Denial-of-service resilience in peer-to-peer file sharing systems

Peer-to-peer (p2p) file sharing systems are characterized by highly replicated content distributed among nodes with enormous aggregate resources for storage and communication. These properties alone are not sufficient, however, to render p2p networks immune to denial-of-service (DoS) attack. In this paper, we study, by means of analytical modeling and simulation, the resilience of p2p file sharing systems against DoS attacks, in which malicious nodes respond to queries with erroneous responses. We consider the filetargeted attacks in current use in the Internet, and we introduce a new class of p2p-network-targeted attacks. In file-targeted attacks, the attacker puts a large number of corrupted versions of a single file on the network. We demonstrate that the effectiveness of these attacks is highly dependent on the clients’ behavior. For the attacks to succeed over the long term, clients must be unwilling to share files, slow in removing corrupted files from their machines, and quick to give up downloading when the system is under attack. In network-targeted attacks, attackers respond to queries for any file with erroneous information. Our results indicate that these attacks are highly scalable: increasing the number of malicious nodes yields a hyperexponential decrease in system goodput, and a moderate number of attackers suffices to cause a near-collapse of the entire system. The key factors inducing this vulnerability are (i) hierarchical topologies with misbehaving “supernodes,” (ii) high path-length networks in which attackers have increased opportunity to falsify control information, and (iii) power-law networks in which attackers insert themselves into high-degree points in the graph. Finally, we consider the effects of client counter-strategies such as randomized reply selection, redundant and parallel download, and reputation systems. Some counter-strategies (e.g., randomized reply selection) provide considerable immunity to attack (reducing the scaling from hyperexponential to linear), yet significantly hurt performance in the absence of an attack. Other counter-strategies yield little benefit (or penalty). In particular, reputation systems show little impact unless they operate with near perfection

Bandwidth-efficient delay- and loss-tolerant overlay routing

Motivation. Peer-to-peer (P2P) systems are mostly deployed in heterogeneous environments with resource availability varying not only across the nodes but also over time. If any of the shared computational, storage or network resources are exhausted, failures and delays occur. The commonly used crash-stop failure model assumes that once a node stops sending messages it never again resumes. Such failures are trivially detected and appropriate algorithms are run that maintain the connectivity and routing efficiency of the P2P overlay under continuous arrivals and departures of the peers (i.e. churn) [6], [4]. The failure detection mechanisms in the crashstop model are typically tuned to minimize th

Fighting Cheating in P2P-based MMVEs with Disjoint Path Routing

In a P2P-based Massively Multiuser Virtual Environment (MMVE) where nodes cannot be trusted, replicating data on multiple nodes is a possibility to increase the reliability to obtain correct data. Current structured P2P networks mostly place replicas in such a way that queries for the replicas travel along similar paths. A malicious node in the common part of all paths can nullify the security gain of replicated data. We therefore propose to combine radix-based prefix routing with a symmetric replication scheme to gain disjoint paths to each of the replicas

Modélisation multimodèle des réseaux dynamiques : cas des réseaux pair-à-pair

National audienceDans cet article, nous présentons une démarche conceptuelle liant des modélisations issues des mondes pair-à-pair et multi-agents afin de prendre en compte le comportement de l'utilisateur dans la modélisation et la simulation des réseaux pair-à-pair. Nous présentons aussi un outil de simulation que nous avons adapté ainsi que nos premiers résultats qui indiquent que cette démarche est cohérente

Environmental security in P2P networks

Abstract-The great impact and growth of P2P networks in recent years make them an interesting target for hackers. But the development of P2P is aimed at improving the behavior of the networks, in computational terms, or to hide the transactions from observers. Security in P2P networks has been usually undervalued and not taken into account. This paper tries to highlight the major topics and challenges regarding P2P security, from a network infrastructure point of view (environmental security), providing some insights in current developments and available techniques that could be used to solve those problems