Ransom.MSIL.CRYNG.A

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.

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 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)
•