Walter, MarkusKeller, JörgWendzel, SteffenWressnegger, ChristianHartmann, LauraFreiling, FelixArmknecht, FrederikReinfelder, Lena2024-04-192024-04-192024978-3-88579-739-5https://dl.gi.de/handle/20.500.12116/43960Mobile communication has become an indispensable part of our daily lives and the requirements are constantly increasing. 5G, the fifth generation of mobile networks, introduced an enhanced radio access technology, called 5G New Radio, to meet the requirements of several new use cases. We analyze the protocol stack of the 5G air interface to assess its suitability for information hiding. Network covert channels hide the very existence of a data transmission within an overt network communication in a way that is not intended for transferring data. The proposed hiding method exploits reserved bits in the header of the Packet Data Convergence Protocol (PDCP) to create a novel covert channel in 5G New Radio. The covert parties are located in the 5G base station and in the mobile device. Our implementation of the covert channel demonstrates that it is possible to achieve a high covert capacity for broadband transmissions. However, we also show that detection and elimination of the covert channel is relatively simple if a network analyzer is used. Therefore, the feasability of the proposed hiding method depends on the particular application scenario.enInformation HidingNetwork SteganographyMobile Networks5GText/Conference Paper10.18420/sicherheit2024_0021617-5468