TY - GEN A1 - Mitseva, Asya A1 - Panchenko, Andriy A1 - Lanze, Fabian A1 - Henze, Martin A1 - Engel, Thomas A1 - Wehrle, Klaus T1 - POSTER: Fingerprinting Tor Hidden Services T2 - In Proceedings of the 2016 ACM SIGSAC Conference on Computer and Communications Security (CCS '16). Association for Computing Machinery, New York, NY, USA Y1 - 2016 SN - 978-1-4503-4139-4 U6 - https://doi.org/10.1145/2976749.2989054 SP - 1766 EP - 1768 PB - ACM CY - New York ER - TY - GEN A1 - Pennekamp, Jan A1 - Hiller, Jens A1 - Reuter, Sebastian A1 - De la Cadena, Wladimir A1 - Mitseva, Asya A1 - Henze, Martin A1 - Engel, Thomas A1 - Wehrle, Klaus A1 - Panchenko, Andriy T1 - Multipathing Traffic to Reduce Entry Node Exposure in Onion Routing T2 - Proceedings of the 27th annual IEEE International Conference on Network Protocols (Poster) (IEEE ICNP 2019), Chicago, Illinois, USA, October 2019 N2 - 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. Y1 - 2019 UR - https://ieeexplore.ieee.org/document/8888029 SN - 978-1-7281-2700-2 SN - 978-1-7281-2701-9 U6 - https://doi.org/10.1109/ICNP.2019.8888029 SN - 2643-3303 SN - 1092-1648 PB - IEEE Press ER - TY - GEN A1 - Hiller, Jens A1 - Pennekamp, Jan A1 - Dahlmanns, Markus A1 - Henze, Martin A1 - Panchenko, Andriy A1 - Wehrle, Klaus T1 - Tailoring Onion Routing to the Internet of Things: Security and Privacy in Untrusted Environments T2 - Proceedings of the 27th annual IEEE International Conference on Network Protocols (IEEE ICNP 2019), Chicago, Illinois, USA, October 2019 N2 - An increasing number of IoT scenarios involve mobile, resource-constrained IoT devices that rely on untrusted networks for Internet connectivity. In such environments, attackers can derive sensitive private information of IoT device owners, e.g., daily routines or secret supply chain procedures, when sniffing on IoT communication and linking IoT devices and owner. Furthermore, untrusted networks do not provide IoT devices with any protection against attacks from the Internet. Anonymous communication using onion routing provides a well-proven mechanism to keep the relationship between communication partners secret and (optionally) protect against network attacks. However, the application of onion routing is challenged by protocol incompatibilities and demanding cryptographic processing on constrained IoT devices, rendering its use infeasible. To close this gap, we tailor onion routing to the IoT by bridging protocol incompatibilities and offloading expensive cryptographic processing to a router or web server of the IoT device owner. Thus, we realize resource-conserving access control and end-toend security for IoT devices. To prove applicability, we deploy onion routing for the IoT within the well-established Tor network enabling IoT devices to leverage its resources to achieve the same grade of anonymity as readily available to traditional devices. KW - Routing, Internet of Things, Protocols, Cryptography, Servers Y1 - 2019 UR - https://ieeexplore.ieee.org/document/8888033 SN - 978-1-7281-2700-2 SN - 978-1-7281-2701-9 U6 - https://doi.org/10.1109/ICNP.2019.8888033 SN - 2643-3303 SN - 1092-1648 PB - IEEE Press ER - TY - GEN A1 - De La Cadena, Wladimir A1 - Mitseva, Asya A1 - Pennekamp, Jan A1 - Hiller, Jens A1 - Lanze, Fabian A1 - Engel, Thomas A1 - Wehrle, Klaus A1 - Panchenko, Andriy T1 - POSTER: Traffic Splitting to Counter Website Fingerprinting T2 - CCS '19 Proceedings of the 2019 ACM SIGSAC Conference on Computer and Communications Security , London, UK, November 11 - 15, 2019. N2 - Website fingerprinting (WFP) is a special type of traffic analysis, which aims to infer the websites visited by a user. Recent studies have shown that WFP targeting Tor users is notably more effective than previously expected. Concurrently, state-of-the-art defenses have been proven to be less effective. In response, we present a novel WFP defense that splits traffic over multiple entry nodes to limit the data a single malicious entry can use. Here, we explore several traffic-splitting strategies to distribute user traffic. We establish that our weighted random strategy dramatically reduces the accuracy from nearly 95% to less than 35% for four state-of-the-art WFP attacks without adding any artificial delays or dummy traffic. Y1 - 2019 UR - https://dl.acm.org/citation.cfm?doid=3319535.3363249 SN - 978-1-4503-6747-9 U6 - https://doi.org/10.1145/3319535.3363249 SP - 2533 EP - 2535 PB - ACM Press CY - New York ER - TY - GEN A1 - Pennekamp, Jan A1 - Henze, Martin A1 - Hohlfeld, Oliver A1 - Panchenko, Andriy T1 - Hi Doppelgänger: Towards Detecting Manipulation in News Comments T2 - Companion Proceedings of the 2019 World Wide Web Conference (WWW '19 Companion), 4th Workshop on Computational Methods in Online Misbehavior (CyberSafety '19), May 13–17, 2019, San Francisco, CA, USA Y1 - 2019 SN - 978-1-4503-6675-5 U6 - https://doi.org/10.1145/3308560.3316496 SP - 197 EP - 205 PB - ACM CY - New York ER - TY - GEN A1 - De la Cadena, Wladimir A1 - Kaiser, Daniel A1 - Mitseva, Asya A1 - Panchenko, Andriy A1 - Engel, Thomas ED - Foley, Simon N. T1 - Analysis of Multi-path Onion Routing-based Anonymization Networks T2 - Data and Applications Security and Privacy XXXIII : 33rd Annual IFIP WG 11.3 Conference, DBSec 2019, Charleston, SC, USA, July 15–17, 2019, Proceedings Y1 - 2019 UR - https://link.springer.com/book/10.1007%2F978-3-030-22479-0 SN - 978-3-030-22478-3 SN - 978-3-030-22479-0 U6 - https://doi.org/10.1007/978-3-030-22479-0_13 SN - 0302-9743 SN - 1611-3349 SP - 240 EP - 258 PB - Springer CY - Frankfurt am Main ER - TY - GEN A1 - Mitseva, Asya A1 - Engel, Thomas A1 - Panchenko, Andriy ED - Reinhardt, Delphine ED - Langweg, Hanno ED - Witt, Bernhard C. ED - Fischer, Mathias T1 - Analyzing PeerFlow - A Bandwidth Estimation System for Untrustworthy Environments T2 - Sicherheit 2020 : Sicherheit, Schutz und Zuverlässigkeit ; Konferenzband der 10. Jahrestagung des Fachbereichs Sicherheit der Gesellschaft für Informatik e.V. (GI) ; 17.- 20. März 2020 in Göttingen Y1 - 2020 SN - 978-3-88579-695-4 U6 - https://doi.org/10.18420/sicherheit2020_02 SP - 29 EP - 40 PB - Gesellschaft für Informatik CY - Bonn ER - TY - GEN A1 - Mitseva, Asya A1 - Aleksandrova, Marharyta A1 - Engel, Thomas A1 - Panchenko, Andriy T1 - Security and Performance Implications of BGP Rerouting-resistant Guard Selection Algorithms for Tor T2 - ICT Systems Security and Privacy Protection : 35th IFIP TC 11 International Conference, SEC 2020, Maribor, Slovenia, September 21–23, 2020 Y1 - 2020 SN - 978-3-030-58201-2 SN - 978-3-030-58200-5 U6 - https://doi.org/10.1007/978-3-030-58201-2_15 SN - 1868-4238 SN - 1868-422X SP - 219 EP - 233 PB - Springer CY - Cham ER - TY - GEN A1 - De la Cadena, Wladimir A1 - Mitseva, Asya A1 - Hiller, Jens A1 - Pennekamp, Jan A1 - Reuter, Sebastian A1 - Filter, Julian A1 - Engel, Thomas A1 - Wehrle, Klaus A1 - Panchenko, Andriy T1 - TrafficSliver: Fighting Website Fingerprinting Attacks with Traffic Splitting T2 - CCS '20: Proceedings of the 2020 ACM SIGSAC Conference on Computer and Communications Security, October 2020 N2 - 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. KW - Traffic Analysis KW - Website Fingerprinting KW - Privacy KW - Anonymous Communication KW - Onion Routing KW - Web Privacy Y1 - 2020 SN - 978-1-4503-7089-9 U6 - https://doi.org/10.1145/3372297.3423351 SP - 1971 EP - 1985 PB - Association for Computing Machinery CY - New York ER - TY - GEN A1 - De la Cadena, Wladimir A1 - Kaiser, Daniel A1 - Panchenko, Andriy A1 - Engel, Thomas T1 - Out-of-the-box Multipath TCP as a Tor Transport Protocol: Performance and Privacy Implications T2 - 2020 IEEE 19th International Symposium on Network Computing and Applications (NCA), 24-27 Nov. 2020, Cambridge, MA, USA Y1 - 2020 SN - 978-1-7281-8326-8 SN - 978-1-7281-8327-5 U6 - https://doi.org/10.1109/NCA51143.2020.9306702 SN - 2643-7929 ER - TY - GEN A1 - Mitseva, Asya A1 - Pennekamp, Jan A1 - Lohmöller, Johannes A1 - Ziemann, Torsten A1 - Hoerchner, Carl A1 - Wehrle, Klaus A1 - Panchenko, Andriy T1 - POSTER: How Dangerous is My Click? Boosting Website Fingerprinting By Considering Sequences of Webpages T2 - Proceedings of the 28th ACM Conference on Computer and Communications Security (ACM CCS 2021), Seoul, Virtual Event, South Korea, November 2021 Y1 - 2021 SN - 978-1-4503-8454-4 U6 - https://doi.org/10.1145/3460120.3485347 SP - 2411 EP - 2413 PB - ACM Press CY - New York ER - TY - GEN A1 - Panchenko, Andriy A1 - Mitseva, Asya A1 - Knabe, Sara T1 - WhisperChord: Scalable and Secure Node Discovery for Overlay Networks T2 - IEEE 46th Conference on Local Computer Networks (LCN), Edmonton, AB, Canada , 4-7 Oct. 2021 N2 - 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. Y1 - 2021 SN - 978-1-6654-1886-7 SN - 978-1-6654-4800-0 U6 - https://doi.org/10.1109/LCN52139.2021.9525008 SN - 0742-1303 SP - 170 EP - 177 PB - IEEE ER - TY - GEN A1 - Panchenko, Andriy A1 - Mitseva, Asya A1 - Ziemann, Torsten A1 - Hering, Till T1 - GuardedGossip: Secure and Anonymous Node Discovery in Untrustworthy Networks T2 - Security and Privacy in Communication Networks : 17th EAI International Conference, SecureComm 2021, Virtual Event, September 6–9, 2021, Proceedings, Part I N2 - Node discovery is a fundamental service for any overlay network. It is a particular challenge to provide unbiased discovery in untrustworthy environments, e.g., anonymization networks. Although a major line of research focused on solving this problem, proposed methods have been shown to be vulnerable either to active attacks or to leak routing information, both threatening the anonymity of users. In response, we propose GuardedGossip—a novel gossip-based node discovery protocol—that achieves an unbiased random node discovery in a fully-decentralized and highly-scalable fashion. It is built on top of a Chord distributed hash table (DHT) and relies on witness nodes and bound checks to resist active attacks. To limit routing information leakages, GuardedGossip uses gossiping to create uncertainty in the process of node discovery. By incorporating the principles of DHTs with the unstructured nature of gossiping in a subtle way, we profit from the strengths of both techniques while carefully mitigating their shortcomings. We show that GuardedGossip provides a sufficient level of security for users even if 20% of the participating nodes are malicious. Concurrently, our system scales gracefully and provides an adequate overhead for its security and privacy benefits. KW - Node lookup KW - DHT KW - Tor KW - Onion routing KW - Anonymity Y1 - 2021 SN - 978-3-030-90018-2 U6 - https://doi.org/10.1007/978-3-030-90019-9_7 SN - 1867-8211 SP - 123 EP - 143 PB - Springer CY - Cham ER - TY - GEN A1 - Vogel, Michael A1 - Schuster, Franka A1 - Kopp, Fabian Malte A1 - König, Hartmut T1 - Data Volume Reduction for Deep Packet Inspection by Multi-layer Application Determination T2 - 2022 IEEE International Conference on Cyber Security and Resilience (CSR), 27-29 July 2022, Rhodes, Greece N2 - Attack detection in enterprise networks is increasingly faced with large data volumes, in part high data bursts, and heavily fluctuating data flows that often cause arbitrary discarding of data packets in overload situations which can be used by attackers to hide attack activities. Attack detection systems usually configure a comprehensive set of signatures for known vulnerabilities in different operating systems, protocols, and applications. Many of these signatures, however, are not relevant in each context, since certain vulnerabilities have already been eliminated, or the vulnerable applications or operating system versions, respectively, are not installed on the involved systems. In this paper, we present an approach for clustering data flows to assign them to dedicated analysis units that contain only signature sets relevant for the analysis of these flows. We discuss the performance of this clustering and show how it can be used in practice to improve the efficiency of an analysis pipeline. Y1 - 2022 UR - https://ieeexplore.ieee.org/abstract/document/9850293 SN - 978-1-6654-9952-1 SN - 978-1-6654-9953-8 U6 - https://doi.org/10.1109/CSR54599.2022.9850293 PB - IEEE ER -