Remove MOSS Ransomware (Virus Removal Guide)

remove moss ransomware virus and revert damage done to the computer system

MOSS ransomware: a file-encrypting computer menace

Contents

MOSS ransomware: a file-encrypting computer menace
- How criminals use encryption to extort computer users
_readme.txt contents: pay the price or lose your data
Distribution methods of this type of malware
Complete removal of MOSS ransomware
Decrypt MOSS files
Frequently Asked Questions

MOSS virus is identified as a ransomware-type computer threat. It originates from the STOP/DJVU malware family which uses RSA 2048-bit military-grade algorithm to encrypt personal files on target computer. PC users affected by this virus will find all their files encrypted and marked with .moss extension, for example, 1.jpg becomes 1.jpg.moss after the cyber attack. After encrypting files in a folder, the virus drops _readme.txt note to provide the victim with a warning to pay a ransom to the criminals in order to decrypt the files. The ransom size typically is $490 to $980 in Bitcoin. Further instructions on how to pay it are only provided after contacting the criminals via given emails: helpmanager@mail.ch and restoremanager@airmail.cc. Additional damage caused by this virus is theft of login credentials saved in web browsers, as it installs AZORULT password-stealer on the system.

In this article, we will explain the modus operandi of this ransomware, ways to remove damage done to the system, and describe chances to recover files.

The malware turns all personal files useless.

How criminals use encryption to extort computer users

To put it shortly, the criminals behind this virus use required technologies to make them the only ones capable of opening your files. As a result, they want you to pay money for tools required to decrypt .moss files back to normal. To prevent any easy data recovery, the malware also deletes Volume Shadow Copies from the system.

MOSS ransomware functionality relies on an algorithm which is designed to scan the victim’s computer or network and encrypt various files on the computer. It is important to mention, that viruses like this are usually able to encode a whole variety of files and formats. In fact, it might affect every file in your computer – from .docx or other Microsoft Office files to .exe or .pdf files.

So, for example, if you have some important and valuable files like your bachelor’s or master’s files, or valuable business information of your company, you might find yourself in big trouble. To avoid that we highly recommend you create backups as often as possible since no one is fully protected from cyberattacks.

Once inside your system, the virus usually uses RSA 2048-bit cipher to make changes to your files. Unfortunately, this type of algorithm is widely known to be almost completely unbreakable – it was designed to transmit secret military information while preventing any third parties from knowing the contents. To explain, every individual case of encryption creates a unique encryption/decryption key pair which is in the hacker’s possession.

Obtaining that key might seem like the only viable option since decoding affected files might take years and an unimaginable amount of resources. However, we advise you strongly against this course of action. That is because there is no guarantee that your files will be restored even after the payment is made.

In fact, there are countless amount of cases in which the criminals stop responding after receiving the money. In addition, it is important to understand that these crooks are using MOSS ransomware simply out of financial benefit. If they see an opportunity to extort more money from you – they will undoubtedly use it.

_readme.txt contents: pay the price or lose your data

Like every other ransomware from STOP/DJVU family, MOSS virus follows the same scheme of blocking access to your files and then leaving a text file with instructions. These instructions tell you that there is a supposed way to retrieve your files. The user is urged to test the decryption tool with a simple test: the victim needs to send one inaccessible file to the provided emails – helpmanager@mail.ch and restoremanager@airmail.cc and then he will receive it decrypted. This is the case as long the encrypted file does not contain any valuable information or is too big (up to 1024kB).

The user is encouraged to pay the price for the decryption key – the message claims, that if he pays up in the first 72 hours, he will get a 50% discount ($490). As mentioned before, you should not meet these demands since it will lead you to unnecessary financial loss. For this reason, it is important to understand there are alternative ways of dealing with this kind of situation. Sometimes the developers of ransom-demanding viruses leave certain flaws in its code. Thus, it might be possible to exploit these and crack the code. Unfortunately, this is rarely the case.

Do not pay the ransom to the criminals. Try the suggested solutions first.
Norbert Webb

Screenshot of the ransom note dropped by the virus.

Most of the time the best strategy you can choose under these circumstances is to remove MOSS ransomware or any type of malware from your system completely and then recovering the files that are stored in your backup. However, keep in mind, that you should restore these files only after the complete termination of this dangerous virus. In addition, we recommend using RESTORO for repairing virus damage on the operating system components.

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This is owing to the fact, that it might corrupt even the back-up files if you are not careful. As for the back-ups themselves, it is best if you keep them in a drive that is disconnected from the internet and other devices. This ensures that you always have a safe way to retrieve your personal data.

Name	MOSS Ransomware Virus
Type	Crypto-virus; File Locker; Ransomware
Malicious files	7EDB.exe (or similar), updatewin.exe
Dropped files	_readme.txt, PersonalID.txt
Origins	STOP/DJVU
Other variants	VYIA, QBAA, FOPA, VTYM, KQGS, XCBG, BPQD (find full list here)
Encryption algorithm	RSA
Version	255th
Ransom note	_readme.txt
Ransom amount	$490 in 3 days, $980 if later
Extension used	.moss
Criminal contact	helpmanager@mail.ch and restoremanager@airmail.cc
Detection name examples	TR/AD.InstaBot.AQ (Avira), Win32.Trojan.PSE.1B347GI (GData), Trojan:Win32/CryptInject!ml (Microsoft), see full list on VT
Symptoms of infection	All personal files on the computer are modified in a way so that they become impossible to open. Their filenames now have an additional extension. Each folder contains text note dropped by the virus. The note demands paying money for data decryption.
Additional damage	The ransomware installs AZORULT Password-Stealer on the infected computer/network. Windows HOSTS file will be maliciously modified to prevent access to computer-related domains. Learn how to reset it here.
Distribution	The ransomware typically hides in a form of software crack or keygen on untrustworthy websites promoting torrents.
Removal	Remove unwanted malware damage using software like RESTORO. You can read its review here.

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Distribution methods of this type of malware

It is no secret that there are a whole bunch of ways that might be exploited by creators of MOSS ransomware to distribute it. One of the most common methods to spread STOP/DJVU ransomware variants like this one and LYLI, NPPH, KOLZ, BOOP, FOQE and others is to include it alongside downloads that are found on various peer-to-peer file sharing sites and platforms. These websites (like zMule, Zippyshare, or Thepiratebay) are the perfect platform to distribute various malware-like programs. So every time before downloading something illegal or from suspicious sources consider this: it might jeopardize your system’s security and that will far outweigh the gained benefits.

Software cracks provided by untrustworthy websites are the primary way of delivering STOP/DJVU ransomware to computer users.

The second most common distribution method is malspam campaigns. To explain it shortly, hackers use a simple social-engineering scheme – sending thousands of deceitful emails to random Internet users. These emails a whole variety of fraudulent information to trick the user into opening an attached file or a link provided in the email. Once this link or file is pressed on, chances are that you might be exposed to cyberattacks. We strongly recommend you to learn more about ransomware prevention ways to keep your computer and personal files secure.

Complete removal of MOSS ransomware

If you see ant symptoms of being attacked by this file-locking virus, you should take immediate action to remove MOSS ransomware before it or AZORULT does more damage to your system. To ensure this, we recommend you use a software that is designed to deal with the most complex viruses that are out there – using robust anti-malware software will help you to resolve these problems effectively and simply.

Our geeks also recommend scanning with RESTORO which will not only make the removal process easier but also will help your system to repair itself after the termination. To ensure successful MOSS virus removal, follow this guide below.

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MOSS 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 MOSS 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 MOSS 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, which also includes data recovery software. 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

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Decrypt MOSS files

Fix and open large MOSS 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 MOSS 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. MOSS ransomware virus is considered the new STOP/DJVU variant, just like VYIA, QBAA, FOPA, VTYM, KQGS, XCBG, BPQD (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 MOSS 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 MOSS 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 MOSS 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 MOSS 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 MOSS 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

✓ How can I open .MOSS files?

You can only open MOSS files if you have the decryption key, or if you were affected by offline encryption type.

✓ How do I know if my files were encrypted with offline or online encryption?

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.

✓ My files contain very important information (family memories). Every tool I used says it is impossible to decrypt. What should I do?

Please follow the guidances provided by the official MOSS 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).

✓ I am afraid virus is still in my computer system. What should I do?

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.

✓ I saw several Youtube videos suggesting secret decryption tools. Can I trust them?

Beware of fake MOSS 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

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.