IT engineers are studying what may be an easier way to fix a long-existing weakness in the Internet's routing system that has the potential to cause major service outages and allow hackers to spy on data.
The problem involves the routers used by every organization and company that owns a block of IP addresses. Those routers communicate constantly with other routers, updating their internal information -- often upwards of 400,000 entries -- on the best way to reach other networks using a protocol called Border Gateway Protocol (BGP).
BGP enables routers to find the best path when, say, a network used to retrieve a web page from South Korea is not working properly. Changes in that routing information are distributed quickly to routers around the world in as few as five minutes.
But the routers do not verify that the route "announcements," as they are called, are correct. Mistakes in entering the information -- or worse yet, a malicious attack -- can cause a network to become unavailable.
It can also cause, for example, a company's Internet traffic to be circuitously routed through another network it does not need to go through, opening the possibility the traffic could be intercepted. The attack is known as "route hijacking," and can't be stopped by any security product.
When routing problems erupt, "it's very difficult to tell if this is fat fingering on a router or malicious," said Joe Gersch, chief operating officer for Secure64, a company that makes Domain Name System (DNS) server software. "It could be a trial run for cyberwarfare."
Data shows that as much as one-third of the world can't reach portions of the Internet at a time due to routing problems, Gersch said.
In February, a routing mistake caused the international traffic for Australian operator Telstra to go through its competitor's network, Dodo, which couldn't handle the traffic surge. In a well-known incident, Pakistan Telecom made an error with BGP after Pakistan's government ordered in 2008 that ISPs block YouTube, which ended up knocking Google's service offline.
In March 2011, a researcher noticed that traffic destined for Facebook on AT&T's network strangely went through China for a while. While the requests would normally go directly to Facebook's network provider, the traffic first went through China Telecom and then to SK Broadband in South Korea before routing to Facebook. Although the incident was characterized as a mistake, it would have been possible for unencrypted Facebook traffic to have been spied on.
"The broader problem here is that much of this critical infrastructure simply relies on players behaving correctly," said Dan Massey, an associate computer science professor at Colorado State University. "In a truly global system like the internet, you must assume that organizations will occasionally make unintentional mistakes."
But "imagine what a determined adversary might be able to do," Massey said. That could include attacks on critical infrastructure, such as power plants, which have become increasingly reliant on the Internet.
The solution is to have routers verify that the IP address blocks announced by others routers actually belong to their networks. One method, Resource Public Key Infrastructure (RPKI), uses a system of cryptographic certificates that verify an IP address block indeed belongs to a certain network.
RPKI is complex, and deployment has been slow. Experts recently came up with an alternate system, nicknamed ROVER for Route Origin Verification, that may be easier.
ROVER stores the legitimate route information within the DNS, the enormous distributed database that translates a domain name into an IP address that can be called into a browser. That route information can be signed with DNSSEC, the security protocol that allows DNS records to be cryptographically signed, which is being widely adopted.
The advantages with ROVER are that no changes need to be made to existing routers, and it can work alongside RPKI. "The whole infrastructure of securing the answer [of whether the route is legitimate] already exists," said Gersch, who has authored two specifications for how to name a route and the type of record that could be inserted into the DNS.
The specifications are currently in "internet daft" status before the Internet Engineering Task Force. The next step to becoming a standard is for a working group to adopt the documents, Gersch said.
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