Ransomware Research

MegaCortex Ransomware

MegaCortex is a malicious ransomware strain that encrypts victim files and demands ransom payment for decryption. First observed in the wild on April 1, 2019, this ransomware has been actively targeting systems worldwide. Security researchers also track this malware under the aliases: MegaCortex 2.0-4.0.

Quick facts

Ransomware Family
MegaCortex
First Seen
April 1, 2019
Known Aliases
MegaCortex 2.0-4.0

How MegaCortex ransomware works

File encryption patterns

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

Extensions added after encryption
.aes128ctr.megac0rtx.m3gac0rtx.m3g4c0rtx

Ransom note and payment demands

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

file!!!_READ_ME_!!!.txt
notes/!!!_READ_ME_!!!.txt
file!!!_READ-ME_!!!.txt
notes/!!!_READ-ME_!!!.txt
file!-!_README_!-!.rtf
notes/!-!_README_!-!.rtf
Location: RootDiscs, Desktop

Technical indicators

Associated executable files

The following executable files are associated with MegaCortex ransomware:

About this analysis

This MegaCortex 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 MegaCortex.

Last updated: December 30, 2025

Detection coverage

Elastio detects MegaCortex inside your data and backups.

The Hunt Engine uses Deep File Inspection to identify MegaCortex 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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