Researchers this week revealed that a major portion of the world's Internet traffic was redirected to China's primary telecommunications carrier for a period of about 20 minutes earlier this year.

"At 15:54 GMT on April 8, 2010, McAfee detected a routing announcement from China’s state-controlled telecommunications company, China Telecom, which advertised 15 percent of the world’s Internet routes," said researchers at security company McAfee in today's blog. "For at least the next 18 minutes -- up until China Telecom withdrew the announcement -- a significant portion of the world's Internet traffic was redirected through China to reach its final destination."

The redirected traffic included data from U.S. military and government networks, civilian organizations, and U.S. allies, such as South Korea, India and Australia, the blog states. Commercial companies were also affected.

"What happened to the redirected traffic during those 18 minutes? That's a great question, but no one except China Telecom operators is in a position to answer it," the blog states. "Emails, instant messages, and VoIP calls could have been intercepted and logged. Data could have also been changed as it was passing through the country as well. The possibilities are numerous and troubling, but definitive answers are unknown."

The incident is one of the biggest routing hijacks McAfee has ever seen, the blog states. "And it could happen again, since a number of major telecommunications companies routing a lot of Internet traffic have the same capability."

The incident is not classified as a cyberattack because websites were not hacked or shut down, McAfee says. In fact, most users probably didn't notice that anything happened at all.

McAfee said it has briefed various government officials during the past six months on this incident, but many were not alarmed, saying their Internet communications are encrypted. "However, encryption works on a basis of trust, and trust can be exploited," the blog says.

Most computer users don’t know that Microsoft, Apple, Google, and other software makers embed root certificates in their operating systems -- certificates that are also trusted to not be abused, the blog says. There are dozens of these certificates embedded on a typical computer configuration. Among the certificates is one from the China Internet Network Information Center, an arm of the Chinese Ministry of Information Industry.

"With the capability to intercept sensitive communications of companies using these trusted certificates embedded in their browsers and operating systems, the owner of the certificate can break by man-in-the-middling many secure SSL communication,s such as secure Web browsing, VPN, and instant messaging," McAfee says.

The incident took advantage of the vulnerabilities in the design of the Internet's fundamental building blocks --namely, its routing protocols – and those vulnerabilities that were present in April remain present today, McAfee says.

"Not only can this problem happen again, but it probably will," the blog says. "We have no way of knowing whether this event was done with malicious intent in mind, or was an accidental failure, as China Telecom operators have suggested. But it's clear that with this capability demonstrated publicly, sooner or later someone will use it for nefarious purposes."

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