Ransom.Win32.SODINOKIBI.THDO

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.

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:

• {Malware Path}\DBG_LOG.TXT → logs all the system changes done by the malware
• %User Temp%\{Random Characters}.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:

• powershell -e {Base-64 Encoded Command} → Deletes shadow copies

It adds the following mutexes to ensure that only one of its copies runs at any one time:

• Global\D2E08536-A08B-1B12-DFD4-7AA58181F7FD

Other System Modifications

This Ransomware adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Facebook_Assistant
vW7 = {Hex Values}

HKEY_LOCAL_MACHINE\SOFTWARE\Facebook_Assistant
Zi51 = {Hex Values}

HKEY_LOCAL_MACHINE\SOFTWARE\Facebook_Assistant
k7Zbb = {Hex Values}

HKEY_LOCAL_MACHINE\SOFTWARE\Facebook_Assistant
SCayjH = {Hex Values}

HKEY_LOCAL_MACHINE\SOFTWARE\Facebook_Assistant
urVMni9 = Appended Extension

HKEY_LOCAL_MACHINE\SOFTWARE\Facebook_Assistant
74uP24hQ = {Hex Values}

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

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

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

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

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

Information Theft

This Ransomware gathers the following data:

• Computer name
• Operating System name
• System Architecture
• Username
• Workgroup

Other Details

This Ransomware adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Facebook_Assistant

It does the following:

• It checks for the system's computer layout and terminates if it is any of the following:
  
  • Russian
  • Ukrainian
  • Belarusian
  • Tajik
  • Armenian
  • Azeri-Latin
  • Georgian
  • Kazakh
  • Kyrgyz-Cyrillic
  • Slovenian
  • Uzbek-Latin
  • Tatar
  • Romanian-Moldova
  • Russian-Moldova
  • Azeri-Cyrillic
  • Uzbek-Cyrillic
  • Syriac
  • Arabic-Syria
• It wipes the contents of the following folder(s):
  
  • backup
• It checks if its privilege level is on SYSTEM level. If it is, it will impersonate the user that ran the first explorer.exe it has found.
• It accepts the following parameters:
  
  • -nolan → avoids encrypting network and shared drives
  • -nolocal → avoids encrypting fixed and removable drives
  • -silent → skips the following:
    • Termination of blacklisted processes and services
    • Removal of shadow copies
  • -path → encrypts the specified directory
  • -fast → fast encryption mode
• It displays the following window where it logs all the system changes which will be written on the {Malware Path}\DBG_LOG.TXT:
  

Ransomware Routine

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

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

It avoids encrypting files found in the following folders:

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

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

• {Original Filename}.{Original File Extension}.{Random Characters}

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

• {Encrypted Directory}\{Appended Extension}-readme.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
• .lnk
• .lock
• .mod
• .mpa
• .msc
• .msi
• .msp
• .msstyles
• .msu
• .nls
• .nomedia
• .ocx
• .prf
• .ps1
• .rom
• .rtp
• .scr
• .shs
• .spl
• .sys
• .theme
• .themepack
• .wpx