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
Rzfu
🤔 Rzfu malware can be classified as ransomware that originates from the DJVU/STOP ransomware family. Its primary purpose is to lock your files. Then, ransomware virus asks its victims for a ransom payment – ($490 – $980) in Bitcoin.
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.
📌 Important Reminder!
It is critical to say that paying off the ransom does not guarantee the successful recovery of your files. The scoundrels behind the Rzfu virus are not trustworthy. There have been instances where people have paid the ransom, only to be denied by the cybercriminals with the decryption key provision.
Rzfu employs a unique key for each victim, with one exception:
- If Rzfu fails to establish a connection with its command and control server (C&C Server) before starting the encryption process, it it uses offline keys. An offline key is not unique and is the same for all users, which allows for the decryption of files encrypted by the ransomware.
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
| Name | Rzfu Virus |
| Ransomware family1 | DJVU/STOP2 ransomware |
| Extension | .rzfu |
| Ransomware note | _readme.txt |
| Ransom | From $490 to $980 (in Bitcoins) |
| Contact | support@fishmail.top, datarestorehelp@airmail.cc |
| Detection | Win32/GenKryptik.GNIZ, Spyware:Win32/Stealc, Trojan:Win32/Gepys.A!MTB |
| Symptoms |
|
| 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 (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 support@fishmail.top.
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: support@fishmail.top Reserve e-mail address to contact us: datarestorehelp@airmail.cc 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.
- Concealing the virus within seemingly legitimate apps, especially utilities provided as freeware or shareware.
- Spreading the virus through spam emails containing suspicious links that lead to the virus installer.
- Exploiting online free hosting resources to host and distribute the virus files discreetly.
- Obtaining pirated software from illegal peer-to-peer (P2P) resources, which may unknowingly contain malware.
Some incidents occurred when the Rzfu virus was disguised as a legit tool, for example, the messages demanding to install a browser update or a vastly needed codec for online media playback. This is typically the way how some online scams aim to force you into installing the ransomware manually, by actually making you directly engage in this process.
Surely, the bogus update alert will not indicate that you are installing the threat. This installation will be hidden under some alert stating that you must install an urgent security update or some questionable program whatsoever.
Without a doubt, the cracked apps represent the threat as well. Using P2P is illegal and may result in the injection of serious malware, including the Rzfu ransomware.
To sum up, what can you do to prevent the injection of the ransomware into your PC? Even though there is no 100% assurance to prevent your PC from getting damaged, there are certain tips I want to give you to shield the Rzfu penetration. You must be careful while setting up free software today.
Make sure you always read what the installer offers aside from the main free program. Stay away from opening dubious email attachments. Do not open files from the unknown addressees. Naturally, your current security program must always be updated.
The malware does not show itself openly. 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, starting from the moment when you boot up your computer.
How To Remove Ransomware?
Remove Rzfu Virus with Gridinsoft Anti-Malware
We have also been using this software on our systems ever since, and it has always been successful in detecting viruses. It has blocked the most common Ransomware as shown from our tests with the software, and we assure you that it can remove Rzfu Virus as well as other malware hiding on your computer.
To use Gridinsoft for remove malicious threats, follow the steps below:
1. Begin by downloading Gridinsoft Anti-Malware, accessible via the blue button below or directly from the official website gridinsoft.com.
2.Once the Gridinsoft setup file (setup-gridinsoft-fix.exe) is downloaded, execute it by clicking on the file.
3.Follow the installation setup wizard's instructions diligently.
4. Access the "Scan Tab" on the application's start screen and launch a comprehensive "Full Scan" to examine your entire computer. This inclusive scan encompasses the memory, startup items, the registry, services, drivers, and all files, ensuring that it detects malware hidden in all possible locations.
Be patient, as the scan duration depends on the number of files and your computer's hardware capabilities. Use this time to relax or attend to other tasks.
5. Upon completion, Anti-Malware will present a detailed report containing all the detected malicious items and threats on your PC.
6. Select all the identified items from the report and confidently click the "Clean Now" button. This action will safely remove the malicious files from your computer, transferring them to the secure quarantine zone of the anti-malware program to prevent any further harmful actions.
8. If prompted, restart your computer to finalize the full system scan procedure. This step is crucial to ensure thorough removal of any remaining threats. After the restart, Gridinsoft Anti-Malware will open and display a message confirming the completion of the scan.
Remember Gridinsoft offers a 6-day free trial. This means you can take advantage of the trial period at no cost to experience the full benefits of the software and prevent any future malware infections on your system. Embrace this opportunity to fortify your computer's security without any financial commitment.
Trojan Killer for “Rzfu Virus” removal on locked PC
In situations where it becomes impossible to download antivirus applications directly onto the infected computer due to malware blocking access to websites, an alternative solution is to utilize the Trojan Killer application.
There is a really little number of security tools that are able to be set up on the USB drives, and antiviruses that can do so in most cases require to obtain quite an expensive license. For this instance, I can recommend you to use another solution of GridinSoft - Trojan Killer Portable. It has a 14-days cost-free trial mode that offers the entire features of the paid version. This term will definitely be 100% enough to wipe malware out.
Trojan Killer is a valuable tool in your cybersecurity arsenal, helping you to effectively remove malware from infected computers. Now, we will walk you through the process of using Trojan Killer from a USB flash drive to scan and remove malware on an infected PC. Remember, always obtain permission to scan and remove malware from a computer that you do not own.
Step 1: Download & Install Trojan Killer on a Clean Computer:
1. Go to the official GridinSoft website (gridinsoft.com) and download Trojan Killer to a computer that is not infected.
2. Insert a USB flash drive into this computer.
3. Install Trojan Killer to the "removable drive" following the on-screen instructions.
4. Once the installation is complete, launch Trojan Killer.
Step 2: Update Signature Databases:
5. After launching Trojan Killer, ensure that your computer is connected to the Internet.
6. Click "Update" icon to download the latest signature databases, which will ensure the tool can detect the most recent threats.
Step 3: Scan the Infected PC:
7. Safely eject the USB flash drive from the clean computer.
8. Boot the infected computer to the Safe Mode.
9. Insert the USB flash drive.
10. Run tk.exe
11. Once the program is open, click on "Full Scan" to begin the malware scanning process.
Step 4: Remove Found Threats:
12. After the scan is complete, Trojan Killer will display a list of detected threats.
13. Click on "Cure PC!" to remove the identified malware from the infected PC.
14. Follow any additional on-screen prompts to complete the removal process.
Step 5: Restart Your Computer:
15. Once the threats are removed, click on "Restart PC" to reboot your computer.
16. Remove the USB flash drive from the infected computer.
Congratulations on effectively removing Rzfu Virus and the concealed threats from your computer! You can now have peace of mind, knowing that they won't resurface again. Thanks to Gridinsoft's capabilities and commitment to cybersecurity, your system is now protected.
Video Guide
How To Decrypt .rzfu Files?
How to restore big files?
Try removing .rzfu extension on a few big files and opening them. This malware has issues with large files encryption. Either the virus read and did not encrypt the file, or it bugged 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 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.
Download and run decryption tool.
Start downloading the decryption tool.
Make sure to launch the decryption utility as an administrator. You need to agree with the license terms that will come up. For this purpose, click on the “Yes” button:
As soon as you accept the license terms, the main decryptor user interface comes up:
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.
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.
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
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.
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 NewlandRecovering 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
No way. These files are encrypted by ransomware. The contents of encrypted files are not available until they are decrypted.
If your data remained in the .rzfu 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.
Of course not. Your encrypted files do not pose a threat to the computer. What happened has already happened.
You need GridinSoft Anti-Malware to remove active system infections. The virus that encrypted your files is most likely still active and periodically runs a test for the ability to encrypt even more files. Also, these viruses install keyloggers and backdoors for further malicious actions (for example, theft of passwords, credit cards) often.
In this situation, you need to prepare the memory stick with a pre-installed Trojan Killer.
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.
The Rzfu 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.
- Pictures that you shared with family and friends that they can just send back to you.
- Photos that you uploaded on social media or cloud services like Carbonite, OneDrive, iDrive, Google Drive, etc
- Attachments in emails you sent or received and saved.
- Files on an older computer, flash drive, external drive, camera memory card, or iPhone where you transferred data to the infected computer.
If the guide doesn’t help you to remove infection, please download the GridinSoft Anti-Malware that I recommended. Do not forget to share your experience in solving the problem. Please leave a comment here! This can help other victims to understand they are not alone. And together we will find ways to deal with this issue.
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Brendan SmithHow To Restore & Decrypt .RZFU Files?
Name: RZFU Ransomware
Description: The RZFU Virus belongs to the STOP/DJVU family of ransomware infections. This malicious software encrypts various file types, including videos, photos, and documents, which become identifiable by a distinct rzfu extension. As a result, the affected files become inaccessible and unusable. Subsequently, the RZFU ransomware demands a ransom payment in Bitcoin from its victims, ranging from $490 to $980.
Operating System: Windows
Application Category: Virus
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