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WORM_VB.JXA

October 08, 2012
 ALIASES:

Worm:Win32/VB.WJ (Microsoft), W32.SillyFDC (Symantec)

 PLATFORM:

Windows 2000, XP, Server 2003

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Copies itself in all available physical drives, Propagates via removable drives

This worm uses the default Windows folder icon to trick users into opening the file. Double-clicking the file executes this malware.

It modifies registry entries to hide files with System and Read-only attributes.

It drops copies of itself in all drives. These dropped copies use the names of the folders located on the said drives for their file names.

  TECHNICAL DETAILS

File Size:

135,168 bytes

File Type:

PE

Memory Resident:

Yes

Initial Samples Received Date:

28 Feb 2011

Payload:

Terminates processes

Installation

This worm drops the following copies of itself into the affected system:

  • %WINDOWS%\{random name_2}.exe

It drops the following copies of itself into the affected system:

  • %WINDOWS%\{random name_1}.exe

It uses the default Windows folder icon to trick users into opening the file. Double-clicking the file executes this malware.

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
@ = %Windows%\{random name_2}.exe

Other System Modifications

This worm adds the following registry entries:

HKEY_CLASSES_ROOT\exefile
NeverShowExt =

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
exefile
NeverShowExt =

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Netlogon\Parameters
DynamicSiteName = Default-First-Site-Name

It modifies the following registry entries:

HKEY_CLASSES_ROOT\exefile
@ =  File Folder

(Note: The default value data of the said registry entry is Application.)

HKEY_CLASSES_ROOT\exefile
TileInfo = prop:

(Note: The default value data of the said registry entry is prop:FileDescription;Company;FileVersion.)

HKEY_CLASSES_ROOT\exefile
InfoTip = prop:

(Note: The default value data of the said registry entry is prop:FileDescription;Company;FileVersion;Create;Size.)

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
exefile
@ =  File Folder

(Note: The default value data of the said registry entry is Application.)

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
exefile
TileInfo = prop:

(Note: The default value data of the said registry entry is prop:FileDescription;Company;FileVersion.)

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
exefile
InfoTip = prop:

(Note: The default value data of the said registry entry is prop:FileDescription;Company;FileVersion;Create;Size.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
HideFileExt = 1

(Note: The default value data of the said registry entry is 0.)

It modifies the following registry entries to hide files with System and Read-only attributes:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
ShowSuperHidden = 0

(Note: The default value data of the said registry entry is 1.)

It modifies the following registry entries to hide files with Hidden attributes:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = 0

(Note: The default value data of the said registry entry is 1.)

Propagation

This worm drops copies of itself in all drives. These dropped copies use the names of the folders located on the said drives for their file names.

Process Termination

This worm terminates the following processes if found running in the affected system's memory:

  • cmd.exe
  • taskmgr.exe

NOTES:
It then hides the original folders to trick users .

  SOLUTION

Minimum Scan Engine:

8.900

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Scan your computer with your Trend Micro product and note files detected as WORM_VB.JXA

Step 3

Terminate this process using Process Explorer

[ Learn More ]
If you still cannot terminate the malware/grayware process because it is not displayed in Process Explorer, please restart your computer in Safe Mode. You may refer to this page for details.DATA_GENERIC
  • Right-click on the said process then choose Properties.
  • Check if the value for the Current Directory is the following:
    DATA_GENERIC
  • If yes, right-click on the malware/grayware process again and choose Kill Process Tree.
  • Repeat steps 4 to 7 for the following processes:
    DATA_GENERIC
  • Close Process Explorer.

    • Step 4

    Delete this registry value

    [ Learn More ]

    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
      • @ = %Windows%\{random name_2}.exe
    • In HKEY_CLASSES_ROOT\exefile
      • NeverShowExt =
    • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\exefile
      • NeverShowExt =
    • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Netlogon\Parameters
      • DynamicSiteName = Default-First-Site-Name

    Step 5

    Restore this modified registry value

    [ Learn More ]

    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_CLASSES_ROOT\exefile
      • From: @ =  File Folder
        To: @ =  Application
    • In HKEY_CLASSES_ROOT\exefile
      • From: TileInfo = prop:
        To: TileInfo = prop:FileDescription;Company;FileVersion
    • In HKEY_CLASSES_ROOT\exefile
      • From: InfoTip = prop:
        To: InfoTip = prop:FileDescription;Company;FileVersion;Create;Size
    • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\exefile
      • From: @ =  File Folder
        To: @ =  Application
    • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\exefile
      • From: TileInfo = prop:
        To: TileInfo = prop:FileDescription;Company;FileVersion
    • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\exefile
      • From: InfoTip = prop:
        To: InfoTip = prop:FileDescription;Company;FileVersion;Create;Size
    • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
      • From: HideFileExt = 1
        To: HideFileExt = 0
    • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
      • From: ShowSuperHidden = 0
        To: ShowSuperHidden = 1
    • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
      • From: Hidden = 0
        To: Hidden = 1

    Step 6

    Scan your computer with your Trend Micro product to delete files detected as WORM_VB.JXA. 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.

    NOTES:

    Note:

    The files to terminate in Step 2 are the {Files noted earlier}.


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