H. Okamura, Michael Grottke, T. Dohi, Kishor S. Trivedi
In this paper, we present a variational Bayesian (VB) approach to computing the interval estimates for nonhomogeneous Poisson process (NHPP) software reliability models. This approach is an approximate method that can produce analytically tractable posterior distributions. We present simple iterative algorithms to compute the approximate posterior distributions for the parameters of the gamma-type NHPP-based software reliability model using either individual failure time data or grouped data. In numerical examples, the accuracy of this VB approach is compared with the interval estimates based on conventional Bayesian approaches, i.e., Laplace approximation, Markov chain Monte Carlo (MCMC) method, and numerical integration. The proposed VB approach provides almost the same accuracy as MCMC, while its computational burden is much lower.
{"title":"Variational Bayesian Approach for Interval Estimation of NHPP-Based Software Reliability Models","authors":"H. Okamura, Michael Grottke, T. Dohi, Kishor S. Trivedi","doi":"10.1109/DSN.2007.101","DOIUrl":"https://doi.org/10.1109/DSN.2007.101","url":null,"abstract":"In this paper, we present a variational Bayesian (VB) approach to computing the interval estimates for nonhomogeneous Poisson process (NHPP) software reliability models. This approach is an approximate method that can produce analytically tractable posterior distributions. We present simple iterative algorithms to compute the approximate posterior distributions for the parameters of the gamma-type NHPP-based software reliability model using either individual failure time data or grouped data. In numerical examples, the accuracy of this VB approach is compared with the interval estimates based on conventional Bayesian approaches, i.e., Laplace approximation, Markov chain Monte Carlo (MCMC) method, and numerical integration. The proposed VB approach provides almost the same accuracy as MCMC, while its computational burden is much lower.","PeriodicalId":405751,"journal":{"name":"37th Annual IEEE/IFIP International Conference on Dependable Systems and Networks (DSN'07)","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115474676","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A quorum system is a collection of sets (quorums) of servers,where any two quorums intersect. Quorum-based protocols underly modern edge-computing architectures and throughput-scalable service implementations. In this paper we propose new algorithms for placing quorums in wide-area networks and tuning which quorums clients access, so as to optimize clients' average response time in quorum-based protocols. We examine scenarios in which the service is lightly loaded and hence network latency is the dominant delay, and in which client-induced load contributes significantly to the delay that clients observe.In each case, we evaluate our algorithms on topologies ranging from 50 to over 150 wide-area locations.
{"title":"Minimizing Response Time for Quorum-System Protocols over Wide-Area Networks","authors":"Florian Oprea, M. Reiter","doi":"10.1109/DSN.2007.66","DOIUrl":"https://doi.org/10.1109/DSN.2007.66","url":null,"abstract":"A quorum system is a collection of sets (quorums) of servers,where any two quorums intersect. Quorum-based protocols underly modern edge-computing architectures and throughput-scalable service implementations. In this paper we propose new algorithms for placing quorums in wide-area networks and tuning which quorums clients access, so as to optimize clients' average response time in quorum-based protocols. We examine scenarios in which the service is lightly loaded and hence network latency is the dominant delay, and in which client-induced load contributes significantly to the delay that clients observe.In each case, we evaluate our algorithms on topologies ranging from 50 to over 150 wide-area locations.","PeriodicalId":405751,"journal":{"name":"37th Annual IEEE/IFIP International Conference on Dependable Systems and Networks (DSN'07)","volume":"116 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115251363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this work, we present the novel idea of route normalization by correcting on the fly routing traffic on behalf of a local router to protect the local network from malicious and misconfigured routing updates. Analogous to traffic normalization for network intrusion detection systems, the proposed RouteNormalizer patches ambiguities and eliminates semantically incorrect routing updates to protect against routing protocol attacks. Furthermore, it serves the purpose of a router firewall by identifying resource-based attacks against routers. Upon detecting anomalous routing changes, it suggests local routing policy modifications to improve route selection decisions. Deploying a RouteNormalizer requires no modification to routers if desired using a transparent TCP proxy setup. In this paper, we present the detailed design of the RouteNormalizer and evaluate it using a prototype implementation based on empirical BGP routing updates. We validate its effectiveness by showing that many well-known routing problems from operator mailing lists are correctly identified.
{"title":"A Firewall for Routers: Protecting against Routing Misbehavior","authors":"Ying Zhang, Z. Morley Mao, Jia Wang","doi":"10.1109/DSN.2007.7","DOIUrl":"https://doi.org/10.1109/DSN.2007.7","url":null,"abstract":"In this work, we present the novel idea of route normalization by correcting on the fly routing traffic on behalf of a local router to protect the local network from malicious and misconfigured routing updates. Analogous to traffic normalization for network intrusion detection systems, the proposed RouteNormalizer patches ambiguities and eliminates semantically incorrect routing updates to protect against routing protocol attacks. Furthermore, it serves the purpose of a router firewall by identifying resource-based attacks against routers. Upon detecting anomalous routing changes, it suggests local routing policy modifications to improve route selection decisions. Deploying a RouteNormalizer requires no modification to routers if desired using a transparent TCP proxy setup. In this paper, we present the detailed design of the RouteNormalizer and evaluate it using a prototype implementation based on empirical BGP routing updates. We validate its effectiveness by showing that many well-known routing problems from operator mailing lists are correctly identified.","PeriodicalId":405751,"journal":{"name":"37th Annual IEEE/IFIP International Conference on Dependable Systems and Networks (DSN'07)","volume":"81 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116212154","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Bloomfield, M. Masera, A. Miller, O. S. Saydjari, C. Weinstock
For critical systems it is important to know whether the system is trustworthy and to be able to communicate, review and debate the level of trust achieved. In the safety domain, explicit Safety Cases are increasingly required by law, regulations and standards. Yet the need to understand risks is not just a safety issue and the type of argumentation used for safety cases is not specific to safety alone. Prior workshops, beginning with one held at DSN 2004, have identified a number of technical, policy and research challenges. The focus of this workshop is on one of these challenges: metrics for assurance cases for security.
{"title":"Assurance Cases for Security: The Metrics Challenge","authors":"R. Bloomfield, M. Masera, A. Miller, O. S. Saydjari, C. Weinstock","doi":"10.1109/DSN.2007.18","DOIUrl":"https://doi.org/10.1109/DSN.2007.18","url":null,"abstract":"For critical systems it is important to know whether the system is trustworthy and to be able to communicate, review and debate the level of trust achieved. In the safety domain, explicit Safety Cases are increasingly required by law, regulations and standards. Yet the need to understand risks is not just a safety issue and the type of argumentation used for safety cases is not specific to safety alone. Prior workshops, beginning with one held at DSN 2004, have identified a number of technical, policy and research challenges. The focus of this workshop is on one of these challenges: metrics for assurance cases for security.","PeriodicalId":405751,"journal":{"name":"37th Annual IEEE/IFIP International Conference on Dependable Systems and Networks (DSN'07)","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122686322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To face the challenges resulting from the increasing density of application software components and higher dependability requirements of the future safety systems in the automotive electronics, a dependability software service to monitor individual application software components in runtime is required in order to improve the overall system dependability. This paper proposes the application of a software watchdog service providing heartbeat monitoring and program flow checking. The software watchdog is integrated in a software platform for the automotive safety electronics. A model-based design with Matlab/Simulink and an evaluation of this software watchdog service in a hardware-in-the-loop validator are also given.
{"title":"Application of Software Watchdog as a Dependability Software Service for Automotive Safety Relevant Systems","authors":"X. Chen, J. Feng, M. Hiller, V. Lauer","doi":"10.1109/DSN.2007.14","DOIUrl":"https://doi.org/10.1109/DSN.2007.14","url":null,"abstract":"To face the challenges resulting from the increasing density of application software components and higher dependability requirements of the future safety systems in the automotive electronics, a dependability software service to monitor individual application software components in runtime is required in order to improve the overall system dependability. This paper proposes the application of a software watchdog service providing heartbeat monitoring and program flow checking. The software watchdog is integrated in a software platform for the automotive safety electronics. A model-based design with Matlab/Simulink and an evaluation of this software watchdog service in a hardware-in-the-loop validator are also given.","PeriodicalId":405751,"journal":{"name":"37th Annual IEEE/IFIP International Conference on Dependable Systems and Networks (DSN'07)","volume":"255 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114363163","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tutorials are an important part of the DSN program. They provide an opportunity for attendees to acquire a basic understanding of, and familiarity with, several state of the art topics related to the dependability, security and resilience of systems and networks. Tutorial proposals providing guidance on how technology can be applied successfully in practical systems were particularly encouraged.
{"title":"DSN 2007 Tutorials","authors":"L. Rodrigues","doi":"10.1109/DSN.2007.33","DOIUrl":"https://doi.org/10.1109/DSN.2007.33","url":null,"abstract":"Tutorials are an important part of the DSN program. They provide an opportunity for attendees to acquire a basic understanding of, and familiarity with, several state of the art topics related to the dependability, security and resilience of systems and networks. Tutorial proposals providing guidance on how technology can be applied successfully in practical systems were particularly encouraged.","PeriodicalId":405751,"journal":{"name":"37th Annual IEEE/IFIP International Conference on Dependable Systems and Networks (DSN'07)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114782324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Workshops at DSN provide a forum for a group of participants (typically 20 to 50 in size) to interact and exchange opinions on topics related to any of the many facets of dependable systems and networks. We welcome participation by professionals from a range of diverse backgrounds who can contribute to advancing the technology and understanding of the workshop subject.
{"title":"DSN 2007 Workshops","authors":"C. Fetzer","doi":"10.1109/DSN.2007.34","DOIUrl":"https://doi.org/10.1109/DSN.2007.34","url":null,"abstract":"Workshops at DSN provide a forum for a group of participants (typically 20 to 50 in size) to interact and exchange opinions on topics related to any of the many facets of dependable systems and networks. We welcome participation by professionals from a range of diverse backgrounds who can contribute to advancing the technology and understanding of the workshop subject.","PeriodicalId":405751,"journal":{"name":"37th Annual IEEE/IFIP International Conference on Dependable Systems and Networks (DSN'07)","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121600412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In a peer-to-peer overlay network, hosts cooperate to forward messages. When a message does not reach its final destination, there are two possible explanations. An intermediate overlay host may have dropped the message due to misconfiguration or malice. Alternatively, a bad link in the underlying IP network may have prevented an earnest, properly configured host from forwarding the data. In this paper, we describe how overlay peers can distinguish between the two situations and ascribe blame appropriately. We generate probabilistic notions of blame using distributed network tomography, fuzzy logic, and secure routing primitives. By comparing application-level drop rates with network characteristics inferred from tomography, we can estimate the likelihood that message loss is due to a misbehaving overlay host or a poor link in the underlying IP network. Since faulty nodes can submit inaccurate tomographic data to the collective, we also discuss mechanisms for detecting such misbehavior.
{"title":"Concilium: Collaborative Diagnosis of Broken Overlay Routes","authors":"James W. Mickens, Brian D. Noble","doi":"10.1109/DSN.2007.27","DOIUrl":"https://doi.org/10.1109/DSN.2007.27","url":null,"abstract":"In a peer-to-peer overlay network, hosts cooperate to forward messages. When a message does not reach its final destination, there are two possible explanations. An intermediate overlay host may have dropped the message due to misconfiguration or malice. Alternatively, a bad link in the underlying IP network may have prevented an earnest, properly configured host from forwarding the data. In this paper, we describe how overlay peers can distinguish between the two situations and ascribe blame appropriately. We generate probabilistic notions of blame using distributed network tomography, fuzzy logic, and secure routing primitives. By comparing application-level drop rates with network characteristics inferred from tomography, we can estimate the likelihood that message loss is due to a misbehaving overlay host or a poor link in the underlying IP network. Since faulty nodes can submit inaccurate tomographic data to the collective, we also discuss mechanisms for detecting such misbehavior.","PeriodicalId":405751,"journal":{"name":"37th Annual IEEE/IFIP International Conference on Dependable Systems and Networks (DSN'07)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115777380","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
N. Carvalho, J. Pereira, R. Oliveira, L. Rodrigues
In epidemic or gossip-based multicast protocols, each node simply relays each message to some random neighbors, such that all destinations receive it at least once with high probability. In sharp contrast, structured multicast protocols explicitly build and use a spanning tree to take advantage of efficient paths, and aim at having each message received exactly once. Unfortunately, when failures occur, the tree must be rebuilt. Gossiping thus provides simplicity and resilience at the expense of performance and resource efficiency. In this paper we propose a novel technique that exploits knowledge about the environment to schedule payload transmission when gossiping. The resulting protocol retains the desirable qualities of gossip, but approximates the performance of structured multicast. In some sense, instead of imposing structure by construction, we let it emerge from the operation of the gossip protocol. Experimental evaluation shows that this approach is effective even when knowledge about the environment is only approximate.
{"title":"Emergent Structure in Unstructured Epidemic Multicast","authors":"N. Carvalho, J. Pereira, R. Oliveira, L. Rodrigues","doi":"10.1109/DSN.2007.40","DOIUrl":"https://doi.org/10.1109/DSN.2007.40","url":null,"abstract":"In epidemic or gossip-based multicast protocols, each node simply relays each message to some random neighbors, such that all destinations receive it at least once with high probability. In sharp contrast, structured multicast protocols explicitly build and use a spanning tree to take advantage of efficient paths, and aim at having each message received exactly once. Unfortunately, when failures occur, the tree must be rebuilt. Gossiping thus provides simplicity and resilience at the expense of performance and resource efficiency. In this paper we propose a novel technique that exploits knowledge about the environment to schedule payload transmission when gossiping. The resulting protocol retains the desirable qualities of gossip, but approximates the performance of structured multicast. In some sense, instead of imposing structure by construction, we let it emerge from the operation of the gossip protocol. Experimental evaluation shows that this approach is effective even when knowledge about the environment is only approximate.","PeriodicalId":405751,"journal":{"name":"37th Annual IEEE/IFIP International Conference on Dependable Systems and Networks (DSN'07)","volume":"74 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132116839","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This practical experience report presents the results of an experiment aimed at building a profile of attacker behavior following a remote compromise. For this experiment, we utilized four Linux honeypot computers running SSH with easily guessable passwords. During the course of our research, we also determined the most commonly attempted usernames and passwords, the average number of attempted logins per day, and the ratio of failed to successful attempts. To build a profile of attacker behavior, we looked for specific actions taken by the attacker and the order in which they occurred. These actions were: checking the configuration, changing the password, downloading a file, installing/running rogue code, and changing the system configuration.
{"title":"Profiling Attacker Behavior Following SSH Compromises","authors":"Daniel Ramsbrock, R. Berthier, M. Cukier","doi":"10.1109/DSN.2007.76","DOIUrl":"https://doi.org/10.1109/DSN.2007.76","url":null,"abstract":"This practical experience report presents the results of an experiment aimed at building a profile of attacker behavior following a remote compromise. For this experiment, we utilized four Linux honeypot computers running SSH with easily guessable passwords. During the course of our research, we also determined the most commonly attempted usernames and passwords, the average number of attempted logins per day, and the ratio of failed to successful attempts. To build a profile of attacker behavior, we looked for specific actions taken by the attacker and the order in which they occurred. These actions were: checking the configuration, changing the password, downloading a file, installing/running rogue code, and changing the system configuration.","PeriodicalId":405751,"journal":{"name":"37th Annual IEEE/IFIP International Conference on Dependable Systems and Networks (DSN'07)","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123551907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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