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Ransom.Win32.MATRIX.SMTH

June 02, 2020
 Analysis by: Clive Fuentebella
 ALIASES:

Generic.Ransom.Matrix.4A233980 (BITDEFENDER)

 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


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.

  TECHNICAL DETAILS

File Size:

1,226,240 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

02 Jun 2020

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 copies of itself into the affected system:

  • {Malware file path}\{Random characters}.exe

It drops the following files:

  • {Malware file path}\{Random characters}.bat
  • {Malware file path}\ALL_dmpfl.fldp
  • {Malware file path}\log.txt
  • %Application Data%\{Random characters}.bmp
  • %Application Data%\{Random characters}.bat
  • %Application Data%\{Random characters}.vbs

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It adds the following processes:

  • "%System%\cmd.exe" /C copy /V /Y "{Malware file path and name}" "{Malware file path}\{Random characters}.exe"
  • "{Malware file path}\{Random characters}.exe" -n
  • "%System%\cmd.exe" /C reg add "HKCU\Control Panel\Desktop" /v Wallpaper /t REG_SZ /d "%Application Data%\{Random characters}.bmp" /f & reg add "HKCU\Control Panel\Desktop" /v WallpaperStyle /t REG_SZ /d "0" /f & reg add "HKCU\Control Panel\Desktop" /v TileWallpaper /t REG_SZ /d "0" /f
  • "%System%\cmd.exe" /C wscript //B //Nologo "%Application Data%\{Random characters}.vbs";
  • "%System%\cmd.exe" /C schtasks /Create /tn DSHCA /tr "%Application Data%\{Random characters}.bat" /sc minute /mo 5 /RL HIGHEST /F
  • "%System%\cmd.exe" /C schtasks /Run /I /tn DSHCA
  • cmd /c ""{Malware file path}\{Random characters}.bat" "{File to be encrypted}"
  • cacls "{File to be encrypted}" /E /G {Computer name}:F /C
  • takeown /F "{File to be encrypted}"
  • %System%\cmd.exe /c {Random characters}.exe -accepteula "{File to be encrypted}" -nobanner
  • vssadmin Delete Shadows /All /Quiet
  • wmic SHADOWCOPY DELETE

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.. %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

Other System Modifications

This Ransomware modifies the following registry entries:

HKEY_CURRENT_USER\Control Panel\Desktop
Wallpaper = %Application Data%\{Random characters}.bmp

HKEY_CURRENT_USER\Control Panel\Desktop
WallpaperStyle = 0

HKEY_CURRENT_USER\Control Panel\Desktop
TileWallpaper = 0

HKEY_CURRENT_USER\Software\Sysinternals\
Handle
EulaAccepted = 1

Other Details

This Ransomware adds the following scheduled tasks:

  • Name: DSHCA
    Path: %Application Data%\{Random characters}.bat

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

Ransomware Routine

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

  • .[{BLOCKED}ans333@criptext.com].{Random characters}.MKES

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

  • {Encrypted file path}\#MKES_INFO#.rtf

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

15.636.05

FIRST VSAPI PATTERN DATE:

22 Jan 2020

VSAPI OPR PATTERN File:

15.637.00

VSAPI OPR PATTERN Date:

23 Jan 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.XXPE50FFF035

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

Deleting Scheduled Tasks

The following {Task Name} - {Task to be run} listed should be used in the steps identified below:

  • Task Name: DSHCA
    Task to be run: %Application Data%\{Random characters}.bat

For Windows 2000, Windows XP, and Windows Server 2003:

  1. Open the Windows Scheduled Tasks. Click Start>Programs>Accessories>
    System Tools>Scheduled Tasks.
  2. Locate each {Task Name} values listed above in the Name column.
  3. Right-click on the said file(s) with the aforementioned value.
  4. Click on Properties. In the Run field, check for the listed {Task to be run}.
  5. If the strings match the list above, delete the task.

For Windows Vista, Windows 7, Windows Server 2008, Windows 8, Windows 8.1, and Windows Server 2012:

  1. Open the Windows Task Scheduler. To do this:
    • On Windows Vista, Windows 7, and Windows Server 2008, click Start, type taskschd.msc in the Search input field, then press Enter.
    • On Windows 8, Windows 8.1, and Windows Server 2012, right-click on the lower left corner of the screen, click Run, type taskschd.msc, then press Enter.
  2. In the left panel, click Task Scheduler Library.
  3. In the upper-middle panel, locate each {Task Name} values listed above in the Name column.
  4. In the lower-middle panel, click the Actions tab. In the Details column, check for the {Task to be run} string.
  5. If the said string is found, delete the task.

Step 6

Search and delete these files

[ 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.
  • {Malware file path}\{Random characters}.exe
  • {Malware file path}\{Random characters}.bat
  • {Malware file path}\ALL_dmpfl.fldp
  • {Malware file path}\log.txt
  • %Application Data%\{Random characters}.bmp
  • %Application Data%\{Random characters}.bat
  • %Application Data%\{Random characters}.vbs

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Ransom.Win32.MATRIX.SMTH. 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 8

Restore encrypted files from backup.

Step 9

Reset your Desktop properties

[ Learn More ]


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