Modbus协议原理及安全性分析

从来源、原理等方面介绍了典型的工业控制网络协议——Modbus协议。首先介绍了协议消息帧的组成方式，协议传输的各种模式，功能码分类和典型的功能码；其次指出了Modbus协议安全问题的产生原因，并从其固有安全问题和实现过程的安全问题两方面详细介绍了Modbus系统面临的安全威胁；最后，针对Modbus系统在现实应用中的问题，提出了需要采取的保护措施。这对提高工业控制网络安全有着重要的现实意义。

Principle and Security Analysis of Modbus Protocol

This paper discusses the industrial control system protocol--Modbus protocol from the source and principle. The components of protocol message frame, various modes of protocol transfer, the classification of functional code and the typical functional code are given first, then the causes of Modbus protocol secur- ity problems pointed out, and the security threats faced by Modbus system are described in detail from the inherent safety problems and the security implementation process, and finally, aiming at the problems in the practical application of the Modbus system, the necessary protection measures are suggested. This would be of important practical significance for improving the safety of industrial control network.