Ransomware Research

Cossy Ransomware

Cossy is a malicious ransomware strain that encrypts victim files and demands ransom payment for decryption. First observed in the wild on December 1, 2018, this ransomware has been actively targeting systems worldwide. Security researchers also track this malware under the aliases: Grafimatriux.

Quick Facts

Ransomware Family
Cossy
First Seen
December 1, 2018
Known Aliases
Grafimatriux

How Cossy Ransomware Works

File Encryption Patterns

Cossy modifies encrypted files using specific patterns to mark them as encrypted:

File extensions added after encryption:

..Защищено RSA-2048

Ransom Note and Payment Demands

After encrypting files, Cossy displays ransom notes demanding payment for file recovery:

fileКак все эту шалашкину контору расшифровать.txt

Ransom message:

notes/Как все эту шалашкину контору расшифровать.txt

Note locations:

EveryFolder
fileКрайне важная инфа.RSA-2048 файл

Ransom message:

notes/Крайне важная инфа.RSA-2048 файл

Note locations:

EveryFolder

Technical Indicators

Associated Executable Files

The following executable files are associated with Cossy ransomware:

  • Cossy.exe
  • Cossy.bin
  • Attachment.rar

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About This Analysis

This Cossy ransomware analysis is part of Elastio's comprehensive ransomware detection database. Elastio provides advanced ransomware protection and recovery solutions, helping organizations defend against and recover from ransomware attacks like Cossy.

Last updated: July 30, 2025

Cossy Ransomware - Detectable by Elastio