@misc{MitsevaPanchenkoLanzeetal., author = {Mitseva, Asya and Panchenko, Andriy and Lanze, Fabian and Henze, Martin and Engel, Thomas and Wehrle, Klaus}, title = {POSTER: Fingerprinting Tor Hidden Services}, series = {In Proceedings of the 2016 ACM SIGSAC Conference on Computer and Communications Security (CCS '16). Association for Computing Machinery, New York, NY, USA}, journal = {In Proceedings of the 2016 ACM SIGSAC Conference on Computer and Communications Security (CCS '16). Association for Computing Machinery, New York, NY, USA}, publisher = {ACM}, address = {New York}, isbn = {978-1-4503-4139-4}, doi = {10.1145/2976749.2989054}, pages = {1766 -- 1768}, language = {en} } @misc{MitsevaPanchenkoEngel, author = {Mitseva, Asya and Panchenko, Andriy and Engel, Thomas}, title = {The state of affairs in BGP security: A survey of attacks and defenses}, series = {Computer Communications}, volume = {124}, journal = {Computer Communications}, issn = {0140-3664}, doi = {10.1016/j.comcom.2018.04.013}, pages = {45 -- 60}, language = {en} } @misc{DelaCadenaKaiserMitsevaetal., author = {De la Cadena, Wladimir and Kaiser, Daniel and Mitseva, Asya and Panchenko, Andriy and Engel, Thomas}, title = {Analysis of Multi-path Onion Routing-based Anonymization Networks}, series = {Data and Applications Security and Privacy XXXIII : 33rd Annual IFIP WG 11.3 Conference, DBSec 2019, Charleston, SC, USA, July 15-17, 2019, Proceedings}, journal = {Data and Applications Security and Privacy XXXIII : 33rd Annual IFIP WG 11.3 Conference, DBSec 2019, Charleston, SC, USA, July 15-17, 2019, Proceedings}, editor = {Foley, Simon N.}, publisher = {Springer}, address = {Frankfurt am Main}, isbn = {978-3-030-22478-3}, issn = {0302-9743}, doi = {10.1007/978-3-030-22479-0_13}, pages = {240 -- 258}, language = {en} } @misc{PennekampHillerReuteretal., author = {Pennekamp, Jan and Hiller, Jens and Reuter, Sebastian and De la Cadena, Wladimir and Mitseva, Asya and Henze, Martin and Engel, Thomas and Wehrle, Klaus and Panchenko, Andriy}, title = {Multipathing Traffic to Reduce Entry Node Exposure in Onion Routing}, series = {Proceedings of the 27th annual IEEE International Conference on Network Protocols (Poster) (IEEE ICNP 2019), Chicago, Illinois, USA, October 2019}, journal = {Proceedings of the 27th annual IEEE International Conference on Network Protocols (Poster) (IEEE ICNP 2019), Chicago, Illinois, USA, October 2019}, publisher = {IEEE Press}, isbn = {978-1-7281-2700-2}, issn = {2643-3303}, doi = {10.1109/ICNP.2019.8888029}, pages = {2}, abstract = {Users of an onion routing network, such as Tor, depend on its anonymity properties. However, especially malicious entry nodes, which know the client's identity, can also observe the whole communication on their link to the client and, thus, conduct several de-anonymization attacks. To limit this exposure and to impede corresponding attacks, we propose to multipath traffic between the client and the middle node to reduce the information an attacker can obtain at a single vantage point. To facilitate the deployment, only clients and selected middle nodes need to implement our approach, which works transparently for the remaining legacy nodes. Furthermore, we let clients control the splitting strategy to prevent any external manipulation.}, language = {en} } @misc{MitsevaEngelPanchenko, author = {Mitseva, Asya and Engel, Thomas and Panchenko, Andriy}, title = {Analyzing PeerFlow - A Bandwidth Estimation System for Untrustworthy Environments}, series = {Sicherheit 2020 : Sicherheit, Schutz und Zuverl{\"a}ssigkeit ; Konferenzband der 10. Jahrestagung des Fachbereichs Sicherheit der Gesellschaft f{\"u}r Informatik e.V. (GI) ; 17.- 20. M{\"a}rz 2020 in G{\"o}ttingen}, journal = {Sicherheit 2020 : Sicherheit, Schutz und Zuverl{\"a}ssigkeit ; Konferenzband der 10. Jahrestagung des Fachbereichs Sicherheit der Gesellschaft f{\"u}r Informatik e.V. (GI) ; 17.- 20. M{\"a}rz 2020 in G{\"o}ttingen}, editor = {Reinhardt, Delphine and Langweg, Hanno and Witt, Bernhard C. and Fischer, Mathias}, publisher = {Gesellschaft f{\"u}r Informatik}, address = {Bonn}, isbn = {978-3-88579-695-4}, doi = {10.18420/sicherheit2020_02}, pages = {29 -- 40}, language = {en} } @misc{MitsevaAleksandrovaEngeletal., author = {Mitseva, Asya and Aleksandrova, Marharyta and Engel, Thomas and Panchenko, Andriy}, title = {Security and Performance Implications of BGP Rerouting-resistant Guard Selection Algorithms for Tor}, series = {ICT Systems Security and Privacy Protection : 35th IFIP TC 11 International Conference, SEC 2020, Maribor, Slovenia, September 21-23, 2020}, journal = {ICT Systems Security and Privacy Protection : 35th IFIP TC 11 International Conference, SEC 2020, Maribor, Slovenia, September 21-23, 2020}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-58201-2}, issn = {1868-4238}, doi = {10.1007/978-3-030-58201-2_15}, pages = {219 -- 233}, language = {en} } @misc{DelaCadenaMitsevaHilleretal., author = {De la Cadena, Wladimir and Mitseva, Asya and Hiller, Jens and Pennekamp, Jan and Reuter, Sebastian and Filter, Julian and Engel, Thomas and Wehrle, Klaus and Panchenko, Andriy}, title = {TrafficSliver: Fighting Website Fingerprinting Attacks with Traffic Splitting}, series = {CCS '20: Proceedings of the 2020 ACM SIGSAC Conference on Computer and Communications Security, October 2020}, journal = {CCS '20: Proceedings of the 2020 ACM SIGSAC Conference on Computer and Communications Security, October 2020}, publisher = {Association for Computing Machinery}, address = {New York}, isbn = {978-1-4503-7089-9}, doi = {10.1145/3372297.3423351}, pages = {1971 -- 1985}, abstract = {Website fingerprinting (WFP) aims to infer information about the content of encrypted and anonymized connections by observing patterns of data flows based on the size and direction of packets. By collecting traffic traces at a malicious Tor entry node — one of the weakest adversaries in the attacker model of Tor — a passive eavesdropper can leverage the captured meta-data to reveal the websites visited by a Tor user. As recently shown, WFP is significantly more effective and realistic than assumed. Concurrently, former WFP defenses are either infeasible for deployment in real-world settings or defend against specific WFP attacks only. To limit the exposure of Tor users to WFP, we propose novel lightweight WFP defenses, TrafficSliver, which successfully counter today's WFP classifiers with reasonable bandwidth and latency overheads and, thus, make them attractive candidates for adoption in Tor. Through user-controlled splitting of traffic over multiple Tor entry nodes, TrafficSliver limits the data a single entry node can observe and distorts repeatable traffic patterns exploited by WFP attacks.We first propose a network-layer defense, in which we apply the concept of multipathing entirely within the Tor network. We show that our network-layer defense reduces the accuracy from more than 98\% to less than 16\% for all state-of-the-art WFP attacks without adding any artificial delays or dummy traffic. We further suggest an elegant client-side application-layer defense, which is independent of the underlying anonymization network. By sending single HTTP requests for different web objects over distinct Tor entry nodes, our application-layer defense reduces the detection rate of WFP classifiers by almost 50 percentage points. Although it offers lower protection than our network-layer defense, it provides a security boost at the cost of a very low implementation overhead and is fully compatible with today's Tor network.}, language = {en} } @misc{DelaCadenaKaiserPanchenkoetal., author = {De la Cadena, Wladimir and Kaiser, Daniel and Panchenko, Andriy and Engel, Thomas}, title = {Out-of-the-box Multipath TCP as a Tor Transport Protocol: Performance and Privacy Implications}, series = {2020 IEEE 19th International Symposium on Network Computing and Applications (NCA), 24-27 Nov. 2020, Cambridge, MA, USA}, journal = {2020 IEEE 19th International Symposium on Network Computing and Applications (NCA), 24-27 Nov. 2020, Cambridge, MA, USA}, isbn = {978-1-7281-8326-8}, issn = {2643-7929}, doi = {10.1109/NCA51143.2020.9306702}, pages = {6}, language = {en} } @misc{MitsevaPennekampLohmoelleretal., author = {Mitseva, Asya and Pennekamp, Jan and Lohm{\"o}ller, Johannes and Ziemann, Torsten and Hoerchner, Carl and Wehrle, Klaus and Panchenko, Andriy}, title = {POSTER: How Dangerous is My Click? Boosting Website Fingerprinting By Considering Sequences of Webpages}, series = {Proceedings of the 28th ACM Conference on Computer and Communications Security (ACM CCS 2021), Seoul, Virtual Event, South Korea, November 2021}, journal = {Proceedings of the 28th ACM Conference on Computer and Communications Security (ACM CCS 2021), Seoul, Virtual Event, South Korea, November 2021}, publisher = {ACM Press}, address = {New York}, isbn = {978-1-4503-8454-4}, doi = {10.1145/3460120.3485347}, pages = {2411 -- 2413}, language = {en} } @misc{PanchenkoMitsevaKnabe, author = {Panchenko, Andriy and Mitseva, Asya and Knabe, Sara}, title = {WhisperChord: Scalable and Secure Node Discovery for Overlay Networks}, series = {IEEE 46th Conference on Local Computer Networks (LCN), Edmonton, AB, Canada , 4-7 Oct. 2021}, journal = {IEEE 46th Conference on Local Computer Networks (LCN), Edmonton, AB, Canada , 4-7 Oct. 2021}, publisher = {IEEE}, isbn = {978-1-6654-1886-7}, issn = {0742-1303}, doi = {10.1109/LCN52139.2021.9525008}, pages = {170 -- 177}, abstract = {Node discovery is a fundamental service for any overlay network, including anonymization networks. Although anonymization and node discovery are two disjoint services, the node discovery has a direct impact on the anonymization. Centralized methods require a trusted third party, limit the network scalability, and are vulnerable to intersection (statistical disclosure) attacks. Therefore, several distributed node discovery methods were proposed to meet the security requirements of anonymization networks through additional structures within Distributed Hash Tables (DHTs). However, they require a high management overhead, a strict cooperation between nodes, and are susceptible to active and passive attacks.We propose WhisperChord—an alternative distributed node discovery approach, which incorporates gossiping into structured overlays. WhisperChord is based on a Chord DHT and neither creates any additional structures within the DHT nor requires any trusted third party. Via simulations, we show that our method provides superior protection against active attacks than prior methods and can effectively thwart information leakages.}, language = {en} }