Researchers knock part of the Internet offline

A university experiment went awry and briefly shut down a small portion of the Internet late last week. The incident occurred Aug. 27 when researchers at Duke University and the Reseaux IP Europeen Network Coordination Centre began distributing experimental border gateway protocol data through RIPE NCC’s systems. The data caused servers across the planet to go offline within minutes, forcing the experiment to shut down quickly.

BGP is used to direct router traffic on the Internet. According to Computerworld, routers running Cisco’s Internetwork Operating System received the experimental data, which was much larger than standard BGP routing code, corrupted it and passed the altered information to other servers. The majority of the routers that received the data cut off their connections with the Cisco routers, causing about 1 percent of the Internet to become inaccessible.

Earl Zmijewski, a general manager with the Internet security firm Renesys, told Computerworld that more than 3,500 blocks of IP addresses became unstable the moment the experiment began. He said that the prefixes were located globally with more than 60 nations affected.

The Friday disruption lasted less than half an hour. Hours after the incident, Cisco released a security advisory stating: “An advertisement of an unrecognized but valid BGP attribute resulted in resetting of several BGP neighbors on 27 August 2010. This advertisement was not malicious but inadvertently triggered this vulnerability.” Cisco also said that it has repaired the bug in its IOS software that caused the incident.

Zimijewski said that while the problems were caused by Cisco’s software, the university team running the experiment should have been more careful. “The days of academics playing with a live network are kind of gone now," he said. "I think it would be foolhardy to try something like this in the future.… I’m amazed that this happened in the first place."

RIPE NCC posted a statement on its Web site noting that the experiment was intended to further understanding of specific aspects of Internet routing behavior. The group said that in the future, it will be stricter about how it runs such experiments and will give Internet operators advance warning.