Research: Are We There Yet? RPKI Deployment Considered
The Resource Public Key Infrastructure (RPKI) system is designed to prevent hijacking of routes at their origin AS. If you don’t know how this system works (and it is likely you don’t, because there are only a few deployments in the world), you can review the way the system works by reading through this post here on rule11.tech.
Gilad, Yossi & Cohen, Avichai & Herzberg, Amir & Schapira, Michael & Shulman, Haya. (2017). Are We There Yet? On RPKI’s Deployment and Security. 10.14722/ndss.2017.23123.
The paper under review today examines how widely Route Origin Validation (ROV) based on the RPKI system has been deployed. The authors began by determining which Autonomous Systems (AS’) are definitely not deploying route origin validation. They did this by comparing the routes in the global RPKI database, which is synchronized among all the AS’ deploying the RPKI, to the routes in the global Default Free Zone (DFZ), as seen from 44 different route servers located throughout the world. In comparing these two, they found a set of routes which the RPKI system indicated should be originated from one AS, but were actually being originated from another AS in the default free zone.
Using this information, the researchers then looked for AS’ through which these routes with a mismatched RPKI and global table origin were advertised. If an AS accepted, and then readvertised, routes with mismatched RPKI and global table origins, they marked this AS as one that does not enforce route origin authentication.
A second, similar check was used to find the mirror set of AS’, those that do perform a route origin validation check. In this case, the authors traced the same type of route—those for which the origin AS the route is advertised with does not match the originating AS in the RPKI–and discovered some AS’ will not readvertise such a route. These AS’ apparently do perform a check for the correct route origin information.
The result is that only one of the 20 Internet Service Providers (ISPs) with the largest number of customers performs route origination validation on the routes they receive. Out of the largest 100 ISPs (again based on customer AS count), 22 appear to perform a route origin validation check. These are very low numbers.
To double check these numbers, the researchers surveyed a group of ISPs, and found that very few of them claim to check the routes they receive against the RPKI database. Why is this? When asked, these providers gave two reasons.
First, these providers are concerned about the problems involved with their connectivity being impacted in the case of an RPKI system failure. For instance, it would be easy enough for a company to become involved in a contract dispute with their naming authority, or with some other organization (two organizations claiming the same AS number, for instance). These kinds of cases could result in many years of litigation, causing a company to effectively lose their connectivity to the global ‘net during the process. This might seem like a minor fear for some, and there might be possible mitigations, but the ‘net is much more statically defined than many people realize, and many operators operate on a razor thin margin. The disruptions caused by such an event could simply put a company out of business.
Second, there is a general perception that the RPKI database is not exactly a “clean” representation of the real world. Since the database is essentially self-reported, there is little incentive to make changes to the database once something in the real world has changed (such as the transfer of address space between organization). It only takes a small amount of old, stale, or incorrect information to reduce the usefulness of this kind of public database. The authors address this concern by examining the contents of the RPKI, and find that it does, in fact, contain a good bit of incorrect information. They develop a tool to help administrators find this information, but ultimately people must use these kinds of tools.
The point of the paper is that the RPKI system, which is seen as crucial to the security of the global Internet, is not being widely used, and deployment does not appear to be increasing over time. One possible takeaway is the community needs to band together and deploy this technology. Another might be that the RPKI is not a viable solution to the problem at hand for various technical and social reasons—it might be time to start looking for another alternative for solving this problem.