Feeds

One in ten DNS servers still vulnerable to poisoning

1.3 million ticking time bombs

Website security in corporate America

Four months after researchers warned of a nasty design flaw in the net's address lookup system, more than 10 per cent of the servers used to resolve domain names on the internet remain "trivially vulnerable" to attack, a new study concludes.

That translates to about 1.3 million domain name system servers that still have not patched against the cache poisoning flaw discovered earlier this year, according to the report, commissioned by DNS hardware supplier Infoblox. Since early July, researcher Dan Kaminsky and a choir of other security experts have been imploring internet service providers, corporations, and large organizations to protect themselves against the flaw by patching programs such as BIND, which helps translate domain names into IP addresses.

"Assuming there are people out there using those name servers, they are in a very, very dangerous situation," said Cricket Liu, vice president of architecture at Infoblox and an author of several books concerning DNS. "This is a really, really serious attack."

The report found that an even larger percentage of the net's name servers - an estimated 44 percent - could be used by miscreants to launch devastating attacks on unwitting third parties. That's because the name servers are available to anyone on the internet rather than only to the members of the company or organization that operates them. In such attacks, perpetrators send so-called recursive DNS servers fraudulent queries that appear to come a victim's computer. The recursive DNS servers then overwhelm the target with more data than it can handle.

The results are part of Infoblox's fourth annual survey of DNS servers. It randomly selected 99.3 million IP addresses and name servers authoritative for 1 million .com and .net domain names. Researchers sent a simple DNS query to each probe address and - based on the result - estimated there are some 11.9 million name servers running on the internet.

The researchers estimated that there are 4.3 million open resolvers on the net that reply to a query. The vast majority of them, at 89 percent, were running version 9 of BIND. BIND 8, bboy MyDNS, and DJ Bernstein TinyDNS ranked second, third, and fourth respectively.

Of the 44 per cent of name servers found to be recursive, 25 per cent of those failed to properly randomize the source ports that send lookup information. As a result, they are vulnerable to Kaminsky's cache poisoning vulnerability. What's more, 30 per cent of DNS servers surveyed permitted zone transfers to arbitrary requesters, which also leaves machines open to denial-of-service attacks.

The patch Kaminsky and others fashioned after discovery of the cache poisoning flaw randomizes the ports DNS servers use to thwart attackers who flood machines with fraudulent results. Results that don't include the correct transaction ID and randomized port number are rejected. The fix is viewed as a temporary measure whose effectiveness will dilute over time.

Over the long term, security experts are looking to a technology known as DNSSec to solve the problem. That involves cryptographically signing the internet's DNS records to guard against forgeries. DNSSec was first proposed in 1999. It has undergone something of a renaissance since Kaminsky took his discovery public.

But so far, Infoblox has found little evidence of widespread use. Just 0.002 percent of DNS zones it tested supported the extensions.

"I had hoped we would see a spike in the adoption of DNSSec, but we really didn't see much of anything," Liu told El Reg. "It says that awareness of DNSSec is not that high, and the people who do know about DNSSec are probably afraid of it." ®

Protecting users from Firesheep and other Sidejacking attacks with SSL

More from The Register

next story
'Kim Kardashian snaps naked selfies with a BLACKBERRY'. *Twitterati gasps*
More alleged private, nude celeb pics appear online
Hackers pop Brazil newspaper to root home routers
Step One: try default passwords. Step Two: Repeat Step One until success
UK.gov lobs another fistful of change at SME infosec nightmares
Senior Lib Dem in 'trying to be relevant' shocker. It's only taxpayers' money, after all
Spies would need SUPER POWERS to tap undersea cables
Why mess with armoured 10kV cables when land-based, and legal, snoop tools are easier?
TOR users become FBI's No.1 hacking target after legal power grab
Be afeared, me hearties, these scoundrels be spying our signals
Snowden, Dotcom, throw bombs into NZ election campaign
Claim of tapped undersea cable refuted by Kiwi PM as Kim claims extradition plot
Freenode IRC users told to change passwords after securo-breach
Miscreants probably got in, you guys know the drill by now
THREE QUARTERS of Android mobes open to web page spy bug
Metasploit module gobbles KitKat SOP slop
BitTorrent's peer-to-peer chat app Bleep goes live as public alpha
A good day for privacy as invisble.im also reveals its approach to untraceable chats
prev story

Whitepapers

Secure remote control for conventional and virtual desktops
Balancing user privacy and privileged access, in accordance with compliance frameworks and legislation. Evaluating any potential remote control choice.
WIN a very cool portable ZX Spectrum
Win a one-off portable Spectrum built by legendary hardware hacker Ben Heck
Storage capacity and performance optimization at Mizuno USA
Mizuno USA turn to Tegile storage technology to solve both their SAN and backup issues.
High Performance for All
While HPC is not new, it has traditionally been seen as a specialist area – is it now geared up to meet more mainstream requirements?
The next step in data security
With recent increased privacy concerns and computers becoming more powerful, the chance of hackers being able to crack smaller-sized RSA keys increases.