Remove OONN Ransomware Virus (2021 Decrypt Guide)
OONN ransomware decrypt tool is held by the cybercriminals
Contents
OONN ransomware (also known as OONN file virus) is a malicious program that encrypts all files on victim’s computer, preventing one from opening them. This virus was developed by STOP/DJVU ransomware authors. Encrypted data will be marked with .oonn extension, for example, document.doc becomes document.doc.oonn. Later, this virus leaves _readme.txt ransom notes in every folder. The note advises victims to contact criminals via helpmanager@mail.ch or restoremanager@airmail.cc emails for file decryption steps.
OONN ransomware, similarly to other STOP/DJVU versions (NLAH, VAWE, ZIDA, REPL, MAAS, VARI, NILE, NORD), leaves a message from cybercriminals in _readme.txt file that serves as a ransom note. The message usually tries to comfort victims by stating that all data can be restored to the primary state. However, people must agree to pay the ransom for OONN file decryptor. The attackers even offer a 50% discount if victims agree to pay up within the first 72 hours of the infection. They ask for $490 in Bitcoins and later double the price to $980.
Bitcoin accounts are used to protect the identity of the cybercriminals, because cryptocurrency-based transactions are almost impossible to trace. Thus, agreeing to pay up even motivates the attackers to continue their malicious and illegal activity. Victims are asked to contact them via helpmanager@mail.ch or restoremanager@airmail.cc emails to receive the specific account details for the transaction. Afterward, the crooks promise to send the decryption software that helps to unlock files. Unfortunately, that is rarely the case.
Like file encryption hasn’t caused enough damage, this dangerous ransomware infiltrates AZORULT password-stealing software that helps to gather your passwords saved in browsers and send them to the attackers. It is only one of the many real-life cases showing that cybercriminals cannot be trusted. They are driven by monetary benefits and are not interested in being fair or just. Therefore, you should never reach out as demanded under any circumstances. There are alternative STOP/DJVU decryption methods.
Even though the decryption software cannot be replicated and only the attackers have it, we strongly suggest you to avoid getting in contact with them. The smartest decision would be to remove OONN ransomware virus as soon as you spot it on your computer. Reaching out to the crooks can lead to further damage or even cause enormous financial losses. Thus, do NOT contact the attackers despite how attractive their offer might seem.
Instead, we recommend performing OONN ransomware removal right after you detect the first symptoms. Since file-encrypting viruses are highly robust, you should either get help from an IT specialist in-person or install professional malware removal software. RESTORO can quickly eliminate malicious files and reverse virus damage on Windows OS registry. Check out the guide below to learn how to start ransomware removal from your computer.
Crypto-malware summary
| Name | OONN ransomware |
| Type | Crypto-malware, File-encrypting virus, File locker |
| Family | STOP/DJVU |
| Executive file | AF52.exe, 5EA6.tmp.exe, 7FG8.tmp.exe or similar |
| Versions | KOOK, NLAH, VAWE, KUUS, ZIPE, PEZI, ZIDA, REPL, MAAS, VARI, BOOP |
| Extension | .oonn |
| Ransom note | .readme.txt |
| Ransom amount | $490 at first and then $980 after 72 hours of the attack |
| Contacts | helpmanager@mail.ch, restoremanager@airmail.cc |
| Symptoms | Victims can spot a fake winupdate.exe process running on their computers and files marked with the extension afterward. Highly experienced computer users can notice the AZORULT malware hidden on their systems as well. |
| Distribution | Spam email campaigns and malicious pop-ups on suspicious sites |
| Decryption | You can either try alternative decryption options or use the latest backups from the Cloud |
| Removal | The safest way to get rid of the ransomware is to run a full system scan with RESTORO or another reputable malware removal software |
You can see a live demonstration of this ransomware encrypting file folder on our computer:
Threat Overview
Name: OONN ransomware
Description: OONN ransomware is a highly malicious computer virus that encrypts files on target computer and leaves _readme.txt notes that demand paying a ransom to cybercriminals.
Offer price: 980
Currency: USD
Operating System: Windows
Application Category: Ransomware
Author: STOP/DJVU authors
- DAMAGE (5)
- DISTRIBUTION (5)
- ENCRYPTION STRENGTH (5)
Overall
5User Review
( votes).oonn file decryption explained
You can expect to decrypt your personal files in the future if you have been affected by offline encryption type. This type is used by the virus when it fails to connect to the Internet network on the target host, which is required to connect to its Command & Control server and obtain an unique encryption/decryption key pair.
In such case, the virus uses offline encryption key, which is the same for all victims under the same scenario umbrella. Therefore, once someone pays for the key and shares it with Emsisoft researchers, they upload it it the said decryptor.
You can check whether your encryption was online or offline by going to C:/SystemID/PersonalID.txt file. If the string here ends in t1, it was offline encryption.
When it comes to online encryption, the only way to restore files for free is to use a data backup.
Pay attention to your download sources and websites you visit
There are several most common ransomware distribution techniques that help infiltrate file-encrypting viruses on the systems. When it comes to specific STOP/DJVU such as OONN ransomware distribution, it is known that the malware operators inject the executable to illegal
Another one of common ransomware distribution techniques is spam email campaigns that can reach every user. The developers of malware try to imitate emails from well-known companies to trick people into opening them. It can be a letter from the bank, software subscription, or others. Bear in mind that emails look exceptionally legitimate.
Usually, the message can inform about some necessary personal data updates that can be completed via the embedded link. Unfortunately, the link is actually malicious and downloads the ransomware executable on the system once clicked. Therefore, you should be very attentive when checking your email and never open letters that look even a tiny bit suspicious or questionable.
Furthermore, some cybercriminals spread ransomware via malicious pop-ups that appear while browsing on less than reliable websites. The pop-up can appear as a notification to update popular software, like Adobe Flash Player or others. If you click on the update button, you start an automatic installation of malware. Likewise, avoid not only browsing on questionable sites but also clicking on pop-ups that appear on your screen.
Practice says that the majority of ransomware victims are not even aware when and how their computers got infected. Cybercriminals disguise this ransomware attack under the imitation of a legitimate-looking Windows update. Victims can see a surprisingly convincing Windows update screen and a winupdate.exe process running on their systems. Many believe that the update causes a system slowdown. Unfortunately, the ransomware uses most of the CPU power to perform the data encryption.
OONN ransomware virus removal tips
Ransomware-type viruses have a highly complex system and numerous different components. Additionally, they might infiltrate other cyber threats alongside. Thus, the safest way to remove OONN ransomware is to install a robust malware removal tool that can get rid of both, the main file-encrypting virus and additional threats.
Once you download the tool, run a full system scan and it will start OONN ransomware virus removal automatically. At first, it puts the malicious elements into quarantine and then uninstalls them without damaging the system. You can start recovering the encrypted data right after the removal is complete. For after-care, we recommend using RESTORO to perform virus damage repair professionally. Follow the instructions below for further information.
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Our team recommends a two-step rescue plan to remove ransomware and other remaining malware from your computer, plus repair caused virus damage to the system:
STEP 1. REMOVE AUTOMATICALLY WITH ROBUST ANTIVIRUS
STEP 2. REPAIR VIRUS DAMAGE TO YOUR COMPUTER
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OONN ransomware Removal Guidelines
Method 1. Enter Safe Mode with Networking
Step 1. Start Windows in Safe Mode with Networking
Before you try to remove OONN ransomware virus, you must start your computer in Safe Mode with Networking. Below, we provide the easiest ways to boot PC in the said mode, but you can find additional ones in this in-depth tutorial on our website – How to Start Windows in Safe Mode. Also, if you prefer a video version of the tutorial, check our guide How to Start Windows in Safe Mode on Youtube.
Instructions for Windows XP/Vista/7 users
- First of all, turn off your PC. Then press the Power button to start it again and instantly start pressing F8 button on your keyboard repeatedly in 1-second intervals. This launches the Advanced Boot Options menu.
- Use arrow keys on the keyboard to navigate down to Safe Mode with Networking option and press Enter.
Instructions for Windows 8/8.1/10/11 users
- Open Windows Start menu, then press down the Power button. On your keyboard, press down and hold the Shift key, and then select Restart option.
- This will take you to Windows Troubleshoot screen. Choose Troubleshoot > Advanced Options > Startup Settings > Restart. Tip: If you can't find Startup Settings, click See more recovery options.
- In Startup Settings, press the right key between F1-F9 to enter Safe Mode with Networking. In this case, it is the F5 key.
Step 2. Remove files associated with the virus
Now, you can search for and remove OONN ransomware files. It is very hard to identify files and registry keys that belong to the ransomware virus, Besides, malware creators tend to rename and change them repeatedly. Therefore, the easiest way to uninstall such type of a computer virus is to use a reliable security program such as INTEGO Antivirus, which also includes data recovery software. For virus damage repair, consider using RESTORO.
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Compatibility: Microsoft Windows
See Full Review
RESTORO is a unique PC Repair Tool which comes with an in-built Avira scan engine to detect and remove spyware/malware threats and uses a patented technology to repair virus damage. The software can repair damaged, missing or malfunctioning Windows OS files, corrupted DLLs, and more. The free version offers a scan that detects issues. To fix them, license key for the full software version must be purchased.
Method 2. Use System Restore
In order to use System Restore, you must have a system restore point, created either manually or automatically.
Step 1. Boot Windows in Safe Mode with Command Prompt
Instructions for Windows XP/Vista/7 users
- Shut down your PC. Start it again by pressing the Power button and instantly start pressing F8 button on your keyboard repeatedly in 1-second intervals. You will see Advanced Boot Options menu.
- Using arrow keys on the keyboard, navigate down to Safe Mode with Command Prompt option and press Enter.
Instructions for Windows 8/8.1/10/11 users
- Launch Windows Start menu, then click the Power button. On your keyboard, press down and hold the Shift key, and then choose Restart option with the mouse cursor.
- This will take you to Windows Troubleshoot screen. Choose Troubleshoot > Advanced Options > Startup Settings > Restart. Tip: If you can't find Startup Settings, click See more recovery options.
- In Startup Settings, press the right key between F1-F9 to enter Safe Mode with Command Prompt. In this case, press F6 key.
Step 2. Start System Restore process
- Wait until system loads and command prompt shows up.
- Type cd restore and press Enter, then type rstrui.exe and press Enter. Or you can just type %systemroot%system32restorerstrui.exe in command prompt and hit Enter.
- This launches System Restore window. Click Next and then choose a System Restore point created in the past. Choose one that was created before ransomware infection.
- Click Yes to begin the system restoration process.
After restoring the system, we recommend scanning the system with antivirus or anti-malware software. In most cases, there won't be any malware remains, but it never hurts to double-check. In addition, we highly recommend checking ransomware prevention guidelines provided by our experts in order to protect your PC against similar viruses in the future.
Alternative software recommendations
Malwarebytes Anti-Malware
Removing spyware and malware is one step towards cybersecurity. To protect yourself against ever-evolving threats, we strongly recommend purchasing a Premium version of Malwarebytes Anti-Malware, which provides security based on artificial intelligence and machine learning. Includes ransomware protection. See pricing options and protect yourself now.
System Mechanic Ultimate Defense
If you're looking for an all-in-one system maintenance suite that has 7 core components providing powerful real-time protection, on-demand malware removal, system optimization, data recovery, password manager, online privacy protection and secure driver wiping technology. Therefore, due to its wide-range of capabilities, System Mechanic Ultimate Defense deserves Geek's Advice approval. Get it now for 50% off. You may also be interested in its full review.
Disclaimer. This site includes affiliate links. We may earn a small commission by recommending certain products, at no additional cost for you. We only choose quality software and services to recommend.
Decrypt OONN files
Fix and open large OONN files easily:
It is reported that STOP/DJVU ransomware versions encrypt only the beginning 150 KB of each file to ensure that the virus manages to affect all files on the system. In some cases, the malicious program might skip some files at all. That said, we recommend testing this method on several big (>1GB) files first.
- Create a copy of encrypted file to a separate folder using Copy > Paste commands.
- Now, right-click the created copy and choose Rename. Select the OONN extension and delete it. Press Enter to save changes.
- In the prompt asking whether you want to make the changes as file might become unusable, click OK.
- Try opening the file.
STOP/DJVU decryption tool usage guide
STOP/DJVU ransomware versions are grouped into old and new variants. OONN ransomware is considered the new STOP/DJVU variant, just like FOPA, VTYM, KQGS, XCBG, BPQD, EYRV, UIGD (find full list here). This means full data decryption is now possible only if you have been affected by offline encryption key. To decrypt your files, you will have to download Emsisoft Decryptor for STOP DJVU, a tool created and maintained by a genius security researcher Michael Gillespie.
Note! Please do not spam the security researcher with questions whether he can recover your files encrypted with online key - it is not possible.
In order to test the tool and see if it can decrypt OONN files, follow the given tutorial.
- Download the decryption tool from Emsisoft.
- Click the little arrow next to your download and choose Show in Folder.
- Now, right-click the file and choose Run as Administrator. If asked, enter administrator's password.
- In UAC window, click Yes.
- Click Yes to agree to software terms in both windows.
- The tool will automatically include C:// disk as a location to decrypt. The file recovery tool will prepopulate the locations to scan, including connected data storage drives or network drives. Click Add folder if you wish to add additional locations.
In Options tab, you can choose to keep encrypted file copies. We recommend leaving this option selected, especially if you do not know if the decryption tool will work. - Click Decrypt to start restoring OONN files. You will see the progress in the Results tab. Here, you can see messages from the tool, such as whether the decryption procedure is successful, or you need to wait for an update.
You might also be informed that online key was used to encrypt your files. In such case, the decryption tool won't work for you, and the only way to recover your files is to use a data backup.
Meanings of decryptor's messages
The OONN decryption tool might display several different messages after failed attempt to restore your files. You might receive one of the following messages:
Error: Unable to decrypt file with ID: [example ID]
This message typically means that there is no corresponding decryption key in the decryptor's database.
No key for New Variant online ID: [example ID]
Notice: this ID appears to be an online ID, decryption is impossible
This message informs that your files were encrypted with online key, meaning no one else has the same encryption/decryption key pair, therefore data recovery without paying the criminals is impossible.
Result: No key for new variant offline ID: [example ID]
This ID appears to be an offline ID. Decryption may be possible in the future.
If you were informed that an offline key was used, but files could not be restored, it means that the offline decryption key isn't available yet. However, receiving this message is extremely good news, meaning that it might be possible to restore your OONN extension files in the future. It can take a few months until the decryption key gets found and uploaded to the decryptor. We recommend you to follow updates regarding the decryptable DJVU versions here. We strongly recommend backing up your encrypted data and waiting.
Report Internet crime to legal departments
Victims of OONN ransomware should report the Internet crime incident to the official government fraud and scam website according to their country:
- In the United States, go to the On Guard Online website.
- In Australia, go to the SCAMwatch website.
- In Germany, go to the Bundesamt für Sicherheit in der Informationstechnik website.
- In Ireland, go to the An Garda Síochána website.
- In New Zealand, go to the Consumer Affairs Scams website.
- In the United Kingdom, go to the Action Fraud website.
- In Canada, go to the Canadian Anti-Fraud Centre.
- In India, go to Indian National Cybercrime Reporting Portal.
- In France, go to the Agence nationale de la sécurité des systèmes d’information.
If you can't find an authority corresponding to your location on this list, we recommend using any search engine to look up "[your country name] report cyber crime". This should lead you to the right authority website. We also recommend staying away from third-party crime report services that are often paid. It costs nothing to report Internet crime to official authorities.
Another recommendation is to contact your country's or region’s federal police or communications authority.
Frequently Asked Questions
You can only open OONN files if you have the decryption key, or if you were affected by offline encryption type.
To figure out whether you were affected by offline encryption, please go to C:/SystemID/PersonalID.txt and see if the string inside of it ends in t1. You can also try using Emsisoft Decryptor for STOP/DJVU.
Please follow the guidances provided by the official OONN decryption tools and believe what they say. If they say it is impossible to decrypt, it really is so. There is no magic tool or human capable of decrypting your files hiding somewhere. Encryption is a technique created to be nearly impossible to decrypt without a special private key (held by the criminals).
We advise scanning with anti-virus, anti-malware, malware removal tools or software like RESTORO to eliminate virus damage on the system. If you do not trust using a single tool, try running one after another. However, we do not recommend keeping several security programs on a computer at once as they can interfere with each other's work.
Beware of fake OONN decryption tools circulating around the web. Cyber criminals are uploading them to various shady websites, also might be promoting them via suspicious Youtube videos. These programs can infect your computer even more heavily (Trojans, miners, etc.). We suggest being extremely cautious around the web. If there will be an official STOP/DJVU decryption tool available, it will be widely discussed in public media.
Frequently Asked Questions
T open .oonn files, you must use a STOP/DJVU decryption tool. However, such file recovery is possible in offline encryption mode only. For all other victims, we recommend data recovery from backups.
It is recommended to create data backups for data of essential importance. As a result, you should be able to recover such data from backups created previously. If that is not the case, check if the offline encryption method was used in the attack, and then wait for STOP/DJVU decryptor updates.
Please come back for updates in STOP/DJVU decryption guide. It usually takes from a couple of weeks to months for OONN decryption key to be uploaded to the decrypter. The article will be updated once the key become publicly available.
Currently, OONN file decryption tool isn’t available. We will update the decryption guide as soon as it appears.
Scott Bolton is a senior content strategist in our Geek’s Advice team. He is exceptionally passionate about covering the latest information technology themes and inspire other team members to follow new innovations. Despite the fact that Scott is an old-timer among the Geeks, he still enjoys writing comprehensive articles about exciting cybersecurity news or quick tutorials.
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View Comments
Error: No key for New Variant online ID: 9Jw30BsImPAdUGrEUu7IQUY33C8ow7TvUTBpp7Ig
Notice: this ID appears to be an online ID, decryption is impossible
This was really helpful - thanks a lot!