Ternary timing covert channel in wireless 802.11

Abstract

Covert channel is one of the most interesting topics in the computer networks security. Covert channel designers are seeking to discover weaknesses in the communications algorithms to use them as the medium for covert transmission. Broadcast nature of wireless channels has provided a favorable environment for the design of the hidden channels. CSMA/CA is used to control channel access in IEEE 802.11 network. Random features of this algorithm can be used to create timing covert channel. The statistical distribution of the free time intervals' duration is used in this paper for covert channel establishment. Hidden messages are sent via manipulating the timing of the overt packets' transmission. Hidden transceiver senses the wireless channel continuously to be adapted to the dynamic network condition and to be less detectable. To increase the covert channel's accuracy, some free interval durations are not used that leads to security degradation. This problem is also covered by a gap covering method that is based on the summation of the channel sensed free time interval distribution and a normal one. Hidden nodes also estimate the number of active nodes and adapt their behavior accordingly to keep their compatibility with the network. The statistical Kolmogorov-Smirnov and regularity tests are used to assess the security of the covert channel. Simulation results show that the proposed covert channel have a high bit rate along with high security.

StegoFrameOrder—MAC Layer Covert Network Channel for Wireless IEEE 802.11 Networks

“…Typical timing solutions for IEEE 802.11 networks that take advantage of their properties (e.g., non-deterministic media access) are also available. An example of such a method has been described in [ 36 ]. Another solution for the timing covert channel has been presented in [ 37 ].…”

ThermoSteg—Covert Channel for Microbolometer Thermographic Cameras

“…One of the most exploited fields is computer network steganography, where two types of covert channels can be distinguished—timing covert channels and storage covert channels. The first type uses the modulation of the interval between two network events, such as the beginning of packet transmissions in wireless channels [ 9 ] or adjusting silence periods in VoLTE transmission [ 10 ]. The other type, storage channels, exploits unused or partially used fields in network protocols, such as the Timestamp field in IEEE 802.11 Beacon frames [ 11 ].…”