Covert Messaging through TCP Timestamps

Covert channels exist in most communications systems and allow individuals to communicate truly undectably. However, covert channels are seldom used due to their complexity. A protocol for sending data over a common class of low-bandwidth covert channels has been developed. The protocol is secure against attack by powerful adversaries. The design of a practical system implementing the protocol on a standard platform (Linux) exploiting a channel in a common communications system (TCP timestamps) is presented. A partial implementation of this system has been accomplished.

[1]  Gustavus J. Simmons,et al.  Subliminal channels; past and present , 2010, Eur. Trans. Telecommun..

[2]  Markus G. Kuhn,et al.  Information hiding-a survey , 1999, Proc. IEEE.

[3]  Christian Cachin,et al.  An information-theoretic model for steganography , 1998, Inf. Comput..

[4]  S. M. Bellovin,et al.  Security problems in the TCP/IP protocol suite , 1989, CCRV.

[5]  Donald E. Eastlake,et al.  US Secure Hash Algorithm 1 (SHA1) , 2001, RFC.

[6]  Craig H. Rowland,et al.  Covert Channels in the TCP/IP Protocol Suite , 1997, First Monday.

[7]  Gustavus J. Simmons,et al.  Results concerning the bandwidth of subliminal channels , 1998, IEEE J. Sel. Areas Commun..

[8]  I. S. Moskowitz,et al.  Covert channels-here to stay? , 1994, Proceedings of COMPASS'94 - 1994 IEEE 9th Annual Conference on Computer Assurance.

[9]  James W. Gray,et al.  Countermeasures and tradeoffs for a class of covert timing channels , 1994 .

[10]  Gustavus J. Simmons,et al.  The Prisoners' Problem and the Subliminal Channel , 1983, CRYPTO.

[11]  Ross J. Anderson,et al.  On the limits of steganography , 1998, IEEE J. Sel. Areas Commun..

[12]  Christian Cachin,et al.  An information-theoretic model for steganography , 2004, Inf. Comput..

[13]  Ira S. Moskowitz,et al.  Simple timing channels , 1994, Proceedings of 1994 IEEE Computer Society Symposium on Research in Security and Privacy.