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!

Error: Please check your email address.
Rocket to Success - Your 10 Tips for Smarter ERP System Selection
Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

Stephen Lawson

PC World
Show Comments


James Cook University - Master of Data Science Online Course

Learn more >


Victorinox Werks Professional Executive 17 Laptop Case

Learn more >



Back To Business Guide

Click for more ›

Brand Post

Most Popular Reviews

Latest Articles


PCW Evaluation Team

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.

Walid Mikhael

Brother QL-820NWB Professional Label Printer

It’s easy to set up, it’s compact and quiet when printing and to top if off, the print quality is excellent. This is hands down the best printer I’ve used for printing labels.

Ben Ramsden

Sharp PN-40TC1 Huddle Board

Brainstorming, innovation, problem solving, and negotiation have all become much more productive and valuable if people can easily collaborate in real time with minimal friction.

Sarah Ieroianni

Brother QL-820NWB Professional Label Printer

The print quality also does not disappoint, it’s clear, bold, doesn’t smudge and the text is perfectly sized.

Ratchada Dunn

Sharp PN-40TC1 Huddle Board

The Huddle Board’s built in program; Sharp Touch Viewing software allows us to easily manipulate and edit our documents (jpegs and PDFs) all at the same time on the dashboard.

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?