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Worm.Win32.ONLINEG.BJIN

June 08, 2023
 Analysis by: Francesca Villasanta
 ALIASES:

Trojan-GameThief.Win32.Magania.awxu (KASPERSKY); Worm:Win32/Taterf.B (MICROSOFT)

 PLATFORM:

Windows

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware


This Worm arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

As of this writing, the said sites are inaccessible.

It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size:

159,282 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

04 Jun 2023

Payload:

Drops files, Terminates processes, Connects to URLs/IPs, Modifies system registry

Arrival Details

This Worm 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:

  • {Drive}\v91qw.com
  • %System%\ierdfgh.exe → with READONLY, HIDDEN, and SYSTEM attributes

It drops the following files:

  • %System%\pytdfse0.dll → with READONLY, HIDDEN, and SYSTEM attributes
  • {Drive}\autorun.inf
  • %System%\drivers\klif.sys → if AVP.exe is not running; deleted afterwards
  • %System%\drivers\cdaudio.sys → if AVP.exe is running; deleted afterwards

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

It injects threads into the following normal process(es):

  • %Windows%\explorer.exe

(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)

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
kxswsoft = %System%\ierdfgh.exe

Other System Modifications

This Worm adds the following registry entries as part of its installation routine:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\KAVsys
Type = 1

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\KAVsys
ErrorControl = 1

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\KAVsys
Start = 1

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\KAVsys
ImagePath = \??\%System%\drivers\klif.sys

HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\AVPsys
Type = 1

HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\AVPsys
Start = 3

HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\AVPsys
ErrorControl = 1

HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\AVPsys
DisplayName = AVPsys

HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\AVPsys
ImagePath = \??\%System%\drivers\cdaudio.sys

It adds the following registry keys as part of its installation routine:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\KAVsys → if AVP.exe is not running

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\AVPsys → if AVP.exe is running

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\KasperskyLab\
protected\AVP7\profiles\
Updater
enabled = 0

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = 2

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced\Folder\Hidden\
SHOWALL
CheckedValue = 0

It deletes the following registry keys:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\KAVsys\Enum

HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\KAVsys\Security

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\KAVsys

Download Routine

This Worm accesses the following websites to download files:

  • http://{BLOCKED}3.com/xrbv/uu1.rar

As of this writing, the said sites are inaccessible.

Other Details

This Worm closes application windows that contain the following strings in the title bar:

  • AVP.Product_Notification
  • AVP.AlertDialog

It deletes the initially executed copy of itself.

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

18.492.03

FIRST VSAPI PATTERN DATE:

06 Jun 2023

VSAPI OPR PATTERN File:

18.493.00

VSAPI OPR PATTERN Date:

07 Jun 2023

Step 1

Trend Micro Predictive Machine Learning detects and blocks malware at the first sign of its existence, before it executes on your system. When enabled, your Trend Micro product detects this malware under the following machine learning name:

     Troj.Win32.TRX.XXPE50FFF069

Step 2

Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 users must disable System Restore to allow full scanning of their computers.

Step 3

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 4

Restart in Safe Mode

[ Learn More ]

Step 5

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
    • kxswsoft =%System%\ierdfgh.exe

Step 6

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: Hidden = 2
      To: Hidden = 1
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: ShowSuperHidden = 0
      To: ShowSuperHidden = 1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Folder\Hidden\SHOWALL
    • From: CheckedValue  = 0
      To: CheckedValue  = 1

Step 7

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\SYSTEM\ControlSet001\Services\KAVsys
  • In HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\KAVsys
  • In HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\AVPsys

Step 8

Search and delete this file

[ Learn More ]
There may be some 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.
  • %System%\drivers\klif.sys
  • %System%\drivers\cdaudio.sys
  • %System%\ierdfgh.exe
  • %System%\pytdfse0.dll
  • {Drive}\v91qw.com
  • {Drive}\autorun.inf

Step 9

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Worm.Win32.ONLINEG.BJIN. 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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