Analysis by: Marfel Tiamzon
 PLATFORM:

Windows 2000, XP, Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel: Propagates via email, Propagates via removable drives

This worm arrives as an attachment to email messages spammed by other malware/grayware or malicious users. It arrives by connecting affected removable drives to a system. It arrives via removable drives.

It uses the default Windows folder icon to trick users into opening the file. Double-clicking the file executes this malware.

It drops copies of itself in removable drives. These dropped copies use the names of the folders located on the said drives for their file names. 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: 526,849 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 30 Aug 2010

Arrival Details

This worm arrives as an attachment to email messages spammed by other malware/grayware or malicious users.

It arrives by connecting affected removable drives to a system.

It arrives via removable drives.

Installation

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

  • C:\KHATRA.exe
  • C:\Windows.exe
  • %Windows%\Xplorer.exe
  • %Windows%\KHATARNAKH.exe
  • %Windows%\WINDOWS.exe
  • %System%\KHATRA.exe
  • %System%\system32.exe
  • %Windows%\system\gHost.exe

(Note: %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.. %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.)

It drops the following component file(s):

  • %WINDOWS%\mario675.cab - also detected as WORM_UTOTI.RHB
  • %WINDOWS%\New WinZip File.cab - also detected as WORM_UTOTI.RHB
  • %WINDOWS%\New WinRAR archive.cab - also detected as WORM_UTOTI.RHB
  • %WINDOWS%\new-screamsaver.com.cab - also detected as WORM_UTOTI.RHB
  • %WINDOWS%\fh_antivirussetup6534.cab - also detected as WORM_UTOTI.RHB
  • %WINDOWS%\kavSetupEng3857.cab - also detected as WORM_UTOTI.RHB
  • %WINDOWS%\Youtube.cab - also detected as WORM_UTOTI.RHB
  • %WINDOWS%\CyberWar.cab - also detected as WORM_UTOTI.RHB
  • %WINDOWS%\New WinRAR ZIP archive.cab - also detected as WORM_UTOTI.RHB
  • %WINDOWS%\supermodels.cab - also detected as WORM_UTOTI.RHB
  • %system%\avphost.dll - detected as TROJ_TRAFOG.B

It uses the default Windows folder icon to trick users into opening the file. Double-clicking the file executes this malware.

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
G_Host = "%WINDOWS%\system\gHost.exe" /Reproduce

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Xplorer = "%WINDOWS%\Xplorer.exe" /Windows

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Taskman = %system%\KHATRA.exe

It modifies the following registry entries to ensure it automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
IMJPMIG8.1 = %WINDOWS%\Xplorer.exe

(Note: The default value data of the said registry entry is %WINDOWS%\IME\imjp8_1\IMJPMIG.EXE /Spoil /RemAdvDef /Migration32 .)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
PHIME2002ASync = %system%\KHATRA.exe

(Note: The default value data of the said registry entry is %system%\IME\TINTLGNT\TINTSETP.EXE /SYNC .)

Other System Modifications

This worm adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run
@ =  

HKEY_LOCAL_MACHINE\SOFTWARE\KHATRA
@ =  

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Schedule
AtTaskMaxHours = 0

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%system%\\KHATRA.exe = %system%\KHATRA.exe:*:Enabled:System

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
Disable Registry Tools = 1

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
NoControlPanel = 1

It modifies the following registry key(s)/entry(ies) as part of its installation routine:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Schedule
NextAtJobId = 2

(Note: The default value data of the said registry entry is 1.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Windows
load = %system%\KHATRA.exe

(Note: The default value data of the said registry entry is {blank}.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Policies\
Explorer
NoDriveTypeAutoRun = ff

(Note: The default value data of the said registry entry is 91.)

It modifies the following registry entries to hide files with Hidden attributes:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = 0

(Note: The default value data of the said registry entry is 1.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
WIndows\CurrentVersion\Explorer\
Advanced\Folder\Hidden\
SHOWALL
CheckedValue = 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:

  • KHATRA.exe

It drops copies of itself in removable drives. These dropped copies use the names of the folders located on the said drives for their file names.

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=KHATRA.exe /OpenDrive
ShellExecute=KHATRA.exe /OpenDrive
Shell\Open\Command=KHATRA.exe /OpenDrive
Shell\Open\Default=1
Shell\Explore\Command=KHATRA.exe /OpenDrive
Shell\Scan for viruses=KHATRA.exe
Shell\Open

  SOLUTION

Minimum Scan Engine: 8.900
FIRST VSAPI PATTERN FILE: 7.424.02
FIRST VSAPI PATTERN DATE: 30 Aug 2010
VSAPI OPR PATTERN File: 7.541.00
VSAPI OPR PATTERN Date: 14 Oct 2010

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

Remove malware files dropped/downloaded by WORM_UTOTI.RHB

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
    • G_Host=%WINDOWS%\system\gHost.exe /Reproduce
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • Xplorer=%WINDOWS%\Xplorer.exe /Windows
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • Taskman=%system%\KHATRA.exe
  • In HKEY_LOCAL_MACHINE\SOFTWARE\
    • KHATRA
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Schedule
    • AtTaskMaxHours=0
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • %system%\KHATRA.exe=%system%\KHATRA.exe:*:Enabled:System
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System
    • Disable Registry Tools=1
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
    • NoControlPanel=1

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 In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • From: IMJPMIG8.1 = %WINDOWS%\Xplorer.exe
      To: %WINDOWS%\IME\imjp8_1\IMJPMIG.EXE /Spoil /RemAdvDef /Migration32
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • From: PHIME2002ASync = %system%\KHATRA.exe
      To: %system%\IME\TINTLGNT\TINTSETP.EXE /SYNC
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Schedule
    • From: NextAtJobId = 2
      To: 1
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows
    • From: load = %system%\KHATRA.exe
      To: {blank}
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Policies\Explorer
    • From: NoDriveTypeAutoRun = ff
      To: 91
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: Hidden=0
      To: 1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WIndows\CurrentVersion\Explorer\Advanced\Folder\Hidden\SHOWALL
    • From: CheckedValue=0
      To: 1

Step 6

Search and delete AUTORUN.INF files created by WORM_UTOTI.RHB that contain these strings

[ Learn More ]
[AutoRun]
Open=KHATRA.exe /OpenDrive
ShellExecute=KHATRA.exe /OpenDrive
Shell\Open\Command=KHATRA.exe /OpenDrive
Shell\Open\Default=1
Shell\Explore\Command=KHATRA.exe /OpenDrive
Shell\Scan for viruses=KHATRA.exe
Shell\Open

Step 7

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