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

The Rzfu virus, known as a ransomware infection, belongs to the STOP family. This malware is notorious for malignant file encryption operations. When the Rzfu virus gets into a computer system, it scans the system for files such as videos, photos, documents, and more. It changes the file structure and adds the “.rzfu” extension to each encrypted file, making them inaccessible and unusable without the decryption key.

Rzfu Virus Overview

The Rzfu virus is a malicious program that ciphers your files and forces you to pay for their restoration. This malware encrypts various file types. ciphered files become identifiable by a distinct “.rzfu” extension. The affected files become impossible to access and use.

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

Rzfu Ransomware operates by Salsa20 encryption algorithms to cipher the files. Since Rzfu virus applies such a strong encryption method, it becomes incredibly difficult, if not impossible, to pick the decryption key without the assistance of the attackers.

Once the files are encrypted, the Rzfu virus displays a ransom note to the victim, demanding a ransom payment in exchange for the decryption key. The ransom note contains instructions on how to pay off the bill and also often contains threats of data loss or increased ransom amounts if the demands are not met within a specified timeframe.

I have compiled a comprehensive list of potential solutions, advice, and approaches to remove the Rzfu virus and recover access to your files. In some cases, you can recover the files, but sometimes, it may be impossible.

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

The Rzfu virus is similar to other DJVU ransomware samples such as Rzml, Rzkd, Teza, and Nzqw. This virus encrypts a wide range of common file types and appends its distinct “.rzfu” extension to all files. For instance, a file named “1.jpg” would be altered to “1.jpg.rzfu” and “2.png” to “2.png.rzfu“.

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

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

Encrypted Files by STOP/DJVU Ransomware

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

_readme.txt (STOP/DJVU Ransomware) – The frightening notification requesting users to pay the ransom to unlock the encrypted data contains these exasperating cautions.

Rzfu ransomware is a malicious program that carries out various actions on a victim’s computer. It initiates its attack by launching the deceptive process known as winupdate.exe, which displays a fake Windows update pop-up to mislead the victim into believing that their PC is slowing down due to a Windows update.

Simultaneously, the ransomware triggers another process, usually named with four random characters, to scan the disk for target files and encrypt them. Afterward, the ransomware deletes Volume Shadow Copies from the system disk using the following CMD command:

vssadmin.exe Delete Shadows /All /Quiet

Once these copies are removed, it becomes nearly impossible to restore the computer to its previous state using System Restore Points. The ransomware operators eliminate built-in Windows recovery options, preventing victims from recovering their files for free. Additionally, the attackers modify the Windows HOSTS file by adding a list of domains and mapping them to the localhost IP. As a result, victims encounter a DNS_PROBE_FINISHED_NXDOMAIN error when trying to access blacklisted websites.

Interestingly, the ransomware also attempts to block access to websites that provide guides for computer users, indicating that the attackers are trying to hinder victims from accessing relevant information about ransomware attacks online. The malware also saves two text files on the victim’s computer, containing details related to the attack—the victim’s public encryption key and personal ID. These files are named bowsakkdestx.txt and PersonalID.txt.

But the malicious activities don’t stop there. Variants of STOP/DJVU ransomware often deploy the Vidar password-stealing Trojan on compromised systems. This threat possesses a wide range of capabilities, including:

• Infiltrating the victim’s computer with malware and executing it to gain unauthorized access.
• Obtaining unauthorized access to login credentials for platforms like 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 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 encryption algorithm used by STOP/Djvu ransomware is AES-256. Consequently, if your data is encrypted with an online decryption key, the chances of recovering your files without paying the ransom are minimal. Each victim has a unique key, making it extremely time-consuming to find a suitable one.

Acquiring the online key through other means is nearly impossible, as it is stored on a remote server controlled by the criminals promoting the Rzfu infection. To receive the decryption code, victims are required to make a payment of $980. They can obtain the payment details by contacting the hackers via email at [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 indicates that the computer user should contact the hackers’ representatives within 72 hours after the attack. 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 highly recommend that you to avoid contacting these fraudsters and do not pay. One of the most real working solution to regain the lost data is just using the available backups, or using Decrypter tool from Emsisoft.

The peculiarity of such viruses is the employment a similar set of actions for decryption key generation. Thus, unless the ransomware is still under the stage of development or exhibits some hard-to-track flaws, manually recovering the ciphered data is a thing you can’t perform. The exclusive resolution to prevent the data loss is to regularly make backups of your important files.

Remember that even if you do maintain such backups regularly, they should 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 optional external hard drive storage. Alternatively, you may refer to the help of online (cloud) information storage.

It goes without saying, when you keep your backup data on your regular device, it may be similarly ciphered as well as other data. For this reason, storing the backup on your 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.

How To Remove Ransomware?

Video Guide

How To Decrypt .rzfu Files?

The newest extensions released around the end of August 2019 after the criminals made changes. This includes Rzml, Rzkd, Teza etc.

As a result of the changes 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.

1. Select folders for decryption.

   Based on the default configurations, the decryptor will automatically choose the available directories in order to decrypt the currently available drives (the connected ones), including the network drives. Extra (optional) locations can be selected with the assistance of the “Add” button.

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

2. 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]

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

Notice: this ID appears to be an online ID, decryption 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.

✓ Remote name could not be resolved

How to Restore .rzfu Files?

In some case ransomware is not doom for your files…

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

Recovering your files with PhotoRec

PhotoRec is an open-source program, which is initially created for files recovery from damaged disks, or for data recovery in case if they are unintentionally deleted. However, as time has gone by, this program adopted the ability to restore the files of 400 different extensions. Hence, it can be used for file restoration after the Rzfu attack.

First, you need to download this app. It is 100% free, but the developer notifies that there is no assurance that the files will be recovered. PhotoRec is distributed in a pack with other tool of the same developer – TestDisk. The downloaded archive will have TestDisk name, but don’t worry. PhotoRec files are right inside.

To run PhotoRec, you need to find and open “qphotorec_win.exe” file. No installation is required – the program has all the files it need inside of the archive, hence, you can mount it on your USB drive, and try to help your friends/parents/anyone who has been attacked by Rzfu ransomware.

Upon the start, you will observe the screen showing you the entire list of your disks. However, this data is probably irrelevand, 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 feature is located at the bottom, too. As it was mentioned, PhotoRec can recover the files of about 400 different formats.

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

Rzfu files recovery Video Guide.

Frequently Asked Questions

1. My files are encrypted by ransomware, what should I do now?
2. About DJVU (STOP) Ransomware.

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