WORM_VBNA.SMG

 Analysis by: Michael Cabel

 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:

Propagates via removable drives

This worm arrives by connecting affected removable drives to a system. It arrives via removable drives.

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

It drops copies of itself in all removable drives.

  TECHNICAL DETAILS

File Size:

98,304 bytes

File Type:

PE

Memory Resident:

Yes

Initial Samples Received Date:

20 Jul 2010

Arrival Details

This worm arrives by connecting affected removable drives to a system.

It arrives via removable drives.

Installation

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

  • %User Profile%\{Random File Name}.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
{Malware File Name Without Extension} = %User Profile%\{Random File Name}.exe

Other System Modifications

This worm 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.)

Propagation

This worm drops copies of itself in all removable drives.

The said .INF file contains the following strings:

[AutoRuN]
aCtioN=Open folder to view files
shELlExecuTE={Malware File Name}.exe
iCON=%SYStEMROOT%\sySTeM32\ShELl32.DLL,4
USEauToplay=1

Other Details

Based on analysis of the codes, it has the following capabilities:

  • It also drops shortcut files with the following file names in removable drives that points to its dropped copy:
  • Documents.lnk
  • Music.lnk
  • New Folder.lnk
  • Passwords.lnk
  • Pictures.lnk
  • Video.lnk

  SOLUTION

Minimum Scan Engine:

8.900

VSAPI OPR PATTERN File:

07.322.09

VSAPI OPR PATTERN Date:

20 Jul 2010

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

Terminate a process file/s detected as WORM_VBNA.SMG

[ Learn More ]

*Note: If the detected file/s is/are not displayed in theWindows Task Manager, continue doing the next steps.

Step 3

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
    • {Malware File Name Without Extension} = %User Profile%\{Random File Name}.exe

Step 4

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\Explorer\Advanced
    • From: ShowSuperHidden = 0
      To: 1

Step 5

Search and delete these files

[ Learn More ]
There may be some component 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

Step 6

Search and delete AUTORUN.INF files created by WORM_VBNA.SMG that contain these strings

[ Learn More ]
[AutoRuN]
aCtioN=Open folder to view files
shELlExecuTE={Malware File Name}.exe
iCON=%SYStEMROOT%\sySTeM32\ShELl32.DLL,4
USEauToplay=1

Step 7

Scan your computer with your Trend Micro product to delete files detected as WORM_VBNA.SMG. 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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