ALIASES:

Trojan:Win32/Sisron (Microsoft); Trojan-FBQE!41988FE82B5A (McAfee); Trojan Horse (Symantec); Trojan-Ransom.Win32.Foreign.byat (Kaspersky); Trojan.Win32.Generic.pak!cobra (Sunbelt); Trojan horse PSW.Generic11.JLR (AVG)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This Trojan 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: 864,256 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 08 May 2013

Arrival Details

This Trojan 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 Trojan creates the following folders:

  • %User Profile%\Common Files

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
openv = "%User Profile%\Common Files\openv.exe"

Other System Modifications

This Trojan adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{50F16B26-467E-11D1-8271-00C04FC3183B}\Programmable

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{50F16B26-467E-11D1-8271-00C04FC3183B}\Control

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{50F16B26-467E-11D1-8271-00C04FC3183B}\Insertable

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
WBEM\WDM
%System%\advapi32.dll[MofResourceName] = "{random characters}"

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{50F16B26-467E-11D1-8271-00C04FC3183B}\InprocServer32
ThreadingModel = "Apartment"

(Note: The default value data of the said registry entry is Apartment.)

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{3F30C968-480A-4C6C-862D-EFC0897BB84B}\InprocServer32
ThreadingModel = "Apartment"

(Note: The default value data of the said registry entry is Apartment.)

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{9DBD2C50-62AD-11D0-B806-00C04FD706EC}\InprocServer32
ThreadingModel = "Apartment"

(Note: The default value data of the said registry entry is Apartment.)

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{EAB841A0-9550-11CF-8C16-00805F1408F3}\InprocServer32
ThreadingModel = "Apartment"

(Note: The default value data of the said registry entry is Apartment.)

It deletes the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{50F16B26-467E-11D1-8271-00C04FC3183B}\InprocServer32

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{50F16B26-467E-11D1-8271-00C04FC3183B}\MiscStatus\
1

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{50F16B26-467E-11D1-8271-00C04FC3183B}\MiscStatus

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{50F16B26-467E-11D1-8271-00C04FC3183B}\ProgID

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{50F16B26-467E-11D1-8271-00C04FC3183B}\ToolboxBitmap32

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{50F16B26-467E-11D1-8271-00C04FC3183B}\TypeLib

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{50F16B26-467E-11D1-8271-00C04FC3183B}\Version

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{50F16B26-467E-11D1-8271-00C04FC3183B}\VersionIndependentProgID

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{50F16B26-467E-11D1-8271-00C04FC3183B}

Dropping Routine

This Trojan drops the following files:

  • %User Temp%\TMP4352$.TMP
  • %User Temp%\RGI1.tmp

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

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 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\SOFTWARE\Classes\CLSID\{50F16B26-467E-11D1-8271-00C04FC3183B}
    • Programmable
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{50F16B26-467E-11D1-8271-00C04FC3183B}
    • Control
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{50F16B26-467E-11D1-8271-00C04FC3183B}
    • Insertable

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • openv = "%User Profile%\Common Files\openv.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WBEM\WDM
    • %System%\advapi32.dll[MofResourceName] = "{random characters}"

Step 5

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\Classes\CLSID\{50F16B26-467E-11D1-8271-00C04FC3183B}\InprocServer32
    • From: ThreadingModel = "Apartment"
      To: ThreadingModel = ""Apartment""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{3F30C968-480A-4C6C-862D-EFC0897BB84B}\InprocServer32
    • From: ThreadingModel = "Apartment"
      To: ThreadingModel = ""Apartment""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{9DBD2C50-62AD-11D0-B806-00C04FD706EC}\InprocServer32
    • From: ThreadingModel = "Apartment"
      To: ThreadingModel = ""Apartment""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{EAB841A0-9550-11CF-8C16-00805F1408F3}\InprocServer32
    • From: ThreadingModel = "Apartment"
      To: ThreadingModel = ""Apartment""

Step 6

Search and delete these components

[ Learn More ]
There may be some components 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.
  • %User Temp%\TMP4352$.TMP
  • %User Temp%\RGI1.tmp

Step 7

Search and delete this folder

[ 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%\Common Files

Step 8

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_VBKRYPT.BJI. 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 9

Restore these deleted registry keys/values 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\Classes\CLSID\{50F16B26-467E-11D1-8271-00C04FC3183B}
    • InprocServer32
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{50F16B26-467E-11D1-8271-00C04FC3183B}\MiscStatus
    • 1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{50F16B26-467E-11D1-8271-00C04FC3183B}
    • MiscStatus
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{50F16B26-467E-11D1-8271-00C04FC3183B}
    • ProgID
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{50F16B26-467E-11D1-8271-00C04FC3183B}
    • ToolboxBitmap32
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{50F16B26-467E-11D1-8271-00C04FC3183B}
    • TypeLib
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{50F16B26-467E-11D1-8271-00C04FC3183B}
    • Version
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{50F16B26-467E-11D1-8271-00C04FC3183B}
    • VersionIndependentProgID
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID
    • {50F16B26-467E-11D1-8271-00C04FC3183B}


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