Ransomware Research

BACKJOHN Ransomware

BACKJOHN is a malicious ransomware strain that encrypts victim files and demands ransom payment for decryption. First observed in the wild on March 1, 2023, this ransomware has been actively targeting systems worldwide.

Quick facts

Ransomware Family
BACKJOHN
First Seen
March 1, 2023

How BACKJOHN ransomware works

File encryption patterns

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

Extensions added after encryption
.BACKJOHN

Ransom note and payment demands

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

fileinfo.txt
notes/info.txt
Location: RootDiscs, Desktop
fileinfo.hta
notes/info.hta
Location: RootDiscs, Desktop

Technical indicators

Associated executable files

The following executable files are associated with BACKJOHN ransomware:

About this analysis

This BACKJOHN 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 BACKJOHN.

Last updated: December 30, 2025

Detection coverage

Elastio detects BACKJOHN inside your data and backups.

The Hunt Engine uses Deep File Inspection to identify BACKJOHN 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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