Oracle has released a free tool that shows how well Internet Exchange Points (IXPs) are doing at filtering out incorrect or malicious traffic-routing information that could lead to major Internet disruptions.
The goal is to help an IXP identify and address gaps in its route-filtering capabilities while providing the broader public with a view of the IXP's role in keeping the Internet safe. An IXP routes traffic between different ISP networks. It is a physical location containing numerous network switches that seamlessly link one service provider's network to another.
Oracle's new IXP Filter Check is part of a broad initiative called the Mutually Agreed Norms for Routing Security (MANRS), which is designed to bolster Internet routing security.
In recent years, Internet routing mistakes — of the accidental and malicious variety — have caused major problems. Last year, for instance, traffic bound for Google got misdirected via an ISP in China, causing intermittent disruptions to the company's search and other services for over an hour. Earlier this year, traffic belonging to major Cloudflare customers ended up getting routed via the network of a small company in Pennsylvania. The misdirection caused many websites on Cloudflare and numerous other service providers to become unavailable to large sections of the Internet for about two hours.
Such disruptions often have been caused by relatively minor configuration errors. Google's traffic, for instance, got misdirected because a small Nigerian ISP accidentally "announced" the wrong routing information for several Google IPs. China Telecom — one of the Nigerian's ISP's network "peers" — accepted the wrong routing information and propagated it widely across the Internet.
In Cloudflare's case, the misdirection resulted from an ISP in Pennsylvania making more or less the same mistake and then Verizon forwarding the wrong routing information to the rest of the Internet. As Cloudflare put it at the time: "This was the equivalent of Waze routing an entire freeway down a neighborhood street."
Not all routing errors are the result of innocent mistakes. In recent years, attackers have used redirection attacks to divert traffic for malicious purposes, including surveillance, distributed denial-of-service attacks, and cryptocurrency mining.
Secure Internet Routing
The Internet Society's MANRS initiative is designed to address the fundamental weaknesses in the Internet's core routing infrastructure that have made such traffic misdirection almost catastrophically easy to make or to pull off. At a high level, it is aimed at ensuring that ISPs and IXPs have measures for quickly spotting and filtering out incorrect routing information — and, equally important, to prevent incorrect routes from being propagated across the Internet.
To be a member of the MANRS program, IXPs are required to filter all route announcements they receive using certain standards that are designed to ensure the legitimacy of routing messages. The goal is to ensure that any routing information that cannot be properly verified — such as its origin — is filtered out.
Oracle's IXP Filter Check is a monitoring service — currently in place at some 200 IXP locations — that basically verifies how well an IXP is doing at filtering out incorrect and malicious routes. "It is a free service that offers third-party review of the routes passed by the route server at an IXP," says Doug Madory, director of Internet analysis at Oracle. "The objective is to publicly report the invalid messages passed so as to help the IXP improve and also to report to the public how the IXP is doing."
The Oracle tool is not designed to help IXP filter route messages. Rather, the objective is to help IXP administrators monitor and analyze the effectiveness of their existing route filtering, Madory notes.
IXP Filter Check uses a filtering mechanism similar to what an IXP would be expected to use as a member of the MANRS initiative. The Oracle tool runs the same checks on routing information that the IXP's filtering mechanisms would, such as ensuring routing messages have proper origin information and prefix lengths.
"If they are correctly filtering invalid routes, then we shouldn't see them," Madory says. "If we do and report it in the tool, then that means the route server admin should go review the filtering [in place]."
According to Madory, IXP Filter Check is the first tool to offer a live and independent analysis of the behavior of route servers at IXPs around the world. He estimates approximately 1,000 entities currently label themselves as IXPs, though many are relatively small or operated by a single telecom.
"The war against insecure routing won't be won by a single technology," Madory notes. But it can be improved over time with measures such as route filtering, he says.
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