WORM_VB.BWX
Windows 2000, Windows XP, Windows Server 2003
Threat Type: Worm
Destructiveness: No
Encrypted: No
In the wild: Yes
OVERVIEW
This worm arrives by connecting affected removable drives to a system.
It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.
It opens a random port to allow a remote user to connect to the affected system. Once a successful connection is established, the remote user executes commands on the affected system.
It deletes itself after execution.
TECHNICAL DETAILS
Arrival Details
This worm arrives by connecting affected removable drives to a system.
Installation
This worm drops the following copies of itself into the affected system and executes them:
- %Program Files%\WindowsUpdate\WINLOGON.EXE
(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)
It drops the following files:
- %Program Files%\WindowsUpdate\time - non-malicious file
(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)
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\Policies\
Explorer\Run
IMJPMIG8.1 = "%Program Files%\WindowsUpdate\WINLOGON.EXE"
Propagation
This worm drops the following copy(ies) of itself in all removable drives:
- RECYCLER.EXE
It drops the following copy of itself in all physical and removable drives:
- System Volume Information{6 spaces}.EXE
It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.
The said .INF file contains the following strings:
[AutoRun]
open=RECYCLER.exe
shell\open\Command=RECYCLER.exe
shell\open\Default=1
Backdoor Routine
This worm opens a random port to allow a remote user to connect to the affected system. Once a successful connection is established, the remote user executes commands on the affected system.
Other Details
This worm deletes itself after execution.
NOTES:
Trend Micro detects the dropped AUTORUN.INF as MAL_OTORUN1.
SOLUTION
Step 1
Identify and terminate files detected as WORM_VB.BWX
- Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
- If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
- If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.
Step 3
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\Policies\Explorer\RunIMJPMIG8.1 = %Program Files%\WindowsUpdate\WINLOGON.EXE
Step 4
Search and delete this file
- %Program Files%\WindowsUpdate\time
Step 5
Search and delete AUTORUN.INF files created by WORM_VB.BWX that contain these strings
[AutoRun]
open=RECYCLER.exe
shell\open\Command=RECYCLER.exe
shell\open\Default=1
Step 6
Scan your computer with your Trend Micro product to delete files detected as WORM_VB.BWX. 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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