DiaSim: A Parameterized Simulator for Pervasive Computing Applications

International audiencePervasive computing applications involve both soft- ware concerns, like any software system, and integration con- cerns, for the constituent networked devices of the pervasive computing environment. This situation is problematic for testing because it requires acquiring, testing and interfacing a variety of software and hardware entities. This process can rapidly become costly and time-consuming when the target environment involves many entities. In this demonstration, we present DiaSim, a simulator for per- vasive computing applications. To cope with widely heterogeneous entities, DiaSim is parameterized with respect to a description of a target pervasive computing environment. This description is used to generate both a programming framework to develop the simulation logic and an emulation layer to execute applications. Furthermore, a simulation renderer is coupled to DiaSim to allow a simulated pervasive system to be visually monitored and debugged

Security for Decentralised Service Location - Exemplified with Real-Time Communication Session Establishment

Decentralised Service Location, i.e. finding an application communication endpoint based on a Distributed Hash Table (DHT), is a fairly new concept. The precise security implications of this approach have not been studied in detail. More importantly, a detailed analysis regarding the applicability of existing security solutions to this concept has not been conducted. In many cases existing client-server approaches to security may not be feasible. In addition, to understand the necessity for such an analysis, it is key to acknowledge that Decentralised Service Location has some unique security requirements compared to other P2P applications such as filesharing or live streaming. This thesis concerns the security challenges for Decentralised Service Location. The goals of our work are on the one hand to precisely understand the security requirements and research challenges for Decentralised Service Location, and on the other hand to develop and evaluate corresponding security mechanisms. The thesis is organised as follows. First, fundamentals are explained and the scope of the thesis is defined. Decentralised Service Location is defined and P2PSIP is explained technically as a prototypical example. Then, a security analysis for P2PSIP is presented. Based on this security analysis, security requirements for Decentralised Service Location and the corresponding research challenges -- i.e. security concerns not suitably mitigated by existing solutions -- are derived. Second, several decentralised solutions are presented and evaluated to tackle the security challenges for Decentralised Service Location. We present decentralised algorithms to enable availability of the DHTs lookup service in the presence of adversary nodes. These algorithms are evaluated via simulation and compared to analytical bounds. Further, a cryptographic approach based on self-certifying identities is illustrated and discussed. This approach enables decentralised integrity protection of location-bindings. Finally, a decentralised approach to assess unknown identities is introduced. The approach is based on a Web-of-Trust model. It is evaluated via prototypical implementation. Finally, the thesis closes with a summary of the main contributions and a discussion of open issues

An Aspect-Oriented Approach to Securing Distributed Systems

International audienceThe increasing size and complexity of distributed systems create a need to raise the level of abstraction for their development. This need becomes critical for pervasive computing where non-functional properties, such as security, must be guaranteed. Architecture description languages (ADLs) propose a promising approach to coping with the size and complexity of pervasive computing systems. A system is defined by a high-level description that may be used to produce a programming framework. However, non-functional properties are not specifically addressed by existing ADL works. To address this issue aspect-oriented programming is a well-proven technique to properly modularize non-functional concerns that can be dealt with by weaving dedicated code into a program. In this paper, we present DiaAspect, an aspect-oriented language for our ADL, DiaSpec. Like most ADLs, DiaSpec exposes features enabling an accurate coordination of aspects. We demonstrate the expressiveness of DiaAspect with two examples of security policies in pervasive computing. We also show how, combining the knowledge of the architecture description with aspect code, improves aspect weaving in the implementation code

Pantaxou: a Domain-Specific Language for Developing Safe Coordination Services

International audienceCoordinating entities in a networked environment has always been a significant challenge for software developers. In recent years, however, it has become even more difficult, because devices have increasingly rich capabilities, combining an ever larger range of technologies (networking, multimedia, sensors, etc.). To address this challenge, we propose a language-based approach to covering the life-cycle of applications coordinating networked entities. Our approach covers the characterization of the networked environment, the specification of coordination applications, the verification of a networked environment and its deployment. It is carried out in practice by a domain-specific language, named Pantaxou. This paper presents the domain-specific language Pantaxou, dedicated to the development of applications for networked heterogeneous entities. Pantaxou has been used to specify a number of coordination scenarios in areas ranging from home automation to telecommunications. The language semantics has been formally defined and a compiler has been developed. The compiler verifies the coherence of a coordination scenario and generates coordination code in Java

Gestion de la Sécurité pour le Cyber-Espace - Du Monitorage Intelligent à la Configuration Automatique

The Internet has become a great integration platform capable of efficiently interconnecting billions of entities, from simple sensors to large data centers. This platform provides access to multiple hardware and virtualized resources (servers, networking, storage, applications, connected objects) ranging from cloud computing to Internet-of-Things infrastructures. From these resources that may be hosted and distributed amongst different providers and tenants, the building and operation of complex and value-added networked systems is enabled. These systems arehowever exposed to a large variety of security attacks, that are also gaining in sophistication and coordination. In that context, the objective of my research work is to support security management for the cyberspace, with the elaboration of new monitoring and configuration solutionsfor these systems. A first axis of this work has focused on the investigation of smart monitoring methods capable to cope with low-resource networks. In particular, we have proposed a lightweight monitoring architecture for detecting security attacks in low-power and lossy net-works, by exploiting different features provided by a routing protocol specifically developed for them. A second axis has concerned the assessment and remediation of vulnerabilities that may occur when changes are operated on system configurations. Using standardized vulnerability descriptions, we have designed and implemented dedicated strategies for improving the coverage and efficiency of vulnerability assessment activities based on versioning and probabilistic techniques, and for preventing the occurrence of new configuration vulnerabilities during remediation operations. A third axis has been dedicated to the automated configuration of virtualized resources to support security management. In particular, we have introduced a software-defined security approach for configuring cloud infrastructures, and have analyzed to what extent programmability facilities can contribute to their protection at the earliest stage, through the dynamic generation of specialized system images that are characterized by low attack surfaces. Complementarily, we have worked on building and verification techniques for supporting the orchestration of security chains, that are composed of virtualized network functions, such as firewalls or intrusion detection systems. Finally, several research perspectives on security automation are pointed out with respect to ensemble methods, composite services and verified artificial intelligence.L’Internet est devenu une formidable plateforme d’intégration capable d’interconnecter efficacement des milliards d’entités, de simples capteurs à de grands centres de données. Cette plateforme fournit un accès à de multiples ressources physiques ou virtuelles, allant des infra-structures cloud à l’internet des objets. Il est possible de construire et d’opérer des systèmes complexes et à valeur ajoutée à partir de ces ressources, qui peuvent être déployées auprès de différents fournisseurs. Ces systèmes sont cependant exposés à une grande variété d’attaques qui sont de plus en plus sophistiquées. Dans ce contexte, l’objectif de mes travaux de recherche porte sur une meilleure gestion de la sécurité pour le cyberespace, avec l’élaboration de nouvelles solutions de monitorage et de configuration pour ces systèmes. Un premier axe de ce travail s’est focalisé sur l’investigation de méthodes de monitorage capables de répondre aux exigences de réseaux à faibles ressources. En particulier, nous avons proposé une architecture de surveillance adaptée à la détection d’attaques dans les réseaux à faible puissance et à fort taux de perte, en exploitant différentes fonctionnalités fournies par un protocole de routage spécifiquement développépour ceux-ci. Un second axe a ensuite concerné la détection et le traitement des vulnérabilités pouvant survenir lorsque des changements sont opérés sur la configuration de tels systèmes. En s’appuyant sur des bases de descriptions de vulnérabilités, nous avons conçu et mis en œuvre différentes stratégies permettant d’améliorer la couverture et l’efficacité des activités de détection des vulnérabilités, et de prévenir l’occurrence de nouvelles vulnérabilités lors des activités de traitement. Un troisième axe fut consacré à la configuration automatique de ressources virtuelles pour la gestion de la sécurité. En particulier, nous avons introduit une approche de programmabilité de la sécurité pour les infrastructures cloud, et avons analysé dans quelle mesure celle-ci contribue à une protection au plus tôt des ressources, à travers la génération dynamique d’images systèmes spécialisées ayant une faible surface d’attaques. De façon complémentaire, nous avonstravaillé sur des techniques de construction automatique et de vérification de chaînes de sécurité, qui sont composées de fonctions réseaux virtuelles telles que pare-feux ou systèmes de détection d’intrusion. Enfin, plusieurs perspectives de recherche relatives à la sécurité autonome sont mises en évidence concernant l’usage de méthodes ensemblistes, la composition de services, et la vérification de techniques d’intelligence artificielle

A SIP-based Programming Framework for Advanced Telephony Applications

International audienceThe scope of telephony is significantly broadening, providing users with a variety of communication modes, including presence status, instant messaging and videoconferencing. Furthermore, telephony is being increasingly combined with a number of non-telephony, heterogeneous resources, consisting of software entities, such as Web services, and hardware entities, such as location-tracking devices. This heterogeneity, compounded with the intricacies of underlying technologies, make the programming of new telephony applications a daunting task. This paper proposes an approach to supporting the development of advanced telephony applications. To do so, we introduce a declarative language over Java to define the entities of a target telephony application area. This definition is passed to a generator to produce a Java programming framework, dedicated to the application area. The generated frameworks provide service discovery and high-level communication mechanisms. These mechanisms are automatically mapped into SIP, making our approach compatible with existing SIP infrastructures and entities. Our work is implemented and has been validated on various advanced telephony applications

Security in peer-to-peer communication systems

P2PSIP (Peer-to-Peer Session Initiation Protocol) is a protocol developed by the IETF (Internet Engineering Task Force) for the establishment, completion and modi¿cation of communication sessions that emerges as a complement to SIP (Session Initiation Protocol) in environments where the original SIP protocol may fail for technical, ¿nancial, security, or social reasons. In order to do so, P2PSIP systems replace all the architecture of servers of the original SIP systems used for the registration and location of users, by a structured P2P network that distributes these functions among all the user agents that are part of the system. This new architecture, as with any emerging system, presents a completely new security problematic which analysis, subject of this thesis, is of crucial importance for its secure development and future standardization. Starting with a study of the state of the art in network security and continuing with more speci¿c systems such as SIP and P2P, we identify the most important security services within the architecture of a P2PSIP communication system: access control, bootstrap, routing, storage and communication. Once the security services have been identi¿ed, we conduct an analysis of the attacks that can a¿ect each of them, as well as a study of the existing countermeasures that can be used to prevent or mitigate these attacks. Based on the presented attacks and the weaknesses found in the existing measures to prevent them, we design speci¿c solutions to improve the security of P2PSIP communication systems. To this end, we focus on the service that stands as the cornerstone of P2PSIP communication systems¿ security: access control. Among the new designed solutions stand out: a certi¿cation model based on the segregation of the identity of users and nodes, a model for secure access control for on-the-¿y P2PSIP systems and an authorization framework for P2PSIP systems built on the recently published Internet Attribute Certi¿cate Pro¿le for Authorization. Finally, based on the existing measures and the new solutions designed, we de¿ne a set of security recommendations that should be considered for the design, implementation and maintenance of P2PSIP communication systems.Postprint (published version

Engineering security into distributed systems: a survey of methodologies

Rapid technological advances in recent years have precipitated a general shift towards software distribution as a central computing paradigm. This has been accompanied by a corresponding increase in the dangers of security breaches, often causing security attributes to become an inhibiting factor for use and adoption. Despite the acknowledged importance of security, especially in the context of open and collaborative environments, there is a growing gap in the survey literature relating to systematic approaches (methodologies) for engineering secure distributed systems. In this paper, we attempt to fill the aforementioned gap by surveying and critically analyzing the state-of-the-art in security methodologies based on some form of abstract modeling (i.e. model-based methodologies) for, or applicable to, distributed systems. Our detailed reviews can be seen as a step towards increasing awareness and appreciation of a range of methodologies, allowing researchers and industry stakeholders to gain a comprehensive view of the field and make informed decisions. Following the comprehensive survey we propose a number of criteria reflecting the characteristics security methodologies should possess to be adopted in real-life industry scenarios, and evaluate each methodology accordingly. Our results highlight a number of areas for improvement, help to qualify adoption risks, and indicate future research directions.Anton V. Uzunov, Eduardo B. Fernandez, Katrina Falkne

Exogenous Coordination of Concurrent Software Components with JavaBIP

A strong separation of concerns is necessary in order to make the design of domain-specific functional components independent from cross-cutting concerns, such as concurrent access to the shared resources of the execution platform. Native coordination mechanisms, such as locks and monitors, allow developers to address these issues. However, such solutions are not modular, they are complex to design, debug and maintain. We present the JavaBIP framework that allows developers to think on a higher level of abstraction and clearly separate the functional and coordination aspects of the system behavior. It implements the principles of the BIP component framework rooted in rigorous operational semantics. It allows the coordination of existing concurrent software components in an exogenous manner, relying exclusively on annotations, component APIs and external specification files. We introduce the annotation and specification syntax of JavaBIP and illustrate its use on realistic examples; present the architecture of our implementation, which is modular and easily extensible; provide and discuss performance evaluation results

Strategic and operational services for workload management in the cloud

In hosting environments such as Infrastructure as a Service (IaaS) clouds, desirable application performance is typically guaranteed through the use of Service Level Agreements (SLAs), which specify minimal fractions of resource capacities that must be allocated by a service provider for unencumbered use by customers to ensure proper operation of their workloads. Most IaaS offerings are presented to customers as fixed-size and fixed-price SLAs, that do not match well the needs of specific applications. Furthermore, arbitrary colocation of applications with different SLAs may result in inefficient utilization of hosts' resources, resulting in economically undesirable customer behavior. In this thesis, we propose the design and architecture of a Colocation as a Service (CaaS) framework: a set of strategic and operational services that allow the efficient colocation of customer workloads. CaaS strategic services provide customers the means to specify their application workload using an SLA language that provides them the opportunity and incentive to take advantage of any tolerances they may have regarding the scheduling of their workloads. CaaS operational services provide the information necessary for, and carry out the reconfigurations mandated by strategic services. We recognize that it could be the case that there are multiple, yet functionally equivalent ways to express an SLA. Thus, towards that end, we present a service that allows the provably-safe transformation of SLAs from one form to another for the purpose of achieving more efficient colocation. Our CaaS framework could be incorporated into an IaaS offering by providers or it could be implemented as a value added proposition by IaaS resellers. To establish the practicality of such offerings, we present a prototype implementation of our proposed CaaS framework