@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{HillerPennekampDahlmannsetal., author = {Hiller, Jens and Pennekamp, Jan and Dahlmanns, Markus and Henze, Martin and Panchenko, Andriy and Wehrle, Klaus}, title = {Tailoring Onion Routing to the Internet of Things: Security and Privacy in Untrusted Environments}, series = {Proceedings of the 27th annual IEEE International Conference on Network Protocols (IEEE ICNP 2019), Chicago, Illinois, USA, October 2019}, journal = {Proceedings of the 27th annual IEEE International Conference on Network Protocols (IEEE ICNP 2019), Chicago, Illinois, USA, October 2019}, publisher = {IEEE Press}, isbn = {978-1-7281-2700-2}, issn = {2643-3303}, doi = {10.1109/ICNP.2019.8888033}, pages = {12}, abstract = {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.}, language = {en} } @misc{DeLaCadenaMitsevaPennekampetal., author = {De La Cadena, Wladimir and Mitseva, Asya and Pennekamp, Jan and Hiller, Jens and Lanze, Fabian and Engel, Thomas and Wehrle, Klaus and Panchenko, Andriy}, title = {POSTER: Traffic Splitting to Counter Website Fingerprinting}, series = {CCS '19 Proceedings of the 2019 ACM SIGSAC Conference on Computer and Communications Security , London, UK, November 11 - 15, 2019.}, journal = {CCS '19 Proceedings of the 2019 ACM SIGSAC Conference on Computer and Communications Security , London, UK, November 11 - 15, 2019.}, publisher = {ACM Press}, address = {New York}, isbn = {978-1-4503-6747-9}, doi = {10.1145/3319535.3363249}, pages = {2533 -- 2535}, abstract = {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.}, language = {en} } @misc{HillerHenzeZimmermannetal., author = {Hiller, Jens and Henze, Martin and Zimmermann, Torsten and Hohlfeld, Oliver and Wehrle, Klaus}, title = {The Case for Session Sharing: Relieving Clients from TLS Handshake Overheads}, series = {2019 IEEE 44th LCN Symposium on Emerging Topics in Networking (LCN Symposium), 14-17 Oct. 2019, Osnabr{\"u}ck, Germany}, journal = {2019 IEEE 44th LCN Symposium on Emerging Topics in Networking (LCN Symposium), 14-17 Oct. 2019, Osnabr{\"u}ck, Germany}, publisher = {IEEE}, isbn = {978-1-7281-2561-9}, doi = {10.1109/LCNSymposium47956.2019.9000667}, pages = {9}, abstract = {In recent years, the amount of traffic protected with Transport Layer Security (TLS) has significantly increased and new protocols such as HTTP/2 and QUIC further foster this emerging trend. However, protecting traffic with TLS has significant impacts on network entities. While the restrictions for middleboxes have been extensively studied, addressing the impact of TLS on clients and servers has been mostly neglected so far. Especially mobile clients in emerging 5G and IoT deployments suffer from significantly increased latency, traffic, and energy overheads when protecting traffic with TLS. In this paper, we address this emerging topic by thoroughly analyzing the impact of TLS on clients and servers and derive opportunities for significantly decreasing latency of TLS communication and downsizing TLS management traffic, thereby also reducing TLSinduced server load. We propose a protocol compatible redesign of TLS session management to use these opportunities and showcase their potential based on mobile device traffic and mobile web-browsing traces. These show promising potentials for latency improvements by up to 25.8\% and energy savings of up to 26.3\%.}, language = {en} }