Ransomware Research

Fantom Ransomware

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

Quick facts

Ransomware Family
Fantom
First Seen
December 1, 2016

How Fantom ransomware works

File encryption patterns

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

Extensions added after encryption
.fantom.locked4.11101010.5444

Ransom note and payment demands

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

file/^RESTORE-FILES\.\d+\.hta$/
notes/RESTORE-FILES.12888.hta
Location: EveryFolder
file/^RESTORE-FILES\.\d+\.txt$/
notes/RESTORE-FILES.11101010.txt
Location: EveryFolder
fileREADME.txt
notes/README.txt
Location: Desktop
fileDECRYPT_YOUR_FILES.HTML
notes/DECRYPT_YOUR_FILES.HTML
Location: EveryFolder
screenshot
notes/638470482749087973.jpg
Location: Desktop

Technical indicators

Associated executable files

The following executable files are associated with Fantom ransomware:

About this analysis

This Fantom 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 Fantom.

Last updated: December 30, 2025

Detection coverage

Elastio detects Fantom inside your data and backups.

The Hunt Engine uses Deep File Inspection to identify Fantom 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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What is Fantom Ransomware? | Elastio