WORM_UTOTI.BQ

 Analysis by: jasperm

 ALIASES:

Symantec: W32.Changeup!gen9 ; Mcafee: Downloader-CJX.gen.o; Kaspersky: Trojan.Win32.VBKrypt.bfqf

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Propagates via removable drives


It drops .LNK files in all removable drives which are shortcut files to the dropped copy.

This worm arrives via removable drives. It may be dropped by other malware. It may be unknowingly downloaded by a user while visiting malicious websites. However, as of this writing, the said sites are inaccessible.

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

It connects to a website to send and receive information.

  TECHNICAL DETAILS

File Size:

Varies

File Type:

PE

Memory Resident:

Yes

Initial Samples Received Date:

09 Feb 2011

Payload:

Compromises system security

Arrival Details

This worm arrives via removable drives.

It may be dropped by other malware.

It may be unknowingly downloaded by a user while visiting malicious websites.

However, as of this writing, the said sites are inaccessible.

Installation

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

  • %User Temp%\{random name}.exe

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.)

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 name}.exe = %User Temp%\{random name}.exe /w

Other System Modifications

This worm 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 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]
action=View the files
open={malware name}.exe
icon=%systemroot%\system32\shell32.dll,4
userautoplay=1

Backdoor Routine

This worm connects to the following websites to send and receive information:

  • ns1.{BLOCKED}ll.net
  • ns1.{BLOCKED}r1253.com
  • ns1.{BLOCKED}hares.org

Other Details

This worm does the following:

  • Drops the following .LNK files in all removable drives which are shortcut files to the dropped copy:
    • Documents.lnk
    • Music.lnk
    • New Folder.lnk
    • Passwords.lnk
    • Pictures.lnk
    • Video.lnk

  SOLUTION

Minimum Scan Engine:

8.900

VSAPI PATTERN File:

7.827.00

VSAPI PATTERN Date:

09 Feb 2011

VSAPI PATTERN Date:

2/9/2011 12:00:00 AM

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

Identify and terminate files detected as WORM_UTOTI.BQ

[ Learn More ]
  1. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  2. If the detected file is not displayed in either Windows Task Manager or Process Explorer, 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 name} = %User Profile%\{random 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: ShowSuperHidden=1

Step 5

Search and delete this file

[ 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_UTOTI.BQ that contain these strings

    [ Learn More ]
    [autorun]
    action=View the files
    open={malware name}.exe
    icon=%systemroot%\system32\shell32.dll,4
    userautoplay=1

    Step 7

    Scan your computer with your Trend Micro product to delete files detected as WORM_UTOTI.BQ. 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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