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Date discovered:21/06/2011
In the wild:Yes
Reported Infections:Low to medium
Distribution Potential:Low
Damage Potential:Low to medium
Static file:Yes
File size:47.104 Bytes
MD5 checksum:45bcbb56dcfb68200719163a933c4f6c
VDF version:
IVDF version:

 General Aliases:
   •  Kaspersky: Backdoor.Win32.VB.nmc
   •  Bitdefender: Backdoor.Generic.634112
   •  GData: Backdoor.Generic.634112

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

Side effects:
   • Drops malicious files
   • Registry modification
   • Makes use of software vulnerability
      •  CVE-2007-1204
      •  MS07-019

 Files It copies itself to the following location:
   • %TEMPDIR%\2ubrc.exe

It overwrites a file.

It deletes the initially executed copy of itself.

It deletes the following file:
   • %TEMPDIR%\mdinstall.inf

The following files are created:


It tries to execute the following files:

– Filename:
   • net.exe stop "Security Center"

– Filename:
   • %TEMPDIR%\2ubrc.exe -d6D7EB75D9C5B904FF8096542E0A41712AD38B1C10062EB22D4B88EF8B3653850007C160B3A4688D69EEACE6196A82B03CF0C2AC2F853DD81734A54287906A3D186CF29860B03F61AB0F184C3B04B23291720C08CEA5BF2F278CA781072868600762191832C32843432F47B2C5B9877221BA6B380114A

– Filename:
   • "%SYSDIR%\grpconv.exe" -o

– Filename:
   • sc config wscsvc start= DISABLED

– Filename:
   • net.exe stop "Windows Firewall/Internet Connection Sharing (ICS)"

– Filename:
   • sc config SharedAccess start= DISABLED

– Filename:
   • net1 stop "Security Center"

– Filename:
   • %TEMPDIR%\2ubrc.exe

– Filename:
   • net1 stop "Windows Firewall/Internet Connection Sharing (ICS)"

– Filename:
   • Rundll32.exe setupapi,InstallHinfSection DefaultInstall 128 %TEMPDIR%\mdinstall.inf

– Filename:
   • cmd /c %TEMPDIR%\iaohblsg.bat

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

– [HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer\
   • "wa59"="%TEMPDIR%\2ubrc.exe"

The following registry key is added:

– [HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce]
   • "GrpConv"=""

The following registry keys are changed:

– [HKCU\Software\Microsoft\Windows\CurrentVersion\GrpConv]
   New value:
   • "Log"="Uninit Application."

– [HKLM\SOFTWARE\Classes\MSProgramGroup\Shell\Open\Command]
   New value:
   • "@"="%SYSDIR%\grpconv.exe %1"

– [HKLM\SOFTWARE\Classes\MSProgramGroup]
   New value:
   • "@"="Microsoft Program Group"

– [HKLM\SOFTWARE\Classes\.grp]
   New value:
   • "@"="MSProgramGroup"

 Hosts The host file is modified as explained:

– In this case existing entries are deleted.

– Access to the following domain is redirected to another destination:
   • localhost

 Backdoor Contact server:
The following:
   •**********?c=%character string%&v=%number%&t=%character string%

 Miscellaneous Mutex:
It creates the following Mutexes:
   • 2ubrc.exewa59dmode
   • 2ubrc.exewa59

 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, July 13, 2011
Description updated by Petre Galan on Wednesday, July 13, 2011

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