Ransomware Research

Jeffery Ransomware

Jeffery is a malicious ransomware strain that encrypts victim files and demands ransom payment for decryption. First observed in the wild on April 1, 2025, this ransomware has been actively targeting systems worldwide.

Quick Facts

Ransomware Family
Jeffery
First Seen
April 1, 2025

How Jeffery Ransomware Works

File Encryption Patterns

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

File extensions added after encryption:

..Jeffery

Ransom Note and Payment Demands

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

fileJEFFERY_README.txt

Ransom message:

notes/JEFFERY_README.txt

Note locations:

Desktop
screenshot

Ransom message:

notes/school-courtyard.jpg

Note locations:

Desktop

Technical Indicators

Associated Executable Files

The following executable files are associated with Jeffery ransomware:

  • School Homework.exe

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About This Analysis

This Jeffery 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 Jeffery.

Last updated: July 30, 2025