Updated More than two weeks after security researchers warned of a critical defect in the net's address lookup system, some of the world's biggest internet service providers - including AT&T, Time Warner and Bell Canada - have yet to install a patch inoculating their subscribers against attacks, according to an informal survey of Register readers.
In all more than a dozen ISPs failed the "Check my DNS" test (see button to the right) on the website of researcher Dan Kaminsky, who discovered the bug. Now that attack code exploiting the vulnerability has been leaked into the wild, millions of subscribers are at risk of being silently redirected to impostor sites that try to install malware or steal sensitive information. Comcast and Plusnet were the only two ISPs we found that weren't vulnerable.
The lack of action comes after Kaminsky, domain name resolution guru Paul Vixie and others have repeatedly warned that the vulnerability has the potential to wreak havoc on the net. Their advisories became more urgent following the leaking of the vulnerability details, which Kaminsky intended to keep private until next month's Black Hat conference in Las Vegas.
"It's obviously not a high enough priority in the minds of large companies yet," said Tom Parker, manager of security consulting at Mu Dynamics, a seller of security products. "It is concerning that there are lots of people out there that haven't done anything about it yet."
To be fair, installing the update that patches the vulnerability takes time at large organizations, said Danny McPherson, chief security officer at Arbor Networks, who previously worked at several ISPs. Getting approval to make big changes can take as long as a month, he says, and usually involves repeatedly testing new configurations and then rolling them out gradually throughout the system.
Even still, Parker said, for most organizations, the fix itself isn't much more complicated than running a software upgrade on a server. (The exception is organizations running version 8 of BIND; they will be forced to upgrade to version 9.)
Subscribers of ISPs that are still vulnerable ought to hardwire an alternate DNS server into their operating system. We're partial to OpenDNS. They've been vulnerability free since at least July 8, when Kaminsky announced the bug.
Other ISPs that were reported vulnerable include: Skybroadband, Carphone Warehouse Broadband, Opal Telecom, T-Mobile, Videotron Telecom, Roadrunner, Orange, Enventis Telecom, Earthlink, Griffin Internet and Jazztel.
Demon Internet was reported as potentially being vulnerable, because a Firewall or NAT in front of the DNS server "appears to be interfering with its port selection policy," according to Kaminsky's test. Readers reported getting the same result for BT and Virgin media, but representatives from both those companies assure us their users aren't exposed.
If we missed any, please leave a comment below, along with the IP address of the DNS server. ®
Our original story listed BT as one of the companies that was reported vulnerable. This was incorrect. As noted above, BT was only reported as being potentially vulnerable, and the company says it isn't. We apologize for the error.
Additionally, a representative from Skynet emailed to say the company has also installed patches. Keep in mind that many ISPs have multiple DNS servers, so results may vary.