WORM_RONTOKBR.BU
Worm:Win32/Brontok.FF (Microsoft); W32/Rontokbro.gen@MM (McAfee); W32.HLLO.A (Symantec); Email-Worm.Win32.Brontok.ai (Kaspersky); Worm.Win32.Brontok.kk (v) (Sunbelt); Worm/VB.FHU (AVG)
Windows 2000, Windows XP, Windows Server 2003
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
127,488 bytes
EXE
Yes
10 Oct 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.
Installation
This worm creates the following folders:
- %Windows%\Shell
(Note: %Windows% is the Windows folder, which is usually C:\Windows.)
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
Wilbert = "%Application Data%\Wilbert.exe"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
smss = "%Windows%\Shell\explorer.exe"
It modifies the following registry entries to ensure it automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Shell = "Explorer.exe %Windows%\Shell\iexplorer.exe"
(Note: The default value data of the said registry entry is Explorer.exe.)
Other System Modifications
This worm modifies the following file(s):
- %System%\msvbvm60.dll
(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)
It adds the following registry keys:
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\NOD32krn
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet002\
Services\NOD32krn
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Norman ZANDA
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Norman NJeeves
It adds the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
ShowSuperHidden = "0"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\NOD32krn
Start = "4"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet002\
Services\NOD32krn
Start = "4"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Norman ZANDA
Start = "4"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Norman NJeeves
Start = "4"
It modifies the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
HideFileExt = "1"
(Note: The default value data of the said registry entry is 1.)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = "2"
(Note: The default value data of the said registry entry is 2.)
Dropping Routine
This worm drops the following files:
- %Windows%\Shell\msvbvm60.dll
- %Application Data%\msvbvm60.dll
(Note: %Windows% is the Windows folder, which is usually C:\Windows.. %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)
This report is generated via an automated analysis system.
SOLUTION
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
Identify and delete files detected as WORM_RONTOKBR.BU using either the Startup Disk or Recovery Console
Step 3
Delete this registry key
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\ControlSet001\Services
- NOD32krn
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet002\Services
- NOD32krn
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services
- Norman ZANDA
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services
- Norman NJeeves
Step 4
Delete this registry value
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
- Wilbert = "%Application Data%\Wilbert.exe"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- smss = "%Windows%\Shell\explorer.exe"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- ShowSuperHidden = "0"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\NOD32krn
- Start = "4"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet002\Services\NOD32krn
- Start = "4"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Norman ZANDA
- Start = "4"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Norman NJeeves
- Start = "4"
Step 5
Restore these modified registry values
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\Windows\CurrentVersion\Explorer\Advanced
- From: HideFileExt = "1"
To: HideFileExt = ""1""
- From: HideFileExt = "1"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- From: Hidden = "2"
To: Hidden = ""2""
- From: Hidden = "2"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
- From: Shell = "Explorer.exe %Windows%\Shell\iexplorer.exe"
To: Shell = ""Explorer.exe""
- From: Shell = "Explorer.exe %Windows%\Shell\iexplorer.exe"
Step 6
Search and delete these components
- %Windows%\Shell\msvbvm60.dll
- %Application Data%\msvbvm60.dll
Step 7
Search and delete this folder
- %Windows%\Shell
Step 8
Scan your computer with your Trend Micro product to delete files detected as WORM_RONTOKBR.BU. 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 deleted/modified files and/or registry entries from backup
*Note: Only Microsoft-related files/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.
- %System%\msvbvm60.dll
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