MAOS ransomware wreaks havoc on computer files
Contents
MAOS ransomware is a highly malicious computer virus that encrypts all files on unprotected systems. Recognized as a variant of STOP/DJVU malware, it appends .maos extension to each file and drops _readme.txt ransom note throughout the computer directories. This virus seeks to extort the user by locking one’s personal files and making it impossible for the victim to access them; it suggests purchasing a file decryption tool and private key from cybercriminals for a specified price that ranges between $490-$980.
To illustrate how files are renamed, see the following example: files originally named 1.jpg, 2.docx, 3.avi will appear as 1.jpg.maos, 2.docx.maos and 3.avi.maos. The same procedure will be applied to each encrypted file. The virus may skip some files that are required for the operating system to function. Unfortunately, cybersecurity experts have also discovered that this ransomware often spreads along with information-stealing Trojans such as Vidar, Azorult and RedLine.

The ransom note states the victim can get a discount
Cybercriminals behind MAOS file-encrypting virus are extremely insolent, and they leave a money-demanding message in _readme.txt ransom notes dropped in various computer locations. They claim the user has to contact them via email using provided email addresses: support@fishmail.top and datarestorehelp@airmail.cc.
In addition, the victim can request a test decryption service and send one encrypted file along victim’s Personal ID and expect the an email reply with a decrypted file version attached.
Next, the note provides decryption tool pricing details. It details that users who contact the attackers within 72 hours will get a 50% discount, which sets the MAOS decryption tool price to $490 instead of the full amount, $980.
However, the crooks will later specify that the user cannot pay in dollars or euros; the only acceptable form of payment is cryptocurrency (Bitcoin). This payment method helps to preserve the cybercriminals’ anonymity, and that is the main reason why they do not accept other payment forms.

In general, it is not advisable to pay ransom for cybercriminals. Not only it does not guarantee data recovery, but it fuels the cybercriminals’ business, allowing them to employ more people and thus infect more computers worldwide.
If you have been affected by this computer threat, we strongly advise taking action to remove MAOS ransomware virus right now. Follow the instructions provided below the article to understand how to boot your computer in Safe Mode with Networking, which is an ideal environment for malware removal. Afterward, consider using INTEGO Antivirus for virus removal. To identify virus damage for your files, download RESTORO.
Ransomware Summary
Name | MAOS Ransomware Virus |
Type | Ransomware; Crypto-malware; Virtual Extortion Virus |
Family | STOP/DJVU |
Encryption type | RSA 2048 + Salsa20 |
Previous versions | JYPO, KIFR, KIOP, KITZ, BOZA, BOTY, COZA (find full list here) |
Version | 615th |
Extension | .maos |
Cybercriminal emails | support@fishmail.top and datarestorehelp@airmail.cc |
Additional malware dropped | Azorult or Vidar Trojan |
Damage | The ransomware uses encryption to maliciously modify all files on the PC and marks their original names with .maos extension. Ransom notes called as _readme.txt will be dropped in every computer folder. This piece of malware usually drags VIDAR Stealer alongside it and also eliminates VSS from the system. On top of that, it tends to modify Windows HOSTS file to restrict computer user’s access to cybersecurity-related websites online. |
Ransom note | _readme.txt |
Ransom demand | $490-$980 in Bitcoin |
Distribution | Victims often download this ransomware along illegal torrent downloads, cracked software, activators, key generators or tools like KMSPico. |
Known software cracks to contain this malware | Corel Draw, Tenorshare 4ukey, Adobe Photoshop, Cubase, Adobe Illustrator, Internet Download Manager, Tally, League of Legends. |
Detection names | Trojan:Win32/Azorult.FW!MTB (Microsoft), Gen:Heur.Mint.Zard.52 (B) (Emsisoft), HEUR:Trojan.Win32.Scarsi.gen (Kaspersky), Gen:Heur.Mint.Zard.52 (BitDefender), Trojan.MalPack.GS (Malwarebytes), ML.Attribute.HighConfidence (Symantec) see all detection name variations on VirusTotal |
Removal | Remove ransomware and related malware from your PC using trustworthy software like INTEGO Antivirus. To repair virus damage on Windows OS files, download and try RESTORO (secure download link). |

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Ransomware distribution explained
Ransomware-type computer threats are distributed via illegal online downloads, fake software update ads, and phishing emails containing malicious attachments. Speaking of MAOS ransomware distribution, it mainly relies on deceptive websites advertising fake software cracks. These websites encourage users to download illegal software copies via direct links or torrents, however, the setup provided in a password-protected file contains a malware loader.
It is important to avoid suspicious websites when looking for a specific software to install. Instead, users should visit official or confirmed websites to download programs. In addition, we strongly recommend you to read this guide on how to avoid rogue websites serving malicious downloads.
On top of that, users should beware that aggressive pop-up or new tab ads that might appear during your browsing sessions may try to convince you to install something you do not need. Therefore, if you ever notice such ad claiming that you need to install some updates, close it and check the official software website for updates and more information.
Another common method that cybercriminals use is sending email spam. In such letters, the criminals impose well-known companies and claim that the user has to open an email attachment to see some important information. Often times, such messages seek to create a sense of urgency and force the target to act without double-checking the reliability of the sender. For this reason, it is highly advisable to stay cautious when checking email, and ignore emails that seem unsolicited.
Remove MAOS ransomware virus and decrypt your files
Users infected with the described ransomware should endeavor to remove MAOS virus without a delay. The guide provided below is a perfect explanation on how this matter should be handled. If you’re unsure on which antivirus brand to trust, our team’s pick is INTEGO Antivirus. You can read its review here.
Additionally, affected computer users should change all of their passwords used on the compromised devices due to the potential sensitive data theft possibly inflicted by Vidar/Azorult/RedLine Stealers.
In order to scan the computer for virus damage and possible repairs, download RESTORO.
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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:
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MAOS Ransomware Virus Removal Guidelines
Method 1. Enter Safe Mode with Networking
Step 1. Start Windows in Safe Mode with Networking
Before you try to remove MAOS Ransomware Virus 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 MAOS Ransomware Virus 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. For virus damage repair, consider using RESTORO.
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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.
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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 MAOS files
Fix and open large MAOS 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 MAOS 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. MAOS Ransomware Virus is considered the new STOP/DJVU variant, just like JYPO, KIFR, KIOP, KITZ, BOZA, BOTY, COZA (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 MAOS 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 MAOS 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 MAOS 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 MAOS 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 MAOS Ransomware Virus 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 MAOS 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 MAOS 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 MAOS 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.

Norbert Webb is the head of Geek’s Advice team. He is the chief editor of the website who controls the quality of content published. The man also loves reading cybersecurity news, testing new software and sharing his insights on them. Norbert says that following his passion for information technology was one of the best decisions he has ever made. “I don’t feel like working while I’m doing something I love.” However, the geek has other interests, such as snowboarding and traveling.
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