Analysis by: Maria Emreen Viray
ALIASES:

HEUR:Trojan-Ransom.Win32.Encoder.pef (KASPERSKY)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE:

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Canal de infección 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.

  TECHNICAL DETAILS

Tamaño del archivo 21,504 bytes
Tipo de archivo EXE
Residente en memoria Yes
Fecha de recepción de las muestras iniciales 12 Nov 2021
Carga útil Connects to URLs/IPs, Drops files, 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 adds the following processes:

  • cmd.exe /c "%SystemRoot%\system32\wbem\wmic process call create "cmd /c CompMgmtLauncher.exe""
  • notepad.exe %Public%\readme.txt
  • vssadmin.exe Delete Shadows /all /quiet
  • cmd /c "start http://{random characters}ssdxwead.{BLOCKED}e.casa/ssdxwead{random characters} "

Other System Modifications

This Ransomware adds the following registry entries:

HKEY_CURRENT_USER\Software\Classes\
{mscfile|ms-settings}\shell\open\
command
(Default) = %System%\wbem\wmic process call create "vssadmin.exe Delete Shadows /all /quiet"

HKEY_CURRENT_USER\Software\Classes\
ms-settings\shell\open\
command
(Default) = regsvr32.exe scrobj.dll /s /u /n /i:%Public%\readme.txt

HKEY_CURRENT_USER\Software\Classes\
ms-settings\shell\open\
command
DelegateExecute = 0

Other Details

This Ransomware connects to the following possibly malicious URL:

  • http://{random characters}ssdxwead.{BLOCKED}e.casa/ssdxwead{random characters}

Ransomware Routine

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

  • .ssdxwead

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

  • %Public%\readme.txt
  • {Encrypted directory}\readme.txt

(Note: %Public% is the folder that serves as a repository of files or folders common to all users, which is usually C:\Users\Public in Windows Vista, 7, and 8.)

  SOLUTION

Motor de exploración mínimo 9.800
Primer archivo de patrones de VSAPI 17.188.07
Primera fecha de publicación de patrones de VSAPI 12 Nov 2021
Versión de patrones OPR de VSAPI 17.189.00
Fecha de publicación de patrones OPR de VSAPI 13 Nov 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.XXPE50FFF050

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

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_CURRENT_USER\Software\Classes\{mscfile|ms-settings}\shell\open\command
    • (Default) = %System%\wbem\wmic process call create "vssadmin.exe Delete Shadows /all /quiet"
  • In HKEY_CURRENT_USER\Software\Classes\ms-settings\shell\open\command
    • (Default) = regsvr32.exe scrobj.dll /s /u /n /i:%Public%\readme.txt
  • In HKEY_CURRENT_USER\Software\Classes\ms-settings\shell\open\command
    • DelegateExecute = 0

Step 5

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.
  • %Public%\readme.txt
  • {Encrypted directory}\readme.txt

Step 6

Scan your computer with your Trend Micro product to delete files detected as Ransom.Win64.MAGNIBER.YJBKM. 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 the following Trend Micro Support pages for more information:

Step 7

Restore encrypted files from backup.


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