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Remove Oonn ransomware (Virus Removal Guide) - Free Instructions

removal by Jake Doevan - - | Type: Ransomware

Oonn ransomware – file-encrypting virus that will ask for a ransom in order to get back your data

Oonn ransomwareOonn ransomware is a file locking virus that stems from Djvu malware family

Oonn ransomware is a data-locking computer infection that targets users all over the world. First spotted in August 2020, the malware is just another addition to the extensive Djvu ransomware family, which consists of almost 250 variants already. Just as its predecessors such as Nile, Kuus, or Erif, the virus is primarily spread via software cracks and other malicious installers, although it does not mean that other infection means are impossible.

As soon as the Oonn files virus gains access to the machine, it encrypts[1] all personal data (archives, pictures, documents, databases, videos, etc.) on the system and drops _readme.txt ransom note, which serves as a notification from the attackers. Inside, victims are warned that the only way to remove .oonn file virus extension is to pay a ransom of $490/$980 in bitcoin digital currency. However, there might be other options when it comes to file decryption, so contacting the attackers via or is not recommended.

Name Oonn ransomware, Oonn file virus, .oonn virus
Type File locking virus, cryptomalware
Malware family Djvu/STOP
Distribution Software cracks and pirated program installers
Encryption method RSA is used to encrypt all non-system and non-executable files on the infected machine
File extension  .oonn 
Ransom note  _readme.txt is dropped on several locations on the infected machine 
Contact Malicious actors ask users to email them via or for negotiation purposes
Malware removal  To completely terminate malware from the infected computer, a full system scan with powerful anti-malware should be performed
Data recovery 

The only secure method to recover files safely is by copying them from backups. Other options include:

  • Using Emsisoft's decryption tool that could help some victims
  • Utilizing third-party recovery software
  • Paying cybercriminals (not recommended by experts)[2] 
Windows fix In case ransomware corrupted some of the system files, it might cause serious performance issues (crashes, lag, errors, etc.). In such a case, we recommend scanning the device with Reimage Reimage Cleaner Intego after an infection is eliminated

As previously mentioned, Oonn ransomware is mainly spread via contaminated executables that can be downloaded from dangerous sources, such as torrent sites. Despite this distribution method being primitive as it does not require complex usage of various features (in contrary to exploit kits and similar), threat actors behind the strain are infecting hundreds of users each day, and are releasing new variants on a regular basis. Currently, Djvu is the most prolific crypto-malware that targets home consumers.

As soon as the virus gains access to the device, it first shows a pop-up that looks identical to that of a Windows update prompt. This is done in order to mislead users and prevent them from terminating the encryption process. This way, the attackers behind the Oonn virus can cause maximum damage to victims and lock the files that are most important to them, including PDF, .jpg, .zip, .doc, .mpg, and many others.

However, since the main goal of Oonn ransomware is not to corrupt Windows system (although this might occur unintentionally – this can lead to the need of OS reinstallation – we recommend attempting a fix with tools such as Reimage Reimage Cleaner Intego) but instead lock files, it skips system and some of the other important files. Besides, many ransomware self-delete after the data encryption is complete, although Oonn ransomware removal might still be needed due to several reasons:

  • Djvu variants are known to be distributed along with other malware, such as banking trojan[3] AZORult;
  • File locking virus might install the data-stealing module into Google Chrome, Mozilla Firefox, MS Edge, or another web browser;
  • If not deleted, it might re-encrypt all files that might have been recovered in different ways.

Also, Oonn files virus might also prevent access to security-related websites that seek to help victims of ransomware. This is done with the help of the Windows “hosts” file, where a set of URLs is held. Since the host's file is not malicious and is a part of any Windows system, the security application can not undo such changes, so you should go to the C:\Windows\System32\drivers\etc\ location and delete the file after you remove Oonn ransomware. 

Oonn ransomware virusOonn ransomware is a type of malware that encrypts all personal files on the system and restricts access to them until ransom is paid

.OONN virus file recovery options

After malware performs the data locking process, users can no longer access .oonn files anymore. Instead, they are presented with a ransom note _readme.txt, which provides the following information:


Don't worry, you can return all your files!
All your files like photos, databases, documents and other important are encrypted with strongest encryption and unique key.
The only method of recovering files is to purchase decrypt tool and unique key for you.
This software will decrypt all your encrypted files.
What guarantees you have?
You can send one of your encrypted file from your PC and we decrypt it for free.
But we can decrypt only 1 file for free. File must not contain valuable information.
You can get and look video overview decrypt tool:
Price of private key and decrypt software is $980.
Discount 50% available if you contact us first 72 hours, that's price for you is $490.
Please note that you'll never restore your data without payment.
Check your e-mail “Spam” or “Junk” folder if you don't get answer more than 6 hours.

To get this software you need write on our e-mail:

Reserve e-mail address to contact us:

Your personal ID:

As evident, crooks behind Oonn ransomware virus are willing to provide “test decryption” and even a discount if contact is made within 72 hours of the infection. However, these are all promises that might never be fulfilled, as cybercriminals care little about users' well being, evidently. Thus, if you pay, you might not only lose .oonn files forever but also a significant sum of money.

However, the question remains – how to open .oonn file extension without paying cybercriminals? The answer to this question is not simple, as each case is individual, and consists of many factors.

As a general misconception, users infected with ransomware believe that they can recover .oonn files as soon as they eliminate ransomware from their systems. However, it is important to understand that security software will not allow you to access your locked data, as it is not designed for such a purpose.

Instead, there are several other options that can sometimes be useful when trying to recover Oonn files. Here are a few examples:

  • You can attempt to use Emsisoft's decryption tool that might be useful in some cases (i.e., if the virus used an offline ID to lock your files and somebody with the same ID paid criminals and then shared the key with security researchers behind the decryptor);
  • Built-in system resources, such as Shadow Volume Copies, might be extremely useful when trying to recover .oonn files. Unfortunately, these backups are deleted by malware if everything goes as planned;
  • Third-party recovery solutions can also be used for the data recovery process – they sometimes might help you retrieve at least some portion of lost files.

Oonn ransomware limited decryption optionsOnce Oonn file virus encrypts data, restoring it might be extremely difficult, if not impossible

First, remove Oonn ransomware and only then attempt to recover .oonn files

What most infected users do not comprehend is that file encryption process and malware infection are two separate functions (although the former is not possible without the latter) and that Oonn virus removal will not allow them to open their lost files. Nonetheless, it is important to perform various steps in the correct order, or recovered data might be encrypted repeatedly. It is also important to repair affected system files, so malicious functions get fully disabled. Try Reimage Reimage Cleaner Intego as a PC repair tool in such a case.

Before you do anything, you should first copy all the encrypted files to another medium – you can choose online could storage such as OneDrive or back it on a physical external drive. Keep in mind that encrypted .oonn files do not have malicious code in them, so they are safe to transfer.

Once that is complete, you can then remove Oonn ransomware from your machine. For that, download and install powerful security software like SpyHunter 5Combo Cleaner or Malwarebytes, and perform a full system scan. Before you scan your device, ensure that anti-malware is fully updated, as it might not recognize the infection right away. Finally, you can then attempt to recover .oonn files with the help of solutions we provide below.

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Reimage Happiness
Intego Happiness
Compatible with Microsoft Windows Supported versions Compatible with OS X Supported versions
What to do if failed?
If you failed to remove virus damage using Reimage Intego, submit a question to our support team and provide as much details as possible.
Reimage Intego has a free limited scanner. Reimage Intego offers more through scan when you purchase its full version. When free scanner detects issues, you can fix them using free manual repairs or you can decide to purchase the full version in order to fix them automatically.
Alternative Software
Different software has a different purpose. If you didn’t succeed in fixing corrupted files with Reimage, try running SpyHunter 5.
Alternative Software
Different software has a different purpose. If you didn’t succeed in fixing corrupted files with Intego, try running Combo Cleaner.

To remove Oonn virus, follow these steps:

Remove Oonn using Safe Mode with Networking

To access Safe Mode with Networking, perform the following actions:

  • Step 1: Reboot your computer to Safe Mode with Networking

    Windows 7 / Vista / XP
    1. Click Start Shutdown Restart OK.
    2. When your computer becomes active, start pressing F8 multiple times until you see the Advanced Boot Options window.
    3. Select Safe Mode with Networking from the list Select 'Safe Mode with Networking'

    Windows 10 / Windows 8
    1. Press the Power button at the Windows login screen. Now press and hold Shift, which is on your keyboard, and click Restart..
    2. Now select Troubleshoot Advanced options Startup Settings and finally press Restart.
    3. Once your computer becomes active, select Enable Safe Mode with Networking in Startup Settings window. Select 'Enable Safe Mode with Networking'
  • Step 2: Remove Oonn

    Log in to your infected account and start the browser. Download Reimage Reimage Cleaner Intego or other legitimate anti-spyware program. Update it before a full system scan and remove malicious files that belong to your ransomware and complete Oonn removal.

If your ransomware is blocking Safe Mode with Networking, try further method.

Remove Oonn using System Restore

System Restore can also sometimes be useful when trying to delete malware:

  • Step 1: Reboot your computer to Safe Mode with Command Prompt

    Windows 7 / Vista / XP
    1. Click Start Shutdown Restart OK.
    2. When your computer becomes active, start pressing F8 multiple times until you see the Advanced Boot Options window.
    3. Select Command Prompt from the list Select 'Safe Mode with Command Prompt'

    Windows 10 / Windows 8
    1. Press the Power button at the Windows login screen. Now press and hold Shift, which is on your keyboard, and click Restart..
    2. Now select Troubleshoot Advanced options Startup Settings and finally press Restart.
    3. Once your computer becomes active, select Enable Safe Mode with Command Prompt in Startup Settings window. Select 'Enable Safe Mode with Command Prompt'
  • Step 2: Restore your system files and settings
    1. Once the Command Prompt window shows up, enter cd restore and click Enter. Enter 'cd restore' without quotes and press 'Enter'
    2. Now type rstrui.exe and press Enter again.. Enter 'rstrui.exe' without quotes and press 'Enter'
    3. When a new window shows up, click Next and select your restore point that is prior the infiltration of Oonn. After doing that, click Next. When 'System Restore' window shows up, select 'Next' Select your restore point and click 'Next'
    4. Now click Yes to start system restore. Click 'Yes' and start system restore
    Once you restore your system to a previous date, download and scan your computer with Reimage Reimage Cleaner Intego and make sure that Oonn removal is performed successfully.

Bonus: Recover your data

Guide which is presented above is supposed to help you remove Oonn from your computer. To recover your encrypted files, we recommend using a detailed guide prepared by security experts.

If your files are encrypted by Oonn, you can use several methods to restore them:

Data Recovery Pro could be a good solution for your file problem

Data Recovery Pro might be used when trying to recover Oonn files. However, keep in mind that chance of success is relatively low.

  • Download Data Recovery Pro;
  • Follow the steps of Data Recovery Setup and install the program on your computer;
  • Launch it and scan your computer for files encrypted by Oonn ransomware;
  • Restore them.

Windows Previous Versions Feature might be of use

If. for some reason, malware failed to delete automated Windows backups, and you had System Restore function enabled, you can attempt to retrieve files one-by-one.

  • Find an encrypted file you need to restore and right-click on it;
  • Select “Properties” and go to “Previous versions” tab;
  • Here, check each of available copies of the file in “Folder versions”. You should select the version you want to recover and click “Restore”.

In some cases, ShadowExplorer could assist you

ShadowExplorer is another automated tool that could retrieve the locked files if malware failed to delete Shadow Volume Copies.

  • Download Shadow Explorer (;
  • Follow a Shadow Explorer Setup Wizard and install this application on your computer;
  • Launch the program and go through the drop down menu on the top left corner to select the disk of your encrypted data. Check what folders are there;
  • Right-click on the folder you want to restore and select “Export”. You can also select where you want it to be stored.

Try Emsisoft's decryption tool for Djvu

Previous variants of Djvu are known to fail to contact the destination server in order to apply a unique encryption pattern to data. If that happens in your case, you might attempt data recovery with the help of Emsisoft's decryption tool specially designed for the Djvu malware family.

Finally, you should always think about the protection of crypto-ransomwares. In order to protect your computer from Oonn and other ransomwares, use a reputable anti-spyware, such as Reimage Reimage Cleaner Intego, SpyHunter 5Combo Cleaner or Malwarebytes

Access your website securely from any location

When you work on the domain, site, blog, or different project that requires constant management, content creation, or coding, you may need to connect to the server and content management service more often. It is a hassle when your website is protected from suspicious connections and unauthorized IP addresses.

The best solution for creating a tighter network could be a dedicated/fixed IP address. If you make your IP address static and set to your device, you can connect to the CMS from any location and do not create any additional issues for server or network manager that need to monitor connections and activities. This is how you bypass some of the authentications factors and can remotely use your banking accounts without triggering suspicious with each login. 

VPN software providers like Private Internet Access can help you with such settings and offer the option to control the online reputation and manage projects easily from any part of the world. It is better to clock the access to your website from different IP addresses. So you can keep the project safe and secure when you have the dedicated IP address VPN and protected access to the content management system.

Recover files after data-affecting malware attacks

While much of the data can be accidentally deleted due to various reasons, malware is one of the main culprits that can cause loss of pictures, documents, videos, and other important files. More serious malware infections lead to significant data loss when your documents, system files, and images get encrypted. In particular, ransomware is is a type of malware that focuses on such functions, so your files become useless without an ability to access them.

Even though there is little to no possibility to recover after file-locking threats, some applications have features for data recovery in the system. In some cases, Data Recovery Pro can also help to recover at least some portion of your data after data-locking virus infection or general cyber infection. 


About the author
Jake Doevan
Jake Doevan - Computer technology expert

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