Internet domain system wide open to fraudulent attack

A large number of DNS servers, a critical part of the Internet's infrastructure, are vulnerable to attacks that could lead to widespread fraud, according to a security researcher.

A scan conducted by Dan Kaminsky, a networking security expert, has found that hundreds of thousands of DNS servers could be vulnerable to a type of attack that routes Internet traffic to malicious websites.

The attack technique, known as DNS cache poisoning, came to public attention when attackers used it to redirect traffic from a large number of financial, entertainment, travel, health and software sites to attackers' servers in order to install malicious code.

Despite the danger, large numbers of servers are still configured in a way that allows the attack to take place, according to Kaminsky. In a scan of about 2.5 million DNS servers, he found that about a tenth, or 230,000, could be vulnerable.

Domain Name System (DNS) servers host a distributed database that allows the translation of domain names (e.g. name.com) to IP addresses. They also route e-mail by listing each domain's mail exchange server. In a cache poisoning attack, a DNS server is compromised so that a legitimate domain name resolves to the attacker's IP address, which can present the user with anything the attacker chooses.

Such techniques have been around for years, but the April incident demonstrated that they are not just theoretical. Nevertheless, many DNS servers have been left in the same vulnerable configurations that were exploited in April. DNS servers are run by all manner of organizations, including corporations and Internet service providers.

At least 230,000 of the servers scanned are configured to forward DNS requests to BIND8 DNS servers, according to Kaminsky. This was one of the vulnerabilities exploited in April, according to the SANS Institute, a security organization. Of those, 13,000 are Windows name servers forwarding to BIND8, making them exceptionally high-risk, Kaminsky said. Another 53,000 at least are very likely to be vulnerable, he said.

The Internet Software Consortium (ISC), which distributes the widely used BIND software, specifically states that BIND4 and BIND8 aren't suitable to act as targets for name server forwarders, because of the ongoing danger of DNS cache poisoning. "There is a current, wide scale Kashpureff-style DNS cache corruption attack which depends on BIND4 and BIND8 as 'forwarders' targets," ISC stated on its Web site. "Upgrade all nameservers used as 'forwarders' to BIND9."

Kaminsky said has only been able to scan a fraction of the existing name servers so far, which he estimated at nine million.

Kaminsky published some of his findings on the Web site of his firm, DoxPara Research, earlier this week. He presented the findings last week at the Black Hat security conference.

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.

Matthew Broersma

Techworld.com
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?