arrow_back
search
close

Ransom.Win32.LOCKBIT.ENK

August 19, 2021
 Analysis by: Clive Fuentebella
 ALIASES:

Win32:LockBit-A [Ransom] (AVAST)

 PLATFORM:

Windows

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

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted: Yes

  • 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 executes then deletes itself afterward.

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

  TECHNICAL DETAILS

File Size:

982,528 bytes

File Type:

EXE

Memory Resident:

Yes

Payload:

Encrypts files, Displays graphics/image, Displays message/message boxes, Drops files, Terminates processes

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 copies of itself into the affected system:

  • {Desktop or temp folder of connected devices}\{Random characters}.exe

It drops the following files:

  • {Drive}\{Random characters}.lock
  • %System%\{Random characters}.ico (Icon image for encrypted files)
  • %User Temp%\{Random characters}.tmp.bmp (Background image)

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.. %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It adds the following processes:

  • "%System%\cmd.exe" /c vssadmin delete shadows /all /quiet & wmic shadowcopy delete & bcdedit /set {default} bootstatuspolicy ignoreallfailures & bcdedit /set {default} recoveryenabled no (Process to delete shadow files)
  • "%System%\cmd.exe" /C ping 127.0.0.7 -n 3 > Nul & fsutil file setZeroData offset=0 length=524288 "{Malware file path and name}" & Del /f /q "{Malware file path and name}" (Process to delete itself)
  • "%System%\mshta.exe" "%Desktop%\LockBit_Ransomware.hta" {GUID} (Process to display ransom note)
  • powershell.exe -Command "Get-ADComputer -filter * -Searchbase '%s' | foreach{ Invoke-GPUpdate -computer $_.name -force -RandomDelayInMinutes 0}" (Process to query connected machines and invoke group policy update)

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.. %Desktop% is the current user's desktop, which is usually C:\Documents and Settings\{User Name}\Desktop on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\Desktop on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It executes then deletes itself afterward.

Autostart Technique

This Ransomware adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{GUID} = "{Malware file path and name}" (Initial value before encryption finishes)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{GUID} = "%Desktop%\LockBit_Ransomware.hta"

Other System Modifications

This Ransomware adds the following registry entries:

HKEY_CURRENT_USER\Software\{Random characters}
Private = {Generated session key}

HKEY_CURRENT_USER\Software\{Random characters}
Public = {Generated session key}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
.lockbit
(Default) = LockBit

HKEY_CLASSES_ROOT\.lockbit
(Default) = LockBit

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
.lockbit\DefaultIcon
(Default) = %System%\{Random characters}.ico

HKEY_CLASSES_ROOT\Lockbit\shell\
Open\Command
(Default) = "%System%\mshta.exe" "%Desktop%\LockBit_Ransomware.hta"

HKEY_CURRENT_USER\Control Panel\Desktop
Wallpaper = %User Temp%\{Random characters}.tmp.bmp

HKEY_CURRENT_USER\Control Panel\Desktop
WallpaperStyle = 2

HKEY_CURRENT_USER\Control Panel\Desktop
TileWallpaper = 0

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

Other Details

This Ransomware adds the following registry keys:

HKEY_CURRENT_USER\Software
{Random characters} =

HKEY_LOCAL_MACHINE\SOFTWARE\Classes
.lockbit =

HKEY_CLASSES_ROOT
.lockbit =

HKEY_CLASSES_ROOT
Lockbit =

It does the following:

  • It enumerates printers in the network to print the ransom note.
  • It uses LDAP queries and connected network shares/volumes to collect connected machines in the network.
  • It performs a group policy update to connected machines for propagation and execution.
  • It performs SMB queries by connecting to {Random IP in the network}:445 for propagation and execution.
  • It creates a scheduled task with random file name to execute the copied ransomware and terminate processes.
  • It bypasses UAC to escalate its privileges on infected machines.
  • It modifies the following files inside the SYSVOL folder for modification of group policies:
    • Registry.pol
    • comment.cmtx
    • NetworkShares.xml
    • Services.xml
    • ScheduledTasks.xml
  • It pushes the following group policy updates to disable malware protection on queried machines:
    • [Software\Policies\Microsoft\Windows Defender;DisableAntiSpyware]
    • [Software\Policies\Microsoft\Windows Defender\Real-Time Protection;DisableRealtimeMonitoring]
    • [Software\Policies\Microsoft\Windows Defender\Spynet;SubmitSamplesConsent]
    • [Software\Policies\Microsoft\Windows Defender\Threats;Threats_ThreatSeverityDefaultAction]
    • [Software\Policies\Microsoft\Windows Defender\Threats\ThreatSeverityDefaultAction]
    • [Software\Policies\Microsoft\Windows Defender\UX Configuration;Notification_Suppress]
  • It terminates the following processes and services with the following strings in their paths:
    • 360doctor
    • 360se
    • acwebbrowser
    • adexplorer
    • adexplorer64
    • adexplorer64a
    • adobe cef
    • adobe desktop service
    • adobecollabsync
    • adobeipcbroker
    • agntsvc
    • autodeskdesktopapp
    • autoruns
    • autoruns64
    • autoruns64a
    • autorunsc
    • autorunsc64
    • autorunsc64a
    • avz
    • axlbridge
    • bedbh
    • benetns
    • bengien
    • beserver
    • brccuxsys
    • brctrlcntr
    • cagservice
    • coresync
    • creative cloud
    • culture
    • dbeng50
    • dbsnmp
    • defwatch
    • dellsystemdetect
    • dumpcap
    • encsvc
    • enterpriseclient
    • excel
    • fbguard
    • fbserver
    • fdhost
    • fdlauncher
    • gdscan
    • glasswire
    • gwctlsrv
    • helper
    • httpd
    • infopath
    • inputpersonalization
    • isqlplussvc
    • j0gnjko1
    • java
    • koaly-exp-engine-service
    • msaccess
    • msdtsrvr
    • mspub
    • mydesktopqos
    • mydesktopservice
    • mysqld
    • node
    • notepad
    • notepad++
    • ocautoupds
    • ocomm
    • ocssd
    • onenote
    • onenotem
    • oracle
    • outlook
    • powerpnt
    • processhacker
    • procexp
    • procexp64
    • procexp64a
    • procmon
    • procmon64
    • procmon64a
    • pvlsvr
    • qbdbmgr
    • qbdbmgrn
    • qbidpservice
    • qbupdate
    • qbw32
    • raccine
    • raccine_x86
    • raccineelevatedcfg
    • raccinesettings
    • ragui
    • raw_agent_svc
    • rdrcef
    • rtvscan
    • sam
    • simply
    • simplyconnectionmanager
    • sqbcoreservice
    • sqlbrowser
    • sqlmangr
    • sqlservr
    • ssms
    • steam
    • supervise
    • sync-taskbar
    • sync-worker
    • synctime
    • sysmon
    • sysmon64
    • systemexplorer
    • systemexplorerservice
    • systemexplorerservice64
    • systemtrayicon
    • tbirdconfig
    • tcpview
    • tcpview64
    • tcpview64a
    • tdsskiller
    • teamviewer
    • teamviewer_service
    • thebat
    • thunderbird
    • titanv
    • tomcat6
    • totalcmd
    • totalcmd64
    • tv_w32
    • tv_x64
    • veeamdeploymentsvc
    • visio
    • vsnapvss
    • vxmon
    • wdswfsafe
    • winword
    • wireshark
    • wordpad
    • wsa_service
    • wxserver
    • wxserverview
    • xfssvccon
    • zhudongfangyu
  • It encrypts files found in the following drive types:
    • Fixed drive
    • Removable drive
    • Network drive
    • RAM disks

Ransomware Routine

This Ransomware avoids encrypting files with the following strings in their file name:

  • autorun.inf
  • bootsect.bak
  • iconcache.db
  • ntldr
  • ntuser.dat.log
  • Restore-My-Files.txt
  • thumbs.db

It avoids encrypting files with the following strings in their file path:

  • $recycle.bin
  • $windows.~bt
  • $windows.~ws
  • all users
  • appdata
  • application data
  • boot
  • common files
  • google
  • intel
  • internet explorer
  • microsoft
  • microsoft shared
  • microsoft.net
  • mozilla
  • msbuild
  • msocache
  • opera
  • perflogs
  • system volume information
  • tor browser
  • windows
  • windows journal
  • windows nt
  • windows.old

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

  • .lockbit

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

  • {Encrypted directory}\Restore-My-Files.txt
  • %Desktop%\LockBit_Ransomware.hta

It avoids encrypting files with the following file extensions:

  • .386
  • .adv
  • .ani
  • .apk
  • .app
  • .bat
  • .bin
  • .cmd
  • .com
  • .cpl
  • .cur
  • .diagcab
  • .diagcgf
  • .diagpkg
  • .dll
  • .dmg
  • .dmp
  • .drv
  • .drv
  • .exe
  • .fnt
  • .fon
  • .gadget
  • .hlp
  • .hlp
  • .hta
  • .icns
  • .ico
  • .ics
  • .idx
  • .ini
  • .ipa
  • .iso
  • .key
  • .lnk
  • .lock
  • .lockbit
  • .mod
  • .mp3
  • .mp4
  • .mpa
  • .msc
  • .msi
  • .msstyles
  • .msp
  • .msu
  • .msu
  • .nls
  • .ocx
  • .otf
  • .part
  • .pif
  • .prf
  • .rdp
  • .reg
  • .rom
  • .rtp
  • .sfcache
  • .shs
  • .spl
  • .sys
  • .theme
  • .tmp
  • .ttf
  • .wad
  • .wav
  • .wma
  • .woff
  • .wpx
  • .xex

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

16.904.06

FIRST VSAPI PATTERN DATE:

14 Aug 2021

VSAPI OPR PATTERN File:

16.905.00

VSAPI OPR PATTERN Date:

15 Aug 2021

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.XXPE50FFF047

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
    • {GUID}="{Malware file path and name}" (Initial value before encryption finishes)
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • {GUID}="%Desktop%\LockBit_Ransomware.hta"

Step 6

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.

  • In HKEY_CURRENT_USER\Software
    • {Random characters}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes
    • .lockbit
  • In HKEY_CLASSES_ROOT
    • .lockbit
  • In HKEY_CLASSES_ROOT
    • Lockbit

Step 7

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.
  • {Desktop or temp folder of connected devices}\{Random characters}.exe
  • {Encrypted directory}\Restore-My-Files.txt
  • %Desktop%\LockBit_Ransomware.hta
  • {Drive}\{Random characters}.lock
  • %System%\{Random characters}.ico
  • %User Temp%\{Random characters}.tmp.bmp

Step 8

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Ransom.Win32.LOCKBIT.ENK. 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.

Step 9

Restore encrypted files from backup.

Step 10

Reset your Desktop properties

[ Learn More ]

Step 11

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


Did this description help? Tell us how we did.