Paper: Prosecting the Citadel botnet - revealing the dominance of the Zeus descendent: part two

Posted by   Virus Bulletin on   Sep 11, 2014

Aditya K. Sood and Rohit Bansal study the malware's behaviour when ran on a physical machine.

Last week, we published the first part of the paper 'Prosecting the Citadel botnet - revealing the dominance of the Zeus descendent'. In it, researchers Aditya K. Sood and Rohit Bansal looked at the design and implementation of the infamous Citadel botnet, as well as the admin panel used by Citadel's botheders.

Today, we publish the second part of the paper. In it, Aditya and Rohit analyse a new sample of the malware. Obtaining suh as sample wasn't trivial, as the malware targets only certain countries and regions and they had to try various VPN servers in different locations before they were successful.

Then they allowed the malware to install, initially in a virtual environment. However, this failed: rather than connecting to the real command and control server, Citadel made various bogus DNS requests in an attempt to confuse researchers. This behaviour is common in today's malware; we wrote about it in much detail a few weeks ago, when we previewed James Wyke's VB2014 paper.

  Bogus DNS traffic sent when the botnet detects it is running inside a virtual environment.

Although far more cumbersome, there is always the option to run the malware on a physical machine. Once they had done that, the researchers were able to capture the traffic the malware made to its C&C server to download the configuration file, after first making sure it was allowed to do so.

In a move which is not uncommon for modern malware, Citadel contains a separate dropper that removes itself once the actual malware is installed. The malware creates an entry in the registry to maintain persistence following reboots. It performs API hooking to conduct its primary function: man-in-the-browser attacks to steal and alter HTTP requests and responses.

The paper concludes with a signature for the Snort IDS, that should help administrators detect Citadel infections on their network, based on the C&C traffic.

The second part of the paper can be viewed here, while a PDF of the full paper can be downloaded here.

Posted on 11 September 2014 by Martijn Grooten

twitter.png
fb.png
linkedin.png
googleplus.png
reddit.png

 

Latest posts:

We are more ready for IPv6 email than we may think

Though IPv6 is gradually replacing IPv4 on the Internet's network layer, email is lagging behind, the difficulty in blocking spam sent over IPv6 cited as a reason not to move. But would we really have such a hard time blocking spam sent over IPv6?

Subtle change could see a reduction in installation of malicious Chrome extensions

Google has made a subtle change to its Chrome browser, banning the inline installation of new extensions, thus making it harder for malware authors to trick users into unwittingly installing malicious extensions.

Paper: EternalBlue: a prominent threat actor of 2017–2018

We publish a paper by researchers from Quick Heal Security Labs in India, who study the EternalBlue and DoublePulsar exploits in full detail.

'North Korea' a hot subject among VB2018 talks

Several VB2018 papers deal explicitly or implicitly with threats that have been attributed to North Korean actors.

Expired domain led to SpamCannibal's blacklist eating the whole world

The domain of the little-used SpamCannibal DNS blacklist had expired, resulting in it effectively listing every single IP address.

We have placed cookies on your device in order to improve the functionality of this site, as outlined in our cookies policy. However, you may delete and block all cookies from this site and your use of the site will be unaffected. By continuing to browse this site, you are agreeing to Virus Bulletin's use of data as outlined in our privacy policy.