The Yzoo virus, also known as a ransomware, is part of the STOP/DJVU family. This malware family is notorious for malicious file ciphering. When the Yzoo virus gets into a computer system, it targets various types of files, such as photos, videos, documents, and more. It changes the file structure and adds the “.yzoo” extension to each encrypted file, making them unusable without the decryption key.
Yzoo Virus Overview
Yzoo
🤔 Yzoo malware belongs to ransomware that originates from the DJVU/STOP family. Its primary purpose is to lock your files. Then, ransomware virus asks its victims for a ransom payment – ($490 – $980) in Bitcoin.
The Yzoo virus is a malicious program that encrypts your files and makes you pay for their decryption. This ransomware encrypts different file types. Encrypted files can be identified by a distinct “.yzoo” extension. The files touched by ransomware become inaccessible and unusable.
Subsequently, the ransomware demands a ransom payment in Bitcoin from its victims, ranging from $490 to $980. In all cases, a ransom text file is named as “_readme.txt“.
Yzoo Ransomware uses Salsa20 encryption algorithms to cipher the targeted files. Since Yzoo virus employs such a robust ciphering method, it becomes pretty difficult, if even possible, to pick the decryption key without cooperating with the attackers.
Once the files are encrypted, the Yzoo virus displays a ransom note to the user, asking for 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 permanent data loss or ransom amounts surge if the ransom is not paid within a specified timeframe.
I have created an all-encompassing list of the solutions, advice, and approaches to remove the Yzoo ransomware and recover your files. In some cases, it may be possible to restore your files, while sometimes, it may be impossible.
📌 Important Reminder!
It is crucial to voice that paying off the bill is not a guarantee of the successful files recovery. The scoundrels who stand behind the Yzoo 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.
Yzoo uses a unique key for every victim, with one exception:
The Yzoo virus is highly similar to other DJVU ransomware variants such as Yzaq, Ppvw, Ppvt, and Ppvs. This virus encrypts a wide range of common file types and appends its distinct “.yzoo” extension to all files. For instance, a file named “1.jpg” would be altered to “1.jpg.yzoo” and “2.png” to “2.png.yzoo“.
Upon successful encryption, the virus creates a special text file named “_readme.txt” and places it in every folder containing the encrypted files. It also adds the readme file to the desktop, so the victim will not miss its appearance even without opening folders.
The image below provides a visual representation of files with the “yzoo” extension:
Encrypted Files by STOP/DJVU Ransomware
| Name | Yzoo Virus |
| Ransomware family1 | DJVU/STOP2 ransomware |
| Extension | .yzoo |
| Ransomware note | _readme.txt |
| Ransom | From $490 to $980 (in Bitcoins) |
| Contact | [email protected], [email protected] |
| Detection | Trojan:Win32/Gozi.RD!MTB, Backdoor.Agent.RD, Trojan:Win32/Aenjaris.AL!bit |
| 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 alarming alert insisting users to pay the ransom to unlock the encoded data contains these frustrating cautions.
Yzoo ransomware arrives as a set of tasks that are needed to perform certain tasks on a victim’s computer. One of the first processes being launched is winupdate.exe, a tricky process that shows a fraudulent Windows update alert during the attack. This is meant to convince the victim that a sudden system slowdown is caused by a Windows update.
Meanwhile, the ransomware runs another process (which name commonly consists of 4 random characters) which initiates scanning the PC for target files and encrypting them. Then the ransomware removes Volume Shadow Copies from the system using the following CMD command:
vssadmin.exe Delete Shadows /All /Quiet
Once deleted, it becomes nearly impossible to retrieve the previous computer state using System Restore Points. The issue is, ransomware operators are getting rid of any built-in Windows methods that could aid the victim to restore files for free. In addition, the rascals modify the Windows HOSTS file by adding a list of domains to it and redirecting them to the localhost IP. As a result, the victim will encounter a DNS_PROBE_FINISHED_NXDOMAIN error when accessing one of the listed websites.
We noticed that ransomware attempts to block websites that publish various how-to guides for computer users. It is clear that by limiting 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 .txt files on the victim’s computer that present attack-related information – the victim’s public encryption key and personal ID. These two files are named bowsakkdestx.txt and PersonalID.txt.
After all these alterations, the malware doesn’t cease. Variants of STOP/DJVU have a tendency to release Vidar password-stealing Trojan on compromised systems. This threat possesses an huge list of capabilities, including:
- Manipulating and viewing files on the victim’s computer without their knowledge.
- Extracting sensitive information such as browser cookies, saved passwords, and browsing history.
- Obtaining unauthorized access to login credentials of Steam, Telegram, and Skype.
- Granting the hackers remote control over the victim’s computer for various malicious activities.
- Stealing cryptocurrency wallets from the victim’s system.
- Gathering sensitive data by running malicious software on the victim’s computer.
The encryption algorithm in STOP/Djvu ransomware is AES-256. So, if your data got encrypted with an online decryption key, the possibility to get your files back without paying the ransom are quite low. Thing is, this key is unique for each victim, and finding a suitable one will take exceptionally big amount of time.
Getting the online key in another way is also nearly impossible. It is kept on a server owned by the hackers who spread the Yzoo malware. For receiving unlocking key 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
How To Remove STOP/Djvu Ransomware?
Video Guide
How To Decrypt .yzoo Files?
How to restore big files?
Try removing .yzoo extension on a few big files and opening them. This malware has issues with large files encryption. Either the virus scanned and did not lock the file, or it failed and did not add the filemarker. If your files are very large (2GB+), the latter is most likely. 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 Yzaq, Ppvw, Ppvt etc.
As a result of the alterations 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.
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Select folders for decryption.
Based on the default configurations, the decryptor will by default choose the accessible directories in order to unlock the currently accessible drives (the connected ones), including the network drives. Extra (optional) locations can be selected with the aid of the “Add” button.
Decryptors usually propose several options considering the specific malware family. The present possible options are presented in the Options tab and can be activated or deactivated there. You may locate a detailed list of the currently active Options below.
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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]
There is no corresponding decryption key in the Emsisoft decryptor’s 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. File recovery without paying the ransom 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.
An offline key was used, 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 might be 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 issues. Try resetting your HOSTS file to default.
How to Restore .yzoo Files?
In some case ransomware is not doom for your files…
The Yzoo ransomware encryption algorithm is next: it encrypts every file byte-by-byte, then saves a file copy, deleting (not overriding!) the initial file. Hence, the data 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 keep this file, but it is absent in the file system and can be overwritten by data that has been loaded to this drive after the deletion. Hence, it is possible to restore 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 free program, which is initially created for files recovery from damaged disks, or for file retrieval in case if they are unintentionally deleted. However, as time has gone by, this program adopted the ability to retrieve the files of 400 different extensions. Hence, it can be used for file restoration after the Yzoo attack.
First, you need to download this app. It is 100% free, but the developer states that there is no assurance that your files will be restored. PhotoRec is spread in a pack with another utility of the same developer – TestDisk. The program archive will bear 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 setup is needed – the program has all the files it need within the archive, hence, you can mount it on your USB drive, and help your friends/parents/anyone who has been attacked by Yzoo ransomware.
After the start, you will witness the screen showing you the full list of your disk spaces. However, this information is presumably useless, because the required menu is placed a bit higher. Click this tab, then choose the disk which was attacked by ransomware.
After selecting the disk, you need to pick the destination folder for the restored files. This menu is located at the lower part of the PhotoRec window. The best selection is to export them on USB drive or any other type of removable disk.
Then, you need to designate 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 begin files recovery by pressing the “Search” button. You will observe the screen where the findings of the scan and recovery are shown.
Yzoo files recovery Video Guide.
Frequently Asked Questions
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