VBS_GOODWORM.NIL


 PLATFORM:

Windows

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

  • 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 drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

  TECHNICAL DETAILS

File Size:

38,177 bytes

File Type:

VBS

Memory Resident:

Yes

Initial Samples Received Date:

24 May 2013

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:

  • %System%\domz.vbs (modified copy)

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

It drops the following files:

  • {Drive Letter}:\domz_info.txt

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
domz = "Wscript.exe %System%\domz.vbs"

Other System Modifications

This Worm modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableTaskMgr = 0

(Note: The default value data of the said registry entry is {user defined}.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
NoRun = 0

(Note: The default value data of the said registry entry is {user defined}.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
NoFolderOptions = 0

(Note: The default value data of the said registry entry is {user defined}.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
NoViewOnDrive = 0

(Note: The default value data of the said registry entry is {user defined}.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableRegistryTools = 0

(Note: The default value data of the said registry entry is {user defined}.)

HKEY_CURRENT_USER\Software\Policies\
Microsoft\Windows\System
DisableCMD = 0

(Note: The default value data of the said registry entry is {user defined}.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
NoAddPrinter = 0

(Note: The default value data of the said registry entry is {user defined}.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
NoLogoff = 0

(Note: The default value data of the said registry entry is {user defined}.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
NoNetworkConnections = 0

(Note: The default value data of the said registry entry is {user defined}.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
NoDesktop = 0

(Note: The default value data of the said registry entry is {user defined}.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
NoDriveTypeAutorun = 255

(Note: The default value data of the said registry entry is {user defined}.)

Propagation

This Worm drops the following copy of itself in all physical and removable drives:

  • {Drive Letter}:\domz_maintenance.vbs (modified copy)

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=wscript.exe domz_maintenance.vbs
shell\Open\Command=wscript.exe domz_maintenance.vbs
shell\Open\Default=1
shell\AutoPlay\Command=wscript.exe domz_maintenance.vbs
shell\Explore\Command=wscript.exe domz_maintenance.vbs

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

9.944.04

FIRST VSAPI PATTERN DATE:

27 May 2013

VSAPI OPR PATTERN File:

9.945.00

VSAPI OPR PATTERN Date:

28 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

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

Identify and terminate files detected as VBS_GOODWORM.NIL

[ Learn More ]
  1. 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.
  2. 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.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

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
    • domz = "Wscript.exe %System%\domz.vbs"

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System
    • From: DisableTaskMgr = 0
      To: DisableTaskMgr = {user defined}
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
    • From: NoRun = 0
      To: NoRun = {user defined}
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
    • From: NoFolderOptions = 0
      To: NoFolderOptions = {user defined}
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
    • From: NoViewOnDrive = 0
      To: NoViewOnDrive = {user defined}
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System
    • From: DisableRegistryTools = 0
      To: DisableRegistryTools = {user defined}
  • In HKEY_CURRENT_USER\Software\Policies\Microsoft\Windows\System
    • From: DisableCMD = 0
      To: DisableCMD = {user defined}
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
    • From: NoAddPrinter = 0
      To: NoAddPrinter = {user defined}
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
    • From: NoLogoff = 0
      To: NoLogoff = {user defined}
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
    • From: NoNetworkConnections = 0
      To: NoNetworkConnections = {user defined}
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
    • From: NoDesktop = 0
      To: NoDesktop = {user defined}
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
    • From: NoDriveTypeAutorun = 255
      To: NoDriveTypeAutorun = {user defined}

Step 6

Search and delete this file

[ Learn More ]
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.
  • {Drive Letter}:\domz_info.txt

Step 7

Search and delete AUTORUN.INF files created by VBS_GOODWORM.NIL that contain these strings

[ Learn More ]
  • [Autorun]
  • open=wscript.exe domz_maintenance.vbs
  • shell\Open\Command=wscript.exe domz_maintenance.vbs
  • shell\Open\Default=1
  • shell\AutoPlay\Command=wscript.exe domz_maintenance.vbs
  • shell\Explore\Command=wscript.exe domz_maintenance.vbs

Step 8

Scan your computer with your Trend Micro product to delete files detected as VBS_GOODWORM.NIL. 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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