To study the private infrastructure, we use an approach to discover 694 private bridges on the Internet and a novel technique to track bridges across IP changes. Our results show that the 55% of public bridges that carry clients are vulnerable to aggressive blocking that 90% of bridge clients use default bridges that are trivial to identify that the concurrent deployment of Pluggable Transports in bridges reduces the security of the most secure transports and that running non-Tor services in the same host as a bridge may harm its anonymity. Then, we measure security relevant properties of public bridges.

First, we examine the security implications of the public data in the CollecTor service, identifying several pieces of data that may be detrimental for the security of bridges. Our analysis of the public infrastructure is twofold. Our study covers both the public infrastructure available to all Tor users, and the previously unreported private infrastructure, comprising private nodes for the exclusive use of those who know their existence.

Leveraging public data sources, and two known Tor issues, we perform the first systematic study on the security of the Tor bridges infrastructure.

So far, no global security analysis of Tor bridges has been performed. Dissecting Tor Bridges: A Security Evaluation of their Private and Public InfrastructuresĪuthor(s): Srdjan Matic, Carmela Troncoso, Juan CaballeroĪssociated Event: NDSS Symposium 2017 Abstract:īridges are onion routers in the Tor Network whose IP addresses are not public.

What is tor bridge