Windows Gets Privacy Boost For DNS

New public-domain 'VPN For DNS' technology encrypts exposed link between Windows machines and DNS
New open-source technology locks down the "last mile" traditionally exposed between a Windows computer and the Domain Name Service (DNS) provider, especially in public WiFi networks.

DNS provider OpenDNS today released a Windows version of its DNSCrypt tool for its customers, as well the open-source code for DNSCrypt. OpenDNS in December first rolled out DNSCrypt versions for the Macintosh and Linux operating systems.

Dan Hubbard, CTO of OpenDNS, says privacy and man-in-the-middle attack concerns are on the rise as users become more mobile. "Our technology takes one of the most important protocols and encrypts that," Hubbard says.

And not all applications for business users require a traditional VPN connection anymore, he says. "There are more things going to the cloud. You can do more of your work without having to VPN or tunnel back to the company," he says.

OpenDNS expects to see developers start deploying DNSCrypt, he says. Some open-source router manufacturers have been discussing adopting it, for example, Hubbard says.

Security expert Dan Kaminsky says OpenDNS's DNSCrypt technology is basically a way to VPN to your connection to the DNS. But it doesn't solve the problem of compromised certificate authorities or DNS cache poisoning, he notes. "It's neat and occasionally helpful, but it's not a fix for DigiNotar in any way. DNSCrypt does nothing to implement end-to-end trust," Kaminsky says. "It's a VPN for DNS traffic, not more than that, but not less." It protects users from man-in-the-middle and spoofing attacks at the DNS protocol specifically, but a determined attacker will likely try more than just an attack at the DNS level. "If an attacker is sitting in a coffee shop and snooping on traffic, there's probably way more interesting stuff than DNS traffic," says Bruce Van Nice, director of product marketing for Nominum. "That's a small part of the problem. If an attacker has the capability to snoop DNS, it seems he would want to capture a lot of other stuff, too."

DNSCrypt can work in concert with DNSSEC, which digitally signs DNS responses to ensure a website is who it says it is, for instance. DNSSEC also helps defend against cache-poisoning attacks.

[ Many companies do not scrutinize their domain-name service traffic, leaving an opening for malware to communicate using the protocol. See Malware To Increasingly Abuse DNS?. ]

OpenDNS's Hubbard says more than 10,000 users are running DNSCrypt just for the Mac, and mainly for open WiFi environments. It uses elliptical curve cryptography to encrypt the traffic between the user and DNS.

DNSCrypt has caught the attention of privacy advocates, too. "OpenDNS is addressing the serious issue of DNS query privacy -- this is an issue that many have otherwise overlooked or incorrectly dismissed as irrelevant. It is an important step forward in network privacy and it will improve the Internet," said security researcher Jacob Applebaum, who is one of the key members of the TOR Project, in a statement when DNSCrypt was first announced in December. "It is wonderful that OpenDNS has decided to build on a free software base and doing so with openly specified ideas is a solid foundation for a safer Internet."

The open-source Windows tool, as well as OpenDNS's commercial software for its customers, are available for download here.

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