WORM_VB.GAW
W32.Heular (Symantec), W32/Huelar-A (Sophos), Worm:Win32/Brontok.FFT (Microsoft), Email-Worm.Win32.VB.fz (Kaspersky)
Windows
Threat Type: Worm
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This worm arrives via removable drives. It 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.
It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.
TECHNICAL DETAILS
Arrival Details
This worm arrives via removable drives.
It 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:
- {malware file name}
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
winlogos.exe = "%Windows%\winlogos.exe /s"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Huelar Services 2.0 = "%System%\huelar.exe"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Microsoft Service Host = "%User Startup%\mscvhost.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 huelar.exe"
(Note: The default value data of the said registry entry is Explorer.exe.)
Other System Modifications
This worm adds the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Window Title = "Huelar Browser"
HKEY_CURRENT_USER\Software\Policies\
Microsoft\Internet Explorer\Control Panel
Homepage = 1
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion
IeakHelpString = "I will always be with you, Huelar!"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer
NoDriveTypeAutoRun = 128
It modifies the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Start Page = "http://www.redtube.com"
(Note: The default value data of the said registry entry is {User defined homepage}.)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
HideFileExt = 1
(Note: The default value data of the said registry entry is 0.)
It creates the following registry entry(ies) to disable Task Manager, Registry Tools and Folder Options:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer
NoFolderOptions = 1
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableRegistryTools = 1
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableTaskMgr = 1
Propagation
This worm drops the following copy(ies) of itself in all removable drives:
- {removable drive letter}:\console.exe
- {removable drive letter}:\x64console.exe
It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.
Dropping Routine
This worm drops the following files:
- {removable drive letter}:\Autorun.inf
- {removable drive letter}:\Folder.htt
- {removable drive letter}:\desktop.ini
- %User Temp%\{random}.TMP
(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)
SOLUTION
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
Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.
Step 3
Enable Registry Editor, Task Manager, and Folder options
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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- winlogos.exe=%Windows%\winlogos.exe /s
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- Huelar Services 2.0=%System%\huelar.exe
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- Microsoft Service Host=%User Startup%\mscvhost.exe
- In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
- Window Title=Huelar Browser
- In HKEY_CURRENT_USER\Software\Policies\Microsoft\Internet Explorer\Control Panel
- Homepage=1
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion
- IeakHelpString=I will always be with you, Huelar!
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer
- NoDriveTypeAutoRun=128
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\Internet Explorer\Main
- From: Start Page=http://www.redtube.com
To: Start Page={User defined homepage}
- From: Start Page=http://www.redtube.com
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- From: HideFileExt=1
To: HideFileExt=0
- From: HideFileExt=1
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
- From: Shell=Explorer.exe huelar.exe
To: Shell=Explorer.exe
- From: Shell=Explorer.exe huelar.exe
Step 6
Search and delete these files
- {removable drive letter}:\Autorun.inf
- {removable drive letter}:\Folder.htt
- {removable drive letter}:\desktop.ini
- %User Temp%\{random}.TMP
- {removable drive letter}:\console.exe
- {removable drive letter}:\x64console.exe
Step 7
Search and delete this folder
Step 8
Scan your computer with your Trend Micro product to delete files detected as WORM_VB.GAW. 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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