Border Gateway Protocol (BGP) is the postal service of the Internet. It’s responsible for looking at all of the available paths that data could travel and picking the best route.
Unfortunately, it isn’t secure, and there have been some major Internet disruptions as a result. But fortunately there is a way to make it secure.
ISPs and other major Internet players (Sprint, Verizon, and others) would need to implement a certification system, called RPKI.
Displaying major operators
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To better understand why BGP’s lack of security is so problematic, let’s look at a simplified model of how BGP is used to route Internet packets.
The Internet is not run by just one company. It’s made up of thousands of autonomous systems with nodes located all around the world, connected to each other in a massive graph.
In essence, the way BGP works is that each node must determine how to route packets using only what it knows from the nodes it connects with directly.
For example, in the simple network A–B–C–D–E, the node A only knows how to reach E based on information it received from B. The node B knows about the network from A and C. And so forth.
A BGP hijack occurs when a malicious node deceives another node, lying about what the routes are for its neighbors. Without any security protocols, this misinformation can propagate from node to node, until a large number of nodes now know about, and attempt to use these incorrect, nonexistent, or malicious routes.
Click “Hijack the request” to visualize how packets are re-routed:
In order to make BGP safe, we need some way of preventing the spread of this misinformation. Since the Internet is so open and distributed, we can’t prevent malicious nodes from attempting to deceive other nodes in the first place. So instead we need to give nodes the ability to validate the information they receive, so they can reject these undesired routes on their own.
Enter Resource Public Key Infrastructure (RPKI), a security framework method that associates a route with an autonomous system. It gets a little technical, but the basic idea is that RPKI uses cryptography to provide nodes with a way of doing this validation.
With RPKI enabled, let’s see what happens to packets after an attempted BGP hijack. Click “Attempt to hijack” to visualize how RPKI allows the network to protect itself by invalidating the malicious routes:
Border Gateway Protocol (BGP) is the postal service of the Internet. When someone drops a letter into a mailbox, the postal service processes that piece of mail and chooses a fast, efficient route to deliver that letter to its recipient. Similarly, when someone submits data across the Internet, BGP is responsible for looking at all of the available paths that data could travel and picking the best route, which usually means hopping between autonomous systems. Learn more →
By default, BGP does not embed any security protocols. It is up to every autonomous system to implement filtering of “wrong routes”. Leaking routes can break parts of the Internet by making them unreachable. It is commonly the result of misconfigurations. Although, it is not always accidental. A practice called BGP hijack consists of redirecting traffic to another autonomous system to steal information (via phishing, or passive listening for instance).
BGP can be made safe if all autonomous systems (AS) only announce legitimate routes. A route is defined as legitimate when the owner of the resource allows its announcement. Filters need to be built in order to make sure only legitimate routes are accepted. There are a few approaches for BGP route validation which vary in degrees of trustability and efficiency. A mature implementation is RPKI.
With 800k+ routes on the Internet, it is impossible to check them manually. Resource Public Key Infrastructure (RPKI) is a security framework method that associates a route with an autonomous system. It uses cryptography in order to validate the information before being passed onto the routers. You can read more about RPKI on the Cloudflare blog.
On May 14th, Job Snijders from NTT will present a free RPKI 101 webinar.
In order to test if your ISP is implementing BGP safely, we announce a legitimate route but we make sure the announcement is invalid. If you can load the website we host on that route, that means the invalid route was accepted by your ISP. A leaked or a hijacked route would likely be accepted too.
Over the years, network operators and developers started working groups to design and deploy standards to overcome unsafe routing protocols. Cloudflare recently joined a global initiative called Mutually Agreed Norms for Routing Security (MANRS). It’s a community of security-minded organizations committed to making routing infrastructure more robust and secure, and members agree to implement filtering mechanisms. New voices are always appreciated.
Share this page. For BGP to be safe, all of the major ISPs will need to embrace RPKI. Sharing this page will increase awareness of the problem which can ultimately pressure ISPs into implementing RPKI for the good of themselves and the general public. You can also reach out to your service provider or hosting company directly and ask them to deploy RPKI and join MANRS. When the Internet is safe, everybody wins.