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Date discovered:17/11/2010
In the wild:Yes
Reported Infections:Low to medium
Distribution Potential:Low to medium
Damage Potential:Low to medium
Static file:Yes
File size:1.262.592 Bytes
MD5 checksum:9f798355fdf4d0b5bd5711333da46c3d
VDF version:
IVDF version:

 General Method of propagation:
   • Autorun feature

   •  Mcafee: W32/YahLover.worm.gen
   •  Sophos: Troj/Agent-GXM
   •  Bitdefender: Trojan.Autoit.ALY
   •  Panda: Trj/Autoit.gen
   •  Eset: Win32/Sohanad.NFS

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

Side effects:
   • Drops malicious files
   • Registry modification

 Files It copies itself to the following locations:
   • %WINDIR%\regsvr.exe
   • %SYSDIR%\svchost .exe
   • %drive%\regsvr.exe
   • %SYSDIR%\regsvr.exe

The following files are created:

%drive%\Autorun.inf This is a non malicious text file with the following content:
   • %code that runs malware%


It tries to execute the following files:

– Filename:
   • %SYSDIR%\cmd.exe /C AT /delete /yes

– Filename:
   • AT /delete /yes

– Filename:
   • %SYSDIR%\cmd.exe /C AT 09:00 /interactive /EVERY:m,t,w,th,f,s,su %SYSDIR%\svchost .exe

– Filename:
   • AT 09:00 /interactive /EVERY:m,t,w,th,f,s,su %SYSDIR%\svchost .exe

 Registry The following registry key is added in order to run the process after reboot:

– [HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
   • "Msn Messsenger"="%SYSDIR%\regsvr.exe"

The following registry keys are added:

– [HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\System]
   • "DisableRegistryTools"=dword:0x00000001
   • "DisableTaskMgr"=dword:0x00000000

– [HKLM\SYSTEM\CurrentControlSet\Services\Schedule]
   • "AtTaskMaxHours"=dword:0x00000000

– [HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer]
   • "NofolderOptions"=dword:0x00000000

– [HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\
   • "shared"="\New Folder .exe"

The following registry key is changed:

– [HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon]
   New value:
   • "Shell"="Explorer.exe regsvr.exe"

 Miscellaneous Accesses internet resources:

 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 Monday, February 28, 2011
Description updated by Petre Galan on Monday, February 28, 2011

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