arXiv subjects

Thomas C. Schmidt

Publications and source records attributed to Thomas C. Schmidt.

At least 73 records · Page 4Linked to original sources

arXiv2021

Security of Alerting Authorities in the WWW: Measuring Namespaces, DNSSEC, and Web PKI

During disasters, crisis, and emergencies the public relies on online services provided by official authorities to receive timely alerts, trustworthy information, and access to relief programs. It is therefore crucial for the authorities to reduce risks when accessing their online services. This includes catering to secure identification of service, secure resolution of name to network service, and content security and privacy as a minimum base for trustworthy communication. In this paper, we take a first look at Alerting Authorities (AA) in the US and investigate security measures related to trustworthy and secure communication. We study the domain namespace structure, DNSSEC penetration, and web certificates. We introduce an integrative threat model to better understand whether and how the online presence and services of AAs are harmed. As an illustrative example, we investigate 1,388 Alerting Authorities. We observe partial heightened security relative to the global Internet trends, yet find cause for concern as about 78% of service providers fail to deploy measures of trustworthy service provision. Our analysis shows two major shortcomings. First, how the DNS ecosystem is leveraged: about 50% of organizations do not own their dedicated domain names and are dependent on others, 55% opt for unrestricted-use namespaces, which simplifies phishing, and less than 4% of unique AA domain names are secured by DNSSEC, which can lead to DNS poisoning and possibly to certificate misissuance. Second, how Web PKI certificates are utilized: 15% of all hosts provide none or invalid certificates, thus cannot cater to confidentiality and data integrity, 64% of the hosts provide domain validation certification that lack any identity information, and shared certificates have gained on popularity, which leads to fate-sharing and can be a cause for instability.

cs.CR↗

arXiv2021

Networking Group Content: RESTful Multiparty Access to a Data-centric Web of Things

Content replication to many destinations is a common use case in the Internet of Things (IoT). The deployment of IP multicast has proven inefficient, though, due to its lack of layer-2 support by common IoT radio technologies and its synchronous end-to-end transmission, which is highly susceptible to interference. Information-centric networking (ICN) introduced hop-wise multi-party dissemination of cacheable content, which has proven valuable in particular for low-power lossy networking regimes. Even NDN, however, the most prominent ICN protocol, suffers from a lack of deployment. In this paper, we explore how multiparty content distribution in an information-centric Web of Things (WoT) can be built on CoAP. We augment the CoAP proxy by request aggregation and response replication functions, which together with proxy caches enable asynchronous group communication. In a further step, we integrate content object security with OSCORE into the CoAP multicast proxy system, which enables ubiquitous caching of certified authentic content. In our evaluation, we compare NDN with different deployment models of CoAP, including our data-centric approach in realistic testbed experiments. Our findings indicate that multiparty content distribution based on CoAP proxies performs equally well as NDN, while remaining fully compatible with the established IoT protocol world of CoAP on the Internet.

cs.NI↗

arXiv2020

Strategies for Integrating Controls Flows in Software-Defined In-Vehicle Networks and Their Impact on Network Security

Current In-Vehicle Networks (IVNs) connect Electronic Control Units (ECUs) via domain busses. A gateway forwards messages between these domains. Automotive Ethernet emerges as a flat, high-speed backbone technology for IVNs that carries the various control flows within Ethernet frames. Recently, Software-Defined-Networking (SDN) has been identified as a useful building block of the vehicular domain, as it allows the differentiation of packets based on all header fields and thus can isolate unrelated control flows. In this work, we systematically explore the different strategies for integrating automotive control flows in switched Ether-networks and analyze their security impact for a software-defined IVN. We discuss how control flow identifiers can be embedded on different layers resulting in a range of solutions from fully exposed embedding to deep encapsulation. We evaluate these strategies in a realistic IVN based on the communication matrix of a production grade vehicle, which we map into a modern Ethernet topology. We find that visibility of automotive control flows within packet headers is essential for the network infrastructure to enable isolation and access control. With an exposed embedding, the SDN backbone can establish and survey trust zones within the IVN and largely reduce the attack surface of connected cars. An exposed embedding strategy also minimizes communication expenses.

cs.NI↗

arXiv2020

IoT Content Object Security with OSCORE and NDN: A First Experimental Comparison

The emerging Internet of Things (IoT) challenges the end-to-end transport of the Internet by low power lossy links and gateways that perform protocol translations. Protocols such as CoAP or MQTT-SN are degraded by the overhead of DTLS sessions, which in common deployment protect content transfer only up to the gateway. To preserve content security end-to-end via gateways and proxies, the IETF recently developed Object Security for Constrained RESTful Environments (OSCORE), which extends CoAP with content object security features commonly known from Information Centric Networks (ICN). This paper presents a comparative analysis of protocol stacks that protect request-response transactions. We measure protocol performances of CoAP over DTLS, OSCORE, and the information-centric Named Data Networking (NDN) protocol on a large-scale IoT testbed in single- and multi-hop scenarios. Our findings indicate that (a) OSCORE improves on CoAP over DTLS in error-prone wireless regimes due to omitting the overhead of maintaining security sessions at endpoints, and (b) NDN attains superior robustness and reliability due to its intrinsic network caches and hop-wise retransmissions.

cs.NI↗

arXiv2020

Uncovering Vulnerable Industrial Control Systems from the Internet Core

Industrial control systems (ICS) are managed remotely with the help of dedicated protocols that were originally designed to work in walled gardens. Many of these protocols have been adapted to Internet transport and support wide-area communication. ICS now exchange insecure traffic on an inter-domain level, putting at risk not only common critical infrastructure but also the Internet ecosystem (e.g., DRDoS~attacks). In this paper, we uncover unprotected inter-domain ICS traffic at two central Internet vantage points, an IXP and an ISP. This traffic analysis is correlated with data from honeypots and Internet-wide scans to separate industrial from non-industrial ICS traffic. We provide an in-depth view on Internet-wide ICS communication. Our results can be used i) to create precise filters for potentially harmful non-industrial ICS traffic, and ii) to detect ICS sending unprotected inter-domain ICS traffic, being vulnerable to eavesdropping and traffic manipulation attacks.

cs.NI↗

arXiv2020

LoRa in the Field: Insights from Networking the Smart City Hamburg with RIOT

Inter-connected sensors and actuators have scaled down to small embedded devices such as wearables, and at the same time meet a massive deployment at the Internet edge: the Internet of Things (IoT). Many of these IoT devices run on low-power batteries and are forced to operate on very constrained resources, namely slow CPUs, tiny memories, and low-power radios. Establishing a network infrastructure that is energy efficient, wireless, and still covers a wide area is a larger challenge in this regime. LoRa is a low complexity long range radio technology, which tries to meet these challenges.With LoRaWAN a network model for widespread deployment has been established, which enjoys open public LoRaWAN dissemination such as with the infrastructure of TheThingsNetwork. In this paper, we report about our experiences with developing and deploying LoRa-based smart city applications as part of the MONICA project in Hamburg. Our contributions are twofold. First, we describe the design and implementation of end-to-end IoT applications based on the friendly IoT operating system RIOT. Second, we report on measurements and evaluations of our large field trials during several public events in the city of Hamburg. Our results show that LoRaWAN provides a suitable communication layer for a variety of Smart City use-cases and IoT applications, but also identifies its limitations and weaknesses.

cs.NI↗

arXiv2019

A QoS Aware Approach to Service-Oriented Communication in Future Automotive Networks

Service-Oriented Architecture (SOA) is about to enter automotive networks based on the SOME/IP middleware and an Ethernet high-bandwidth communication layer. It promises to meet the growing demands on connectivity and flexibility for software components in modern cars. Largely heterogeneous service requirements and time-sensitive network functions make Quality-of-Service (QoS) agreements a vital building block within future automobiles. Existing middleware solutions, however, do not allow for a dynamic selection of QoS. This paper presents a service-oriented middleware for QoS aware communication in future cars. We contribute a protocol for dynamic QoS negotiation along with a multi-protocol stack, which supports the different communication classes as derived from a thorough requirements analysis. We validate the feasibility of our approach in a case study and evaluate its performance in a simulation model of a realistic in-car network. Our findings indicate that QoS aware communication can indeed meet the requirements, while the impact of the service negotiations and setup times of the network remain acceptable provided the cross-traffic during negotiations stays below 70% of the available bandwidth.

cs.NI↗

arXiv2019

DoS Protection through Credit Based Metering -- Simulation-Based Evaluation for Time-Sensitive Networking in Cars

Ethernet is the most promising solution to reduce complexity and enhance the bandwidth in the next generation in-car networks. Dedicated Ethernet protocols enable the real-time aspects in such networks. One promising candidate is the IEEE 802.1Q Time-Sensitive Networking protocol suite. Common Ethernet technologies, however, increases the vulnerability of the car infrastructure as they widen the attack surface for many components. In this paper proposes an IEEE 802.1Qci based algorithm that on the one hand, protects against DoS attacks by metering incoming Ethernet frames. On the other hand, it adapts to the behavior of the Credit Based Shaping algorithm, which was standardized for Audio/Video Bridging, the predecessor of Time-Sensitive Networking. A simulation of this proposed Credit Based Metering algorithm evaluates the concept.

cs.NI↗

arXiv2019

Eco: A Hardware-Software Co-Design for In Situ Power Measurement on Low-end IoT Systems

Energy-constrained sensor nodes can adaptively optimize their energy consumption if a continuous measurement exists. This is of particular importance in scenarios of high dynamics such as energy harvesting or adaptive task scheduling. However, self-measuring of power consumption at reasonable cost and complexity is unavailable as a generic system service. In this paper, we present Eco, a hardware-software co-design enabling generic energy management on IoT nodes. Eco is tailored to devices with limited resources and thus targets most of the upcoming IoT scenarios. The proposed measurement module combines commodity components with a common system interfaces to achieve easy, flexible integration with various hardware platforms and the RIOT IoT operating system. We thoroughly evaluate and compare accuracy and overhead. Our findings indicate that our commodity design competes well with highly optimized solutions, while being significantly more versatile. We employ Eco for energy management on RIOT and validate its readiness for deployment in a five-week field trial integrated with energy harvesting.

eess.SP↗

arXiv2019

A Lesson in Scaling 6LoWPAN -- Minimal Fragment Forwarding in Lossy Networks

This paper evaluates two forwarding strategies for fragmented datagrams in the IoT: hop-wise reassembly and a minimal approach to directly forward fragments. Minimal fragment forwarding is challenged by the lack of forwarding information at subsequent fragments in 6LoWPAN and thus requires additional data at nodes. We compared the two approaches in extensive experiments evaluating reliability, end-to-end latency, and memory consumption. In contrast to previous work and due to our alternate setup, we obtained different results and conclusions. Our findings indicate that direct fragment forwarding should be deployed only with care, since higher packet transmission rates on the link-layer can significantly reduce its reliability, which in turn can even further reduce end-to-end latency because of highly increased link-layer retransmissions.

cs.NI↗

arXiv2019

SDN4CoRE: A Simulation Model for Software-Defined Networking for Communication over Real-Time Ethernet

Ethernet has become the next standard for automotive and industrial automation networks. Standard extensions such as IEEE 802.1Q Time-Sensitive Networking (TSN) have been proven to meet the real-time and robustness requirements of these environments. Augmenting the TSN switching by Software-Defined Networking functions promises additional benefits: A programming option for TSN devices can add much value to the resilience, security, and adaptivity of the environment. Network simulation allows to model highly complex networks before assembly and is an essential process for the design and validation of future networks. Still, a simulation environment that supports programmable real-time networks is missing. This paper fills the gap by sharing our simulation model for Software-Defined Networking for Communication over Real-Time Ethernet (SDN4CoRE) and present initial results in modeling programmable real-time networks. In a case study, we show that SDN4CoRE can simulate complex programmable real-time networks and allows for testing and verifying the programming of real-time devices.

cs.NI↗

arXiv2019

Bluetooth Mesh under the Microscope: How much ICN is Inside?

Bluetooth (BT) mesh is a new mode of BT operation for low-energy devices that offers group-based publish-subscribe as a network service with additional caching capabilities. These features resemble concepts of information-centric networking (ICN), and the analogy to ICN has been repeatedly drawn in the BT community. In this paper, we compare BT mesh with ICN both conceptually and in real-world experiments. We contrast both architectures and their design decisions in detail. Experiments are performed on an IoT testbed using NDN/CCNx and BT mesh on constrained RIOT nodes. Our findings indicate significant differences both in concepts and in real-world performance. Supported by new insights, we identify synergies and sketch a design of a BT-ICN that benefits from both worlds.

cs.NI↗

arXiv2019

Gain More for Less: The Surprising Benefits of QoS Management in Constrained NDN Networks

Quality of Service (QoS) in the IP world mainly manages forwarding resources, i.e., link capacities and buffer spaces. In addition, Information Centric Networking (ICN) offers resource dimensions such as in-network caches and forwarding state. In constrained wireless networks, these resources are scarce with a potentially high impact due to lossy radio transmission. In this paper, we explore the two basic service qualities (i) prompt and (ii) reliable traffic forwarding for the case of NDN. The resources we take into account are forwarding and queuing priorities, as well as the utilization of caches and of forwarding state space. We treat QoS resources not only in isolation, but correlate their use on local nodes and between network members. Network-wide coordination is based on simple, predefined QoS code points. Our findings indicate that coordinated QoS management in ICN is more than the sum of its parts and exceeds the impact QoS can have in the IP world.

cs.NI↗

arXiv2019

A DTLS Abstraction Layer for the Recursive Networking Architecture in RIOT

On the Internet of Things (IoT), devices continuously communicate with each other, with a gateway, or other Internet nodes. Often devices are constrained and use insecure channels for their communication, which exposes them to a selection of attacks that may extract sensitive pieces of information or manipulate dialogues for the purpose of sabotaging. This paper presents a new layer in the RIOT networking architecture to seamlessly integrate secure communication between applications using DTLS. The layer acts as a modular abstraction layer of the different DTLS implementations, enabling swapping of the underlying implementation with just a few lines of code. This paper also introduces credman, a new module to manage credentials used for (D)TLS connections.

cs.NI↗

arXiv2019

Software-Defined Networks Supporting Time-Sensitive In-Vehicular Communication

Future in-vehicular networks will be based on Ethernet. The IEEE Time-Sensitive Networking (TSN) is a promising candidate to satisfy real-time requirements in future car communication. Software-Defined Networking (SDN) extends the Ethernet control plane with a programming option that can add much value to the resilience, security, and adaptivity of the automotive environment. In this work, we derive a first concept for combining Software-Defined Networking with Time-Sensitive Networking along with an initial evaluation. Our measurements are performed via a simulation that investigates whether an SDN architecture is suitable for time-critical applications in the car. Our findings indicate that the control overhead of SDN can be added without a delay penalty for the TSN traffic when protocols are mapped properly.

cs.NI↗

arXiv2019

Security for the Industrial IoT: The Case for Information-Centric Networking

Industrial production plants traditionally include sensors for monitoring or documenting processes, and actuators for enabling corrective actions in cases of misconfigurations, failures, or dangerous events. With the advent of the IoT, embedded controllers link these `things' to local networks that often are of low power wireless kind, and are interconnected via gateways to some cloud from the global Internet. Inter-networked sensors and actuators in the industrial IoT form a critical subsystem while frequently operating under harsh conditions. It is currently under debate how to approach inter-networking of critical industrial components in a safe and secure manner. In this paper, we analyze the potentials of ICN for providing a secure and robust networking solution for constrained controllers in industrial safety systems. We showcase hazardous gas sensing in widespread industrial environments, such as refineries, and compare with IP-based approaches such as CoAP and MQTT. Our findings indicate that the content-centric security model, as well as enhanced DoS resistance are important arguments for deploying Information Centric Networking in a safety-critical industrial IoT. Evaluation of the crypto efforts on the RIOT operating system for content security reveal its feasibility for common deployment scenarios.

cs.NI↗

arXiv2018

ICNLoWPAN -- Named-Data Networking for Low Power IoT Networks

Information Centric Networking is considered a promising communication technology for the constrained IoT, but NDN was designed only for standard network infrastructure. In this paper, we design and evaluate an NDN convergence layer for low power lossy links that (1) augments the NDN stateful forwarding with a highly efficient name eliding, (2) devises stateless compression schemes for standard NDN use cases, (3) adapts NDN packets to the small MTU size of IEEE 802.15.4, and (4) generates compatibility with 6LoWPAN so that IPv6 and NDN can coexist on the same LoWPAN links. Our findings indicate that stateful compression can reduce the size of NDN data packets by more than 70% in realistic examples. Our experiments show that for common use cases ICNLoWPAN saves 33% of transmission resources over NDN, and about 20% over 6LoWPAN.

cs.NI↗

arXiv2018

A Configurable Transport Layer for CAF

The message-driven nature of actors lays a foundation for developing scalable and distributed software. While the actor itself has been thoroughly modeled, the message passing layer lacks a common definition. Properties and guarantees of message exchange often shift with implementations and contexts. This adds complexity to the development process, limits portability, and removes transparency from distributed actor systems. In this work, we examine actor communication, focusing on the implementation and runtime costs of reliable and ordered delivery. Both guarantees are often based on TCP for remote messaging, which mixes network transport with the semantics of messaging. However, the choice of transport may follow different constraints and is often governed by deployment. As a first step towards re-architecting actor-to-actor communication, we decouple the messaging guarantees from the transport protocol. We validate our approach by redesigning the network stack of the C++ Actor Framework (CAF) so that it allows to combine an arbitrary transport protocol with additional functions for remote messaging. An evaluation quantifies the cost of composability and the impact of individual layers on the entire stack.

cs.DC↗