Mdk4y Ransomware

Also Known As: Mdk4y virus
Distribution: Low
Damage level: Severe

Mdk4y ransomware removal instructions

What is Mdk4y?

Mdk4y is a computer infection classified as ransomware. Ransomware-type viruses are malicious programs that cyber criminals use to encrypt data stored on victims' computers. To regain access to their data, users are encouraged to pay a ransom. This particular computer infection was discovered by Leo. Mdk4y renames each encrypted file by adding the ".mdk4y" extension. For example, "1.jpg" becomes "1.jpg.mdk4y". It also places the "HOW_TO_RETURN_FILES.txt" ransom message in all folders on infected computers and runs a process in Task Manager (the name of which is a random string).

The "HOW_TO_RETURN_FILES.txt" message states that this ransomware has encrypted all data using AES-256 cryptography. To retrieve their files (decrypt them), Mdk4y's victims must use a decryption tool and key that can be obtained by contacting the developers via the email address. The tool is not free and the cost is unknown (probably issued when cyber criminals are contacted), however, it is stated that the cost will increase daily. If Mdk4y developers are not contacted within a week following encryption, the decryption key is deleted and data remains locked (encrypted) indefinitely. Do not contact these cyber criminals or any other ransomware developers. Generally, they ignore victims even if payments for decryption tools/keys are transferred. Cyber criminals often lock data using encryption algorithms (such as AES, RSA, and so on) that cannot be decrypted without their involvement (since the cryptography algorithms generate unique keys). Cyber criminals store these keys on remote servers controlled only by them. There are no tools capable of decrypting Mdk4y encryption free of charge - the best option in this case is to use an existing data backup and restore all files from there.

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

Mdk4y decrypt instructions

Mdk4y is a malicious program similar to many other programs of this type, such as Crypt0r, Tro, and Tfude. Most ransomware-type viruses share two main similarities: they block access to data by encryption and keep it in this state unless a ransom is paid (a decryption tool is purchased). Common differences are cryptography algorithm used for encryption and cost of tool required for decryption. Typically, people who have computers infected with ransomware are forced to contact cyber criminals, since only they can provide decryption tools or keys. Furthermore, they often use cryptographies that are 'uncrackable', unless the ransomware-type program is in development or contains bugs/flaws. Therefore, create regular data backups and keep them stored on unplugged devices or remote servers. If not, backups are encrypted together with regular data.

How did ransomware infect my computer?

The exact method that cyber criminals use to proliferate Mdk4y ransomware is unknown, however, they often employ spam email campaigns, trojans, dubious software download sources, and fake software updaters. Spam campaigns cause ransomware-type computer infections through malicious email attachments. Cyber criminals send emails that contain various files such as Microsoft Office documents, executable files, archive files, PDF documents, and so on. The main goal is to trick people into opening the included attachment. Once opened, it downloads and installs ransomware or other infections. Trojans are malware-type programs that, if installed, proliferate other computer infections and cause chain infections. Cyber criminals often use various untrustworthy software download sources to distribute malicious ransomware-type programs. They present infected files as legitimate, however, once downloaded and installed they infect computers with viruses such as ransomware. Some examples of dubious software download sources are third party downloaders (and installers), unofficial websites, and peer-to-peer networks (torrents, eMule, and so on). Using these sources, users are often tricked into downloading/installing computer infections. Fake software updaters are used to proliferate ransomware and other viruses. Generally, these updaters infect systems by downloading malicious programs rather than the updates or by exploiting outdated software bugs/flaws.

Threat Summary:
NameMdk4y virus
Threat TypeRansomware, Crypto Virus, Files locker
SymptomsCan't open files stored on your computer, previously functional files now have a different extension, for example my.docx.locked. A ransom demanding message is displayed on your desktop. Cyber criminals are asking to pay a ransom (usually in bitcoins) to unlock your files.
Distribution methodsInfected email attachments (macros), torrent websites, malicious ads.
DamageAll 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.

To eliminate Mdk4y virus our malware researchers recommend scanning your computer with Spyhunter.
▼ Download Spyhunter
Free scanner checks if your computer is infected. To remove malware, you have to purchase the full version of Spyhunter.

How to protect yourself from ransomware infections?

To avoid computer infections by ransomware, browse the web, download, install and update software with caution. Attachments (or web links) included in emails received from unknown/suspicious addresses should not be opened without studying them first. If the email is irrelevant or suspicious, ignore it. Do not download (or install) software using third party downloaders/installers. These tools are usually monetized by promoting (bundling) untrustworthy/rogue applications. Avoid downloading software using peer-to-peer networks. Download software using official, trustworthy sources and direct links. Keep software updated but use legitimate tools provided by official software developers, and not third party updaters. Finally, have reputable anti-virus/anti-spyware software installed and enabled at all times. If your computer is already infected with Mdk4y, we recommend running a scan with Spyhunter for Windows to automatically eliminate this ransomware.

Text presented in Mdk4y ransomware text file :

Dear manager,
your database server has been locked, your databases files are encrypted and you have unfortunately "lost" all your data, Encryption was produced using unique key AES-256 generated for this server.
To decrypt files you need to obtain the decryption key and tool.
All encrypted files ends with .charm
To obtain the program for this server, which will decrypt all files, you need to write me to email: "";
Before payment you can send us one small file (100..500 kilobytes) and we will decrypt it - it's your guarantee that we have decryption tool. And send us your userkey
We don't know who are you, All what we need is some money.
Don't panic if we don't answer you during 24 hours. It means that we didn't received your letter and write us again.
You can use one of that bitcoin exchangers for transfering bitcoin:
You dont need install bitcoin programs - you need only use one of this exchangers or other exchanger that you can find in for your country.
Please use english language in your letters. If you don't speak english then use to translate your letter on english language.
You don't have enough time to think each day payment will increase and after one week your key will be deleted and your files will be locked forever.

Screenshot of files encrypted by Mdk4y (".mdk4y" extension):

Files encrypted by Mdk4y

Screenshot of a malicious Mdk4y process (named as a random string):

mdk4y ransomware process in task manager named as random string

Mdk4y ransomware removal:

Instant automatic removal of Mdk4y virus: Manual threat removal might be a lengthy and complicated process that requires advanced computer skills. Spyhunter is a professional automatic malware removal tool that is recommended to get rid of Mdk4y virus. Download it by clicking the button below:
▼ DOWNLOAD Spyhunter By downloading any software listed on this website you agree to our Privacy Policy and Terms of Use. Free scanner checks if your computer is infected. To remove malware, you have to purchase the full version of Spyhunter.

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 Mdk4y 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 Mdk4y 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 Mdk4y 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 Mdk4y 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 Mdk4y, 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 Mdk4y 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, as well as 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 Mdk4y ransomware: