Analysis by: Sabrina Sioting
 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

This worm adds registry entries to enable its automatic execution at every system startup.

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: 151,830 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 28 Oct 2009

Installation

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

  • %System Root%\RECYCLER\S-1-5-21-1414516153-1488376560-025727152-7968\MsMxEng.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 files:

  • %System Root%\RECYCLER\S-1-5-21-1414516153-1488376560-025727152-7968\Desktop.ini
  • %System Root%\RECYCLER\S-1-5-21-8232957759-6216920188-034413666-0993\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%\RECYCLER\S-1-5-21-1414516153-1488376560-025727152-7968
  • %System Root%\RECYCLER\S-1-5-21-8232957759-6216920188-034413666-0993

(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\
Windows NT\CurrentVersion\Winlogon
Taskman = %System Root%\RECYCLER\S-1-5-21-1414516153-1488376560-025727152-7968\MsMxEng.exe =

Propagation

This worm creates the following folders in all removable drives:

  • USBVAULT

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

  • USBVAULT\us.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:

;{garbage}
[autorun[
[autorun
open=USBVAULT\us.exe
:cmp
icon=%SystemRoot%\system32\SHELL32.dll,4
;{garbage}
action=Open folder to view files using Windows Explorer
;{garbage}
:je0
;{garbage}
shell\\open\\command=USBVAULT/us.exe
;{garbage}
:nop
;{garbage}
shell\\explore\\\command=USBVAULT/us.exe
;{garbage}
UseautoplAy=1

  SOLUTION

Minimum Scan Engine: 8.900
VSAPI PATTERN File: 6.582.01
VSAPI PATTERN Date: 28 Oct 2009
VSAPI PATTERN Date: 10/28/2009 12:00:00 AM

Step 1

For Windows ME and XP users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

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 NT\CurrentVersion\Winlogon
    Taskman = %System Root%\RECYCLER\S-1-5-21-1414516153-1488376560-025727152-7968\MsMxEng.exe

Step 3

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%\RECYCLER\S-1-5-21-1414516153-1488376560-025727152-7968
  • %System Root%\RECYCLER\S-1-5-21-8232957759-6216920188-034413666-0993

Step 4

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

[ Learn More ]
;{garbage}
[autorun[
[autorun
open=USBVAULT\us.exe
:cmp
icon=%SystemRoot%\system32\SHELL32.dll,4
;{garbage}
action=Open folder to view files using Windows Explorer
;{garbage}
:je0
;{garbage}
shell\\open\\command=USBVAULT/us.exe
;{garbage}
:nop
;{garbage}
shell\\explore\\\command=USBVAULT/us.exe
;{garbage}
UseautoplAy=1

Step 5

Scan your computer with your Trend Micro product to delete files detected as WORM_AUTORUN.OMI 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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