Analysis by: Mc Justine De Guzman
ALIASES:

Ransom:Win64/Snatch.V!MTB (Microsoft) ; Gen:Variant.Ransom.Snatch.1 (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. It avoids encrypting files with the following file extensions.

  TECHNICAL DETAILS

File Size: 2,602,496 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 03 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 files:

  • {malware file path}\{random characters1}.bat -> used to query for services, is deleted afterwards
  • {malware file path}\{random characters2}.bat -> used to delete all shadows, is deleted afterwards

It adds the following processes:

  • cmd /c "{malware file path}\{random characters1}.bat
  • cmd /c "{malware file path}\{random characters2}.bat

Process Termination

This Ransomware terminates processes or services that contain any of the following strings if found running in the affected system's memory:

  • SQL
  • BACKUP
  • TEAM
  • EXCHANGE

Ransomware Routine

This Ransomware avoids encrypting files found in the following folders:

    • Directories located in %System Root%:
      • windows
      • perflogs
      • recovery
      • $recycle.bin
    • Directories located in %ProgramData%:
      • microsoft
      • start menu
      • templates
      • favorites
    • Directories located in %Program Files%:
      • uninstall information
      • mozilla maintenance service
      • microsoft.net
      • windows portable devices
      • windows sidebar
      • windows photo viewer
      • windows nt
      • windows media player
      • windows mail
      • windows journal
      • windows defender
      • tap-windows
      • reference assemblies
      • mozilla firefox
      • microsoft games
      • msbuild
      • internet explorer
      • dvd maker
      • common files
      • system volume information
      • $recycle.bin
      • perflogs
      • windows

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000(32-bit), Server 2003(32-bit), XP, Vista(64-bit), 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit) , or C:\Program Files (x86) in Windows XP(64-bit), Vista(64-bit), 7(64-bit), 8(64-bit), 8.1(64-bit), 2008(64-bit), 2012(64-bit) and 10(64-bit).)

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

  • .{random characters}

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

  • {encrypted folder}\HOW TO RESTORE YOUR FILES.TXT

It avoids encrypting files with the following file extensions:

  • .exe
  • .dll
  • .sys
  • .ini

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 15.940.05
FIRST VSAPI PATTERN DATE: 19 Jun 2020
VSAPI OPR PATTERN File: 15.941.00
VSAPI OPR PATTERN Date: 20 Jun 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

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.  
  • {encrypted folder}\HOW TO RESTORE YOUR FILES.TXT

Step 6

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 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Ransom.Win64.SNATCH.AC. 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.


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