VBS_AUTORUN.BXI

October 09, 2012
 Analysis by: Roland Marco Dela Paz
 ALIASES:

Symantec: VBS.Runauto; Microsoft: Worm:VBS/Radier.B

 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

It drops a copy if itself along with the AUTORUN.INF file in mapped drives.

This worm arrives by connecting affected removable drives to a system. It arrives by accessing affected shared networks.

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:

15,414 bytes

File Type:

VBS

Memory Resident:

Yes

Initial Samples Received Date:

23 Mar 2011

Arrival Details

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

It arrives by accessing affected shared networks.

Installation

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

  • %System%\.vbe
  • %Windows%\.vbe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.. %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
explorer\run
{system name} = ".vbe"

Other System Modifications

This worm adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE
{system name} = ""

It modifies the following registry entries to hide files with Hidden 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 the following copy(ies) of itself in all removable drives:

  • .vbs

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:

Raider 8.01
[autorun]
open=wscript.exe .\.vbs
shell\open\command=wscript.exe .\.vbs
shell\open\default=1

NOTES:
It also drops a copy if itself along with the AUTORUN.INF file in mapped drives.

  SOLUTION

Minimum Scan Engine:

8.900

VSAPI OPR PATTERN File:

7.921.00

VSAPI OPR PATTERN Date:

23 Mar 2011

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.

  • In HKEY_LOCAL_MACHINE\SOFTWARE
    • {system name}

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\explorer\run
    • {system name} = ".vbe"

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

Step 6

Search and delete AUTORUN.INF files created by VBS_AUTORUN.BXI that contain these strings

[ Learn More ]
Raider 8.01
[autorun]
open=wscript.exe .\.vbs
shell\open\command=wscript.exe .\.vbs
shell\open\default=1

Step 7

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