Ransomware Research

Kozy.Jozy Ransomware

Kozy.Jozy is a malicious ransomware strain that encrypts victim files and demands ransom payment for decryption. First observed in the wild on June 1, 2016, this ransomware has been actively targeting systems worldwide.

Quick facts

Ransomware Family
Kozy.Jozy
First Seen
June 1, 2016

How Kozy.Jozy ransomware works

File encryption patterns

Kozy.Jozy modifies encrypted files using specific patterns to mark them as encrypted:

Extensions added after encryption
./\.[A-F0-9]{20}_\d{1,2}_[A-Z0-9]{4,5}\b/

Ransom note and payment demands

After encrypting files, Kozy.Jozy displays ransom notes demanding payment for file recovery:

message
notes/note.txt
screenshot
notes/w.jpg
Location: Desktop

About this analysis

This Kozy.Jozy 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 Kozy.Jozy.

Last updated: December 30, 2025

Detection coverage

Elastio detects Kozy.Jozy inside your data and backups.

The Hunt Engine uses Deep File Inspection to identify Kozy.Jozy 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.

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What is Kozy.Jozy Ransomware? | Elastio