ALIASES:

Worm:Win32/Vobfus.gen!O (Microsoft); VBObfus.ca (McAfee); Trojan.Win32.Jorik.Vobfus.kao, Trojan.Win32.Jorik.Vobfus.kao (Kaspersky); Trojan.Win32.Generic!BT (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: 327,680 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 27 Jun 2013

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
kuwis = "%User Profile%\kuwis.exe /B"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
kuwis = "%User Profile%\kuwis.exe /Q"

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
kuwis = "%User Profile%\kuwis.exe /N"

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Other System Modifications

This worm adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
ShowSuperHidden = "0"

Other Details

This worm connects to the following possibly malicious URL:

  • http://17143.{BLOCKED}s.eu:443/LO?a

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine: 9.300

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
    • kuwis = "%User Profile%\kuwis.exe /B"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /Q"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /j"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /O"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /Y"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /n"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /o"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /A"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /F"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /x"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /U"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /i"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /M"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /d"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /D"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /p"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /k"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /u"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /g"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /c"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /y"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /f"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /m"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /q"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /z"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /h"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /X"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /T"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /v"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /E"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /N"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /a"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /Z"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /P"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /J"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /e"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /S"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /t"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /G"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /s"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /W"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /R"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /C"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /V"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /H"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /K"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /l"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /w"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /L"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /I"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • kuwis = "%User Profile%\kuwis.exe /r"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • ShowSuperHidden = "0"

Step 4

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


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