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Remove .mdk4y Ransomware Infections

This article will aid you to remove .mdk4y Ransomware. Follow the ransomware removal instructions provided at the end of the article.

.mdk4y Ransomware is one that encrypts your data and demands money as a ransom to get it restored. Files will receive the .mdk4y extension. The .mdk4y Ransomware will leave ransomware instructions as a desktop wallpaper image. Keep on reading the article and see how you could try to potentially recover some of your locked files and data.

Threat Summary

Name .mdk4y ransomware
Type Ransomware, Cryptovirus
Short Description The ransomware encrypts files by placing the .mdk4y before the affected files on your computer system and demands a ransom to be paid to allegedly recover them.
Symptoms The ransomware will encrypt your files and leave a ransom note with payment instructions.
Distribution Method Spam Emails, Email Attachments
Detection Tool See If Your System Has Been Affected by malware


Malware Removal Tool

User Experience Join Our Forum to Discuss .mdk4y ransomware.
Data Recovery Tool Windows Data Recovery by Stellar Phoenix Notice! This product scans your drive sectors to recover lost files and it may not recover 100% of the encrypted files, but only few of them, depending on the situation and whether or not you have reformatted your drive.

.mdk4y Ransomware – Distribution Techniques

The .mdk4y ransomware is a new release that is attributed to the Kraken ransomware family. At the moment of writing this article no in-depth information is available about it which probably means that the sent volume of infections is low. This may mean that the virus is still being developed and a testing wave has been initiated or that an early version has been leaked onto the web. Whatever the reason the hackers behind it will probably attempt different tactics in order to judge which one would be the most effective at infecting as much victims as possible.

Most ransomware will be spread via SPAM email messages that use both phishing and SPAM tactics in order to coerce as much targets into infecting themselves as possible. They will be designed as legitimate notifications from a well-known company, portal or product that the victims might recognize. The .mdk4y ransomware files can be either attached directly to the messages as file attachments or linked in the body contents via multimedia content and in text links.

The creation of malicious web sites is the other popular tactic which is done by the hackers. They will create fake landing pages, download portals or other web addresses that can impersonate popular and safe sites. Most of the successful ones use stolen or hacker-made security certificates and similar sounding domain names.

To deliver more files and increase the number of potentially affected users the hackers can also send them via file-sharing networks like BitTorrent. It is used by computer users to share both legitimate and pirate content such as applications, movies, games, e-books and etc.

The .mdk4y ransomware samples can additionally be embedded in other files to create the so-called payload carriers of which there are two popular variants:

  • Software Installers — The criminals behind the malware can modify the legitimate setup files of popular applications to lead to the virus infections. Choices include system utilities, productivity and office apps, as well as creativity suites and games. Whenever one of these files is run the ransomware installation will begin in the background.
  • Malicious Documents — The same strategy can be used to modify documents across all popular formats: spreadsheets, databases, text documents and presentations. Whenever one of them is opened by a victim user it will spawn a notification prompt requesting that the built-in macros (scripts) to be enabled in order to “correctly view” the file.

In order to carry out larger .mdk4y ransomware attacks the hackers may use malicious browser plugins which are also known as hijackers. They are widely deployed to the relevant repositories using fake (or stolen) developer credentials and user reviews. The elaborate descriptions promise new features and enhancements. As soon as they are installed the .mdk4y ransomware will be installed. Most of the hijackers additionally will change the settings of the browsers by redirecting the victims to a hacker-controlled landing page. Modifications include the default home page, search engine and new tabs page.

.mdk4y Ransomware – Detailed Analysis

The .mdk4y ransomware is a new samples that belongs to the Kraken ransomware family. As such the behavior patterns that are known from the previous versions will probably be used. It is possible that follow-up versions of it will be developed with additional features and upgraded code.

The Kraken ransomware infections are notorious for impacting as many devices as possible during a single infection which is attributed to the fact that some of the samples may have launched an advanced data harvesting module. It is used to gather sensitive data that can be grouped into two main categories:

  • Personal Data — The engine can be programmed to extract data that can directly expose the identity of the victim users. This is possible due to the fact that the engine can scan for specific strings both in the hard disk contents, memory and the Windows Registry. This leads to the exposure of their name, address, location, interests and any stored account credentials.
  • Machine Information — The engine can harvest metrics about the infected computers, specifically the hardware components, user configuration, boot options and regional settings. The bulk of the collected is run through an algorithm that takes the collected information and as a result an unique infection ID is generated. It can uniquely identify each compromised machine.

This information can be used to identify if any security software can be bypassed. This is done by scanning the hard disk contents, memory, Windows Registry values and other sources for applications and services that can interfere with the proper virus execution. The list of affected software includes anti-virus products, firewalls, virtual machine hosts and debug environments. As soon as any of them are identified their real-time engines will be stopped, in other cases the whole applications can be removed altogether.

As soon as the .mdk4y ransomware has taken control of the computer it will be able to modify the system according to the built-in instructions of the hackers. One of the most popular actions is the installation of the threat as a persistent threat. This is done by modifying system settings, boot options and configuration files to make the malicious automatically to start once the computer is booted.

Interaction with the Windows Registry is also widely considered — changes made to strings belonging to the operating system can cause services to fail to start and severe performance and stability issues. On the other hand modifications to individual applications can render them unusable or to exit with unexpected errors. Corruption of user data is also possible.

Hooking up to existing processes is used to extract information about the user activities. Additionally advanced infections can start a Trojan infection which establishes a secure connection to a hacker-controlled service. It allows the criminals to spy on the victims, harvest the collected information and additionally take over control of the machines at any given time.

As this sample belongs to the Kraken ransomware family it is expected that it will be pushed via large-scale attack methods as soon as an upgraded version is ready.

.mdk4y Ransomware – Encryption Process

The .mdk4y ransomware follows the typical behavior as previously reported by the Kraken ransomware family. A powerful cipher will be used to encrypt sensitive data based on a list of target file extensions. Most of them will act against the following data:

  • Archives
  • Backups
  • Databases
  • Images
  • Music
  • Videos

All affected files will be assigned the .mdk4y extension indicating that they have been processed by the virus. A standard ransomware note will be created in a file called HOW_TO_RETURN_FILES.txt.

Remove .mdk4y Ransomwareand Try to Restore Data

If your computer system got infected with the .mdk4y ransomware virus, you should have a bit of experience in removing malware. You should get rid of this ransomware as quickly as possible before it can have the chance to spread further and infect other computers. You should remove the ransomware and follow the step-by-step instructions guide provided below.

Martin Beltov

Martin graduated with a degree in Publishing from Sofia University. As a cyber security enthusiast he enjoys writing about the latest threats and mechanisms of intrusion.

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Attention! SensorsTechForum strongly recommends that all malware victims should look for assistance only by reputable sources. Many guides out there claim to offer free recovery and decryption for files encrypted by ransomware viruses. Be advised that some of them may only be after your money.

As a site that has been dedicated to providing free removal instructions for ransomware and malware since 2014, SensorsTechForum’s recommendation is to only pay attention to trustworthy sources.

How to recognize trustworthy sources:

  • Always check "About Us" web page.
  • Profile of the content creator.
  • Make sure that real people are behind the site and not fake names and profiles.
  • Verify Facebook, LinkedIn and Twitter personal profiles.


with Anti-Malware
We recommend you to download SpyHunter and run free scan to remove all virus files on your PC. This saves you hours of time and effort compared to doing the removal yourself.
SpyHunter 5 free remover allows you, subject to a 48-hour waiting period, one remediation and removal for results found. Read EULA and Privacy Policy

About the .mdk4y ransomware Research

The content we publish on SensorsTechForum.com, this .mdk4y ransomware how-to removal guide included, is the outcome of extensive research, hard work and our team’s devotion to help you remove the specific malware and restore your encrypted files.

How did we conduct the research on this ransomware?

Our research is based on an independent investigation. We are in contact with independent security researchers, and as such, we receive daily updates on the latest malware and ransomware definitions.

Furthermore, the research behind the .mdk4y ransomware ransomware threat is backed with VirusTotal and the NoMoreRansom project.

To better understand the ransomware threat, please refer to the following articles which provide knowledgeable details.


1. How to Recognize Spam Emails with Ransomware
2. How Does Ransomware Encryption Work?
3. How to Decrypt Ransomware Files
4. Ransomware Getting Greedier and Bigger, Attacks Increase by 40%
5. 1 in 5 Americans Victim of Ransomware

Windows Mac OS X

How to Remove .mdk4y ransomware from Windows.

Step 1: Boot Your PC In Safe Mode to isolate and remove .mdk4y ransomware


Manual Removal Usually Takes Time and You Risk Damaging Your Files If Not Careful!
We Recommend To Scan Your PC with SpyHunter

Keep in mind, that SpyHunter’s scanner is only for malware detection. If SpyHunter detects malware on your PC, you will need to purchase SpyHunter's malware removal tool to remove the malware threats. Read our SpyHunter 5 review. Click on the corresponding links to check SpyHunter's EULA, Privacy Policy and Threat Assessment Criteria

1. Hold Windows Key + R.

2. The "Run" Window will appear. In it, type "msconfig" and click OK.

3. Go to the "Boot" tab. There select "Safe Boot" and then click "Apply" and "OK".

Tip: Make sure to reverse those changes by unticking Safe Boot after that, because your system will always boot in Safe Boot from now on.

4. When prompted, click on "Restart" to go into Safe Mode.

5. You can recognise Safe Mode by the words written on the corners of your screen.

Step 2: Uninstall .mdk4y ransomware and related software from Windows

Here is a method in few easy steps that should be able to uninstall most programs. No matter if you are using Windows 10, 8, 7, Vista or XP, those steps will get the job done. Dragging the program or its folder to the recycle bin can be a very bad decision. If you do that, bits and pieces of the program are left behind, and that can lead to unstable work of your PC, errors with the file type associations and other unpleasant activities. The proper way to get a program off your computer is to Uninstall it. To do that:

1. Hold the Windows Logo Button and "R" on your keyboard. A Pop-up window will appear.

2. In the field type in "appwiz.cpl" and press ENTER.

3. This will open a window with all the programs installed on the PC. Select the program that you want to remove, and press "Uninstall"

Follow the instructions above and you will successfully uninstall most programs.

Step 3: Clean any registries, created by .mdk4y ransomware on your computer.

The usually targeted registries of Windows machines are the following:

  • HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
  • HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
  • HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunOnce
  • HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnce

You can access them by opening the Windows registry editor and deleting any values, created by .mdk4y ransomware there. This can happen by following the steps underneath:

1. Open the Run Window again, type "regedit" and click OK.

2. When you open it, you can freely navigate to the Run and RunOnce keys, whose locations are shown above.

3. You can remove the value of the virus by right-clicking on it and removing it.

Tip: To find a virus-created value, you can right-click on it and click "Modify" to see which file it is set to run. If this is the virus file location, remove the value.

Before starting "Step 4", please boot back into Normal mode, in case you are currently in Safe Mode.
This will enable you to install and use SpyHunter 5 successfully.

Step 4: Scan for .mdk4y ransomware with SpyHunter Anti-Malware Tool

1. Click on the "Download" button to proceed to SpyHunter's download page.

It is recommended to run a scan before purchasing the full version of the software to make sure that the current version of the malware can be detected by SpyHunter. Click on the corresponding links to check SpyHunter's EULA, Privacy Policy and Threat Assessment Criteria.

2. After you have installed SpyHunter, wait for it to update automatically.


3. After the update process has finished, click on the 'Malware/PC Scan' tab. A new window will appear. Click on 'Start Scan'.


4. After SpyHunter has finished scanning your PC for any files of the associated threat and found them, you can try to get them removed automatically and permanently by clicking on the 'Next' button.


If any threats have been removed, it is highly recommended to restart your PC.

Video Guide for Automatic and Fast Removal

Step 5 (Optional): Try to Restore Files Encrypted by .mdk4y ransomware.

Ransomware infections and .mdk4y ransomware aim to encrypt your files using an encryption algorithm which may be very difficult to decrypt. This is why we have suggested a data recovery method that may help you go around direct decryption and try to restore your files. Bear in mind that this method may not be 100% effective but may also help you a little or a lot in different situations.

1. Download the recommended Data Recovery software by clicking on the link underneath:

Simply click on the link and on the website menus on the top, choose Data Recovery - Data Recovery Wizard for Windows or Mac (depending on your OS), and then download and run the tool.

Step 6: How to Restore Files Encrypted by Ransomware (Video Guide)

Windows Mac OS X

Get rid of .mdk4y ransomware from Mac OS X.

Step 1: Uninstall .mdk4y ransomware and remove related files and objects

Manual Removal Usually Takes Time and You Risk Damaging Your Files If Not Careful!
We Recommend To Scan Your Mac with SpyHunter for Mac
Keep in mind, that SpyHunter for Mac needs to purchased to remove the malware threats. Click on the corresponding links to check SpyHunter’s EULA and Privacy Policy

1. Hit the ⇧+⌘+U keys to open Utilities. Another way is to click on “Go” and then click “Utilities”, like the image below shows:

2. Find Activity Monitor and double-click it:

3. In the Activity Monitor look for any suspicious processes, belonging or related to .mdk4y ransomware:

Tip: To quit a process completely, choose the “Force Quit” option.

4. Click on the "Go" button again, but this time select Applications. Another way is with the ⇧+⌘+A buttons.

5. In the Applications menu, look for any suspicious app or an app with a name, similar or identical to .mdk4y ransomware. If you find it, right-click on the app and select “Move to Trash


6. Select Accounts, after which click on the Login Items preference.

Your Mac will then show you a list of items that start automatically when you log in. Look for any suspicious apps identical or similar to .mdk4y ransomware. Check the app you want to stop from running automatically and then select on the Minus (“-“) icon to hide it.

7. Remove any left-over files that might be related to this threat manually by following the sub-steps below:

  • Go to Finder.
  • In the search bar type the name of the app that you want to remove.
  • Above the search bar change the two drop down menus to “System Files” and “Are Included” so that you can see all of the files associated with the application you want to remove. Bear in mind that some of the files may not be related to the app so be very careful which files you delete.
  • If all of the files are related, hold the ⌘+A buttons to select them and then drive them to “Trash”.

In case you cannot remove .mdk4y ransomware via Step 1 above:

In case you cannot find the virus files and objects in your Applications or other places we have shown above, you can manually look for them in the Libraries of your Mac. But before doing this, please read the disclaimer below:

Disclaimer! If you are about to tamper with Library files on Mac, be sure to know the name of the virus file, because if you delete the wrong file, it may cause irreversible damage to your MacOS. Continue on your own responsibility!

1: Click on "Go" and Then "Go to Folder" as shown underneath:

2: Type in "/Library/LauchAgents/" and click Ok:

3: Delete all of the virus files that have similar or the same name as .mdk4y ransomware. If you believe there is no such file, do not delete anything.

You can repeat the same procedure with the following other Library directories:

→ ~/Library/LaunchAgents

Tip: ~ is there on purpose, because it leads to more LaunchAgents.

Click the button below below to download SpyHunter for Mac and scan for .mdk4y ransomware:


SpyHunter for Mac

Step 3 (Optional): Try to Restore Files Encrypted by .mdk4y ransomware.

Ransomware infections and .mdk4y ransomware aim to encrypt your files using an encryption algorithm which may be very difficult to decrypt. This is why we have suggested a data recovery method that may help you go around direct decryption and try to restore your files. Bear in mind that this method may not be 100% effective but may also help you a little or a lot in different situations.

1. Download the recommended Data Recovery software by clicking on the link underneath:

Simply click on the link and on the website menus on top, choose Data Recovery - Data Recovery Wizard for Windows or Mac (depending on your OS), and then download and run the tool.

.mdk4y ransomware FAQ

What is .mdk4y ransomware ransomware and how does it work?

.mdk4y ransomware is a ransomware infection - the malicious software that enters your computer silently and blocks either access to the computer itself or encrypt your files.

Many ransomware viruses use sophisticated encryption algorithm how to make your files inaccessible. The goal of ransomware infections is to demand that you pay a ransom payment to get access to your files back.

How does .mdk4y ransomware ransomware infect my computer?

Via several ways..mdk4y ransomware Ransomware infects computers by being sent via phishing e-mails, containing virus attachment.

This attachment is usually masked as an important document, like an invoice, bank document or even a plane ticket and it looks very convincing to users.

After you download and execute this attachment, a drive-by download occurs and your computer is infected with the ransomware virus.

Another way, you may become a victim of .mdk4y ransomware is if you download a fake installer, crack or patch from a low reputation website or if you click on a virus link. Many users report getting a ransomware infection by downloading torrents.

How to open ..mdk4y ransomware files?

You can't. At this point the ..mdk4y ransomware files are encrypted. You can only open them once they are decrypted.

Decryptor did not decrypt my data. What now?

Do not panic and backup the files. If a decryptor did not decrypt your ..mdk4y ransomware files successfully, then do not despair, because this virus is still new.

One way to restore files, encrypted by .mdk4y ransomware ransomware is to use a decryptor for it. But since it's a new virus, advised that the decryption keys for it may not be out yet and available to the public. We will update this article and keep you posted as soon as this decryptor is released.

How Do I restore "..mdk4y ransomware" files (Other Methods)?

Yes, sometimes files can be restored. We have suggested several file recovery methods that could work if you want to restore ..mdk4y ransomware files.

These methods are in no way 100% guarantee that you will be able to get your files back. But if you have a backup, your chances of success are much greater.

How do I get rid of .mdk4y ransomware ransomware virus?

The safest way and the most efficient one for the removal of this ransomware infection is the use a professional anti malware software. It will scan for and locate .mdk4y ransomware ransomware and then remove it without causing any additional harm to your important ..mdk4y ransomware files.

Also, keep in mind that viruses like .mdk4y ransomware ransomware also install Trojans and keyloggers that can steal your passwords and accounts. Scanning your computer with an anti-malware software will make sure that all of these virus components are removed and your computer is protected in the future.

What to Do If nothing works?

There is still a lot you can do. If none of the above methods seem to work for you, then try these methods:

  • Try to find a safe computer from where you can can login on your own line accounts like One Drive, iDrive, Google Drive and so on.
  • Try to contact your friends, relatives and other people so that they can check if they have some of your important photos or documents just in case you sent them.
  • Also, check if some of the files that were encrypted it can be re-downloaded from the web.
  • Another clever way to get back some of your files is to find another old computer, a flash drive or even a CD or a DVD where you may have saved your older documents. You might be surprised what will turn up.
  • You can also go to your email account to check if you can send any attachments to other people. Usually what is sent the email is saved on your account and you can re-download it. But most importantly, make sure that this is done from a safe computer and make sure to remove the virus first.

More tips you can find on our forums, where you can also asks any questions about your ransomware problem.

How to Report Ransomware to Authorities?

In case your computer got infected with a ransomware infection, you can report it to the local Police departments. It can help authorities worldwide track and determine the perpetrators behind the virus that has infected your computer. Below, we have prepared a list with government websites, where you can file a report in case you are a victim of a cybercrime:

Cyber-security authorities, responsible for handling ransomware attack reports in different regions all over the world:

Reports may be responded to in different timeframes, depending on your local authorities.

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