Analysis by: Thea Patrice Tajonera
ALIASES:

Ransom:Win32/Lockbit.SB (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

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.

  TECHNICAL DETAILS

File Size: 982,528 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 05 Aug 2021

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:

  • %System%\65F641.ico -> used to change icon of encrypted files
  • %System%\spool\PRINTERS\00002.SPL
  • %System%\spool\PRINTERS\00003.SPL
  • %System%\spool\PRINTERS\00004.SPL
  • %System%\spool\PRINTERS\00005.SPL
  • %System%\spool\PRINTERS\00006.SPL

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

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
  • /c vssadmin Delete Shadows /All /Quiet
  • /c bcdedit /set {default} recoveryenabled No
  • /c bcdedit /set {default} bootstatuspolicy ignoreallfailures
  • /c wmic SHADOWCOPY /nointeractive
  • /c wevtutil cl security
  • /c wevtutil cl system
  • /c wevtutil cl application
  • /c vssadmin Delete Shadows /All /Quiet
  • /c bcdedit /set {default} recoveryenabled No
  • /c bcdedit /set {default} bootstatuspolicy ignoreallfailures
  • /c wmic SHADOWCOPY /nointeractive
  • /c wevtutil cl security
  • /c wevtutil cl system
  • /c wevtutil cl application

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

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
{95F630D2-3E3E-99B4-7712-771ED0BF3787} = "{Malware Path}\{Malware Filename}.exe"

Other System Modifications

This Ransomware adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
.lockbit\DefaultIcon
{Default} = %System%\65F641.ico

Other Details

This Ransomware adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
.lockbit

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
.lockbit\DefaultIcon

HKEY_CURRENT_USER\Software\65F641D23E7012

Ransomware Routine

This Ransomware appends the following extension to the file name of the encrypted files:

  • {Original Filename}.{Original Extension}.lockbit

It leaves text files that serve as ransom notes containing the following text:

  • {Encrypted Directory}\Restore-My-Files.txt

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 16.886.05
FIRST VSAPI PATTERN DATE: 05 Aug 2021
VSAPI OPR PATTERN File: 16.887.00
VSAPI OPR PATTERN Date: 06 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.XXPE50FFF046

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\Software\Microsoft\Windows\CurrentVersion\Run
    • {95F630D2-3E3E-99B4-7712-771ED0BF3787} = "{Malware Path}\{Malware Filename}.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.lockbit\DefaultIcon
    • {Default} = %System%\65F641.ico

Step 5

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.

  • HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.lockbit
  • HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.lockbit\DefaultIcon
  • HKEY_CURRENT_USER\Software\65F641D23E7012

Step 6

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%\65F641.ico
  • %System%\spool\PRINTERS\00002.SPL
  • %System%\spool\PRINTERS\00003.SPL
  • %System%\spool\PRINTERS\00004.SPL
  • %System%\spool\PRINTERS\00005.SPL
  • %System%\spool\PRINTERS\00006.SPL
  • {Encrypted Directory}\Restore-My-Files.txt

Step 7

Scan your computer with your Trend Micro product to delete files detected as Ransom.Win32.LOCKBIT.ENI. 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 8

Restore encrypted files from backup.


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