arrow_back
search
close

WORM_VOBFUS.SMAE

October 08, 2013
 ALIASES:

Worm:Win32/Vobfus.gen!H (Microsoft); Downloader-CJX.gen.v (McAfee); W32.Changeup!gen11 (Symantec); Worm.Win32.WBNA.cm, Worm.Win32.WBNA.cm (Kaspersky); Trojan.Win32.Vobfus.gen (v) (Sunbelt); Trojan:W32/Injector.F (FSecure)

 PLATFORM:

Windows 2000, Windows, XP, Windows Server 2003

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW


This worm arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

  TECHNICAL DETAILS

File Size:

253,952 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

04 Nov 2011

Arrival Details

This worm arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Autostart Technique

This worm adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
yaituex = "%User Profile%\yaituex.exe /w"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
yaituex = "%User Profile%\yaituex.exe /t"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
yaituex = "%User Profile%\yaituex.exe /G"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
yaituex = "%User Profile%\yaituex.exe /l"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
yaituex = "%User Profile%\yaituex.exe /X"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
yaituex = "%User Profile%\yaituex.exe /S"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
yaituex = "%User Profile%\yaituex.exe /o"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
yaituex = "%User Profile%\yaituex.exe /L"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
yaituex = "%User Profile%\yaituex.exe /f"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
yaituex = "%User Profile%\yaituex.exe /z"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
yaituex = "%User Profile%\yaituex.exe /p"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
yaituex = "%User Profile%\yaituex.exe /s"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
yaituex = "%User Profile%\yaituex.exe /c"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
yaituex = "%User Profile%\yaituex.exe /K"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
yaituex = "%User Profile%\yaituex.exe /j"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
yaituex = "%User Profile%\yaituex.exe /E"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
yaituex = "%User Profile%\yaituex.exe /g"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
yaituex = "%User Profile%\yaituex.exe /F"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
yaituex = "%User Profile%\yaituex.exe /Z"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
yaituex = "%User Profile%\yaituex.exe /A"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
yaituex = "%User Profile%\yaituex.exe /W"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
yaituex = "%User Profile%\yaituex.exe /D"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
yaituex = "%User Profile%\yaituex.exe /T"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
yaituex = "%User Profile%\yaituex.exe /k"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
yaituex = "%User Profile%\yaituex.exe /v"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
yaituex = "%User Profile%\yaituex.exe /J"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
yaituex = "%User Profile%\yaituex.exe /C"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
yaituex = "%User Profile%\yaituex.exe /Y"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
yaituex = "%User Profile%\yaituex.exe /q"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
yaituex = "%User Profile%\yaituex.exe /I"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
yaituex = "%User Profile%\yaituex.exe /x"

Other System Modifications

This worm modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
WBEM\WDM
%System%\advapi32.dll[MofResourceName] = "LowDateTime:-878345984,HighDateTime:29653303***Binary mof compiled successfully"

(Note: The default value data of the said registry entry is LowDateTime:-1618731008,HighDateTime:29653597***Binary mof compiled successfully.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
WBEM\WDM
%System%\DRIVERS\ACPI.sys[ACPIMOFResource] = "LowDateTime:-1893836544,HighDateTime:29653288***Binary mof compiled successfully"

(Note: The default value data of the said registry entry is LowDateTime:-1618731008,HighDateTime:29653597***Binary mof compiled successfully.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
WBEM\WDM
%System%\DRIVERS\mssmbios.sys[MofResource] = "LowDateTime:246686720,HighDateTime:29653305***Binary mof compiled successfully"

(Note: The default value data of the said registry entry is LowDateTime:-1618731008,HighDateTime:29653597***Binary mof compiled successfully.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
WBEM\WDM
%System%\DRIVERS\intelppm.sys[PROCESSORWMI] = "LowDateTime:1716098048,HighDateTime:29653287***Binary mof compiled successfully"

(Note: The default value data of the said registry entry is LowDateTime:-1618731008,HighDateTime:29653597***Binary mof compiled successfully.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
WBEM\WDM
%System%\DRIVERS\ipnat.sys[IPNATMofResource] = "LowDateTime:741130752,HighDateTime:29653288***Binary mof compiled successfully"

(Note: The default value data of the said registry entry is LowDateTime:-1618731008,HighDateTime:29653597***Binary mof compiled successfully.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
WBEM\WDM
%System%\Drivers\HTTP.sys[UlMofResource] = "LowDateTime:-2038869248,HighDateTime:29653287***Binary mof compiled successfully"

(Note: The default value data of the said registry entry is LowDateTime:-1618731008,HighDateTime:29653597***Binary mof compiled successfully.)

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.200

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Restart in Safe Mode

[ Learn More ]

Step 3

Delete this registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • yaituex="%User Profile%\yaituex.exe /w"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • yaituex="%User Profile%\yaituex.exe /t"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • yaituex="%User Profile%\yaituex.exe /G"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • yaituex="%User Profile%\yaituex.exe /l"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • yaituex="%User Profile%\yaituex.exe /X"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • yaituex="%User Profile%\yaituex.exe /S"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • yaituex="%User Profile%\yaituex.exe /o"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • yaituex="%User Profile%\yaituex.exe /L"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • yaituex="%User Profile%\yaituex.exe /f"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • yaituex="%User Profile%\yaituex.exe /z"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • yaituex="%User Profile%\yaituex.exe /p"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • yaituex="%User Profile%\yaituex.exe /s"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • yaituex="%User Profile%\yaituex.exe /c"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • yaituex="%User Profile%\yaituex.exe /K"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • yaituex="%User Profile%\yaituex.exe /j"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • yaituex="%User Profile%\yaituex.exe /E"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • yaituex="%User Profile%\yaituex.exe /g"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • yaituex="%User Profile%\yaituex.exe /F"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • yaituex="%User Profile%\yaituex.exe /Z"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • yaituex="%User Profile%\yaituex.exe /A"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • yaituex="%User Profile%\yaituex.exe /W"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • yaituex="%User Profile%\yaituex.exe /D"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • yaituex="%User Profile%\yaituex.exe /T"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • yaituex="%User Profile%\yaituex.exe /k"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • yaituex="%User Profile%\yaituex.exe /v"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • yaituex="%User Profile%\yaituex.exe /J"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • yaituex="%User Profile%\yaituex.exe /C"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • yaituex="%User Profile%\yaituex.exe /Y"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • yaituex="%User Profile%\yaituex.exe /q"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • yaituex="%User Profile%\yaituex.exe /I"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • yaituex="%User Profile%\yaituex.exe /x"

Step 4

Restore these modified registry values

[ Learn More ]

Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WBEM\WDM
    • From: %System%\advapi32.dll[MofResourceName]="LowDateTime:-878345984,HighDateTime:29653303***Binary mof compiled successfully"
      To: %System%\advapi32.dll[MofResourceName]=LowDateTime:-1618731008,HighDateTime:29653597***Binary mof compiled successfully
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WBEM\WDM
    • From: %System%\DRIVERS\ACPI.sys[ACPIMOFResource]="LowDateTime:-1893836544,HighDateTime:29653288***Binary mof compiled successfully"
      To: %System%\DRIVERS\ACPI.sys[ACPIMOFResource]=LowDateTime:-1618731008,HighDateTime:29653597***Binary mof compiled successfully
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WBEM\WDM
    • From: %System%\DRIVERS\mssmbios.sys[MofResource]="LowDateTime:246686720,HighDateTime:29653305***Binary mof compiled successfully"
      To: %System%\DRIVERS\mssmbios.sys[MofResource]=LowDateTime:-1618731008,HighDateTime:29653597***Binary mof compiled successfully
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WBEM\WDM
    • From: %System%\DRIVERS\intelppm.sys[PROCESSORWMI]="LowDateTime:1716098048,HighDateTime:29653287***Binary mof compiled successfully"
      To: %System%\DRIVERS\intelppm.sys[PROCESSORWMI]=LowDateTime:-1618731008,HighDateTime:29653597***Binary mof compiled successfully
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WBEM\WDM
    • From: %System%\DRIVERS\ipnat.sys[IPNATMofResource]="LowDateTime:741130752,HighDateTime:29653288***Binary mof compiled successfully"
      To: %System%\DRIVERS\ipnat.sys[IPNATMofResource]=LowDateTime:-1618731008,HighDateTime:29653597***Binary mof compiled successfully
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WBEM\WDM
    • From: %System%\Drivers\HTTP.sys[UlMofResource]="LowDateTime:-2038869248,HighDateTime:29653287***Binary mof compiled successfully"
      To: %System%\Drivers\HTTP.sys[UlMofResource]=LowDateTime:-1618731008,HighDateTime:29653597***Binary mof compiled successfully

Step 5

Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_VOBFUS.SMAE. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.


Did this description help? Tell us how we did.