Ransom.Win32.BLACKMATTER.THGOCBA

 Analysis by: Maria Emreen Viray

 ALIASES:

Trojan-Ransom.BlackMatter (IKARUS)

 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

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:

68,608 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

03 Aug 2021

Payload:

Connects to URLs/IPs, Encrypts files, Displays message/message boxes, Disables services, Terminates processes, Steals information

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:

  • used as wallpaper:
    • %ProgramData%\{appended ransomware extension}.bmp

(Note: %ProgramData% is a version of the Program Files folder where any user on a multi-user computer can make changes to programs. This contains application data for all users. This is usually C:\ProgramData on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit), or C:\Documents and Settings\All Users on Windows Server 2003(32-bit), 2000(32-bit) and XP.)

It adds the following processes:

  • if -safe is used:
    • bcdedit /set {current} safeboot network

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

  • Global\{Generated hash based on GUID}

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\RunOnce
*{random} = {malware path}\{malware name}

Other System Modifications

This Ransomware adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\{appended ransomware extension}
hScreen = {screen height}

HKEY_LOCAL_MACHINE\SOFTWARE\{appended ransomware extension}
wScreen = {screen width}

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
AutoAdminLogon = 1

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
DefaultUserName = Administrator

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
DefaultDomainName = {Computer name}

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
DefaultPassword = {random string}

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

HKEY_CURRENT_USER\Control Panel\Desktop
WallPaper = %ProgramData%\{appended ransomware extension}.bmp

HKEY_CURRENT_USER\Control Panel\Desktop
WallpaperStyle = 10

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:

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

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

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

Information Theft

This Ransomware gathers the following data:

  • Machine GUID
  • Computer name
  • Hostname
  • Username
  • Domain
  • OS Architecture
  • Language
  • Disk information (free size, disk size)
  • Total number of files
  • Total number of encrypted files

Stolen Information

This Ransomware sends the gathered information via HTTP POST to the following URL:

  • http://{BLOCKED}hacks.com/{encrypted gathered information}
  • http://{BLOCKED}den.com/{encrypted gathered information}

Other Details

This Ransomware adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\{appended ransomware extension} → deleted after execution

It does the following:

  • If not executed with admin rights, it will relaunch itself as admin
  • It encrypts fixed, removable and network drives
  • It deletes files in recycle bin folder for removable and fixed drives
  • It uses WQL to delete shadow copies
  • It attempts logging in to infected machine using the following credentials:
    • Username: {BLOCKED}er@{BLOCKED}p.com
      Password: {BLOCKED}er
    • Username: {BLOCKED}h@{BLOCKED}p.com
      Password: {BLOCKED}19
    • Username: {BLOCKED}r@{BLOCKED}p.com
      Password: {BLOCKED}**

It accepts the following parameters:

  • -path {target path} → specifies directory to be encrypted
  • -wall → changes wallpaper only
  • -safe → 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:

  • ntuser.ini
  • ntuser.dat.log
  • autorun.inf
  • thumbs.db
  • desktop.ini
  • boot.ini
  • ntldr
  • ntuser.dat
  • iconcache.db
  • bootsect.bak
  • bootfont.bin
  • {appended ransomware extension}.README.txt

It avoids encrypting files found in the following folders:

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

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

  • {string generated from Machine GUID}

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

  • {appended ransomware 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
  • pdb
  • prf
  • ps1
  • rom
  • rtp
  • scr
  • shs
  • spl
  • sys
  • theme
  • themepack
  • wpx

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

16.882.02

FIRST VSAPI PATTERN DATE:

03 Aug 2021

VSAPI OPR PATTERN File:

16.883.00

VSAPI OPR PATTERN Date:

04 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

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\Microsoft\Windows NT\CurrentVersion\Winlogon
    • AutoAdminLogon = 1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • DefaultUserName = Administrator
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • DefaultDomainName = {Computer name}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • DefaultPassword = {random string}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce
    • *{random} = {malware path}\{malware name}

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\{appended ransomware extension}

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.
  • %ProgramData%\{extension}.bmp
  • {appended ransomware extension}.README.txt

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.BLACKMATTER.THGOCBA. 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.


Did this description help? Tell us how we did.