ALIASES:

Worm:Win32/VB.VX (Microsoft); W32/Rontokbro.gen@MM (McAfee); Trojan.Win32.Vilsel.bozg (Kaspersky); Mal/VB-F, Mal/VB-F, Mal/VB-F (Sophos); Trojan.Win32.Generic!BT (Sunbelt); Trojan horse VB.AUHN (AVG)

 PLATFORM:

Windows

 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.

It disables Task Manager, Registry Editor, and Folder Options.

  TECHNICAL DETAILS

File Size: 360,448 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 07 Mar 2015

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_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
gpmce = "\Angel2.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
gpmce = "\Angel2.exe"

Other System Modifications

This worm adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
system

HKEY_CURRENT_USER\Software\Policies\
Microsoft\Windows\System

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
DisableThumbnailCache = "1"

HKEY_CURRENT_USER\Software\Policies\
Microsoft\Windows\System
disableCMD = "2"

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
start page = "www.gpmce.net"

(Note: The default value data of the said registry entry is http://www.microsoft.com/isapi/redir.dll?prd=ie&pver=6&ar=msnhome.)

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
search page = "www.booble.com"

(Note: The default value data of the said registry entry is http://www.microsoft.com/isapi/redir.dll?prd=ie&ar=iesearch.)

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{20D04FE0-3AEA-1069-A2D8-08002B30309D}
LocalizedString = "@%SystemRoot%\system32\SHELL32.dll,-8964"

(Note: The default value data of the said registry entry is {random values}.)

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{645FF040-5081-101B-9F08-00AA002F954E}
LocalizedString = "@%SystemRoot%\system32\shell32.dll,-9216"

(Note: The default value data of the said registry entry is {random values}.)

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{645FF040-5081-101B-9F08-00AA002F954E}\DefaultIcon
empty = "%SystemRoot%\Explorer.exe,0"

(Note: The default value data of the said registry entry is {random values}.)

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{645FF040-5081-101B-9F08-00AA002F954E}\DefaultIcon
full = "%SystemRoot%\Explorer.exe,0"

(Note: The default value data of the said registry entry is {random values}.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = "1"

(Note: The default value data of the said registry entry is 2.)

It creates the following registry entry(ies) to disable Task Manager, Registry Tools and Folder Options:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
NoFolderOptions = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
system
DisableTaskMgr = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
system
DisableRegistryTools = "1"

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine: 9.700

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

Enable Registry Editor, Task Manager, and Folder options

[ Learn More ]
By doing this step, you also enable other applications/programs disabled by this malware/grayware/spyware.

Step 4

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies
    • system
  • In HKEY_CURRENT_USER\Software\Policies\Microsoft\Windows
    • System

Step 5

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
    • gpmce = "\Angel2.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • gpmce = "\Angel2.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • DisableThumbnailCache = "1"
  • In HKEY_CURRENT_USER\Software\Policies\Microsoft\Windows\System
    • disableCMD = "2"

Step 6

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_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
    • From: start page = "www.gpmce.net"
      To: start page = ""http://www.microsoft.com/isapi/redir.dll?prd=ie&pver=6&ar=msnhome""
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
    • From: search page = "www.booble.com"
      To: search page = ""http://www.microsoft.com/isapi/redir.dll?prd=ie&ar=iesearch""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{20D04FE0-3AEA-1069-A2D8-08002B30309D}
    • From: LocalizedString = "@%SystemRoot%\system32\SHELL32.dll,-8964"
      To: LocalizedString = ""{random values}""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{645FF040-5081-101B-9F08-00AA002F954E}
    • From: LocalizedString = "@%SystemRoot%\system32\shell32.dll,-9216"
      To: LocalizedString = ""{random values}""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{645FF040-5081-101B-9F08-00AA002F954E}\DefaultIcon
    • From: empty = "%SystemRoot%\Explorer.exe,0"
      To: empty = ""{random values}""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{645FF040-5081-101B-9F08-00AA002F954E}\DefaultIcon
    • From: full = "%SystemRoot%\Explorer.exe,0"
      To: full = ""{random values}""
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: Hidden = "1"
      To: Hidden = ""2""

Step 7

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