common methods of protocol analysis. On the basis of this, this paper puts forward a method to analyze the protocol of instant messaging software: by locating the cryptographic function in binary software. In order to extract the decrypted plaintext protocol message, and use the protocol format extraction method to analyze the obtained protocol data. In order to obtain the format information of the protocol message, the work of this paper mainly includes: 1. The research of cryptographic function location technology. Through the research of instruction feature and the change of entropy of I / O parameter information in the implementation of cryptographic algorithm. A new method of cryptographic function location based on feature is proposed. Based on the study of the dependency among key ciphertext / plaintext and cipher algorithm a new method of cryptographic function location based on cyclic data stream is proposed and its application range is discussed. The paper compares the two methods in terms of time overhead and implementation complexity. 2. Research on protocol format extraction technology. Dynamically track the execution track of the analyzed software parse routine. 2. This paper summarizes the parsing process of the main protocol fields in the protocol message by the parsing routine, and proposes a method to extract the main protocol fields and their semantic information. The extracted fields and their semantic information are added to the protocol field tree to complete the protocol analysis. 3. The prototype system based on Pin is designed and implemented. First of all. Based on the research of dynamic stain analysis technology in the field of protocol analysis, this paper designs and implements an efficient method of stain propagation tracking. Then, this paper discusses the design and implementation details of each module in the IMPA system in detail. The system is evaluated from two aspects: function test and comparison test. The results of function test show the effectiveness of the proposed method and compare it with the existing methods. The method proposed in this paper can locate the location of cryptographic function more accurately and extract the format information of protocol message effectively.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN918.4

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