Virus:TR/Assist.aor
Date discovered:20/11/2009
Type:Trojan
In the wild:Yes
Reported Infections:Low
Distribution Potential:Low
Damage Potential:Low
Static file:Yes
File size:53.248 Bytes
MD5 checksum:9effff1d92cf1edd113452efc159c035
IVDF version:7.10.01.41 - Friday, November 20, 2009

 General Aliases:
   •  Mcafee: W32/Koobface.worm.gen.d
   •  Panda: W32/Koobface.IW.worm
   •  Eset: Win32/Koobface.NCL
   •  Bitdefender: Worm.Generic.100650


Platforms / OS:
   • Windows 2000
   • Windows XP
   • Windows 2003


Side effects:
   • Downloads a malicious file
   • Drops malicious files
   • Registry modification

 Files It copies itself to the following location:
   • %WINDIR%\mstre23.exe



It deletes the initially executed copy of itself.



It deletes the following files:
   • C:\vx\sd.dat
   • %WINDIR%\dxxdv34567.bat
   • c:\3.reg



The following files are created:

– c:\3.reg This is a non malicious text file with the following content:
   • %code that runs malware%

– %malware execution directory%\sd.dat
– %WINDIR%\dxxdv34567.bat Furthermore it gets executed after it was fully created. This batch file is used to delete a file.
– %WINDIR%\mmsmark3.dat



It tries to download a file:

– The locations are the following:
   • http://www.electronicstoday.org/**********/?action=msgen&v=23
   • http://trip4x4.co.il/**********/?action=msgen&v=23
   • http://shyoow.co.il/**********/?action=msgen&v=23
   • http://iek-triandr.thess.sch.gr/**********/?action=msgen&v=23
   • http://www.electronicstoday.org/**********/?action=msgen&a=544453496&v=23
   • http://juanfurlan.com.ar/**********/?action=msgen&v=23
   • http://sigmai.co.il/**********/?action=msgen&v=23
   • http://cosmeticscenter.co.il/**********/?action=msgen&v=23

 Registry The following registry key is added:

– [HKCR\Mime\Database\Content Type\application/xhtml+xml]
   • "CLSID"="{25336920-03F9-11cf-8FD0-00AA00686F13}"
   • "Encoding"=hex:08,00,00,00
   • "Extension"=".xml"

 Miscellaneous  Checks for an internet connection by contacting the following web site:
   • http://www.google.com

 File details Runtime packer:
In order to aggravate detection and reduce size of the file it is packed with a runtime packer.

Description inserted by Petre Galan on Wednesday, March 17, 2010
Description updated by Petre Galan on Wednesday, March 17, 2010

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