Worm:W32/Agent.BTZ: Worms are computer programs that replicate independently by copying themselves to other systems.


Automatic action

Based on the settings of your F-Secure security product, it will either move the file to the quarantine where it cannot spread or cause harm, or remove it.

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Technical Details

Creates these files:

The files "winview.ocx" and "mswmpdat.tlb" holds the log of the files and their location that the malware has installed. The content of these file are encrypted. The file "muxbde40.dll" is the malware itself with a different name.

Spreading function

The worm spreads by creating an AUTORUN.INF file to the root of each drive with the malicious .dll file. The contents of the file are as follows:

shell\open\Command=rundll32.exe .\\[RANDOM].dll,InstallM

Note: [RANDOM] represents a random name that the worm creates for the dll. If the malware detects a new partition, or usb stick for example, it will get infected immediately. The registry keys are used to make sure that the malware gets launched when the computer starts.

File System Changes

Creates these files:

  • %windir%\system32\muxbde40.dll
  • %windir%\system32\winview.ocx
  • %temp%\6D73776D706461742E746C62FA.tmp
  • %windir%\system32\mswmpdat.tlb

Network Connections

Attempts to download files from:

  • https://worldnews.ath.cx/update/img0008/[REMOVED].jpg

Registry Modifications

Sets these values:

  • HKLM\Software\Classes\CLSID\{FBC38650-8B81-4BE2-B321-EEFF22D7DC62} (default) = Java.Runtime.52
  • HKLM\Software\Classes\CLSID\{FBC38650-8B81-4BE2-B321-EEFF22D7DC62}\InprocServer32\ (default) = C:\WINDOWS\system32\muxbde40.dll
  • HKLM\Software\Classes\CLSID\{FBC38650-8B81-4BE2-B321-EEFF22D7DC62}\InprocServer32\ ThreadingModel = Apartment
  • HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\ShellServiceObjectDelayLoad\ UpdateCheck = {FBC38650-8B81-4BE2-B321-EEFF22D7DC62}

Creates these keys:

  • HKLM\Software\Microsoft\Windows\CurrentVersion\StrtdCfg
  • HKLM\Software\Classes\CLSID\{FBC38650-8B81-4BE2-B321-EEFF22D7DC62}
  • HKLM\Software\Classes\CLSID\{FBC38650-8B81-4BE2-B321-EEFF22D7DC62}\InprocServer32\

Date Created: 2008-06-26 15:41:53.0

Date Last Modified: 2008-06-26 16:54:32.0