WORM_AUTORUN.ENI

 Analysis by: Abraham Latimer Camba

 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:

Via removable drives, , Downloaded from the Internet, Dropped by other malware, Propagates via removable drives

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.

It does not have any backdoor routine.

It connects to certain URLs. It may do this to remotely inform a malicious user of its installation. It may also do this to download possibly malicious files onto the computer, which puts the computer at a greater risk of infection by other threats. As of this writing, the said sites are inaccessible.

It does not have any information-stealing capability.

  TECHNICAL DETAILS

File Size:

100,864 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

18 Dec 2009

Payload:

Connects to URLs/IPs

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 and executes them:

  • %System Root%\Recycle\X-5-4-27-2345678318-4567890223-4234567884-2341\Bcuzz.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%\Recycle\X-5-4-27-2345678318-4567890223-4234567884-2341\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 with attributes set to System and Hidden to prevent users from discovering and removing its components:

  • %System Root%\Recycle
  • %System Root%\Recycle\X-5-4-27-2345678318-4567890223-4234567884-2341

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

It injects itself into the following processes as part of its memory residency routine:

  • explorer.exe

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\{28ABC5C0-4FCB-11CF-AAX5-21CX1C987893}
StubPath = "%System Root%\Recycle\X-5-4-27-2345678318-4567890223-4234567884-2341\Bcuzz.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\{28ABC5C0-4FCB-11CF-AAX5-21CX1C987893}

Propagation

This worm creates the following folders in all removable drives:

  • {Drive Letter}:\Recycle
  • {Drive Letter}:\Recycle\X-5-4-27-2345678318-4567890223-4234567884-2341

It drops the following copy(ies) of itself in all removable drives:

  • {Drive Letter}:\Recycle\X-5-4-27-2345678318-4567890223-4234567884-2341\Bcuzz.exe

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=Recycle\X-5-4-27-2345678318-4567890223-4234567884-2341\Bcuzz.exe
icon=%SystemRoot%\system32\SHELL32.dll,4
action=Open folder to view files
shell\open=Open
shell\open\command=Recycle\X-5-4-27-2345678318-4567890223-4234567884-2341\Bcuzz.exe
shell\open\default=1

Backdoor Routine

This worm does not have any backdoor routine.

Download Routine

This worm connects to the following malicious URLs:

  • http://www.{BLOCKED}zy.com

As of this writing, the said sites are inaccessible.

Information Theft

This worm does not have any information-stealing capability.

NOTES:

Other Details

This worm does not have rootkit capabilities.

This worm does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

6.700.06

FIRST VSAPI PATTERN DATE:

18 Dec 2009

VSAPI OPR PATTERN File:

6.701.00

VSAPI OPR PATTERN Date:

18 Dec 2009

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
    • {28ABC5C0-4FCB-11CF-AAX5-21CX1C987893}

Step 4

Search and delete these folders

[ 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%\Recycle
  • {Drive Letter}:\Recycle

Step 5

Search and delete AUTORUN.INF files created by WORM_AUTORUN.ENI that contain these strings

[ Learn More ]
    [autorun]
    open=Recycle\X-5-4-27-2345678318-4567890223-4234567884-2341\Bcuzz.exe
    icon=%SystemRoot%\system32\SHELL32.dll,4
    action=Open folder to view files
    shell\open=Open
    shell\open\command=Recycle\X-5-4-27-2345678318-4567890223-4234567884-2341\Bcuzz.exe
    shell\open\default=1

Step 6

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