Indirect DNS Covert Channel based on Base 16 Matrix for Stealth Short Message Transfer

Covert Channel are the methods to conceal a message in the volatile medium carrier such as radio signal and network packets. Until now, covert channels based on the packet length produce abnormal packet length when the length of the message is long. Abnormal packet length, especially in the normal network will expose the covert channels to network security perimeter. Therefore, it motivates the study to propose a new method based on reference matrix to hide the secret message in DNS request. Normal DNS request packet was collected from the campus network. The proposed packets length covert channel was compared with normal DNS request packets. The study found that the new purpose covert channels produce normal DNS packet length according to the campus network.