The Abandoned Side of the Internet: Hijacking Internet Resources When Domain Names Expire

The vulnerability of the Internet has been demonstrated by prominent IP prefix hijacking events. Major outages such as the China Telecom incident in 2010 stimulate speculations about malicious intentions behind such anomalies. Surprisingly, almost all discussions in the current literature assume that hijacking incidents are enabled by the lack of security mechanisms in the inter-domain routing protocol BGP. In this paper, we discuss an attacker model that accounts for the hijacking of network ownership information stored in Regional Internet Registry (RIR) databases. We show that such threats emerge from abandoned Internet resources (e.g., IP address blocks, AS numbers). When DNS names expire, attackers gain the opportunity to take resource ownership by re-registering domain names that are referenced by corresponding RIR database objects. We argue that this kind of attack is more attractive than conventional hijacking, since the attacker can act in full anonymity on behalf of a victim. Despite corresponding incidents have been observed in the past, current detection techniques are not qualified to deal with these attacks. We show that they are feasible with very little effort, and analyze the risk potential of abandoned Internet resources for the European service region: our findings reveal that currently 73 /24 IP prefixes and 7 ASes are vulnerable to be stealthily abused. We discuss countermeasures and outline research directions towards preventive solutions.Comment: Final version for TMA 201

CAIR: Using Formal Languages to Study Routing, Leaking, and Interception in BGP

The Internet routing protocol BGP expresses topological reachability and policy-based decisions simultaneously in path vectors. A complete view on the Internet backbone routing is given by the collection of all valid routes, which is infeasible to obtain due to information hiding of BGP, the lack of omnipresent collection points, and data complexity. Commonly, graph-based data models are used to represent the Internet topology from a given set of BGP routing tables but fall short of explaining policy contexts. As a consequence, routing anomalies such as route leaks and interception attacks cannot be explained with graphs. In this paper, we use formal languages to represent the global routing system in a rigorous model. Our CAIR framework translates BGP announcements into a finite route language that allows for the incremental construction of minimal route automata. CAIR preserves route diversity, is highly efficient, and well-suited to monitor BGP path changes in real-time. We formally derive implementable search patterns for route leaks and interception attacks. In contrast to the state-of-the-art, we can detect these incidents. In practical experiments, we analyze public BGP data over the last seven years

Eine Evaluation von Schwächen in der Architektur des Internet-Routings

The Internet is a vital part of today's life and a critical business infrastructure. At its core, Internet routing is based on trust and is thus vulnerable to attacks. To study such attacks, we derive a rigorous routing model and develop novel detection techniques. We apply these concepts in practice and learn that there is a real threat. This work opens up new research directions towards a mitigation of attacks and can support the development of a secure routing architecture in the future.Das Internet ist zentraler Teil der heutigen Gesellschaft und eine kritische Infrastruktur. Dennoch ist das auf Vertrauen basierende Routing im Internet angreifbar. Mit Hilfe eines präzisen Routing-Modells werden unterschiedliche Angriffstypen diskutiert und neuartige Erkennungstechniken entwickelt. Durch deren Einsatz in der Praxis wird das reale Gefährdungspotential bestimmt. Neben der Bekämpfung von Angriffen kann diese Arbeit auch zum Aufbau einer sicheren Routing-Architektur beitragen