Analysis by: Abby Roana Javelosa


Ransom:MSIL/Filecoder.EL!MTB (Microsoft), Ransom.Cring (Malwarebytes)




  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes


Infection Channel: 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 executes then deletes itself afterward.

It encrypts files with specific file extensions. It drops files as ransom note.


File Size: 17,408 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 26 Jan 2021
Payload: Displays graphics/image, Deletes 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.


This Ransomware drops and executes the following files:

  • {malware directory}\kill.bat
  • {malware directory}\killme.bat

It executes then deletes itself afterward.

Other System Modifications

This Ransomware disables the system’s recovery features using the following:

  • net stop BMR Boot Service /y
  • net stop NetBackup BMR MTFTP Service /y
  • sc config SQLTELEMETRY start= disabled
  • sc config SQLTELEMETRY$ECWDB2 start= disabled
  • sc config SQLWriter start= disabled
  • sc config SstpSvc start= disabled

Other Details

This Ransomware does the following:

  • It requires the argument "cc" to be able to run.
  • Through the dropped file, kill.bat, it forcefully deletes files with the following strings and file extensions using del /s /f /q command in drives D:\, E:\, F:\, G:\, and H:\ if available:
    • *.VHD
    • *.bac
    • *.bak
    • *.wbcat
    • *.bkf
    • Backup*.*
    • backup*.*
    • *.set
    • *.win
    • *.dsk
  • If not executed as administrator:
    • It will encrypt files.
    • It will not drop ransom notes.
    • It will not be able to create killme.bat, and thus will not be able to delete itself.
    • It will encounter problems upon attempting to write in the System drive (C:\)
  • In executing kill.bat, it forcefully terminates the following programs through taskkill /IM /F command:
    • mspub.exe
    • mydesktopqos.exe
    • mydesktopservice.exe
  • If run without arguments, the program will write the following message in a console and terminate itself:
    • "donot cry :)"
  • It will log the files it successfully encrypted and display the following message in a console:
    • "Finished :("
  • It checks for either conditions before accessing a drive for encryption:
    • Drive is not a Fixed Drive nor a Removable Drive.
    • Drive is ready or accessible for read/write operations.

It deletes the following files to remove its traces in the system:

  • {malware directory}\kill.bat
  • {malware directory}\killme.bat

Ransomware Routine

This Ransomware encrypts files with the following extensions:

  • .vhdx
  • .ndf
  • .wk
  • .xlsx
  • .txt
  • .doc
  • .xls
  • .mdb
  • .mdf
  • .sql
  • .bak
  • .ora
  • .pdf
  • .ppt
  • .dbf
  • .zip
  • .rar
  • .aspx
  • .php
  • .jsp
  • .bkf
  • .csv
  • file extensions that start with the strings above

It avoids encrypting files with the following strings in their file path:

  • C:\Windows

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

  • .cring

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

  • %System%\deReadMe!!!.txt (if running as administrator)
  • {malware directory}\deReadMe!!!.txt (if running as administrator)


Minimum Scan Engine: 9.800
VSAPI OPR PATTERN File: 16.521.00
VSAPI OPR PATTERN Date: 06 Feb 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.XXPE50FFF041

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

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 directory}\kill.bat
  • {malware directory}\killme.bat
  • %System%\deReadMe!!!.txt
  • {malware directory}\deReadMe!!!.txt

Step 5

Scan your computer with your Trend Micro product to delete files detected as Ransom.MSIL.CRYNG.A. 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 6

Restore encrypted files from backup.

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