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StupidJapan Virus – How to Remove It

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

StupidJapan Virus is one that encrypts your data and demands money as a ransom to get it restored. The StupidJapan Virus will leave ransomware instructions as a lockscreen instance thereby making it impossible to interact with the computer in an ordinary way. Keep on reading the article and see how you could try to potentially recover some of your locked files and data.

Threat Summary

Name StupidJapan
Type Ransomware, Cryptovirus
Short Description The ransomware will demands a ransom sum to be paid to allegedly recover the computer.
Symptoms The ransomware will install a lockscreen window 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 StupidJapan.
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.

StupidJapan Virus – Distribution Techniques

We have received security reports of a dangerous new infection carrying the StupidJapan virus. The collected releases of this ransomware have been identified in an ongoing attack campaign. So far the number of collected samples are low in number which does not give out which is the main method of distribution. We anticipate that once the attacks are launched at a larger scale the infections will utilize several of the most popular techniques.

Many ransomware threats like the StupidJapan virus are spread via email SPAM messages which utilize various social engineering techniques. They are created in a way which impersonates popular services or companies. The infected files can be either linked or attached directly to the messages.

Another similar tactic relies on the creation of web sites that impersonate download portals or vendor pages. These two techniques are also used to spread infected payloads of which there are two main types:

  • Infected Documents — The hackers can craft documents of all popular types: presentations, spreadsheets, text documents and databases. When they are opened by users will be asked to enable the built-in scripts. This will lead to the virus infection.
  • Application Installers — The other popular infection method is the inclusion of the virus code in application installers across all popular software that is downloaded by end users: productivity, office tools, creativity suites and system utilities.

Large-scale infection campaigns can be caused by the use of browser hijackers which are dangerous extensions made for the most popular web browsers. They are frequently uploaded to their relevant plugin repositories with fake user reviews and developer credentials. The descriptions offered often promise feature additions and performance optimizations. As soon as they are installed the hijacker will deliver the ransomware code along with the execution of other commands as configured by the hackers.

All virus-related files can also be spread via file-sharing networks like BitTorrent. They are used to share both legitimate content and pirate versions of both software and multimedia files.

StupidJapan Virus – Detailed Analysis

The StupidJapan virus does not appear to originate from any of the known malware families. This probably means that the hackers have made it by themselves or have commissioned it through an order made in the hacker underground markets.

The ransomware seems to target mainly English-speaking users, the limited number of launched attacks suggest that the captured samples are merely early versions or a test release. We anticipate that future updates to its code will add many more additions to its code base. At the moment only the encryption module is present.

Further updates will probably incorporate a traditional infection pattern. Once the virus code has infiltrated the machine it will launch a data harvesting component. Using its built-in engine it can scan and extract contents from the hard drive, operating system and memory that is grouped into two main categories:

  • Private Information — The engine will hijack data that can directly expose the identity of the users: their name, address, phone number and any stored account credentials. This includes all popular forms such as username, password, email address and secret question & answer combination.
  • Machine ID Information — The collected data can also include such as operating system conditions, hardware components information and other user regional settings. They are fed through a special algorithms that computes an unique machine ID which is assigned to every different machine.

This information can be sent to the hackers using a network connection or used by another component called security bypass — it will scan for the presence of security software and services that can block the virus activity. The list may include most popular anti-virus products, firewalls and debug environments.

When these two modules have finished running the infection engine will be able to access the whole system. This allows them to carry out various changes such as the following:

  • Persistent Installation — The StupidJapan virus can be installed in a persistent way which will automatically start the ransomware as soon as the computer is launched. Modifications to the boot settings and system configuration will make it very hard to remove using manual methods. This option can also disable the boot recovery menu.
  • Windows Registry Changes — Modifications to existing values inside the Windows Registry can lead to problems both to the operating system, its services and any third-party installed applications. This can disable certain functions or altogether make it impossible to start them. Other consequences include serious system stability issues.
  • Trojan Horse Infection — If a Trojan virus infection is configured as an additional payload delivery the client will establish a secure connection to a hacker-controlled server. It will allow the hacker operators to spy on the users, steal their files and take over control of the machines at any given time.
  • Additional Payload Delivery — Other threats can be delivered to the infected machines include all popular forms of malware.

Some of the dangerous consequences of having such ransomware installed is their ability to delete system data which makes recovery much more difficult. Possible consequences include the deletion of System Backups and Shadow Volume Copies. In such cases the use of a professional-grade backup and recovery software must be used, refer to our instructions for more information.

Ransomware infections of this type can lead to the installation of malware such as cryptocurrency miners which will take advantage of the available system resources in order to download and execute resources-intensive tasks. Once the completed ones are reported to their relevant servers the hacker operators will receive digital currency directly into their wallets.

The other major threat that is combined often with ransomware is the delivery of browser hijackers. They represent malicious plugins made for the most popular web browsers which will trigger redirects to hacker-controlled sites, hijack data and change the browser settings.

Further updates may bring other changes to the infected computers.

StupidJapan Virus – Encryption Process

When all preliminary components have finished executing the encryption engine will be started. As these are test releases their ransomware component was switched off. The future versions will probably use a built-in list of target file type extensions. An example one is the following:

  • Archives
  • Backups
  • Documents
  • Music
  • Videos
  • Photos

When the encryption has completed a lockscreen instance will be shown to the victims. This replaces the traditional ransomware note technique by “locking out” the users. As long as the StupidJapan virus is installed on the victim machines it will show an application frame that reads the following message:

Are You Stupid Japan?
Let’s have yours.
The facts are being heard.
Do not regret it later and apologize quickly!
What to do.
Your personality will be known to the world as garbage.
I apologize to the Republic of Korea officially sorry!

Remove StupidJapan Virus and Try to Restore Data

If your computer system got infected with the StupidJapan 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 StupidJapan Research

The content we publish on SensorsTechForum.com, this StupidJapan 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 StupidJapan 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 StupidJapan from Windows.

Step 1: Boot Your PC In Safe Mode to isolate and remove StupidJapan


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 StupidJapan 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 StupidJapan 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 StupidJapan 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 StupidJapan 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 StupidJapan.

Ransomware infections and StupidJapan 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 StupidJapan from Mac OS X.

Step 1: Uninstall StupidJapan 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 StupidJapan:

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 StupidJapan. 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 StupidJapan. 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 StupidJapan 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 StupidJapan. 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 StupidJapan:


SpyHunter for Mac

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

Ransomware infections and StupidJapan 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.

StupidJapan FAQ

What is StupidJapan ransomware and how does it work?

StupidJapan 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 StupidJapan ransomware infect my computer?

Via several ways.StupidJapan 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 StupidJapan 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 .StupidJapan files?

You can't. At this point the .StupidJapan 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 .StupidJapan files successfully, then do not despair, because this virus is still new.

One way to restore files, encrypted by StupidJapan 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 ".StupidJapan" files (Other Methods)?

Yes, sometimes files can be restored. We have suggested several file recovery methods that could work if you want to restore .StupidJapan 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 StupidJapan 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 StupidJapan ransomware and then remove it without causing any additional harm to your important .StupidJapan files.

Also, keep in mind that viruses like StupidJapan 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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