Analysis by: Glaizel Mallari
ALIASES:

Ransom:Win32/LockFile.ALK!MTB (MICROSOFT)

 PLATFORM:

Windows

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

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet, Dropped by other malware

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

It drops files as ransom note. It avoids encrypting files with the following file extensions.

  TECHNICAL DETAILS

File Size: 194560 bytes
File Type: EXE
Initial Samples Received Date: 14 Jul 2025
Payload: Drops files, Deletes files, Terminates processes, Disables services

Arrival Details

This Ransomware 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 Ransomware drops the following files:

  • {8 random uppercase letters}.cmd → deleted afterwards
  • %Program Data%\F8C6A8.ico → icon of the encrypted files
  • %Program Data%\F8C6A8.bmp → desktop wallpaper after encryption

It adds the following processes:

  • chcp 65001
  • cmd /c "{malware directory}\{8 random uppercase letters}.cmd"

Other System Modifications

This Ransomware deletes the following files:

  • {8 ransom uppercase letters}.cmd

It changes the desktop wallpaper by modifying the following registry entries:

HKEY_CURRENT_USER\Control Panel\Desktop
Wallpaper data = %ProgramData%\F8C6A8.bmp

It sets the system's desktop wallpaper to the following image:


Process Termination

This Ransomware terminates the following services if found on the affected system:

  • applicationframehost
  • certsrv
  • cmd
  • conhost
  • csrss
  • ctfmon
  • dashost
  • dfsrs
  • dfssvc
  • dllhost
  • dns
  • dropbox
  • dwm
  • explorer
  • fontdrvhost
  • idle
  • ismserv
  • logonui
  • lsaiso
  • lsass
  • lsm
  • microsoft.activedirectory.webservices
  • msdtc
  • msmpeng
  • mstsc
  • nissrv
  • onedrive
  • openconsole
  • powershell
  • rdpclip
  • registry
  • rundll32
  • runtimebroker
  • rustdesk
  • searchapp
  • searchfilterhost
  • searchindexer
  • searchprotocolhost
  • searchui
  • securityhealthservice
  • services
  • shellexperiencehost
  • sihost
  • smartscreen
  • smss
  • spoolsv
  • svchost
  • svhost
  • system
  • taskhostw
  • taskmgr
  • trustedinstaller
  • vds
  • vmcompute
  • vmms
  • vmwp
  • vssvc
  • windowsterminal
  • wininit
  • winlogon
  • wlanext
  • wmiprvse
  • wudfhost
  • wwahost
  • anydesk|wrapper
  • DefWatch
  • ccEvtMgr
  • ccSetMgr
  • SavRoam
  • Sqlservr
  • sqlagent
  • sqladhlp
  • Culserver
  • RTVscan
  • sqlbrowser
  • SQLADHLP
  • QBIDPService
  • Intuit.QuickBooks.FCS
  • QBCFMonitorService
  • msmdsrv
  • tomcat6
  • zhudongfangyu
  • vmware-usbarbitator64h
  • vmwareconverter
  • dbsrv12
  • dbeng8
  • MSSQL$MICROSOFT##WID
  • MSSQL$VEEAMSQL2012
  • SQLAgent$VEEAMSQL2012
  • SQLBrowser
  • SQLWriter
  • FishbowlMySQL
  • MSSQL$MICROSOFT##WID
  • MySQL57
  • MSSQL$KAV_CS_ADMIN_KIT
  • MSSQLServerADHelper100
  • SQLAgent$KAV_CS_ADMIN_KIT
  • msftesqlExchange
  • MSSQL$MICROSOFT##SSEE
  • MSSQL$SBSMONITORING
  • MSSQL$SHAREPOINT
  • MSSQLFDLauncher$SBSMONITORING
  • MSSQLFDLauncher$SHAREPOINT
  • SQLAgent$SBSMONITORING
  • SQLAgent$SHAREPOINT
  • QBFCService
  • QBVSS
  • YooBackup
  • YooIT
  • vss
  • sql
  • svc$
  • MSSQL
  • MSSQL$
  • memtas
  • mepocs
  • veeam
  • backup
  • bedbg
  • PDVFSService
  • BackupExecVSSProvider
  • BackupExecAgentAccelerator
  • BackupExecAgentBrowser
  • BackupExecDiveciMediaService
  • BackupExecJobEngine
  • BackupExecManagementService
  • BackupExecRPCService
  • MVArmor
  • MVarmor64
  • stc_raw_agent
  • VSNAPVSS
  • VeeamTransportSvc
  • VeeamDeploymentService
  • VeeamNFSSvc
  • AcronisAgent
  • ARSM
  • AcrSch2Svc
  • CASAD2DWebSvc
  • CAARCUpdateSvc
  • WSBExchange
  • MSExchange
  • MSExchange$

It terminates the following processes if found running in the affected system's memory:

  • taskhost.exe
  • explorer.exe
  • VMwareTray.exe
  • smtoolsd.exe
  • GrooveMonitor.exe
  • svchost.exe
  • SearchIndexer.exe
  • sysmon.exe
  • unsecapp.exe
  • vdisk.exe
  • WUDFHost.exe
  • procmon.exe
  • SysTracerx32.exe
  • TcpLogView.exe
  • ProcessHacker.exe
  • Fiddler.exe
  • conhost.exe
  • msdtc.exe
  • sublime_text.exe
  • plugin_host.exe
  • powershell.exe
  • smss.exe
  • csrss.exe
  • wininit.exe
  • winlogon.exe
  • spoolsv.exe
  • services.exe
  • lsass.exe
  • vserver.exe
  • OllyDbg.exe

Other Details

This Ransomware does the following:

  • It changes the file icon of the encrypted files into the following image:

Ransomware Routine

This Ransomware avoids encrypting files found in the following folders:

  • $Recycle.Bin
  • Windows
  • System Volume Information
  • Program Files
  • Users\All Users
  • Program Data
  • $Windows.~BT
  • $Windows.~WS
  • Config.MSI

It appends the following extension to the file name of the encrypted files:

  • .F8C6A8.dlock

It drops the following file(s) as ransom note:

  • {encrypted directory}\Read Me.F8C6A8.txt

  • F:\Read Me.F8C6A8.txt

It avoids encrypting files with the following file extensions:

  • .386
  • .adv
  • .ani
  • .bat
  • .bin
  • .cab
  • .cmd
  • .com
  • .cpl
  • .cur
  • .deskthemepack
  • .diagcab
  • .diagcfg
  • .diagpkg
  • .dll
  • .drv
  • .exe
  • .hlp
  • .hta
  • .icl
  • .icns
  • .ico
  • .ics
  • .idx
  • .key
  • .ldf
  • .lnk
  • .loc
  • .mod
  • .mpa
  • .msc
  • .msi
  • .msp
  • .msstyles
  • .msu
  • .nls
  • .nomedia
  • .ocx
  • .pdb
  • .prf
  • .ps1
  • .rom
  • .rtp
  • .scr
  • .search-ms
  • .shs
  • .spl
  • .sys
  • .theme
  • .themepack
  • .wpx

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 20.638.03
FIRST VSAPI PATTERN DATE: 12 Dec 2025
VSAPI OPR PATTERN File: 20.639.00
VSAPI OPR PATTERN Date: 13 Dec 2025

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.XXPE50FFF100

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

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\Control Panel\Desktop
    • Wallpaper = %Program Data%\F8C6A8.bmp

Step 5

Search and delete these files

[ 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.
  • %Program Data%\F8C6A8.ico
  • %Program Data%\F8C6A8.bmp
  • F:\Read Me.F8C6A8.txt
  • {encrypted directory}\Read Me.F8C6A8.txt

Step 6

Scan your computer with your Trend Micro product to delete files detected as Ransom.Win32.DEADLOCK.THLABBE. 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:

Step 7

Restore encrypted files from backup.


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