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WORM_VB.SMGF

October 12, 2012
 ALIASES:

Worm:Win32/Vobfus.gen!N (Microsoft); VBObfus.bc (McAfee); W32.Changeup (Symantec); Worm.Win32.VBNA.ayut (Kaspersky); Trojan.Win32.Generic.pak!cobra (Sunbelt)

 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:

344,064 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.

Installation

This worm creates the following folders:

  • %User Profile%\Application Data
  • %User Profile%\Application Data\D0939
  • %Program Files%\LP
  • %Program Files%\LP\F02D
  • %User Profile%\Microsoft\Dr Watson

(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.. %Program Files% is the default Program Files folder, usually C:\Program Files.)

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
siizuo = "%User Profile%\siizuo.exe /f"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
siizuo = "%User Profile%\siizuo.exe /O"

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

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
siizuo = "%User Profile%\siizuo.exe /r"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
siizuo = "%User Profile%\siizuo.exe /y"

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
siizuo = "%User Profile%\siizuo.exe /b"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
siizuo = "%User Profile%\siizuo.exe /V"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
siizuo = "%User Profile%\siizuo.exe /U"

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
siizuo = "%User Profile%\siizuo.exe /h"

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

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
siizuo = "%User Profile%\siizuo.exe /n"

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

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
siizuo = "%User Profile%\siizuo.exe /H"

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

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
siizuo = "%User Profile%\siizuo.exe /P"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
siizuo = "%User Profile%\siizuo.exe /a"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
siizuo = "%User Profile%\siizuo.exe /M"

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

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

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

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

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

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
siizuo = "%User Profile%\siizuo.exe /m"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
siizuo = "%User Profile%\siizuo.exe /B"

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
siizuo = "%User Profile%\siizuo.exe /R"

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
siizuo = "%User Profile%\siizuo.exe /u"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
siizuo = "%User Profile%\siizuo.exe /e"

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

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

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

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
siizuo = "%User Profile%\siizuo.exe /i"

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

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

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
siizuo = "%User Profile%\siizuo.exe /d"

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
DFF.exe = "%Program Files%\LP\F02D\DFF.exe"

It registers as a system service to ensure its automatic execution at every system startup by adding the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\.i8042prt

Other System Modifications

This worm deletes the following files:

  • %User Profile%\bghost.exe
  • %User Profile%\wevtapi.dll
  • %User Profile%\taskmgr.exe

(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)

It adds the following registry keys:

HKEY_LOCAL_MACHINE\Software\Classes\
Interface\{5171463b-76a3-9033-2274-75c8f0a0edb6}

HKEY_CURRENT_USER\Software\WinRAR

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{5171463b-76a3-9033-2274-75c8f0a0edb6}
u = "3343553"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\.i8042prt
Type = "1"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\.i8042prt
Start = "3"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\.i8042prt
ImagePath = "\*"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\wscsvc
Start = "3"

HKEY_CURRENT_USER\Software\WinRAR
HWID = "{random values}"

HKEY_CURRENT_USER\Software\WinRAR
Client Hash = "{random values}"

It deletes the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
PCHealth\ErrorReporting\DW

Dropping Routine

This worm drops the following files:

  • U
  • L
  • 2387fd88\L\suianxvn
  • %Program Files%\LP\F02D\1.tmp
  • %Program Files%\LP\F02D\DFF.exe
  • %User Profile%\tmp.html

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files.. %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)

Other Details

This worm connects to the following possibly malicious URL:

  • http://baloons.{BLOCKED}d.to:30309/a

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.200

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Restart in Safe Mode

[ Learn More ]

Step 3

Delete this registry key

[ 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_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services
    • .i8042prt
  • In HKEY_LOCAL_MACHINE\Software\Classes\Interface
    • {5171463b-76a3-9033-2274-75c8f0a0edb6}
  • In HKEY_CURRENT_USER\Software
    • WinRAR

Step 4

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
    • siizuo = "%User Profile%\siizuo.exe /f"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /O"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /q"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /o"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /r"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /y"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /g"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /b"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /V"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /U"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /x"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /h"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /F"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /w"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /n"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /I"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /p"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /H"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /j"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /C"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /P"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /a"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /M"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /A"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /G"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /c"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /S"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /X"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /t"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /m"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /B"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /J"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /R"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /D"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /u"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /e"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /T"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /E"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /z"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /Z"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /i"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /k"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /L"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /Y"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /d"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • siizuo = "%User Profile%\siizuo.exe /v"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • DFF.exe = "%Program Files%\LP\F02D\DFF.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{5171463b-76a3-9033-2274-75c8f0a0edb6}
    • u = "3343553"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\.i8042prt
    • Type = "1"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\.i8042prt
    • Start = "3"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\.i8042prt
    • ImagePath = "\*"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\wscsvc
    • Start = "3"
  • In HKEY_CURRENT_USER\Software\WinRAR
    • HWID = "{random values}"
  • In HKEY_CURRENT_USER\Software\WinRAR
    • Client Hash = "{random values}"

Step 5

Search and delete these folders

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %User Profile%\Application Data
  • %User Profile%\Application Data\D0939
  • %Program Files%\LP
  • %Program Files%\LP\F02D
  • %User Profile%\Microsoft\Dr Watson

Step 6

Search and delete these files

[ Learn More ]
There may be some component files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.
  • U
  • L
  • 2387fd88\L\suianxvn
  • %Program Files%\LP\F02D\1.tmp
  • %Program Files%\LP\F02D\DFF.exe
  • %User Profile%\tmp.html

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_VB.SMGF. 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.

Step 8

Restore these deleted files from backup

*Note: Only Microsoft-related keys/values will be restored. If this malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.

  • %User Profile%\bghost.exe
  • %User Profile%\wevtapi.dll
  • %User Profile%\taskmgr.exe

Step 9

Restore this deleted registry key/value from backup

*Note: Only Microsoft-related keys/values will be restored. If the malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\PCHealth\ErrorReporting
    • DW


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