“Fixing the Internet”
Communications of the ACM, August 2021, Vol. 64 No. 8, Pages 16-17
By Keith Kirkpatrick
Few people pay much attention to how the electrical grid works until there is an outage. The same is often true for the Internet.
Yet unlike the electrical grid, where direct attacks are infrequent, vulnerabilities and security issues with the Internet’s routing protocol have led to numerous, frequent malicious attacks that have resulted in widespread service outages, intercepted and stolen personal data, and the use of seemingly legitimate Web sites to launch massive spam campaigns.
The Internet is an interconnected global network of autonomous systems or network operators, like Internet service providers (ISPs), corporate networks, content delivery networks (such as Hulu or Netflix), and cloud computing companies such as Google and Microsoft Cloud. The Border Gateway Protocol (BGP) is used to ensure data can be directed between networks along the most efficient path, similar to how a GPS navigation system maintains a database of street addresses and can assess distance and congestion when selecting the optimal route to a destination.
Each autonomous system connected to the Internet has an Internet Protocol (IP) address, which is its network interface, and provides the location of the host within the network; this allows other networks to establish a path to that host. BGP routers managed by an ISP control the flow of data packets containing content between networks, and maintains a standard routing table used to direct packets in transit. BGP makes routing decisions based on paths, rules, or network policies configured by each network’s administrator.
BGP was first described in a document assembled by the Internet Society’s Network Working Group in June 1989 and was first put into use in 1994. BGP is extremely scalable, allowing tens of thousands of networks around the world to be connected together, and if a router or path becomes unavailable, it can quickly adapt to send packets through another reconnection. However, because the protocol was designed and still operates on a trust model that accepts that any information exchanged by networks is always valid, it remains susceptible to issues such as information exchange failures due to improperly formatted or incorrect data. BGP can also be at the mercy of routers too slow to respond to updates, or that run out of memory or storage, situations that can cause network timeouts, bad routing requests, and processing problems.
Aftab Siddiqui, senior manager of Internet technology at the Internet Society, says the initial BGP protocol was conceived by experts at research institutions, defense organizations, and equipment vendors. “When they designed [BGP], it was based on the premise that everybody trusts each other,” Siddiqui says. “Fast-forward 30 years, I’m pretty sure we cannot claim that anymore.”
On the other hand, RPKI, a distributed public database of cryptographically signed records containing routing information supplied by autonomous systems or networks, is considered to be the ultimate “truth” for network information, according to Siddiqui. RPKI is carried out by a process known as route origin validation (ROV), which uses route origin authorizations (ROAs)—digitally signed objects that fix an IP address to a specific network or autonomous system—to establish the list of prefixes a network is authorized to announce.
However, it is not just Google that is working to implement better practices, such as moving to RPKI or implementing ROV. “There’s Netflix, Akamai, Microsoft, Cloudflare, and other top providers,” Siddiqui says. “So, if you want to pair with them, then [smaller] operators will need to fix their registry information, and only then will they be able to talk to [the large content delivery networks and cloud providers].”
While getting the majority of the 70,000+ global networks on board with using RPKI and other best practices for network routing is a high bar to clear (and one that likely will take years to achieve), Hansen says it is imperative to close this loophole.
About the Author:
Keith Kirkpatrick is principal of 4K Research & Consulting, LLC, based in New York, NY, USA.