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 drops copies of itself in all removable drives. It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.
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 drops the following copies of itself into the affected system:
- %User Profile%\{random filename}.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.)
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 filename} = %User Profile%\{random filename}.exe
Other System Modifications
This worm 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 copies of itself in all removable drives.
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:
{garbage characters}
[autorun]
ICoN={random filename}.ico
{garbage characters}
open={random filename}.ExE
{garbage characters}
uSeAUtOpLAY=1
{garbage characters}
NOTES:
This malware drops .LNK files in removable drives that point to a copy of itself. This is done to automatically execute dropped copies when the said drives are accessed. These .LNK files use the following file names:
- Documents.lnk
- Music.lnk
- New Folder.lnk
- Passwords.lnk
- Pictures.lnk
- Video.lnk
It also uses the names of existing folders and names of files with the following extensions:
- .avi
- .bmp
- .doc
- .gif
- .jpe
- .jpg
- .mp3
- .mp4
- .mpg
- .pdf
- .png
- .tif
- .txt
- .wav
- .wma
- .wmv
- .xls
This routine enables the copy of the worm to execute first before opening the real folder or file. It then changes the attributes of the original folders and files to Hidden and System to avoid early detection. It also adds the following non-malicious files in removable drives:
- {random filename}.ico
- x.mpeg
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.SMKV
Step 3
Restart in Safe Mode
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To restart in Safe Mode:
• For Windows 2000 users
- Restart your computer.
- Press F8 when you see the Starting Windows bar at the bottom of the screen.
- Choose the Safe Mode option from the Windows Advanced Options menu then press Enter.
• For Windows XP users
- Restart your computer.
- Press F8 after the Power-On Self Test (POST) routine is done. If the Windows Advanced Options menu does not appear, try restarting then pressing F8 several times when the POST screen appears.
- Choose the Safe Mode option from the Windows Advanced Options menu then press Enter.
• For Windows Server 2003 users
- Restart your computer.
- Press F8 after Windows starts up. If the Windows Advanced Options menu does not appear, try restarting again and pressing F8 several times afterward.
- On the Windows Advanced Option menu, use the arrow keys to select Safe Mode then press Enter.
• For Windows Vista and Windows 7 users
- Restart your computer.
- Press F8 after the Power-On Self Test (POST) routine is done. If the Advanced Boot Options menu does not appear, try restarting and then pressing F8 several times after the POST screen is displayed.
- On the Advanced Boot Options menu, use the arrow keys to select the Safe Mode option, and then press Enter.
Step 4
Delete this registry value
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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 filename} = %User Profile%\{random filename}.exe
To delete the registry value this malware created:
- Open Registry Editor. To do this, click Start>Run, type regedit in the text box provided, then press Enter.
- In the left panel of the Registry Editor window, double-click the following:
HKEY_CURRENT_USER>Software>Microsoft>Windows>CurrentVersion>Run - In the right panel, locate and delete the entry:
{random filename} = %User Profile%\{random filename}.exe - Close Registry Editor.
Step 5
Restore this modified registry value
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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: 1
To restore the registry value this malware/grayware modified:
- Open Registry Editor. Click Start>Run, type REGEDIT in the text box provided, and then press Enter.
- In the left panel, double-click the following:
HKEY_CURRENT_USER>Software>Microsoft>Windows>CurrentVersion>Explorer>Advanced - In the right panel, locate the registry value:
ShowSuperHidden = 0 - Right-click on the value name and choose Modify. Change the value data of this entry to:
ShowSuperHidden = 1 - Close Registry Editor.
Step 6
Search and delete AUTORUN.INF files created by WORM_VOBFUS.SMKV that contain these strings
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{garbage characters}
[autorun]
ICoN={random filename}.ico
{garbage characters}
open={random filename}.ExE
{garbage characters}
uSeAUtOpLAY=1
{garbage characters}
To identify and delete AUTORUN.INF files created:
- Right-click the Start button then choose Search... or Find..., depending on the version of Windows you are running.
- In the Named input box, type:
AUTORUN.INF - In the Look in: drop-down list, select a drive, then press Enter.
- Select the file, then open using Notepad.
- Check if the following lines are present in the file:
{garbage characters}
[autorun]
ICoN={random filename}.ico
{garbage characters}
open={random filename}.ExE
{garbage characters}
uSeAUtOpLAY=1
{garbage characters}
- If the lines are present, delete the file.
- Repeat steps 3 to 6 for the remaining AUTORUN.INF files in other remaining removable drives.
- Close Search Results.
Step 7
Search and delete this file
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There may be some files that are hidden. Please make sure you check the
Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.
Documents.lnk
Music.lnk
New Folder.lnk
Passwords.lnk
Pictures.lnk
Video.lnk
{random filename}.ico
x.mpeg
To manually delete a malware/grayware file from an affected system:
• For Windows 2000, Windows XP, and Windows Server 2003:
- Right-click Start then click Search....
- In the left panel, click All Files.
- In the Named input box, type the following:
Documents.lnk
Music.lnk
New Folder.lnk
Passwords.lnk
Pictures.lnk
Video.lnk
{random filename}.ico
x.mpeg
- In the Look In drop-down list, select My Computer then press Enter.
- Once located, select the file then press SHIFT+DELETE to delete it.
• For Windows Vista and Windows 7 users:
- Click Start>Computer.
- In the Search input box, type the following:
Documents.lnk
Music.lnk
New Folder.lnk
Passwords.lnk
Pictures.lnk
Video.lnk
{random filename}.ico
x.mpeg
- 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.
Step 8
Scan your computer with your Trend Micro product to delete files detected as WORM_VOBFUS.SMKV. 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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