Analysis by: Joshua Paul Ignacio
ALIASES:

N/A

 PLATFORM:

Windows

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

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel: Dropped by other malware

This Ransomware arrives as a component bundled with malware/grayware packages.

  TECHNICAL DETAILS

File Size: 2,030 bytes
File Type: BAT
Memory Resident: No
Initial Samples Received Date: 07 Apr 2021
Payload: Executes files

Arrival Details

This Ransomware arrives as a component bundled with malware/grayware packages.

Installation

This Ransomware adds the following processes:

  • schtasks /Change /TN "{Scheduled Task Name}" /Disable → Disables anti-virus and anti-malware related scheduled tasks where {Scheduled Task Name} can by any of the following:
    • Microsoft\Windows\ExploitGuard\ExploitGuard MDM policy Refresh
    • Microsoft\Windows\Windows Defender\Windows Defender Cache Maintenance
    • Microsoft\Windows\Windows Defender\Windows Defender Cleanup
    • Microsoft\Windows\Windows Defender\Windows Defender Scheduled Scan
    • Microsoft\Windows\Windows Defender\Windows Defender Verification
  • Deletes registry entries:
    • reg delete "HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Explorer\StartupApproved\Run" /v "Windows Defender" /f
    • reg delete "HKCU\Software\Microsoft\Windows\CurrentVersion\Run" /v "Windows Defender" /f
    • reg delete "HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run" /v "WindowsDefender" /f
    • reg delete "HKCR\*\shellex\ContextMenuHandlers\EPP" /f
    • reg delete "HKCR\Directory\shellex\ContextMenuHandlers\EPP" /f
    • reg delete "HKCR\Drive\shellex\ContextMenuHandlers\EPP" /f

Other System Modifications

This Ransomware adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\WMI\Autologger\
DefenderApiLogger
Start = 0

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\WMI\Autologger\
DefenderAuditLogger
Start = 0

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\WdBoot
Start = 4

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\WdFilter
Start = 4

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\WdNisDrv
Start = 4

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\WdNisSvc
Start = 4

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\WinDefend
Start = 4

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\SecurityHealthService
Start = 4

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows Defender
DisableAntiSpyware = 1

Other Details

This Ransomware adds the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\WMI\Autologger\
DefenderApiLogger

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\WMI\Autologger\
DefenderAuditLogger

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\WdBoot

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\WdFilter

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\WdNisDrv

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\WdNisSvc

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\SecurityHealthService

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows Defender

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 16.752.03
FIRST VSAPI PATTERN DATE: 31 May 2021
VSAPI OPR PATTERN File: 16.753.00
VSAPI OPR PATTERN Date: 01 Jun 2021

Step 1

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 2

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 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_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\WMI\Autologger\DefenderApiLogger
    • Start = 0
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\WMI\Autologger\DefenderAuditLogger
    • Start = 0
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\services\WdBoot
    • Start = 4
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\services\WdFilter
    • Start = 4
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\services\WdNisDrv
    • Start = 4
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\services\WdNisSvc
    • Start = 4
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\services\WinDefend
    • Start = 4
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\services\SecurityHealthService
    • Start = 4

Step 4

Restore this modified registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator’s help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender
    • From: DisableAntiSpyware = 1
    • To: DisableAntiSpyware = 0

Step 5

Scan your computer with your Trend Micro product to delete files detected as Ransom.BAT.MOUNTLOCKER.COMPA. 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 the following Trend Micro Support pages for more information:


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