57 research outputs found

    Investigating Survivability of Configuration Management Tools in Unreliable and Hostile Networks

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    A configuration management system (CMS) can control large networks of computers. A modern CMS is idempotent and describes infrastructure as code, so that it uses a description of the desired state of a system to automatically correct any deviations from a defined goal. As this requires both complete control of the slave systems and unquestioned ability to provide new instructions to slaves, the CMS is highly valuable target for attackers. Criminal malware networks already survive in hostile, heterogeneous networks, and therefore, the concepts from those systems could be applied to benign enterprise CMSs. We describe one such concept, the hidden master architecture, and compare its survivability to existing systems using attack trees

    Computer viruses and electronic mail

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    Today the Internet is a valuable source of information as well as a powerful communication medium, with undoubted social and economic benefits, however it also poses some security risks. Virsuses may hide in email attachments or in appartently innocent applications directly downloadable from the Internet. In this work we give a brief overview of virus types and main defense techniques. Then we present statistical data of virus attacks revealed by an anti-virus SW activated on our e-mail server, and discuss results in terms of virus types and temporal distribution

    RICIS Symposium 1992: Mission and Safety Critical Systems Research and Applications

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    This conference deals with computer systems which control systems whose failure to operate correctly could produce the loss of life and or property, mission and safety critical systems. Topics covered are: the work of standards groups, computer systems design and architecture, software reliability, process control systems, knowledge based expert systems, and computer and telecommunication protocols

    Systematizing Decentralization and Privacy: Lessons from 15 Years of Research and Deployments

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    Decentralized systems are a subset of distributed systems where multiple authorities control different components and no authority is fully trusted by all. This implies that any component in a decentralized system is potentially adversarial. We revise fifteen years of research on decentralization and privacy, and provide an overview of key systems, as well as key insights for designers of future systems. We show that decentralized designs can enhance privacy, integrity, and availability but also require careful trade-offs in terms of system complexity, properties provided, and degree of decentralization. These trade-offs need to be understood and navigated by designers. We argue that a combination of insights from cryptography, distributed systems, and mechanism design, aligned with the development of adequate incentives, are necessary to build scalable and successful privacy-preserving decentralized systems

    On Integrating Failure Localization with Survivable Design

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    In this thesis, I proposed a novel framework of all-optical failure restoration which jointly determines network monitoring plane and spare capacity allocation in the presence of either static or dynamic traffic. The proposed framework aims to enable a general shared protection scheme to achieve near optimal capacity efficiency as in Failure Dependent Protection(FDP) while subject to an ultra-fast, all-optical, and deterministic failure restoration process. Simply put, Local Unambiguous Failure Localization(L-UFL) and FDP are the two building blocks for the proposed restoration framework. Under L-UFL, by properly allocating a set of Monitoring Trails (m-trails), a set of nodes can unambiguously identify every possible Shared Risk Link Group (SRLG) failure merely based on its locally collected Loss of Light(LOL) signals. Two heuristics are proposed to solve L-UFL, one of which exclusively deploys Supervisory Lightpaths (S-LPs) while the other jointly considers S-LPs and Working Lightpaths (W-LPs) for suppressing monitoring resource consumption. Thanks to the ``Enhanced Min Wavelength Max Information principle'', an entropy based utility function, m-trail global-sharing and other techniques, the proposed heuristics exhibit satisfactory performance in minimizing the number of m-trails, Wavelength Channel(WL) consumption and the running time of the algorithm. Based on the heuristics for L-UFL, two algorithms, namely MPJD and DJH, are proposed for the novel signaling-free restoration framework to deal with static and dynamic traffic respectively. MPJD is developed to determine the Protection Lightpaths (P-LPs) and m-trails given the pre-computed W-LPs while DJH jointly implements a generic dynamic survivable routing scheme based on FDP with an m-trail deployment scheme. For both algorithms, m-trail deployment is guided by the Necessary Monitoring Requirement (NMR) defined at each node for achieving signaling-free restoration. Extensive simulation is conducted to verify the performance of the proposed heuristics in terms of WL consumption, number of m-trails, monitoring requirement, blocking probability and running time. In conclusion, the proposed restoration framework can achieve all-optical and signaling-free restoration with the help of L-UFL, while maintaining high capacity efficiency as in FDP based survivable routing. The proposed heuristics achieve satisfactory performance as verified by the simulation results

    A formal protocol test procedure for the Survivable Adaptable Fiber Optic Embedded Network (SAFENET)

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    This thesis focuses upon a new method for verifying the correct operation of a complex, high speed fiber optic communication network. These networks are of growing importance to the military because of their increased connectivity, survivability, and recohttp://archive.org/details/aformalprotocolt1094539864Lieutenant, United States NavyApproved for public release; distribution is unlimited

    Multi-Layer Architektur und System Design von Internet Protocol (IP) und Optischen Netzwerken

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    The modeling of multi-layer networks is well-researched problem, but existing models for IP-optical integration do not consider technology specific capabilities and operational aspects for employing dynamic optical circuits in IP networks. This thesis presents an ILP-based model which identifies and incorporates novel constraints for numerous technology specific aspects, such as IP forwarding capabilities and behavior of routing protocols. Novel solutions for critical operational aspects of IP-optical integration, such as optical circuit decommissioning and computation under unknown traffic conditions, are also proposed in this thesis. The thesis identifies changes in routing as a major deterrent for employing dynamic optical circuits in IP networks, and proposes the new Optical Bypass approach to address the same. Quantitative studies presented indicate that the introduction of an optical circuit under this approach significantly reduces the effect on IP routing, while lowering optical capacity requirements as compared to the traditional SPF based approaches. The proposed solution can also compute near-optimal solutions under unknown IP traffic matrix conditions, making it ideal for application in dynamic network scenarios. The thesis also addresses specific management challenges with IP-optical integration, and outlines solutions to address the same. The solutions are built around enabling coordination of management subsystems in the two network layers. The thesis presents the general architecture to facilitate coordination between management subsystems in a programmable fashion and demonstrates the capability of the architecture to be used in legacy as well as SDN-capable infrastructure. The thesis also outlines the design and implementation of the first open-source PCE, which is a critical management subsystem for enabling multi-layer path computation in IP-optical networks.GrundsĂ€tzlich ist die Modellierung von Multilayer-Netzen ein bekanntes Problem, dennoch lassen die vorhandenen Modelle fĂŒr IP-optische Integration viele technologiespezifische Eigenschaften und kritische Aspekte bei Einrichtung und Betrieb dynamischer optischer Verbindungen in IP-Netzwerken außer Acht. Hierzu gehören vor allem die Eigenheiten des Forwarding, sowie das Verhalten von Routingprotokollen. Die vorliegende Dissertation prĂ€sentiert ein ILP Modell, dass solche Aspekte und Bedingungen identifiziert und integriert, sowie die Notwendigkeit hierfĂŒr anhand numerischer Evaluierung nachweist. Die Modellierungsaspekte der IP-optischen Integration umfassen bezĂŒglich des Netzbetriebs vor allem Probleme wie die optimale Berechnung im Falle einer unbekannten Verkehrsmatrix sowie deren Verbindungsabbau. Ein wesentliches Hindernis in dynamische IP-optischen Netzwerken sind die aus ihrer Einrichtung resultierenden protokollspezifischen Änderungen im Routing. Als Lösung wird der optische Bypass vorgeschlagen. Die Untersuchungen zeigen, dass der Einsatz optischer BypĂ€sse die Auswirkungen auf das IP-Routing stark reduziert und gleichzeitig die dafĂŒr notwendigen KapazitĂ€tsanforderungen verringert. Damit sind optische BypĂ€sse ebenfalls fĂŒr Anwendungsszenarien geeignet, in denen die IP-Verkehrsmatrix nicht bekannt ist. Im Weiteren werden noch Probleme aus dem Bereich Netzwerkmanagement behandelt, die sich spezifisch aus der IP-optischen Integration entwickeln, und es werden entsprechende LösungsansĂ€tze vorgestellt. Diese basieren auf der Abstimmung und dem koordinierten Betrieb der Management-Subsysteme in den beiden betroffenen Netzschichten. Gezeigt wird dann eine allgemeine Architektur, die eine Koordination von Management-Subsystemen (auch fĂŒr SDN), in programmierbarer Form ermöglicht. Außerdem wird der Entwurf und die Implementierung des Open Source PCE beschrieben, welches die Berechnung von Multilayer Verbindungswegen in IP-optischen Netzwerken ermöglicht

    Intrusion detection and management over the world wide web

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    As the Internet and society become ever more integrated so the number of Internet users continues to grow. Today there are 1.6 billion Internet users. They use its services to work from home, shop for gifts, socialise with friends, research the family holiday and manage their finances. Through generating both wealth and employment the Internet and our economies have also become interwoven. The growth of the Internet has attracted hackers and organised criminals. Users are targeted for financial gain through malware and social engineering attacks. Industry has responded to the growing threat by developing a range defences: antivirus software, firewalls and intrusion detection systems are all readily available. Yet the Internet security problem continues to grow and Internet crime continues to thrive. Warnings on the latest application vulnerabilities, phishing scams and malware epidemics are announced regularly and serve to heighten user anxiety. Not only are users targeted for attack but so too are businesses, corporations, public utilities and even states. Implementing network security remains an error prone task for the modern Internet user. In response this thesis explores whether intrusion detection and management can be effectively offered as a web service to users in order to better protect them and heighten their awareness of the Internet security threat

    Achieving network resiliency using sound theoretical and practical methods

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    Computer networks have revolutionized the life of every citizen in our modern intercon- nected society. The impact of networked systems spans every aspect of our lives, from financial transactions to healthcare and critical services, making these systems an attractive target for malicious entities that aim to make financial or political profit. Specifically, the past decade has witnessed an astounding increase in the number and complexity of sophisti- cated and targeted attacks, known as advanced persistent threats (APT). Those attacks led to a paradigm shift in the security and reliability communities’ perspective on system design; researchers and government agencies accepted the inevitability of incidents and malicious attacks, and marshaled their efforts into the design of resilient systems. Rather than focusing solely on preventing failures and attacks, resilient systems are able to maintain an acceptable level of operation in the presence of such incidents, and then recover gracefully into normal operation. Alongside prevention, resilient system design focuses on incident detection as well as timely response. Unfortunately, the resiliency efforts of research and industry experts have been hindered by an apparent schism between theory and practice, which allows attackers to maintain the upper hand advantage. This lack of compatibility between the theory and practice of system design is attributed to the following challenges. First, theoreticians often make impractical and unjustifiable assumptions that allow for mathematical tractability while sacrificing accuracy. Second, the security and reliability communities often lack clear definitions of success criteria when comparing different system models and designs. Third, system designers often make implicit or unstated assumptions to favor practicality and ease of design. Finally, resilient systems are tested in private and isolated environments where validation and reproducibility of the results are not publicly accessible. In this thesis, we set about showing that the proper synergy between theoretical anal- ysis and practical design can enhance the resiliency of networked systems. We illustrate the benefits of this synergy by presenting resiliency approaches that target the inter- and intra-networking levels. At the inter-networking level, we present CPuzzle as a means to protect the transport control protocol (TCP) connection establishment channel from state- exhaustion distributed denial of service attacks (DDoS). CPuzzle leverages client puzzles to limit the rate at which misbehaving users can establish TCP connections. We modeled the problem of determining the puzzle difficulty as a Stackleberg game and solve for the equilibrium strategy that balances the users’ utilizes against CPuzzle’s resilience capabilities. Furthermore, to handle volumetric DDoS attacks, we extend CPuzzle and implement Midgard, a cooperative approach that involves end-users in the process of tolerating and neutralizing DDoS attacks. Midgard is a middlebox that resides at the edge of an Internet service provider’s network and uses client puzzles at the IP level to allocate bandwidth to its users. At the intra-networking level, we present sShield, a game-theoretic network response engine that manipulates a network’s connectivity in response to an attacker who is moving laterally to compromise a high-value asset. To implement such decision making algorithms, we leverage the recent advances in software-defined networking (SDN) to collect logs and security alerts about the network and implement response actions. However, the programma- bility offered by SDN comes with an increased chance for design-time bugs that can have drastic consequences on the reliability and security of a networked system. We therefore introduce BiFrost, an open-source tool that aims to verify safety and security proper- ties about data-plane programs. BiFrost translates data-plane programs into functionally equivalent sequential circuits, and then uses well-established hardware reduction, abstrac- tion, and verification techniques to establish correctness proofs about data-plane programs. By focusing on those four key efforts, CPuzzle, Midgard, sShield, and BiFrost, we believe that this work illustrates the benefits that the synergy between theory and practice can bring into the world of resilient system design. This thesis is an attempt to pave the way for further cooperation and coordination between theoreticians and practitioners, in the hope of designing resilient networked systems

    Effective bootstrapping of Peer-to Peer networks over Mobile Ad-hoc networks

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    Mobile Ad-hoc Networks (MANETs) and Peer-to-Peer (P2P) networks are vigorous, revolutionary communication technologies in the 21st century. They lead the trend of decentralization. Decentralization will ultimately win clients over client/server model, because it gives ordinary network users more control, and stimulates their active participation. It is a determinant factor in shaping the future of networking. MANETs and P2P networks are very similar in nature. Both are dynamic, distributed. Both use multi-hop broadcast or multicast as major pattern of traffic. Both set up connection by self-organizing and maintain connection by self-healing. Embodying the slogan networking without networks, both abandoned traditional client/server model and disclaimed pre-existing infrastructure. However, their status quo levels of real world application are widely divergent. P2P networks are now accountable for about 50 ~ 70% internet traffic, while MANETs are still primarily in the laboratory. The interesting and confusing phenomenon has sparked considerable research effort to transplant successful approaches from P2P networks into MANETs. While most research in the synergy of P2P networks and MANETs focuses on routing, the network bootstrapping problem remains indispensable for any such transplantation to be realized. The most pivotal problems in bootstrapping are: (1) automatic configuration of nodes addresses and IDs, (2) topology discovery and transformation in different layers and name spaces. In this dissertation research, we have found novel solutions for these problems. The contributions of this dissertation are: (1) a non-IP, flat address automatic configuration scheme, which integrates lower layer addresses and P2P IDs in application layer and makes simple cryptographical assignment possible. A related paper entitled Pastry over Ad-Hoc Networks with Automatic Flat Address Configuration was submitted to Elsevier Journal of Ad Hoc Networks in May. (2) an effective ring topology construction algorithm which builds perfect ring in P2P ID space using only simplest multi-hop unicast or multicast. Upon this ring, popular structured P2P networks like Chord, Pastry could be built with great ease. A related paper entitled Chord Bootstrapping on MANETs - All Roads lead to Rome will be ready for submission after defense of the dissertation
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