Apple AirPort Can Be Grounded with IP Header Hole

Attackers can exploit Apple's AirPort Extreme wireless routers using the IPv6 protocol.

Attackers can nail Apples AirPort Extreme wireless routers thanks to—yet again—the way the IPv6 protocol handles Type 0 routing headers.

Its long been known these routing headers can be used in IPv4 to crazily bounce network packets back and forth between hops on their route, potentially causing denial of service. The fact that they can be exploited in exactly the same way in the "next-generation" Internet protocol—IPv6—means that developers just never learned their lesson, security people have long said.

It looks like Apple developers finally learned their lesson with AirPort. The company on Aug. 29 released Firmware version 7.2.1 for AirPort Extreme 802.11n base stations.

Attackers can craft IPv6 packets that can slash network bandwidth—i.e., cause denial of service—according to an advisory from Apple Security. Apples updating its router firmware by disabling support for Type 0 routing headers but says that the weakness isnt resident in the Gigabit Ethernet version of AirPort Extreme Base Station with 802.11n, which is based on an IEEE 802.11n draft spec.

eWEEK spoke about this same problem with two security researchers back in May at the CanSecWest security conference. At that time, EADS Corporate Research Center Research Engineers Philippe Biondi and Arnaud Ebalard showed that when you can specify where your nodes route packets, you can create a loop—for example, from hop A to hop B to hop A to hop B—that exponentially jacks up Internet traffic, thus causing a DDoS. The problem isnt new, but exploiting it has more payoff in IPv6, given that you can put in more packet hops.


Click here to read how Apple fixed a bug in the Apple Airport wireless router.

The ability of users to route their own packets—a procedure optimized automatically in todays IPv4 Internet—allows not only DDoS attacks, but also the ability to bypass security. The well-known security issue has long since been removed from IPv4; by default, all routing engines now turn it off.

This vulnerability is easy to fix with RH-sensitive filters, but back in May security researchers told eWEEK that nasty surprises still lie in wait for developers as the Internet shifts to a new protocol version that hasnt had its wrinkles ironed out over a decade, as has IPv4.

"Its just one example of how in moving from IPv4 to IPv6 people havent learned their lesson. Theyve created the same problem" that was fixed long ago, said Nicolas Fischbach, senior manager of network engineering security at Colt Telecom Group, in Zurich, Switzerland, at the time.

Bob Hinden, chairman of the IPv6 working group at Internet Engineering Task Force, said in May that nobody was losing time in fixing the IPv6 hole. "The implementer community is rapidly enabling fixes and the standards body is rapidly trying to change it so it cant be used in a bad way," Hinden said at the time.

Whether Apple fixed it "rapidly" is up to interpretation. Back in June it put out an update to Mac OS X—Version 10.4.10—that supposedly sealed the Type 0 routing header hole in the operating system.

For more info, check out Apples AirPort Extreme site.

Apple also plans to post info on its Security Updates site.

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