Virus:Worm/Zimuse.A
Date discovered:25/01/2010
Type:Worm
In the wild:Yes
Reported Infections:Medium
Distribution Potential:Low to medium
Damage Potential:Medium to high
Static file:No
IVDF version:7.10.03.65 - Monday, January 25, 2010

 General Method of propagation:
• Autorun feature


Aliases:
   •  Symantec: W32.Zimuse
   •  Kaspersky: Virus.Win32.Mseus.a
   •  F-Secure: Dropped:Worm.Zimus.A
   •  Sophos: W32/Mseus-A
   •  VirusBuster: Worm.Mseus.A
   •  Eset: Win32/Zimuse.B
   •  Bitdefender: Worm.Zimuse.A


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


Side effects:
   • Drops malicious files
   • Registry modification


Right after execution it runs a windows application which will display the following window:


 Files It copies itself to the following location:
   • %SYSDIR%\tokset.dll



It deletes the following files:
   • C:\NTDETECT.COM
   • C:\NTLDR
   • C:\BOOTMGR
   • C:\HYBERFILE.SYS
   • C:\BOOT.INI



The following files are created:

– Non malicious file:
   • c:\IQTEST\Iqtest.exe

– c:\IQTEST\Readme.txt This is a non malicious text file with the following content:
   • Iqtest is configured. To start of IQ test, run IQTEST.EXE in this folder.

– %drive%\ainf.inf This is a non malicious text file with the following content:
   • [autorun]
     shellexecute=zipsetup.exe /H

– %WINDIR%\system32 \DRIVERS\Mstart.sys Further investigation pointed out that this file is malware, too. Detected as: Worm/Zimuse.A.4

– %SYSDIR%\DRIVERS\Mseu.sys Further investigation pointed out that this file is malware, too. Detected as: Worm/Zimuse.A.1

– %SYSDIR%\msues.exe Further investigation pointed out that this file is malware, too. Detected as: Worm/Zimuse.A.2

 Registry The following registry keys are added in order to run the processes after reboot:

– [HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
   • Dump="%PROGRAM FILES%\Dump\Dump.exe"

– [HKLM\SYSTEM\ControlSet001\Services\Eventlog\System\MSTART]
   • EventMessageFile=%SystemRoot%\System32\Drivers\MSTART.SYS;%WINDIR%\MSTART.SYS
   • TypesSupported=dword:7

 File details Programming language:
 The malware program was written in MS Visual C++.


Runtime packer:
In order to aggravate detection and reduce size of the file it is packed with the following runtime packer:
   • PE Compact

Description inserted by Thomas Wegele on Tuesday, January 26, 2010
Description updated by Thomas Wegele on Tuesday, January 26, 2010

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