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Category: Malware

Type: Email-Worm

Aliases: Packed.Win32.Tibs.ab


Packed.Win32.Tibs.ab has rootkit functionality and it mass mails itself. This malware uses peer to peer networks (P2P) to spread. It also has the same functionality with Worm Zhelatin variants.


Automatic action

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

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Technical Details

Files that are detected as Packed.Win32.Tibs.ab has similar functionality withEmail-Worm.Win32.Zhelatin variants. On execution, the following are the changes made to the system:

File System Changes

Creates these files:

  • %windir%\system32\windev-[random_numbers].sys
  • %windir%\system32\windev-peers.ini

Registry Modifications

Sets these values:

  • HKLM\System\CurrentControlSet\Services\windev-[random_numbers] ImagePath = %systemdir%\windev-[random_numbers].sys

**NOTE: Usually %systemdir% is C:\Windows\system32

Stealth Features

Hides these files:

  • %windir%\system32\windev-peers.ini
  • %windir%\system32\windev-[random_numbers].sys

The installed component has rootkit functionality that can enable its process to be hidden from unsuspecting users.

A text file is also dropped which contains a possible lists of clients for the worm's peer-to-peer network. The details for the peer names and access ports are encoded. Example of the text file:


Another noticeable characteristic for this malware is that it tries to connect to a lot of predefined IP addresses using UDP.Furthermore, the files that are detected as Packed.Win32.Tibs.ab are usually downloaded from clicking links from heavily spammed emails such as those that we detect as HTML/Postcards.N@troj.