A Protocol for Building Secure and Reliable Covert Channel

This paper presents a secure and lightweight protocol for reliable data transfer through moderate bandwidth covert channels. Though data transfer through covert channels is not unprecedented, existing covert channels have been restricted to covert transmission of only small amounts of data. This paper demonstrates that it is possible to transmit large amounts of data covertly with sophisticated support such as security and reliability. The proposed protocol exploits ICMP echo request as covert medium, and uses OS finger-printing techniques to simulate real TCP/IP stack behavior for further security enhancements.