Threat description




Zhelatin.KC is a bot that communicates via Overnet P2P protocol and is mainly used to send spam. It has rootkit functionalities that hide its presence in the infected system.


Automatic action

Depending on the settings of your F-Secure security product, it will either automatically delete, quarantine or rename the suspect file, or ask you for a desired action.

More scanning & removal options

More information on the scanning and removal options available in your F-Secure product can be found in the Help Center.

You may also refer to the Knowledge Base on the F-Secure Community site for more information.

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Technical Details

Zhelatin.KC does the following upon initial installation:

  • Disable Windows File Protection
  • Creates a copy called %WindowsDirectory%\spooldr.exe
  • Drop its rootkit component %SystemDirectory%\spooldr.sys
  • Infects %SystemDirectory%\dllcache\tcpip.sys
  • Exits current process

The other routines of the malware are continued after the infected system is rebooted.The following is how the malware is launched during system startups:

  • The infected tcpip.sys gets loaded by the OS
  • The infected tcpip.sys loads spooldr.sys
  • Spooldr.sys injects spooldr.exe to the explorer.exe process

Once loaded, spooldr.exe creates a file called spooldr.cfg which contains its initial list of peers in the current directory of the running process. Since it does not have its own process, it will take the current directory of explorer.exe instead. This usually leads to spooldr.cfg being created in the home directory of the current user. Additionally, Spooldr.sys hides all filenames that start with "spooldr" in the system, therefore you might not find the created files once the rootkit has been loaded.The malware then tries to communicate with the other peers via the Overnet P2P protocol on how to proceed.The malware has the ability to do the following:

  • Harvest email addresses but avoid those that contain certain strings
  • Download messages to be use in spam
  • Send spam emails

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