Analysis by: Maria Emreen Viray
ALIASES:

Ransom:Win32/Revil.A (MICROSOFT)

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

  TECHNICAL DETAILS

File Size: 140,800 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 10 Sep 2021
Payload: Drops files, Encrypts files, Displays graphics/image, Disables services, Displays message/message boxes, Others

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:

  • %User Temp%\{Random}.bmp → used as wallpaper

(Note: %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:

  • if -smode parameter is used (Restart the machine to Safe Mode with networking)
    • bcdedit /set {current} safeboot network

Other System Modifications

This Ransomware adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\XMT0qpW
JgC = {Hex Values}

HKEY_LOCAL_MACHINE\SOFTWARE\XMT0qpW
CsUQ = {Hex Values}

HKEY_LOCAL_MACHINE\SOFTWARE\XMT0qpW
5XB29 = {Hex Values}

HKEY_LOCAL_MACHINE\SOFTWARE\XMT0qpW
6mna6tT = .{Ransomware Extension}

HKEY_LOCAL_MACHINE\SOFTWARE\XMT0qpW
OKDigiPr = {Hex Values}

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
DefaultPassword = U1k$NEIq3c6Q → if -smode parameter is used

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\RunOnce
*Ponyaz = {Malware Path}\{Malware Name}.exe → if -smode parameter is used

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\RunOnce
*b2I0uo = bcdedit /deletevalue {current} safeboot → if -smode parameter is used

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
AutoAdminLogon = 1 → if -smode parameter is used

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
DefaultUserName = {username} → if -smode parameter is used

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

HKEY_CURRENT_USER\Control Panel\Desktop
Wallpaper = %User Temp%\{Random}.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:

  • memtas
  • sophos
  • svc$
  • vss
  • backup
  • mepocs
  • veeam
  • sql

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

  • ocssd
  • mydesktopqos
  • msaccess
  • thunderbird
  • mspub
  • firefox
  • sqbc oreservice
  • visio
  • winword
  • excel
  • synctime
  • thebat
  • oneno te
  • tbirdconfig
  • oracle
  • infopath
  • powerpnt
  • isqlplussvc
  • dbsnmp
  • ocomm
  • mydesktopservice
  • dbeng50
  • agntsvc
  • encsvc
  • xfssvccon
  • steam
  • ocautoupds
  • wordpad
  • sql
  • outlook

Information Theft

This Ransomware gathers the following data:

  • Computer name
  • User name
  • Workgroup
  • Processor
  • Operating System
  • System Architecture

Other Details

This Ransomware adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\XMT0qpW

It does the following:

  • It wipes contents of the following folder: backup
  • It empties recycle bin and deletes shadow copies
  • It searches for files to encrypt in remote drives, fixed drives, removable drives, and network resources

It accepts the following parameters:

  • -silent → skips the following:
    • Termination of blacklisted processes and services
    • Removal of shadow copies
  • -path → specifies directory to be encrypted
  • -nolocal → avoids encrypting fixed and removable drives
  • -nolan → avoids encrypting network and shared drives
  • -fast → fast encryption mode
  • -smode → executes ransomware routine on safe mode by:
    • modifying Winlogon registry:
      • to enable automatic logon
      • to set default username, domain name, and password
    • adding specific process to enable safeboot
    • shutting system down after

Ransomware Routine

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

  • bootsect.bak
  • ntuser.ini
  • thumbs.db
  • desktop.ini
  • boot.ini
  • ntldr
  • bo otfont.bin
  • ntuser.dat
  • ntuser.dat.log
  • iconcache.db
  • autorun.inf

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

  • msocache
  • windows.old
  • google
  • $windows.~bt
  • perflogs
  • application data
  • boot
  • tor browser
  • mozilla
  • program files (x86)
  • program data
  • program files
  • intel
  • system volume information
  • appdata
  • $recycle.bin
  • windows
  • $windows.~ws

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

  • {Original File Path and Name}.{Original Extension}.{Random characters}

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

  • {Ransomware Extension}-readme.txt

It avoids encrypting files with the following file extensions:

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

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 16.964.07
FIRST VSAPI PATTERN DATE: 13 Sep 2021
VSAPI OPR PATTERN File: 16.965.00
VSAPI OPR PATTERN Date: 14 Sep 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.XXPE50FFF048

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_LOCAL_MACHINE\SOFTWARE\XMT0qpW
    • JgC =  {Hex Values}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\XMT0qpW
    • CsUQ =  {Hex Values}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\XMT0qpW
    • 5XB29 =  {Hex Values}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\XMT0qpW
    • 6mna6tT =  .{Ransomware Extension}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\XMT0qpW
    • OKDigiPr =  {Hex Values}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • AutoAdminLogon = 1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • DefaultUserName = {username}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • DefaultPassword = U1k$NEIq3c6Q
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce
    • *Ponyaz = {Malware Path}\{Malware Name}.exe
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce
    • *b2I0uo = bcdedit /deletevalue {current} safeboot

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.

  • HKEY_LOCAL_MACHINE\SOFTWARE\XMT0qpW

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.
  • {Ransomware Extension}-readme.txt
  • %User Temp%\{Random}.bmp

Step 8

Reset your Desktop properties

[ Learn More ]

Step 9

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Ransom.Win32.SODINOKIBI.YABIJ. 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 10

Restore encrypted files from backup.


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