AT&T Facebook traffic takes a loop through China

Traffic destined for Facebook from AT&T’s servers took a strange loop though China and South Korea on Tuesday, according to a security researcher.

Barrett Lyon, who has worked for companies such as EveryDNS, did a traceroute—a command that allows a user to see which network providers were used to reach a desired Website—to Facebook while on AT&T’s network.

Lyon wrote on his blog that data from AT&T customers would usually go directly to Facebook’s network provider. But due to what Lyon characterized as a routing mistake, the traffic first went through China Telecom and then to SK Broadband in South Korea before routing to Facebook.

Routing errors are not uncommon on the part of network operators. In insignificant cases, it can allow traffic to take circuitous routes to destinations. But in the worst scenarios, it can mean Websites in certain IP ranges could be unreachable.

In 2008, Pakistan Telecom made an error with BGP (Border Gateway Protocol), which is used to configure routers used by network providers to exchange traffic. After Pakistan’s government ordered that ISPs block YouTube, Pakistan Telecom misconfigured BGP and made YouTube unreachable to users worldwide.

In this case, the concern outlined by Lyon is data safety: If Facebook users did not have encryption enabled, it would be possible for those network operators to see the data.

“What could have happened with your data?” Lyon wrote. “Most likely absolutely nothing. Yet China is well known for its harmful networking practices by limiting network functionality and spying on its users, and when your data is flowing over their network, your data could be treated as any Chinese citizens’.”

Information that could be harvested could include session ID information, personal information, e-mail, photos, chat conversations and an idea of who a person knows via their Facebook profile, Lyon wrote.

Facebook uses SSL (Secure Sockets Layer) encryption technology, indicated by “https” in the URL, when users log into the site.

If users do not specify that it should be used throughout their entire session, however, Facebook drops the more secure connection by changing their security preferences.

Neither Facebook nor AT&T were available for an immediate comment.

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