Facebook traffic mysteriously passes through Chinese ISP

For a short time on Tuesday, internet traffic sent between Facebook and subscribers to AT&T's internet service passed through hardware belonging to the state-owned China Telecom before reaching its final destination, a security researcher said.

An innocent routing error is the most likely explanation for the highly circuitous route, but it's troubling nonetheless, said Barrett Lyon, the independent researcher who helped discover the anomaly and later blogged about it. Human rights groups have long accused China's government of snooping on the internet communications of dissidents, and last year Google claimed it and dozens of other companies were on the receiving end of a sophisticated hacking campaign carried out by the Chinese.

During a window that lasted 30 minutes to an hour Tuesday morning, all unencrypted traffic passing between AT&T customers and Facebook might have been open to similar monitoring. Lyon said he has no evidence any data was in fact snarfed, but he said the potential for that is certainly there because the hardware belonged to China Telecom, which in turn is owned by the Chinese government.

“This kind of thing happens all the time, sometimes on accident and sometimes on purpose,” he told The Reg. “I think people should talk about it at the very least.”

It's not the first time traffic has been diverted through Chinese networks under mysterious circumstances. In March and April of last year, traffic to as much as 15 percent of the world's internet destinations was briefly diverted through China. Networks used by Dell, Apple, CNN, and Starbucks were all affected. At least one of those incidents was the result of erroneous BGP, or Border Gateway Protocol, routes that were quickly corrected.

Unlike those incidents, Tuesday's diversion appeared to affect only traffic traveling between AT&T users and Facebook. Lyon discovered the anomaly by telnetting into AT&T's IP Services Route Monitor (telnet://route-server.ip.att.net) and typing various commands, such as “show ip bgp 69.171.224.20/20.”

Traceroute commands executed during the brief window Tuesday morning on machines connected to AT&T's network also verified that Facebook-bound traffic was traveling over AS4134, the Autonomous System belonging to China Telecom, Lyon said.

Facebook issued a statement that read:

We are investigating a situation today that resulted in a small amount of a single carrier's traffic to Facebook being misdirected. We are working with the carrier to determine the cause of this error.

Our initial checks of the latency of the requests indicate that no traffic passed through China.

The statement left open the possibility that Facebook traffic passed through China Telecom hardware located in Europe or elsewhere.

The incident comes two months after Facebook started offering its users the option of using always-on SSL to encrypt their sessions from beginning to end. Previously, only logins and other select transactions were protected, leaving online chats, photo uploads and other activities wide open to anyone who had the ability to monitor the networks between the user and Facebook.

Facebook has said it hopes to turn on SSL by default in the future, but don't count on that happening anytime soon. In the meantime, users must activate it manually, by going to Account Settings > Account Security and checking the box that says “Browse Facebook on a secure connection (https) whenever possible.” ®