Analysis by: Jay Bradley Nebre
ALIASES:

Generic.Ransom.Matrix.C9DC3407(Bitdefender)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 REPORTED INFECTION:

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted:

  • 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: 1,075,200 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 18 Dec 2019

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:

  • {Malware Path}\oRNAgyie.exe" -n
  • WMIC.exe shadowcopy delete /nointeractive
  • vssadmin.exe delete shadows /all /quiet

Other System Modifications

This Ransomware adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
README = C:\Program Files\Windows NT\Accessories\wordpad.exe" "%Application Data%\#ReadMe_T0_Decrypt_Files.rtf

Dropping Routine

This Ransomware drops the following files:

  • {Malware Path}\oRNAgyie.exe
  • %Application Data%\#ReadMe_T0_Decrypt_Files.rtf.
  • {Malware Path}\KEYIDS.KLST

(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:

  • .[Bitmine8@tutanota.com]

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

  • {Encrypted Folder}\#ReadMe_T0_Decrypt_Files.rtf

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 15.646.08
FIRST VSAPI PATTERN DATE: 27 Jan 2020
VSAPI OPR PATTERN File: 15.647.00
VSAPI OPR PATTERN Date: 28 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.XXPE50FFF034

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • README = %Application Data%\#ReadMe_T0_Decrypt_Files.rtf

Step 5

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.
  • {Malware Path}\oRNAgyie.exe
  • %Application Data%\#ReadMe_T0_Decrypt_Files.rtf.
  • {Malware Path}\KEYIDS.KLST

Step 6

Restore encrypted files from backup.

Step 7

Enabling Volume Shadow Service

  1. Run the command prompt (cmd.exe) as administrator.
  2. Enable Volume Shadow Service by typing the following command:
    net start vss

Step 8

Scan your computer with your Trend Micro product to delete files detected as Ransom.Win32.MATRIX.AL. 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:


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