DNS software hole allows Web attacks

The flaw in two widely used versions of BIND (Berkeley Internet Name Domain), distributed free by the Internet Software Consortium (ISC), could be exploited immediately by unscrupulous programmers if they can write a program to take advantage of it, said Jim Magdych, security research manager at the Computer Vulnerability Emergency Response Team (COVERT) at PGP Security, a Network Associates business. Developing this might take only a few days, he said.

COVERT and ISC, along with Carnegie-Mellon University's Computer Emergency Response Team (CERT) Coordination Centre, will shortly announce a fix for the vulnerability and plan by that time to have the fix available on ISC's Web page, http://www.isc.org/. The flaw was discovered a few weeks ago, Magdych said.

"If this just showed up in the wild, it could have a pretty serious impact on the Internet at large," Magdych said.

The vulnerability exists in versions 4 and 8 of BIND, the software used in "the vast majority" of DNS servers, though not in the recently released version 9, Magdych said.

DNS servers translate the commands used to access Internet resources, such as Web URLs (Universal Resource Locators) and e-mail addresses, into numbered IP (Internet Protocol) addresses. The TSig (Transaction Signatures) vulnerability lets hackers take control of DNS servers and command them to redirect or block Internet requests sent to them.

A TSig attack could have effects similar to those of the denial-of-service attacks that kept users from reaching Microsoft Web sites last week, or even more serious effects, Magdych said. For example, hackers could take over a financial Web site, re-create the site's login screen, and direct user names and passwords to a server where they could be stolen.

Skilled hackers who break in to corporate DNS servers could block or redirect e-mail and even sabotage access to corporate databases over Internet-based company intranets.

"This is probably the most significant vulnerability to date in BIND," he said. "It's really important that everyone who's affected by this either applies the patch or upgrades to BIND 9."

All hackers will need to do is write a program that sends certain messages as requests to DNS servers. The messages would be interpreted as commands that would open up the server to exploitation.

Although the vulnerability is a subtle one, there are hackers who could act on it quickly if made aware of it, Magdych said.

"When a new vulnerability is discovered, it's just a matter of time before someone develops a program to exploit that vulnerability. Those exploits are then distributed by the community of crackers," or unscrupulous hackers, Magdych said.

"It's certainly not going to be something that takes months. Among our adversaries there are some very talented individuals," he said.

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.

Stephen Lawson

PC World
Show Comments

Cool Tech

Toys for Boys

Family Friendly

Stocking Stuffer

SmartLens - Clip on Phone Camera Lens Set of 3

Learn more >

Christmas Gift Guide

Click for more ›

Brand Post

Most Popular Reviews

Latest Articles

Resources

PCW Evaluation Team

Aysha Strobbe

Microsoft Office 365/HP Spectre x360

Microsoft Office continues to make a student’s life that little bit easier by offering reliable, easy to use, time-saving functionality, while continuing to develop new features that further enhance what is already a formidable collection of applications

Michael Hargreaves

Microsoft Office 365/Dell XPS 15 2-in-1

I’d recommend a Dell XPS 15 2-in-1 and the new Windows 10 to anyone who needs to get serious work done (before you kick back on your couch with your favourite Netflix show.)

Maryellen Rose George

Brother PT-P750W

It’s useful for office tasks as well as pragmatic labelling of equipment and storage – just don’t get too excited and label everything in sight!

Cathy Giles

Brother MFC-L8900CDW

The Brother MFC-L8900CDW is an absolute stand out. I struggle to fault it.

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.

Featured Content

Product Launch Showcase

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?