NNLL Virus (.NNLL File) 🔐 Decrypt & Removal Guide

The Nnll virus, is a ransomware, a type of malware famous for malicious file ciphering. Once the Nnll virus infects a system, it scans the system for files such as documents, videos, photos, and more. It alters the file structure and appends the “.nnll” extension to each file, making them unusable without the decryption.

Nnll Virus Overview

Nnll

🤔 Nnll malware is similar to DJVU/STOP family. It duplicates the ransom note, naming policies, and runtime behavior. However, the rest of the facts regarding this ransomware sample point at its different origins. It may be someone’s copy of Djvu ransomware, or a new build of one from its original masters.

The Nnll virus is a type of malware that ciphers your files and coerces you into paying for their recovery. This malware ciphers different file types. Encrypted files are identifiable by a distinct “.nnll” extension. As a result, the files touched by ransomware become impossible to access and use.

After that, the ransomware demands a file decryption payment in Bitcoin from the victims, ranging from $490 to $980. In all cases, a text file with ransom payment guidances is named as “_readme.txt“.

Nnll Ransomware works with Salsa20 encryption algorithms to scramble the contents of the targeted files. Since Nnll virus utilizes such a robust ciphering method, it becomes pretty hard, if not impossible, to pick the decryption key without cooperating with the attackers.

Once the files are encrypted, the Nnll virus displays a ransom note to the victim, asking for a ransom payment for the decryption key. The ransom note provides instructions on the ways of making the payment and often contains threats of permanent data loss or increased ransom amounts if the ransom is not paid within a specified timeframe.

I have compiled an all-encompassing list of potential solutions, tips, and methods to stop the Nnll malware and decrypt and recover your files. There are situations where it may be possible to restore your files, while sometimes, it may be impossible.

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📌 Important Reminder!

It is critical to say that paying off the bill is not a guarantee of the successful files recovery. The crooks behind the Nnll virus are known for their untrustworthiness. There have been instances where people have paid the ransom, only to be denied by the cybercriminals with the decryption key provision.

Nnll employs a unique key for each victim, with one exception:

The Nnll virus is highly similar to other DJVU ransomware samples like Wwhu, Wwpl, Wwty, and Wwza. This virus encrypts a wide range of common file types and appends its distinct “.nnll” extension to all files. For instance, a file named “1.jpg” would be altered to “1.jpg.nnll” and “2.png” to “2.png.nnll“.

Upon successful encryption, the virus spawns a special text file named “_readme.txt” and places it in every folder containing the encrypted files. It as well adds this file to the desktop, so the user will not miss its appearance even without opening folders.

The image below provides a visual representation of files with the “nnll” extension:

Encrypted Files by NNLL Ransomware

Name	Nnll Virus
Ransomware family¹	Copy of DJVU/STOP² ransomware
Extension	.nnll
Ransomware note	_readme.txt
Ransom	From $490 to $980 (in Bitcoins)
Contact	[email protected], [email protected]
Detection	Win32/TrojanDownloader.AutoHK.GR, Trojan:Win32/Glupteba.MU!MTB, Win32/TrojanDownloader.Tovkater.IB
Symptoms	Encrypted most of your files (photos, videos, documents) and adds a particular “.nnll” extension; Can delete Volume Shadow copies to make victim’s attempts to restore data impossible; Adds a list of domains to HOSTS file to block access to certain security-related sites; Installs password-stealing Trojan on the system, like Vidar Stealer or RedLine Stealer; Manages to install a SmokeLoader backdoor;
Fix Tool	To remove possible malware infections, scan your PC: 6-day free trial available.

This message asking payment is for restore files via decryption key:

_readme.txt (NNLL Ransomware) – The frightening warning insisting users to pay off the ransom to unlock the encoded data contains these annoying admonitions.

Nnll ransomware arrives as a set of operations that are needed to perform different tasks on a victim’s computer. One of the primary ones being launched is winupdate.exe, a deceptive process that displays a fraudulent Windows update alert during the attack. That is needed to convince the victim that their PC has become slow because of a Windows update.

Simultaneously, the ransomware runs another process (usually named by four random characters) which starts scanning the disk for target files and ciphering them. Next, the ransomware removes Volume Shadow Copies from the disk by the following CMD command:

vssadmin.exe Delete Shadows /All /Quiet

Once deleted, it becomes virtually impossible to retrieve the previous computer state using System Restore Points. The concern is, ransomware operators are getting rid of any built-in Windows techniques that could help the victim to regain files for free. In addition, the crooks modify the Windows HOSTS file by appending a list of domains to it and directing them to the localhost IP. As a result, the victim will witness a DNS_PROBE_FINISHED_NXDOMAIN error when accessing one of the listed websites.

We noticed that ransomware endeavors to block websites that developed various how-to guides for computer users. It is obvious that by restricting specific domains, the malefactors are attempting to prevent the victim from accessing relevant and helpful ransomware-attack-related information online. The virus also keeps two text files on the victim’s computer that present attack-related information – the public key of this victim and personal ID. These two files are named bowsakkdestx.txt and PersonalID.txt.

After all these alterations, the malware doesn’t stop. Variants of NNLL are inclined to deploy Vidar password-stealing Trojan on compromised systems. This threat has an large list of capabilities, including:

Infiltrating the victim’s computer with malware and executing it to gain unauthorized access.
Obtaining unauthorized access to login credentials of Steam, Telegram, and Skype.
Manipulating and viewing files on the victim’s computer without their knowledge.
Stealing cryptocurrency wallets from the victim’s system.
Granting the hackers remote control over the victim’s computer for various malicious activities.
Extracting sensitive information such as browser cookies, saved passwords, and browsing history.

The cryptography algorithm used by NNLL virus is AES-256. So, once your data is encrypted with an online decryption key, the chances to get your files back are quite low. Thing is, the key is unique for each victim, and picking it will take exceptionally big amount of time.

Obtaining the online key in another way is also merely impossible. It is kept on a remote server owned by the criminals who spread the Nnll malware. For receiving decrypting code the payment should be $980. To obtain the payment details, the victims should contact the hackers by email ([email protected]).

The message by the ransomware states the following information:

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:

https://we.tl/t-WJa63R98Ku

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:

[email protected]

Reserve e-mail address to contact us:

[email protected]

Your personal ID:
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

Do not pay the ransom!

Please, try to use the available backups, or Decrypter tool

_readme.txt file also states that the computer owner must get in touch with the hackers’ representatives during 72 hours starting from the moment of files were encrypted. If the 72hrs demand is met, hackers grant a 50% off. Thus the ransom amount will be minimized down to $490.

Yet, stay away from paying off the ransom! I strongly recommend that you do not contact these frauds and do not pay. One of the most real working solution to retrieve the lost data is just using the available backups, or using Decrypter tool from Emsisoft.

The peculiarity of such viruses is the application a similar set of actions to generate the unique decryption key. Thus, unless the ransomware is still in development or possesses with some hard-to-track encryption, manual data recovery is a thing you can’t perform. The exclusive resolution to prevent the data loss is to regularly make backups of your critical files.

Remember that even if you do create such backups regularly, they ought to be located into a specific location without loitering, not being connected to your main workstation. For instance, the backup may be kept on the USB flash drive or some alternative external hard drive storage. Optionally, you may turn to the help of online (cloud) information storage.

It goes without saying, when you maintain your backup on your regular device, it may be similarly ciphered as well as other data. For this reason, placing the backup on your computer’s disk is surely not a wise idea.

How I was infected?

Ransomware has a various methods to built into your system. But it doesn’t really matter what way had place in your case.

Ransomware attack following a successful phishing attempt.

Nevertheless, these are the common leaks through which it may be injected into your PC:

Utilizing online free hosting resources to distribute the virus discreetly.
Disguising the virus installer within other apps, particularly utilities offered as freeware or shareware.
Propagation through spam emails containing dubious links leading to the virus installation.
Downloading pirated software from illegal peer-to-peer (P2P) resources, which may include hidden malware.

There were cases when the Nnll virus was disguised as a legit tool, for example, the messages asking to start a browser update or a vastly needed codec for online media playback. This is usually the way how some online frauds aim to force you into installing the ransomware manually, by actually making you directly engage in this process.

Surely, the fraudulent update alert will not indicate that you are installing the threat. This process will be disguised under some alert stating that you must install an urgent security update or some questionable program whatsoever.

Of course, the software cracks represent the harm too. Using P2P is illegal and may end up with the introduction of serious malware, including the Nnll ransomware.

To sum up, what can you do to evade the penetration of the ransomware into your PC? Even though there is no 100% assurance to prevent your PC from getting compromised, there are some tips I want to give you to shield the Nnll penetration. You must be vigilant while using free software today.

Make sure you always read what the installer offers aside from the main free program. Stay away from launching questionable email attachments. Do not run files from the unknown senders. Naturally, your current anti-malware program must always be updated.

The malware does not states openly about itself. It will not appear in the list of your available programs. However, it will be masked under some malicious process running consistently in the background, that starts at the moment when you launch your computer.

How To Remove Ransomware?

Video Guide

How To Decrypt .nnll Files?

How to restore big files?

Try deleting .nnll extension on a few big files and opening them. This malware has issues with large files encryption. Either the virus scanned and did not encode the file, or it failed and did not add the filemarker. If you have files that are very large (2GB+), such a situation is highly probable. Please, let me know in comments if that will work for you.

The newest extensions released around the end of August 2019 after the criminals made changes. This includes Wwhu, Wwpl, Wwty etc.

As a outcome of the modifications made by the criminals, STOPDecrypter is no longer supported. It has been replaced with the Emsisoft Decryptor for STOP Djvu Ransomware developed by Emsisoft.

You can download free decryption tool here: Decryptor for STOP Djvu.

Select folders for decryption.

Based on the default configurations, the decryptor will by default choose the available directories in order to unlock the currently accessible drives (the connected ones), including the network drives. You can select additional locations with the “Add” button.

Decryptors generally offer several options depending on the specific malware family. The present possible options are displayed in the Options tab and can be enabled or turned off there. You may locate a detailed list of the currently active Options below.

Click on the “Decrypt” button.

As soon as you add all the desired locations for decryption into the list, click on the “Decrypt” button in order to initiate the decryption procedure.

Note that the main screen may turn you to a status view, letting you know of the active process and the decryption statistics of your data:

The decryptor will notify you as soon as the decryption procedure is completed. If you need the report for your personal papers, you can save it by choosing the “Save log” button. Note that it is also possible to copy it directly to your clipboard and to paste it into emails or messages here if you need to do so.

The Emsisoft Decryptor might display different messages after a failed attempt to restore your files:

✓ Error: Unable to decrypt file with ID: [your ID]

Emsisoft failed to find a correspondnig decryption key in their database.

✓ No key for New Variant online ID: [your ID]

Notice: this ID appears to be an online ID, decryption is impossible

Malware used an online key to cipher your files. So no one else has the same encryption/decryption key pair. Recovery of files without paying the criminals is impossible. 🙁

✓ Result: No key for new variant offline ID: [example ID]

This ID appears be an offline ID. Decryption may be possible in the future.

Malware used an offline key, though the file recovery operation failed (the offline decryption key isn’t available yet). But, this message is a good news for you, since it is possible to restore your files in the future. 🙂
It can take a few weeks or months until the decryption key gets found and uploaded to the decryptor. Please follow updates regarding the decryptable DJVU versions here.

✓ Remote name could not be resolved

This stands for a DNS issue present in your system. Our first recommendation is to reset your HOSTS file back to default.

How to Restore .nnll Files?

In some case ransomware is not doom for your files…

The Nnll ransomware encryption mechanism sequence is next: it ciphers every file byte-by-byte, then saves a duplicate, deleting (not overriding!) the original file. Thus, the data of the file location on the disk drive is lost, but the original file is not removed from the drive. The cell, or the sector where this file was kept, can still contain this file, but it is not present in the file system and can be overwritten by data that has been loaded to this drive after the removal. Hence, it is possible to retrieve your files using special software.

I recently had my pc infected by the this virus. It managed to bypass 2 Antivirus software and 2 malware fighters.

Anyway, after realizing it was an online algorithm, it is impossible to retrieve my encrypted files. I also had my backup drive plugged in at the time of the virus, and this was also infected, or so I thought. Every folder within my backup drive had been infected and was encrypted. However, despite losing some important files, I retrieved almost 80% of my 2TB storage.

When I started going through the folders, I noticed the readme.txt ransom note in every folder. I opened some of the folders and found that all files that were not in a subfolder within that folder had been encrypted. However, I found a flaw and glimmer of hope when I went into the subfolders in other folders and found that these files had not been encrypted. Every folder within my c and d drives, including subfolders, had been encrypted, but this was not the case with the backup drive. Having subfolders created within a folder has saved 80% of my data.

As I said, I believe this to be only a small loophole on a backup drive. I’ve since found a further 10 % of my data on another hard drive on a different pc. So my advice is if you use a backup drive, create subfolders. I was lucky, I guess. But I was also unlucky that the virus hit as I was transferring some files from my backup.

Hopefully, this can help some other people in my situation.

Jamie Newland

Some pointers for recovery repair of Nnll files (true for all STOP/DJVU variants):

I have seen Stop/Djvu variants fail to encrypt deeper nested folders, so that you can check that. You may find those are not encrypted.

This ransomware saves encrypted data to a new file, deletes the original. So there’s a slight chance part of that deleted file can be recovered using file recovery software. It’s unlikely the folder structure can be restored, so a free tool like PhotoRec may be as good as any.

This ransomware only partially encrypts (about the first 150 KB), so depending on file size and type of data, the not encrypted part may be recoverable.

Joep

Recovering your files with PhotoRec

PhotoRec is an free program, which is initially created for file retrieval from damaged disks, or for data recovery in case if they are unintentionally deleted. However, as time has gone by, this program received the ability to recover the files of 400 different file types. Hence, it can be used for data recovery after the Nnll attack.

First, you need to download this app. It is 100% free, but the developer notifies that there is no guarantee that the files will be restored. PhotoRec is spread in a pack with another program of the same developer – TestDisk. The resulting archive will bear TestDisk name, but don’t worry. PhotoRec files are right inside.

To open PhotoRec, you need to find and open “qphotorec_win.exe” file. No installation process is required – this program has all the files it need within the archive, hence, you can fit it on your USB drive, and help your friends/parents/anyone who has been attacked by Nnll ransomware.

Upon the start, you will see the screen showing you the entire list of your disk spaces. However, this data is likely unhelpful, because the required menu is placed a bit higher. Click this bar, then choose the disk which was attacked by ransomware.

After choosing the disk, you need to select the destination folder for the recovered files. This menu is located at the lower part of the PhotoRec window. The best choice is to export them on USB drive or any other type of removable disk.

Then, you need to indicate the file formats. This choice is located at the bottom, too. As it was mentioned, PhotoRec can restore the files of about 400 different formats.

Finally, you can start files restoration by pressing the “Search” button. You will observe the screen where the findings of the scan and recovery are shown.

Nnll files recovery Video Guide.

Frequently Asked Questions

🤔 How can I open “.nnll” files?

No way. These files are encrypted by ransomware. The contents of encrypted files are not available until they are decrypted.

🤔 Encrypted files contain important information. How can I decrypt them urgently?

If your data remained in the .nnll files are very valuable, then most likely you made a backup copy. If not, then you can try to restore them through the system function – Restore Point. All other methods will require patience.

🤔 You have advised using GridinSoft Anti-Malware to remove Nnll. Does this mean that the program will delete my encrypted files?

Of course not. Your encrypted files do not pose a threat to the computer. What happened has already happened.

🤔 This virus has blocked infected PC: I can’t get the activation code.

In this situation, you need to prepare the memory stick with a pre-installed

🤔 Decryptor did not decrypt all my files, or not all of them were decrypted. What should I do?

Have patience. You are infected with the new version of STOP/DJVU ransomware, and decryption keys have not yet been released. Follow the news on our website. We will keep you posted on when new keys or new decryption programs appear.

🤔 What can I do right now?

The Nnll ransomware encrypts only the first 150KB of files. So MP3 files are rather large, some media players (Winamp for example) may be able to play the files, but – the first 3-5 seconds (the encrypted portion) will be missing. You can try to find a copy of an original file that was encrypted: Files you downloaded from the Internet that were encrypted and you can download again to get the original.