How to remove the Nols ransomware from your operating system

Also Known As: Nols virus
Distribution: Moderate
Damage level: Severe

Nols ransomware removal instructions

What is Nols?

Belonging to the Djvu ransomware family, Nols is a piece of malicious software. It is designed to encrypt data and demand a ransom for its decryption (i.e. payment for a decryption tool and unique key). During the encryption process all files are renamed with the ".nols" extensions. Therefore, a file titled something like "1.jpg" appears like "1.jpg.nols", and so forth for all the affected files. After this process is complete, Nols creates a text file - "_readme.txt" and drops it into every folder.

The ransom note within the "_readme.txt" states that the victim's data has been encrypted. To decrypt it, the user will need the decryption software and unique key (generated individually for each victim). These tools can be purchased from the developers of Nols. To prove their ability to restore the data, the cyber criminals offer to decrypt one file for free. They will do so, as long as it does not contain valuable information (likely implying that it cannot be a database, backup, large excel sheet and similar). The size of the ransom is 980 USD. However, the message states that if users contact the criminals in 72 hours, the price will be reduced by fifty percent. There are email addresses provided and victims are informed that if they do not receive a response in 6 hours, they are to check their "Spam/Junk" folder for it. The note also claims that without buying these tools, users will not be able to recover their data. Unfortunately, this is often true. Usually, ransomware programs use strong encryptions, which cannot be "cracked" by any free decryption software. In most cases, only the software, which encrypted the data is capable of decrypting it. Despite this, it is expressly advised against communicating with cyber criminals or meeting the ransom demands. In most cases of ransomware infection, even when victims pay - they do not receive any decryption tools. Thereby leaving their data permanently damaged. The only possible solution is restoring the encrypting from a backup. However, one had to be made before the infection and stored separately.

Screenshot of a message encouraging users to pay a ransom to decrypt their compromised data:

Nols decrypt instructions

All ransomware shares many similarities in-between; e.g. WerdUtaPAY IT OR LOST ITOmniSphere are akin to Nols. All malicious programs of this type encrypt data and demand ransoms to be paid. They differ by the cryptographic algorithm they use (symmetric or asymmetric) and the size of the ransom. Cyber criminals prefer digital currencies (e.g. cryptocurrencies, pre-paid vouchers, etc.), as transactions made in such are difficult/impossible to trace. Manual decryption (without interference of a certain ransomware's developers) is impossible, unless the software is still in development and/or has flaws/bugs. To ensure data safety from data encrypting and damaging attacks, it is recommenced to keep backups in unplugged storage devices and/or remote servers. Ideally, multiple copies should be stored in different locations.

How did ransomware infect my computer?

Malicious content (ransomware and other malware) is typically spread via spam campaigns, trojans, untrustworthy download channels, software "cracking" (activation) tools and fake updaters. Massive scale spam campaigns are used to send deceptive emails, containing virulent attachments. These emails are usually disguised as "official", "important", "urgent" and similar. The infectious attachments within (or web-links leading to such) can be in various file formats (e.g. executable and archive files, PDF and Microsoft Office documents, JavaScript, etc.). Once opened (executed, run) they cause the infection by downloading/installing malware. Trojans are malicious programs designed to cause chain infections (i.e. they download/install additional malware). Untrustworthy download sources (e.g. sharing networks, third party downloaders, etc.) can offer malicious software or content bundled with such. Illegal software activation tools ("cracks") can download/install malware, instead of activating licensed product. Fake software infect systems by exploiting weaknesses in outdated programs and/or install malware, rather than the promised updates.

Threat Summary:
Name Nols virus
Threat Type Ransomware, Crypto Virus, Files locker
Detection Names Avast (FileRepMalware), BitDefender (Trojan.GenericKD.41924862), ESET-NOD32 (A Variant Of Win32/Kryptik.GXMI), Kaspersky (Trojan-Downloader.Win32.Upatre.iehr), Full List (VirusTotal)
Encrypted Files Extension .nols
Ransom Demanding Message _readme.txt text file
Ransom Amount $980/$490
Cyber Criminal Contact gorentos@bitmessage.ch, gerentosrestore@firemail.cc
Symptoms Cannot open files stored on your computer, previously functional files now have a different extension (for example, my.docx.locked). A ransom demand message is displayed on your desktop. Cyber criminals demand payment of a ransom (usually in bitcoins) to unlock your files.
Additional Information This malware is designed to show a fake Windows Update window and modify the Windows "hosts" file to prevent users from accessing cyber security websites (more information below).
Distribution methods Infected email attachments (macros), torrent websites, malicious ads, unofficial activation and updating tools.
Damage All files are encrypted and cannot be opened without paying a ransom. Additional password-stealing trojans and malware infections can be installed together with a ransomware infection.
Removal

To eliminate Nols virus our malware researchers recommend scanning your computer with Spyhunter.
▼ Download Spyhunter
Free scanner checks if your computer is infected. To remove malware, you have to purchase the full version of Spyhunter.

How to protect yourself from ransomware infections?

Irrelevant and/or suspicious emails, especially received from unknown senders (addresses), must not be read. Any attachments found in this mail must never be opened, as doing so will result in an infection. Only official and verified download sources should be used. Peer-to-Peer sharing networks (BitTorrent, eMule, Gnutella, etc.), unofficial and free file-hosting websites, third party downloaders and similar - are considered to be untrustworthy; therefore are advised against use. Software should be activated using legal means, not via "cracking" tools - as they are considered to be high-risk. The same extends to software updating, in other words - it should updated using functions/tools provided by genuine developers. Users are advised to have a dependable anti-virus/anti-spyware software installed and kept up-to-date. Said programs should be used to perform regular system scans and for the removal of detected threats. If your computer is already infected with Nols, we recommend running a scan with Spyhunter for Windows to automatically eliminate this ransomware.

Text presented in Nols ransomware's text file ("_readme.txt"):

ATTENTION!

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:
hxxps://we.tl/t-vzAZbtWtGh
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:
gorentos@bitmessage.ch

Reserve e-mail address to contact us:
gerentosrestore@firemail.cc

Your personal ID:
-

Screenshot of files encrypted by Nols (".nols" extension):

Files encrypted by Nols

Screenshot of fake Windows update pop-up displayed during the encryption:

Fake Windows pop-up displayed by Nols during the encryption

IMPORTANT NOTE! - As well as encrypting data, ransomware-type infections from the Djvu malware family also add a number of entries to the Windows "hosts" file. The entries contain URLs of various websites, most of which are related to malware removal. This is done to prevent users from accessing malware security websites and seeking help. Our website (PCrisk.com) is also on the list. Removing these entries, however, is simple - you can find detailed instructions in this article (note that, although the steps are shown in the Windows 10 environment, the process is virtually identical on all versions of the Microsoft Windows operating system).

Screenshot of websites added to Windows hosts file:

Tro Ransomware adding websites to Windows Hosts file

There are currently two versions of Djvu ransomware infections: old and new. The old versions were designed to encrypt data by using a hard-coded "offline key" whenever the infected machine had no internet connection or the server was timing out/not responding. Therefore, some victims were able to decrypt data using a tool developed by cyber security researcher, Michael Gillespie, however, since the encryption mechanism has been slightly changed (hence the new version, released in August, 2019), the decrypter no longer works and it is not supported anymore. If your data has been encrypted by an older version, you might be able to restore it with the another tool developed by Emsisoft and Michael Gillespie. It supports a total of 148 Djvu's variants and you can find more information, as well as download link and decryption instructions in Emsisoft's official page.

Screenshot of Djvu decryption tool by Emsisoft and Michael Gillespie:

Djvu ransomware decrypter by Michael Gillespie and Emsisoft

Additionally, Emsisoft is now providing a service that allows to decrypt data (again, only if it was encrypted by Djvu variants released before August, 2019) for those victims who have a pair of the same file before and after the encryption. All victims have to do is upload a pair of original and encrypted file to Emsisoft's Djvu decryption page and download the aforementioned decryption tool (the download link will be provided after uploading files). Note that the file processing may take some time so be patient. It is also worth mentioning that the system must have an Internet connection during the entire decryption process, otherwise it will fail.

Screenshot of Emsisoft's Djvu decryption service page:

Djvu ransomware decryption service by Emsisoft

Nols ransomware removal:

Instant automatic removal of Nols virus: Manual threat removal might be a lengthy and complicated process that requires advanced computer skills. Spyhunter is a professional automatic malware removal tool that is recommended to get rid of Nols virus. Download it by clicking the button below:
▼ DOWNLOAD Spyhunter By downloading any software listed on this website you agree to our Privacy Policy and Terms of Use. Free scanner checks if your computer is infected. To remove malware, you have to purchase the full version of Spyhunter.

Quick menu:

Step 1

Windows XP and Windows 7 users: Start your computer in Safe Mode. Click Start, click Shut Down, click Restart, click OK. During your computer start process, press the F8 key on your keyboard multiple times until you see the Windows Advanced Option menu, and then select Safe Mode with Networking from the list.

Safe Mode with Networking

Video showing how to start Windows 7 in "Safe Mode with Networking":

Windows 8 users: Start Windows 8 is Safe Mode with Networking - Go to Windows 8 Start Screen, type Advanced, in the search results select Settings. Click Advanced startup options, in the opened "General PC Settings" window, select Advanced startup. Click the "Restart now" button. Your computer will now restart into the "Advanced Startup options menu". Click the "Troubleshoot" button, and then click the "Advanced options" button. In the advanced option screen, click "Startup settings". Click the "Restart" button. Your PC will restart into the Startup Settings screen. Press F5 to boot in Safe Mode with Networking.

Windows 8 Safe Mode with networking

Video showing how to start Windows 8 in "Safe Mode with Networking":

Windows 10 users: Click the Windows logo and select the Power icon. In the opened menu click "Restart" while holding "Shift" button on your keyboard. In the "choose an option" window click on the "Troubleshoot", next select "Advanced options". In the advanced options menu select "Startup Settings" and click on the "Restart" button. In the following window you should click the "F5" button on your keyboard. This will restart your operating system in safe mode with networking.

windows 10 safe mode with networking

Video showing how to start Windows 10 in "Safe Mode with Networking":

Step 2

Log in to the account infected with the Nols virus. Start your Internet browser and download a legitimate anti-spyware program. Update the anti-spyware software and start a full system scan. Remove all entries detected.

If you cannot start your computer in Safe Mode with Networking, try performing a System Restore.

Video showing how to remove ransomware virus using "Safe Mode with Command Prompt" and "System Restore":

1. During your computer start process, press the F8 key on your keyboard multiple times until the Windows Advanced Options menu appears, and then select Safe Mode with Command Prompt from the list and press ENTER.

Boot your computer in Safe Mode with Command Prompt

2. When Command Prompt mode loads, enter the following line: cd restore and press ENTER.

system restore using command prompt type cd restore

3. Next, type this line: rstrui.exe and press ENTER.

system restore using command prompt rstrui.exe

4. In the opened window, click "Next".

restore system files and settings

5. Select one of the available Restore Points and click "Next" (this will restore your computer system to an earlier time and date, prior to the Nols ransomware virus infiltrating your PC).

select a restore point

6. In the opened window, click "Yes".

run system restore

7. After restoring your computer to a previous date, download and scan your PC with recommended malware removal software to eliminate any remaining Nols ransomware files.

To restore individual files encrypted by this ransomware, try using Windows Previous Versions feature. This method is only effective if the System Restore function was enabled on an infected operating system. Note that some variants of Nols are known to remove Shadow Volume Copies of the files, so this method may not work on all computers.

To restore a file, right-click over it, go into Properties, and select the Previous Versions tab. If the relevant file has a Restore Point, select it and click the "Restore" button.

Restoring files encrypted by CryptoDefense

If you cannot start your computer in Safe Mode with Networking (or with Command Prompt), boot your computer using a rescue disk. Some variants of ransomware disable Safe Mode making its removal complicated. For this step, you require access to another computer.

To regain control of the files encrypted by Nols, you can also try using a program called Shadow Explorer. More information on how to use this program is available here.

shadow explorer screenshot

To protect your computer from file encryption ransomware such as this, use reputable antivirus and anti-spyware programs. As an extra protection method, you can use programs called HitmanPro.Alert and EasySync CryptoMonitor, which artificially implant group policy objects into the registry to block rogue programs such as Nols ransomware.

Note that Windows 10 Fall Creators Update includes a "Controlled Folder Access" feature that blocks ransomware attempts to encrypt your files. By default, this feature automatically protects files stored in the Documents, Pictures, Videos, Music, Favorites, and Desktop folders.

Controll Folder Access

Windows 10 users should install this update to protect their data from ransomware attacks. Here is more information on how to get this update and add an additional protection layer from ransomware infections.

HitmanPro.Alert CryptoGuard - detects encryption of files and neutralises any attempts without need for user-intervention:

hitmanproalert ransomware prevention application

Malwarebytes Anti-Ransomware Beta uses advanced proactive technology that monitors ransomware activity and terminates it immediately - before reaching users' files:

malwarebytes anti-ransomware

  • The best way to avoid damage from ransomware infections is to maintain regular up-to-date backups. More information on online backup solutions and data recovery software Here.

Other tools known to remove Nols ransomware:

About the author:

Tomas Meskauskas

Tomas Meskauskas - expert security researcher, professional malware analyst.

I am passionate about computer security and technology. I have an experience of over 10 years working in various companies related to computer technical issue solving and Internet security. I have been working as an author and editor for pcrisk.com since 2010. Follow me on Twitter and LinkedIn to stay informed about the latest online security threats. Contact Tomas Meskauskas.

PCrisk security portal is brought by a company RCS LT. Joined forces of security researchers help educate computer users about the latest online security threats. More information about the company RCS LT.

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Malware activity

Global virus and spyware activity level today:

Medium threat activity
Medium

Increased attack rate of infections detected within the last 24 hours.

QR Code
Nols virus QR code
A QR code (Quick Response Code) is a machine-readable code which stores URLs and other information. This code can be read using a camera on a smartphone or a tablet. Scan this QR code to have an easy access removal guide of Nols virus on your mobile device.
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Platform: Windows

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