Researchers unleash DNS attack code

HD Moore unveils two exploits for Dan Kaminsky's critical Internet routing bug

Just days after details of a critical bug in the Domain Name System (DNS) software went public, researchers released attack code that can silently redirect users to unintended sites.

HD Moore, the creator of the Metasploit penetration testing framework, and a hacker who goes by the alias "I)ruid," published the attack code in two parts Wednesday and Thursday to several security mailing lists and to the Computer Academic Underground Web site.

The two exploits do essentially the same thing, said Andrew Storms, director of security operations at nCircle Network Security; both poison a DNS server's cache, and therefore can, at least temporarily, replace the legitimate addresses in that cache with bogus destinations. Users steering to what they believe are valid sites could, if they pull the routing information from a victimized DNS server, be sent instead to a fake site such as a phony banking site, where they could be easily duped into divulging confidential information.

Wednesday's exploit, explained Storms, lets an attacker poison a DNS server's cache with a single malicious entry, but Thursday's attack code allows a hacker to poison large quantities of domains with one fell swoop. "This second exploit has the potential for a much larger impact," said Storms, "and could result in potentially thousands of fake addresses inserted into a DNS server's cache.

HD Moore, however, noted that the single entry exploit of Tuesday gives attackers more anonymity, while Thursday's exploit requires hackers to have a real DNS server. "That means they'll be less anonymous," Moore said, adding that it would be possible to trace the DNS requests back to the fake server operated by the attacker, then have it taken offline by, for instance, the host provider.

"Both [kinds of attacks] will be difficult to detect," Storm said. "It will probably take an end user to raise the flag when they go to their banking site, for example, and then report, 'Hey, this just doesn't look quite right.'" Digging through the enormous amount of data generated by a DNS server -- hundreds of thousands of results in an hour at a company like nCircle, said Storms -- is simply impossible.

The DNS cache poisoning bug exploited by Moore's and I)ruid's attack code was first announced earlier this month by Dan Kaminsky, director of penetration testing at US-based IOActive. The bug, which Kaminsky uncovered earlier this year, was patched that same day by several major vendors, including Cisco Systems, Internet Systems Consortium and Microsoft.

Although Kaminsky declined to publicly disclose technical information, he briefed several fellow security researchers after he was criticized for overstating the seriousness of the threat. Those researchers recanted, and said Kaminsky's research was on target.

Monday, however, a German hacker went public with his guesses about the bug's details. His speculation was confirmed later in the day by Matasano Security, a consultancy that included at least one researcher who had been briefed on the bug by Kaminsky.

Join the newsletter!

Or

Sign up to gain exclusive access to email subscriptions, event invitations, competitions, giveaways, and much more.

Membership is free, and your security and privacy remain protected. View our privacy policy before signing up.

Error: Please check your email address.
Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

Gregg Keizer

Computerworld
Show Comments

Brand Post

Most Popular Reviews

Latest Articles

Resources

PCW Evaluation Team

Luke Hill

MSI GT75 TITAN

I need power and lots of it. As a Front End Web developer anything less just won’t cut it which is why the MSI GT75 is an outstanding laptop for me. It’s a sleek and futuristic looking, high quality, beast that has a touch of sci-fi flare about it.

Emily Tyson

MSI GE63 Raider

If you’re looking to invest in your next work horse laptop for work or home use, you can’t go wrong with the MSI GE63.

Laura Johnston

MSI GS65 Stealth Thin

If you can afford the price tag, it is well worth the money. It out performs any other laptop I have tried for gaming, and the transportable design and incredible display also make it ideal for work.

Andrew Teoh

Brother MFC-L9570CDW Multifunction Printer

Touch screen visibility and operation was great and easy to navigate. Each menu and sub-menu was in an understandable order and category

Louise Coady

Brother MFC-L9570CDW Multifunction Printer

The printer was convenient, produced clear and vibrant images and was very easy to use

Edwina Hargreaves

WD My Cloud Home

I would recommend this device for families and small businesses who want one safe place to store all their important digital content and a way to easily share it with friends, family, business partners, or customers.

Featured Content

Product Launch Showcase

Latest Jobs

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?