Boffins devise early-warning bot spotter

Conficker's Achilles Heel

Got Tips? 16 Reg comments

Researchers have devised a way to easily detect internet names generated by so-called domain-fluxing botnets, a method that could provide a first-alarm system of sorts that alerts admins of infections on their networks.

Botnets including Conficker, Kraken and Torpig use domain fluxing to make it harder for security researchers to disrupt command and control channels. Malware instructs infected machines to report to dozens, or even tens of thousands, of algorithmically generated domains each day to find out if new instructions or updates are available. The botnet operators need to own only a few of the addresses in order to stay in control of the zombies. White hats effectively must own all of them.

It's a clever architecture, but it has an Achilles Heel: The botnet-generated domain names – which include names such as joftvvtvmx.org, ejfjyd.mooo.com, and mnkzof.dyndns.org – exhibit tell-tale signs they were picked by an algorithm rather than a human being. By analyzing DNS, or domain name system, traffic on a network, the method can quickly pinpoint and disrupt infections.

“In this regards, our proposed methodology can point to the presence of bots within a network and the network administrator can disconnect bots from their C&C server by filtering out DNS queries to such algorithmically generated domain names,” the researchers wrote in a paper that was presented this week at the ACM Internet Measurement Conference in Australia.

The method uses techniques from signal detection theory and statistical learning to detect domain names generated from a variety of algorithms, including those based on pseudo-random strings, dictionary-based words, and words that are pronounceable but not in any dictionary. It has a 100-percent detection rate with no false positives when 500 domains are generated per top-level domain. When 50 domains are mapped to the same TLD, the 100-percent detection rate remains, but false positives jump to 15 percent.

The technique was developed by Sandeep Yadav, Ashwath K.K. Reddy, and A.L. Narasimha Reddy of Texas A&M's Electrical and Computer Engineering department, and Supranamaya Ranjan of Sunnyvale, California-based Narus. A PDF of their paper is here. ®

Sponsored: Webcast: Ransomware has gone nuclear

SUBSCRIBE TO OUR WEEKLY TECH NEWSLETTER


Keep Reading

What's inside the mystery box?

Linksys forces password reset for Smart Wi-Fi accounts after router DNS hack pointed users at COVID-19 malware

Firm blames successful cred-stuffing attack for customer pwnage
Three Canadians in an office discussing maple syrup reserves

Canada's .ca overlord rolls out free privacy-protecting DNS-over-HTTPS service for folks in Great White North

L’ACEI lance le Bouclier canadien dans le but de protéger gratuitement la vie privée et la sécurité des Canadiens en ligne
Hand emerges from wave - help

DNS this week stands for Drowning Needed Services: Design flaw in name server system can be exploited to flood machines offline

Microsoft, BIND, Google, Cloudflare, Amazon, others fix up software or offer workarounds
In memoriam

RIP Dyn Dynamic DNS :'( Oracle to end Dyn-asty by axing freshly gobbled services, shoving customers into its cloud

Meanwhile, staff face cuts – and doesnotexist.com may not exist by next year
Firefox logo

Firefox now defaults to DNS-over-HTTPS for US netizens and some are dischuffed about this

Good for privacy – or an alarming move towards further internet centralisation?
An illustration of two young people looking over a fence at the internet, with the word 'censored' on the fence

Cloudflare family-friendly DNS service flubs first filtering foray: Vital LGBTQ, sex-ed sites blocked 'by mistake'

Updated For a biz that prides itself on not censoring the internet, it sure likes censoring the internet
DNS

Cloudflare is over the moon because its pro-privacy 1.1.1.1 DNS service got a clean bill of health from everyone's favorite auditor – KPMG

Proved for all sites, proved for all sites, there is nothing else we can do
annoyed at receiving spam email

Baby, I swear it's déjà vu: TalkTalk customers unable to opt out of ISP's ad-jacking DNS – just like six years ago

Updated Have you tried turning it off and on again? Yes!

Biting the hand that feeds IT © 1998–2020