From RSA: Vulnerability could permit router control

Researcher Dan Kaminsky said he has discovered a browser vulnerability that potentially puts millions of users of wireless routers and other web-facing devices at risk to a domain name system (DNS) attack.

Kaminsky, in a presentation on Tuesday at the RSA Conference in San Francisco, told audience members that users running devices with default or easy-to-guess passwords are at risk to hackers gaining control of them.

The attack works by tricking users into visiting a malicious webpage that correctly guesses the username and password – then leverages JavaScript to let cybercrooks change the DNS configurations, enable remote management and download firmware updates, Kaminsky, director of penetration testing at IOActive, said.

He demonstrated the attack on a D-Link router, a widely deployed device in businesses. But the same technique works on other devices with web-facing interfaces, such as printers, Kaminsky said.

“I own the internet for you,” he said, describing what hackers will gain in a successful attack. “Every mail you send goes through me. Every website you go to goes through me. I am on your LAN.”

David Ulevitch, founder and chief executive officer of OpenDNS, said after the presentation that users can't apply traditional web filtering solutions because the attack uses a private IP address to take over a user's internet.

His company's solution filters responses from private IP addresses.

“Browsers really have no idea what they should be doing,” he said. “Most corporate networks allow DNS to pass through like a fire hose.”

Kaminsky stressed that the problem does not reside in the router. Instead, there is a policy vulnerability in the browser that makes it errantly trust these malicious IP addresses.

“It's the browser's job not to leak connectivity,” he said.

He suggested IT administrators attach new passwords to devices.

“If default passwords weren't so wildly popular, this would probably still be an issue but it wouldn't be the catastrophe that it is now,” said Kaminsky, who in 2005 discovered the Sony rootkit. "This problem isn't going away anytime soon."

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