Remove M3g4c0rtx ransomware from the operating system

Also Known As: M3g4c0rtx virus
Distribution: Low
Damage level: Severe

M3g4c0rtx ransomware removal instructions

What is M3g4c0rtx?

M3g4c0rtx is a new, significantly updated variant of MegaCortex ransomware. This variation was discovered by MalwareHunterTeam. It operates by encrypting victims' data, changing their Windows log-in passwords, and demanding ransom payments. During the encryption process, all affected files are appended with the ".m3g4c0rtx" extension. For example, "1.jpg" appears as "1.jpg.m3g4c0rtx". After this process is complete, a Rich Text Format file ("!-!_README_!-!.rtf") is stored on the desktop. M3g4c0rtx also changes the user's Windows account password and, therefore, access is denied when the system is rebooted.

The "!-!_README_!-!.rtf" file contains the ransom message. Victims are informed that their network has been infected with MegaCortex malware. It states that users' credentials (account passwords) have been changed and their data has been encrypted. The cyber criminals behind M3g4c0rtx assert that only they are capable of recovering the compromised data. The message contains two email addresses, which victims are to use to contact the criminals. As 'proof' that file restoration is possible, two encrypted files from any device on the infected network can be sent free of charge for decryption. After this is done, users are promised that they will receive further instructions. Once the ransom is paid, the developers of M3g4c0rtx promise to send decryption software/tools and the modified credentials (log-in information). Furthermore, it is stated that the affected data has been downloaded to a secure location. Victims are warned that should the transaction not be made (i.e., the ransom not paid), the private information will be publicized. Should an agreement be reached and executed, the data will be deleted. It is unclear, whether the criminals actually copy the information - such claims are often false. Most malicious programs of this type use strong encryption, which typically cannot be broken with free tools. Only the software that originally encrypted the files can decrypt them. Regardless, you are strongly advised against meeting the ransom demands or communicating with cyber criminals. Despite paying, users often receive none of the necessary tools to recover their data. Removing M3g4c0rtx will not restore the affected files, however, it will prevent further encryption. The only viable solution is to recover data from a backup, if one was made prior to the infection and stored separately. As for the changed account passwords, there are tools available, which are capable of restoring access to devices.

Screenshot of a message encouraging users to pay a ransom to decrypt their compromised data:

M3g4c0rtx decrypt instructions

M3gac0rtx, HakbitDecrypme, and FuxSocy are just some examples of malware similar to M3g4c0rtx. The common traits of all ransomware include ransom demands and data encryption, however, the cryptographic algorithm they use (symmetric or asymmetric) and ransom sizes often differ. These ransom sums commonly vary between three-digit and four-digit sums. Cyber criminals tend to prefer digital currencies (e.g. cryptocurrencies, pre-paid vouchers, etc.), as these transactions are difficult/impossible to trace. Unless ransomware is still in development and/or has certain flaws/bugs, manual decryption without the involvement of the developers is generally impossible. To ensure data safety, store backups on remote servers and/or unplugged storage devices. Ideally, multiple backup copies should be stored in different locations.

How did ransomware infect my computer?

Ransomware and other malware is commonly spread via trojans, spam campaigns, untrustworthy download sources, illegal software activation ("cracking") tools and fake updaters. Trojans are malicious programs, designed to cause chain infections (i.e., they download/install additional malware). Previous variants of MegaCortex were proliferated through network access provided by trojans. Spam campaigns are used to send out thousands of deceptive emails containing infectious attachments (or links leading to them). These emails are usually disguised as "official", "important", "urgent" or as similar priority mail. The dangerous attachments come in various formats (e.g. archive and executable files, Microsoft Office and PDF documents, JavaScript, etc.). Once opened, they begin downloading/installing malicious software. Unofficial and free file-hosting websites, Peer-to-Peer sharing networks (BitTorrent, Gnutella, eMule, etc.) and other third party downloaders are untrustworthy and more likely to offer deceptive and/or bundled content. Software "cracking" tools can download/install malware, rather than activating licensed products. Fake updaters exploit the weaknesses of outdated programs and/or simply install malware, rather than the promised updates.

Threat Summary:
Name M3g4c0rtx virus
Threat Type Ransomware, Crypto Virus, Files locker.
Encrypted Files Extension .m3g4c0rtx
Ransom Demanding Message !-!_README_!-!.rtf
Cyber Criminal Contact and
Detection Names Avast (FileRepMalware), BitDefender (Trojan.GenericKD.32683279), ESET-NOD32 (A Variant Of Win32/Filecoder.NYM), Kaspersky (Trojan.Win32.DelShad.bnp), Full List Of Detections (VirusTotal)
Rogue Process Name Defender
Symptoms Cannot open files stored on your computer, previously functional files now have a different extension (for example, my.docx.locked). A ransom demand message is displayed on your desktop. Cyber criminals demand payment of a ransom (usually in bitcoins) to unlock your files.
Distribution methods Infected email attachments (macros), torrent websites, malicious ads.
Damage All files are encrypted and cannot be opened without paying a ransom. Additional password-stealing trojans and malware infections can be installed together with a ransomware infection.
Malware Removal (Windows)

To eliminate possible malware infections, scan your computer with legitimate antivirus software. Our security researchers recommend using Malwarebytes.
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How to protect yourself from ransomware infections?

Do not open suspicious and/or irrelevant emails, especially suspect mail received from unknown senders. Any attachments (or links) found in these emails must never be opened, as they are the source of a potential infection. Programs should be researched and downloaded only from official and verified channels. Software should be activated with tools/functions provided by legitimate developers. Illegal activation tools ("cracks") are high-risk and should not be used. The same extends to software updating. Third party updaters are often bogus and install malware rather than updates. Have a reputable anti-virus/anti-spyware suite installed and kept up-to-date. This software should be used to perform regular system scans and for the removal of detected threats/issues. If your computer is already infected with M3g4c0rtx, we recommend running a scan with Malwarebytes for Windows to automatically eliminate this ransomware.

Text presented in M3g4c0rtx ransomware Rich Text Format file ("!-!_README_!-!.rtf"):

Your company's network has been breached and infected with MegaCortex Malware.

All of your user credentials have been changed and your files have been encrypted.
We ensure that the only way to retrieve your data swiftly and securely is with our software.
Restoration of your data requires a private key which only we possess.

To confirm that our decryption software works email to us 2 files from random computers.
You will receive further instructions after you send us the test files.

After receiving payment we will provide you with the decryptor including its full source code and credentials to your computers.
We have also downloaded your data to a secure location. In the unfortunate event of us not coming to an agreement we will have no choice but to make this data public.
Once the transaction is finalized all of copies of data we have downloaded will be erased.
We will provide any assistance if needed.

Contact emails:

Screenshot of files encrypted by M3g4c0rtx (".m3g4c0rtx" extension):

Files encrypted by M3g4c0rtx

Screenshot of M3g4c0rtx process ("Defender") in Task Manager:

m3g4c0rtx ransomware process

Message displayed by M3g4c0rtx ransomware on Windows start-up:

m3g4c0rtx ransomware startup message

M3g4c0rtx ransomware changing Windows user password:

m3g4c0rtx ransomware changes windows password

M3g4c0rtx ransomware removal:

Instant automatic malware removal: Manual threat removal might be a lengthy and complicated process that requires advanced computer skills. Malwarebytes is a professional automatic malware removal tool that is recommended to get rid of malware. Download it by clicking the button below:
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Quick menu:

Step 1

Windows XP and Windows 7 users: Start your computer in Safe Mode. Click Start, click Shut Down, click Restart, click OK. During your computer start process, press the F8 key on your keyboard multiple times until you see the Windows Advanced Option menu, and then select Safe Mode with Networking from the list.

Safe Mode with Networking

Video showing how to start Windows 7 in "Safe Mode with Networking":

Windows 8 users: Start Windows 8 is Safe Mode with Networking - Go to Windows 8 Start Screen, type Advanced, in the search results select Settings. Click Advanced startup options, in the opened "General PC Settings" window, select Advanced startup. Click the "Restart now" button. Your computer will now restart into the "Advanced Startup options menu". Click the "Troubleshoot" button, and then click the "Advanced options" button. In the advanced option screen, click "Startup settings". Click the "Restart" button. Your PC will restart into the Startup Settings screen. Press F5 to boot in Safe Mode with Networking.

Windows 8 Safe Mode with networking

Video showing how to start Windows 8 in "Safe Mode with Networking":

Windows 10 users: Click the Windows logo and select the Power icon. In the opened menu click "Restart" while holding "Shift" button on your keyboard. In the "choose an option" window click on the "Troubleshoot", next select "Advanced options". In the advanced options menu select "Startup Settings" and click on the "Restart" button. In the following window you should click the "F5" button on your keyboard. This will restart your operating system in safe mode with networking.

windows 10 safe mode with networking

Video showing how to start Windows 10 in "Safe Mode with Networking":

Step 2

Log in to the account infected with the M3g4c0rtx virus. Start your Internet browser and download a legitimate anti-spyware program. Update the anti-spyware software and start a full system scan. Remove all entries detected.

If you cannot start your computer in Safe Mode with Networking, try performing a System Restore.

Video showing how to remove ransomware virus using "Safe Mode with Command Prompt" and "System Restore":

1. During your computer start process, press the F8 key on your keyboard multiple times until the Windows Advanced Options menu appears, and then select Safe Mode with Command Prompt from the list and press ENTER.

Boot your computer in Safe Mode with Command Prompt

2. When Command Prompt mode loads, enter the following line: cd restore and press ENTER.

system restore using command prompt type cd restore

3. Next, type this line: rstrui.exe and press ENTER.

system restore using command prompt rstrui.exe

4. In the opened window, click "Next".

restore system files and settings

5. Select one of the available Restore Points and click "Next" (this will restore your computer system to an earlier time and date, prior to the M3g4c0rtx ransomware virus infiltrating your PC).

select a restore point

6. In the opened window, click "Yes".

run system restore

7. After restoring your computer to a previous date, download and scan your PC with recommended malware removal software to eliminate any remaining M3g4c0rtx ransomware files.

To restore individual files encrypted by this ransomware, try using Windows Previous Versions feature. This method is only effective if the System Restore function was enabled on an infected operating system. Note that some variants of M3g4c0rtx are known to remove Shadow Volume Copies of the files, so this method may not work on all computers.

To restore a file, right-click over it, go into Properties, and select the Previous Versions tab. If the relevant file has a Restore Point, select it and click the "Restore" button.

Restoring files encrypted by CryptoDefense

If you cannot start your computer in Safe Mode with Networking (or with Command Prompt), boot your computer using a rescue disk. Some variants of ransomware disable Safe Mode making its removal complicated. For this step, you require access to another computer.

To regain control of the files encrypted by M3g4c0rtx, you can also try using a program called Shadow Explorer. More information on how to use this program is available here.

shadow explorer screenshot

To protect your computer from file encryption ransomware such as this, use reputable antivirus and anti-spyware programs. As an extra protection method, you can use programs called HitmanPro.Alert and EasySync CryptoMonitor, which artificially implant group policy objects into the registry to block rogue programs such as M3g4c0rtx ransomware.

Note that Windows 10 Fall Creators Update includes a "Controlled Folder Access" feature that blocks ransomware attempts to encrypt your files. By default, this feature automatically protects files stored in the Documents, Pictures, Videos, Music, Favorites, and Desktop folders.

Controll Folder Access

Windows 10 users should install this update to protect their data from ransomware attacks. Here is more information on how to get this update and add an additional protection layer from ransomware infections.

HitmanPro.Alert CryptoGuard - detects encryption of files and neutralises any attempts without need for user-intervention:

hitmanproalert ransomware prevention application

Malwarebytes Anti-Ransomware Beta uses advanced proactive technology that monitors ransomware activity and terminates it immediately - before reaching users' files:

malwarebytes anti-ransomware

  • The best way to avoid damage from ransomware infections is to maintain regular up-to-date backups. More information on online backup solutions and data recovery software Here.

Other tools known to remove M3g4c0rtx ransomware:

About the author:

Tomas Meskauskas

Tomas Meskauskas - expert security researcher, professional malware analyst.

I am passionate about computer security and technology. I have an experience of over 10 years working in various companies related to computer technical issue solving and Internet security. I have been working as an author and editor for since 2010. Follow me on Twitter and LinkedIn to stay informed about the latest online security threats. Contact Tomas Meskauskas.

PCrisk security portal is brought by a company RCS LT. Joined forces of security researchers help educate computer users about the latest online security threats. More information about the company RCS LT.

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Removal Instructions in other languages
Malware activity

Global malware activity level today:

Medium threat activity

Increased attack rate of infections detected within the last 24 hours.

QR Code
M3g4c0rtx virus QR code
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