Feeds

Botnet agent plays lost sheep to avoid detection

The Kraken wakes

Website security in corporate America

The latest variants of Kraken have thrown up innovations in black hat stealth technology that are making botnets spawned by the malware harder to detect and dismantle.

Analysis of the source code of the new variant of the Kraken (AKA Bobax) bot by Australian anti-virus firm PC Tools has revealed a domain name generation algorithm designed to allow infected machines to search for possible control servers, rather than relying on a single server that can more easily be dismantled by security researchers.

In addition, compromised nodes speak to a control server using HTTP traffic instead of the more traditional approach of using IRC channels. IRC channel traffic is more obviously suspicious. Data sent between compromised machines and control servers is encrypted and features randomly generated headers in a bid to further disguise dodgy communications, PC Tools explains.

In order to evade host intrusion prevention systems, such as firewalls, the new variant of Kraken 'talks' to its control centres via HTTP (the 'language' that web browsers use to talk to websites), using pseudo-random dynamic DNS names, with a variable length from seven to 12 characters, followed with one of the domain suffixes: dyndns.org, yi.org, mooo.com, dynserv.com, com, cc or net. The commands and data that the bot exchanges with the control centres is encrypted and also uses randomly generated 'bogus' headers to stay hidden under the firewall radar.

Using this approach the Kraken bot calculates the likely coordinates of its control server, without knowing where it is. PC Tools likens the approach to a lost sheep trying to locate its shepherd.

PC Tools reckons the latest variants of Kraken were distributed via MSN Messenger. It uses a random word generating engine to vary the name of infectious files prospective marks are invited to open, a feature designed to confuse spam filters.

The Australian information security firm reports that it detected infections by the latest variant Kraken bot across the world over the last week or so. Further technical analysis of the malware, and its underpinning algorithms, can be found here.

Kraken rose to prominence amid reports earlier this month that it had outstripped the Storm botnet in the number of compromised PCs it controlled. Security researchers are split over whether the malware agent itself is new on the scene or not, as well as the strength of the zombie army it commands. ®

Protecting users from Firesheep and other Sidejacking attacks with SSL

More from The Register

next story
Home Depot: 56 million bank cards pwned by malware in our tills
That's about 50 per cent bigger than the Target tills mega-hack
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
Critical Adobe Reader and Acrobat patches FINALLY make it out
Eight vulns healed, including XSS and DoS paths
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
Blood-crazed Microsoft axes Trustworthy Computing Group
Security be not a dirty word, me Satya. But crevice, bigod...
Snowden, Dotcom, throw bombs into NZ election campaign
Claim of tapped undersea cable refuted by Kiwi PM as Kim claims extradition plot
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.