Network Covert Channel Of Defense-related Technology Research

TCP/IP protocols are the most popular protocols among the inter-protocols in the Internet. As there are a lot of redundancies in the TCP/IP protocols that can be used for covert communication, many covert communication techniques based on network are developed recently. The abuses of covert communication channels will bring security threats caused by problems such as the leak of seceret information. Thus the counter defending techniques are urgently needed to safeguard it.In this paper, topics on the defending system, detecting techniques and security audit techniques of network covert channels are studied on the bases of the summarizing the states of art of network covert channels technologies. The main achievements are as follows:1. Propose an omnibearing defending system of network covert channel communications consisting of detection, audit and active defence, set up the corresponding defending mechanism and strategy of network covert channels, complete the defend arrangement for network covert channels.2. Six-dimension vectors are exacted according to the characteristic of TCP/IP protocols in nomal network communications, and support vector machines based detecting algorithms are designed. The results of experiment verify the validating of the algorithms.3. In consideration of practicability of the defening system, a grading response mechanism of covert channels is designed. Suspicious behaviors on communication links can be managed differently according to the grading mechanism metioned above.4. Accomplish the designing and implementation of the defending system software for network covert channels. The experimental results demonstrate that the system is effective for defending covert channels.