Misdirected Internet Traffic: A Security HeadacheMisdirected Internet Traffic: A Security Headache

Enterprises should be proactive in tracing routes taken by their Internet traffic; the results could be alarming.

Do you know how your traffic travels over the Internet? It may be passing through other countries, and you can't tell that this is happening. The implications are that someone may be spying on your traffic or even altering content before traffic reaches the correct destination.

This became apparent when I read a blog post by Jim Cowie of Renesys , titled "The New Threat: Targeted Internet Traffic Misdirection." The article opened my eyes to what may be occurring when Internet traffic is maliciously re-routed before it reaches the intended destination. Renesys learned of these situations while monitoring traffic for their customers.

What is Happening?
Jim's blog mentions that organizations in at least 150 cities in the U.S., Europe and parts of Asia have experienced one or more Man-in-the-Middle (MITM) attacks. A MITM attack can steal someone else's traffic, inspect it in a few milliseconds (thereby adding essentially undetectable latency to the connecting path) and even modify the content before delivery. This is different than a simple route attack where traffic may be delivered to another destination, because the traffic keeps flowing to the intended destination. This makes detection of the malicious behavior very difficult for the average enterprise network operator.

The Belarus and Iceland Connections
Jim's blog provided an example of a route trace from Guadalajara, Mexico to Washington, DC. The Mexican provider, Alestra, would normally hand it off to PCCW for relay through Laredo, TX. PCCW forwards it to the Washington, DC metro area, where they would normally hand it to Qwest/CenturyLink for delivery. Instead, because of false routes being advertised along the way, the traffic ended up being diverted through Belarus and Russia before finally reaching DC.

This behavior was stopped in May 2013, but a new attack location was then found to be passing traffic through Iceland. The 17 events of Icelandic diversion continued from July 31 to August 19, 2013. Both of these Belarus and Iceland situations were observed directly by Renesys staff using their trace tools.

Renesys observed about 1,500 individual IP blocks during their testing period. Some lasted minutes while others lasted days, and the attacks were generated in multiple countries.

The Implications
First of all, these forms of attacks should not happen. Part of the problem is that some service providers wind up allowing the misrouting of traffic. The average Internet administrator in the enterprise may never discover the traffic rerouting. The ease of creating this rerouting condition is probably occurring because no one is looking specifically for this problem.

The most likely victims of this behavior are financial institutions like banks and card processing companies. Governments are also candidates. Knowing the imaginations of attackers, I expect that most organizations using the Internet will be vulnerable to this malicious traffic re-routing.

MITM was originally a theoretical concern, but it is now a reality. A big part of the problem is that many Internet routes are NOT signed and secured by the ISPs. One ISP accepts the routing information from another ISP without verification, assuming it is correct and legal.

This presents a problem because the enterprise cannot do anything about the routing tables. So it is up to the enterprise to check and trace the routes to see if the routing information has been compromised. If malicious activity is discovered, then the enterprise needs to alert their ISP of the situation. Since this may not be a high priority for ISPs, enterprises should keep tracing the route and monitor for correction, as the fix may be delayed, or the offending ISPs will not or cannot readily resolve the problem.

What may be worse is that after the re-routing fix has been implemented, it could happen again. If it is not resolved quickly, enterprises can threaten the ISP with public disclosure or attempt to change or cancel their service agreement with the ISP because the rerouting has created a considerable security vulnerability.