Analysis by: Patrick Noel Collado
ALIASES:

a variant of Win32/Kryptik.HGZV trojan (Nod32), W32/Kryptik.CGZ.gen!Eldorado (generic, not disinfectable) (FPRot)

 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: Dropped by other malware, Downloaded from the Internet

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 avoids encrypting files with the following file extensions.

  TECHNICAL DETAILS

File Size: 165,888 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 25 Oct 2020
Payload: Displays message/message boxes, Disables services, Terminates processes, Displays graphics/image, Encrypts files

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 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 mutexes to ensure that only one of its copies runs at any one time:

  • Global\{GUID}

Other System Modifications

This Ransomware adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\BlackLivesMatter
K6a = {hex values}

HKEY_LOCAL_MACHINE\SOFTWARE\BlackLivesMatter
kZpZ = {hex values}

HKEY_LOCAL_MACHINE\SOFTWARE\BlackLivesMatter
28XOs = {hex values}

HKEY_LOCAL_MACHINE\SOFTWARE\BlackLivesMatter
mlEdtU = {hex values}

HKEY_LOCAL_MACHINE\SOFTWARE\BlackLivesMatter
SUdOP6A = .{appended extension}

HKEY_LOCAL_MACHINE\SOFTWARE\BlackLivesMatter
etdwNrNw = {hex values}

It modifies the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\Session Manager
PendingFileRenameOperations = {adds ??\{Malware Path}\{Malware Name}.exe to the existing list}

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:

  • agntsvc
  • avagent
  • avscc
  • bedbh
  • benetns
  • bengien
  • beserver
  • CagService
  • cvd
  • cvfwd
  • CVMountd
  • CVODS
  • dbeng50
  • dbsnmp
  • DellSystemDetect
  • disk+work
  • encsvc
  • EnterpriseClient
  • excel
  • firefox
  • infopath
  • isqlplussvc
  • msaccess
  • mspub
  • mydesktopqos
  • mydesktopservice
  • ocautoupds
  • ocomm
  • ocssd
  • onenote
  • oracle
  • outlook
  • powerpnt
  • pvlsvr
  • QBCFMonitorService
  • QBDBMgrN
  • QBIDPService
  • raw_agent_svc
  • SAP
  • saphostexec
  • saposcol
  • sapstartsrv
  • sqbcoreservice
  • sql
  • steam
  • synctime
  • tbirdconfig
  • TeamViewer.exe
  • TeamViewer_Service.exe
  • thebat
  • thunderbird
  • tv_w32.exe
  • tv_x64.exe
  • VeeamDeploymentSvc
  • VeeamNFSSvc
  • VeeamTransportSvc
  • visio
  • vsnapvss
  • vxmon
  • winword
  • wordpad
  • xfssvccon

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

  • agntsvc
  • avagent
  • avscc
  • bedbh
  • benetns
  • bengien
  • beserver
  • CagService
  • cvd
  • cvfwd
  • CVMountd
  • CVODS
  • dbeng50
  • dbsnmp
  • DellSystemDetect
  • disk+work
  • encsvc
  • EnterpriseClient
  • excel
  • firefox
  • infopath
  • isqlplussvc
  • msaccess
  • mspub
  • mydesktopqos
  • mydesktopservice
  • ocautoupds
  • ocomm
  • ocssd
  • onenote
  • oracle
  • outlook
  • powerpnt
  • pvlsvr
  • QBCFMonitorService
  • QBDBMgrN
  • QBIDPService
  • raw_agent_svc
  • SAP
  • saphostexec
  • saposcol
  • sapstartsrv
  • sqbcoreservice
  • sql
  • steam
  • synctime
  • tbirdconfig
  • TeamViewer.exe
  • TeamViewer_Service.exe
  • thebat
  • thunderbird
  • tv_w32.exe
  • tv_x64.exe
  • VeeamDeploymentSvc
  • VeeamNFSSvc
  • VeeamTransportSvc
  • visio
  • vsnapvss
  • vxmon
  • winword
  • wordpad
  • xfssvccon

Other Details

This Ransomware adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\BlackLivesMatter

It does the following:

  • It will terminate itself if the affected system's keyboard layout is any of the following:
    • Arabic - Syria
    • Armenian
    • Azerbaijan
    • Azerbaijani - Azerbaijan (Cyrillic)
    • Belarusian
    • Georgian
    • Kazakhstan
    • Kyrgyzstan
    • Romanian - (Moldova)
    • Russian
    • Russian - (Moldova)
    • Syriac - Syria
    • Tajikistan
    • Tatar – Russia
    • Turkmenistan
    • Ukrainian
    • Uzbek - Uzbekistan (Cyrillic)
    • Uzbekistan
  • It wipes the contents of the following folder(s):
    • archive
    • back
    • backup
    • bck
  • It accepts the following arguments:
    • -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
  • It removes the encrypted folder's access control list permissions if the current user has full control

Ransomware Routine

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

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

It avoids encrypting files found in the following folders:

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

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

  • .{random characters}

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

  • {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
  • ldf
  • lnk
  • lock
  • mod
  • mpa
  • msc
  • msi
  • msp
  • msstyles
  • msu
  • nls
  • nomedia
  • ocx
  • prf
  • ps1
  • rom
  • rtp
  • scr
  • shs
  • spl
  • sys
  • theme
  • themepack
  • wpx

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 16.310.03
FIRST VSAPI PATTERN DATE: 26 Oct 2020
VSAPI OPR PATTERN File: 16.311.00
VSAPI OPR PATTERN Date: 27 Oct 2020

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.XXPE50FFF037

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 key: HKEY_LOCAL_MACHINE\SOFTWARE\BlackLivesMatter
    • K6a = {Hex values}

  • In key: HKEY_LOCAL_MACHINE \SOFTWARE\BlackLivesMatter
    • kZpZ = {Hex values}

  • In HKEY_LOCAL_MACHINE \SOFTWARE\BlackLivesMatter
    • 28XOs = {Hex values}

  • In HKEY_LOCAL_MACHINE \SOFTWARE\BlackLivesMatter
    • mlEdtU = {Hex values}

  • In HKEY_LOCAL_MACHINE \SOFTWARE\BlackLivesMatter
    • SUdOP6A = .{appended extension}

  • In HKEY_LOCAL_MACHINE \SOFTWARE\BlackLivesMatter
    • etdwNrNw = {Hex values} 

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_LOCAL_MACHINE \SOFTWARE\BlackLivesMatter

Step 7

Restore this modified 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\SYSTEM\ControlSet001\Control\Session Manager
    • PendingFileRenameOperations = {remove {Malware Path}\{Malware Name}.exe from the list}

Step 8

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.
  • %User Temp%\{random characters}.bmp
  • {encrypted directory}\{appended extension}-readme.txt

Step 9

Reset your Desktop properties

[ Learn More ]

Step 10

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Ransom.Win32.SODINOKIBI.AUWUJDES. 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 11

Restore encrypted files from backup.

NOTES:
To restore the encrypted folders’ access control list permissions, run the command prompt or cmd.exe as an administrator then add following arguments:

  • icacls "{full path of the folder}" /reset /t /c /l
The full control permission of the current user is not restored by the said command so it must also be manually done by editing the permissions in the Security tab in the folders’ properties.


Did this description help? Tell us how we did.