Analysis by: kathleenno
ALIASES:

W32.Ircbrute (Symantec); VirTool:Win32/VBInject.gen!DA (Microsoft); Trojan.Win32.VBKrypt.ig (Kaspersky); Generic.dx!pww (Mcafee)

 PLATFORM:

Windows 2000, Windows XP, Windows 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 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.

  TECHNICAL DETAILS

File Size: 57,345 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 01 Apr 2011

Installation

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

  • %System Root%\X\DELETED\MarCh3.exe

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

It drops the following non-malicious file:

  • %System Root%\X\DELETED\Desktop.ini

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

It creates the following folders:

  • %System Root%\X\DELETED

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

Autostart Technique

This worm adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{67KLN5J0-4OPM-33WE-AAX5-21KC2A3453432}
StubPath = %System Root%\X\DELETED\MarCh3.exe

Other System Modifications

This worm adds the following registry keys as part of its installation routine:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{67KLN5J0-4OPM-33WE-AAX5-21KC2A3453432}

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:

[autorun]
open=X\DELETED\MarCh3.exe
;{garbage characters}
;{garbage characters}
action=Open folder to view files
shell\open=Open
shell\open\command=X\DELETED\MarCh3.exe
shell\open\default=1

  SOLUTION

Minimum Scan Engine: 8.900
FIRST VSAPI PATTERN FILE: currently processing (renaming)

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

Restart in Safe Mode

[ Learn More ]

Step 3

Delete this registry key

[ 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. Before you could do this, you must restart in Safe Mode. For instructions on how to do this, you may refer to this page If the preceding step requires you to restart in safe mode, you may proceed to edit the system registry.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components
    • {67KLN5J0-4OPM-33WE-AAX5-21KC2A3453432}

Step 4

Search and delete this folder

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %System Root%\X\DELETED
  • In the Look In drop-down list, select My Computer, then press Enter.
  • Once located, select the folder then press SHIFT+DELETE to permanently delete the folder.

    • Step 5

    Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_VBINJECT.AR. 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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