WORM_VOBFUS.DCQ
Troj/VB-GOM (Sophos), a variant of Win32/VBObfus.FY trojan (ESET)
Windows 2000, Windows XP, Windows Server 2003
Threat Type: Worm
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
Downloaded from the Internet, Dropped by other malware, Propagates via flashdrives, Propagates via shared drives, Propagates via network shares
This worm arrives by connecting affected removable drives to a system. 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 drops copies of itself into network drives. It drops copies of itself in removable drives. These dropped copies use the names of the folders located on the said drives for their file names. It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.
It executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system. As of this writing, the said sites are inaccessible.
It terminates itself if it detects it is being run in a virtual environment.
TECHNICAL DETAILS
268,800 bytes
EXE
Yes
22 May 2013
Connects to URLs/IPs, Downloads files
Arrival Details
This worm arrives by connecting affected removable drives to a system.
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 drops the following copies of itself into the affected system:
- %User Profile%\{random file name}.exe
- %User Profile%\Passwords.exe
- %User Profile%\Porn.exe
- %User Profile%\Secret.exe
- %User Profile%\Sexy.exe
(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.)
It drops the following files:
- {drive letter}:\x.mpeg
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
{random file name} = "%User Profile%\{random file name}.exe /{random character}"
Other System Modifications
This worm adds the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows\WindowsUpdate\
AU
NoAutoUpdate = "1"
It modifies the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
ShowSuperHidden = "0"
(Note: The default value data of the said registry entry is 1.)
Propagation
This worm drops the following copy of itself in all physical and removable drives:
- {drive letter}:\{random file name}.exe
- {drive letter}:\Passwords.exe
- {drive letter}:\Porn.exe
- {drive letter}:\Secret.exe
- {drive letter}:\Sexy.exe
It drops copies of itself into network drives.
It drops copies of itself in removable drives. These dropped copies use the names of the folders located on the said drives for their file names.
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={random file name}.exe
icon={random file name}.exe,0
or
{garbage characters}
[autorun]
{garbage characters}
open={random}.eXE
{garbage characters}
ACTION={random number}
UseautopLAY=1
{garbage characters}
Download Routine
This worm accesses the following websites to download files:
- {BLOCKED}1.{BLOCKED}e{random number}.{domain}
It then executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.
As of this writing, the said sites are inaccessible.
Other Details
This worm terminates itself if it detects it is being run in a virtual environment.
It terminates itself if any of the following file(s) are present:
- sbiedll.dll (Sandboxie component)
- snxhk.dll (AVAST component)
NOTES:
Where {domain} can be any of the following:
- .com
- .net
- .org
- .biz
- .info
It queries the HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Disk\Enum registry key for the following registry data strings to check if it is running in a virtual environment.
- VIRTUAL
- VMWARE
- VBOX
- QEMU
It uses the file names of of files with the following extensions:
- mp3
- avi
- wma
- wmv
- wav
- mpg
- mp4
- doc
- txt
- xls
- jpg
- jpe
- bmp
- gif
- tif
- png
It then sets the attribute of the original folders in the removable drives to Hidden and System to trick users into thinking that the dropped copies are the legitimate folders.
The copies dropped in mapped network drives uses the same file names as the ones used in the removable drives.
SOLUTION
9.300
9.932.10
21 May 2013
9.933.00
22 May 2013
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
Scan your computer with your Trend Micro product and note files detected as WORM_VOBFUS.DCQ
Step 3
Restart in Safe Mode
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
- {random file name} = "%User Profile%\{random file name}.exe /{random character}"
- {random file name} = "%User Profile%\{random file name}.exe /{random character}"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate\AU
- NoAutoUpdate = "1"
- NoAutoUpdate = "1"
Step 5
Restore this modified 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\Explorer\Advanced
- From: ShowSuperHidden = "0"
To: ShowSuperHidden = 1
- From: ShowSuperHidden = "0"
Step 6
Search and delete AUTORUN.INF files created by WORM_VOBFUS.DCQ that contain these strings
open={random file name}.exe
icon={random file name}.exe,0
or
{garbage characters}
[autorun]
{garbage characters}
open={random}.eXE
{garbage characters}
ACTION={random number}
UseautopLAY=1
{garbage characters}
Step 7
Search and delete these files
- {drive letter}:\x.mpeg
Step 8
Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_VOBFUS.DCQ. 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
Search and delete this file
• For Windows Vista and Windows 7 users:
- Click Start>Computer.
- In the Search input box, type the following:
DATA_GENERIC - Once located, select the file then press SHIFT+DELETE to delete it.
*Note: Read the following Microsoft page if these steps do not work on Windows 7.
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