@article {rios2022cpa, title = {Constrained Proximity Attacks on Mobile Targets}, journal = {ACM Transactions on Privacy and Security (TOPS)}, volume = {25}, number = {10}, year = {2022}, month = {05/2022}, pages = {1 - 29}, publisher = {Association for Computer Machinery (ACM)}, abstract = {

Proximity attacks allow an adversary to uncover the location of a victim by repeatedly issuing queries with fake location data. These attacks have been mostly studied in scenarios where victims remain static and there are no constraints that limit the actions of the attacker. In such a setting, it is not difficult for the attacker to locate a particular victim and quantifying the effort for doing so is straightforward. However, it is far more realistic to consider scenarios where potential victims present a particular mobility pattern. In this paper, we consider abstract (constrained and unconstrained) attacks on services that provide location information on other users in the proximity. We derive strategies for constrained and unconstrained attackers, and show that when unconstrained they can practically achieve success with theoretically optimal effort. We then propose a simple yet effective constraint that may be employed by a proximity service (for example, running in the cloud or using a suitable two-party protocol) as countermeasure to increase the effort for the attacker several orders of magnitude both in simulated and real-world cases.

}, keywords = {Location Privacy, mobility pattern, proximity attacks, quantification}, issn = {2471-2566}, doi = {10.1145/3498543}, author = {Xueou Wang and Xiaolu Hou and Ruben Rios and Nils Ole Tippenhauer and Martin Ochoa} } @article {HFNR2019, title = {Cybersecurity Profiles based on Human-Centric IoT Devices}, journal = {Human-centric Computing and Information Sciences}, volume = {9}, number = {1}, year = {2019}, pages = {1-23}, publisher = {Springer}, issn = {2192-1962}, doi = {10.1186/s13673-019-0200-y}, author = {Ana Nieto and Ruben Rios} } @article {rios2013a, title = {Covert Communications through Network Configuration Messages}, journal = {Computers \& Security}, volume = {39, Part A}, year = {2013}, month = {Nov 2013}, pages = {34 - 46}, publisher = {Elsevier}, abstract = {

Covert channels are a form of hidden communication that may violate the integrity of systems. Since their birth in Multi-Level Security systems in the early 70{\textquoteright}s they have evolved considerably, such that new solutions have appeared for computer networks mainly due to vague protocols specifications. In this paper we concentrate on short-range covert channels and analyze the opportunities of concealing data in various extensively used protocols today. From this analysis we observe several features that can be effectively exploited for subliminal data transmission in the Dynamic Host Configuration Protocol (DHCP). The result is a proof-of-concept implementation, HIDE\_DHCP, which integrates three different covert channels each of which accommodate to different stealthiness and capacity requirements. Finally, we provide a theoretical and experimental analysis of this tool in terms of its reliability, capacity, and detectability.

}, keywords = {Covert channels, Information Warfare, Intrusion Detection, Network Security, System Information Security}, issn = {0167-4048}, doi = {10.1016/j.cose.2013.03.004}, author = {Ruben Rios and Jose A. Onieva and Javier Lopez} } @inproceedings {Rios2008, title = {Clasificaci{\'o}n de canales encubiertos. Un nuevo canal: Covert_DHCP}, booktitle = {X Reuni{\'o}n Espa{\~n}ola de Criptolog{\'\i}a y Seguridad de la Informaci{\'o}n (RECSI{\textquoteright}08)}, year = {2008}, month = {Sept.}, pages = {325-336}, address = {Salamanca (Spain)}, abstract = {

Los canales encubiertos son una forma de comunicaci\ón oculta que puede vulnerar la integridad de los sistemas. Desde sus inicios en sistemas de seguridad multinivel a principios de los a\ños 70 han evolucionado considerablemente, apareciendo soluciones para redes de computadores debido a la especificaci\ón de algunos protocolos. Por este motivo, se hace un estudio sobre las t\écnicas que se han utilizado para crear los canales, as\í como sobre las distintos obst\áculos que han tratado de mermar su actividad. Asimismo, se presenta una nueva clasificaci\ón que trata de albergar la mayor cantidad de canales encubiertos existentes en la actualidad. Por \último, se analiza un protocolo ampliamente extendido en la actualidad, DHCP, en busca de posibilidades de albergar informaci\ón encubierta. A partir de este an\álisis se implementan distintas versiones de un canal encubierto haciendo uso de este protocolo.

}, keywords = {Canales encubiertos, control de accesos y detecci{\'o}n de intrusos, seguridad en redes, seguridad en sistemas de informaci{\'o}n}, isbn = {978-84-691-5158-7}, author = {Ruben Rios and Jose A. Onieva}, editor = {Luis Hern{\'a}ndez Encinas and Angel Martin del Rey} }