Ransomware Research

C0hen Ransomware

C0hen is a malicious ransomware strain that encrypts victim files and demands ransom payment for decryption. First observed in the wild on December 1, 2019, this ransomware has been actively targeting systems worldwide.

Quick facts

Ransomware Family
C0hen
First Seen
December 1, 2019

How C0hen ransomware works

File encryption patterns

C0hen modifies encrypted files using specific patterns to mark them as encrypted:

Extensions added after encryption
.c0hen

Ransom note and payment demands

After encrypting files, C0hen displays ransom notes demanding payment for file recovery:

message
notes/note.txt
Location: OnceOnCompletion

Technical indicators

Associated executable files

The following executable files are associated with C0hen ransomware:

About this analysis

This C0hen ransomware analysis is part of Elastio's comprehensive ransomware detection database. Elastio provides advanced ransomware protection and recovery, helping organizations defend against and recover from ransomware attacks like C0hen.

Last updated: December 30, 2025

Detection coverage

Elastio detects C0hen inside your data and backups.

The Hunt Engine uses Deep File Inspection to identify C0hen across live data, replicated data, and backups. If this family is in your environment, Elastio finds it before encryption completes. Run a scan against your recovery points to confirm.

See How the Hunt Engine WorksRequest a Demo

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