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

The Yyza virus, categorized as a ransomware infection, is a member of the STOP family. This malware is notorious for its malicious activities involving the encryption of files. Upon infiltrating a computer, the Yyza virus specifically targets a range of file types, including photos, videos, documents, and more. It alters the structure of these files and appends the “.yyza” extension to each one, rendering them inaccessible without the requisite decryption key.

Yyza Virus Overview

Yyza

🤔 Yyza malware can be classified as ransomware that belongs to the DJVU/STOP ransomware family. Its main target is to cipher your files. Then, this ransomware asks its victims to pay the ransom – ($490 – $980) in Bitcoin.

The Yyza virus is a type of malware that encrypts your files and makes you pay for their restoration. This ransomware encrypts different file types. ciphered files can be identified by a distinct “.yyza” extension. The affected files become inaccessible and unusable.

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

Yyza Ransomware operates by Salsa20 encryption algorithms to cipher the files. Since Yyza virus employs such a strong ciphering method, it becomes quite hard, if not impossible, to find the decryption key without the assistance of the attackers.

Once Yyza malware finishes the encryption, it shows a ransom note to the user, demanding a ransom payment for the decryption key. The ransom note provides instructions on how to make the payment and often includes threats of permanent data loss or increased ransom amounts if the ransom is not paid within a specified timeframe.

I have made an all-encompassing list of potential solutions, advice, and methods to disable the Yyza virus and recover access to your files. In some cases, it may be possible to restore your files, but sometimes, it may be impossible.

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📌 Important Note!

It is critical to note that paying off the bill does not guarantee the successful recovery of your files. The individuals who stand behind the Yyza 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.

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

The Yyza virus bears resemblance to other DJVU ransomware samples like Tasa, Yytw, Wspn, and Taoy. This virus encrypts a wide range of common file types and appends its distinct “.yyza” extension to all files. For instance, a file named “1.jpg” would be altered to “1.jpg.yyza” and “2.png” to “2.png.yyza“.

After successful encryption, malware 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 victim will not miss its appearance even without opening folders.

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

Encrypted Files by STOP/DJVU Ransomware

Name	Yyza Virus
Ransomware family¹	DJVU/STOP² ransomware
Extension	.yyza
Ransomware note	_readme.txt
Ransom	From $490 to $980 (in Bitcoins)
Contact	[email protected], [email protected]
Detection	Backdoor:Win32/Kelihos.F, TrojanDropper:Win32/Injector.A!MTB, MSIL/GenKryptik.GMLZ
Symptoms	Installs password-stealing Trojan on the system, like Vidar Stealer or RedLine Stealer; Adds a list of domains to HOSTS file to block access to certain security-related sites; Encrypts most of your files (photos, videos, documents) and adds a particular “.yyza” extension; Manages to install a SmokeLoader backdoor; Can delete Volume Shadow copies to make victim’s attempts to restore data impossible;
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 scary warning demanding users to pay off the ransom to unlock the encoded data contains these exasperating warnings.

The Yyza ransomware executes a series of actions to carry out specific functions on a victim’s computer actively. One of the initial actions involves launching the deceptive process named winupdate.exe, which presents a counterfeit Windows update prompt during the attack. This ruse aims to mislead the victim into believing that their computer’s sluggishness is due to a Windows update.

Simultaneously, the ransomware initiates another process with a randomly generated name consisting of four characters. This process scans the victim’s PC for target files and encrypts them. Subsequently, the ransomware eliminates Volume Shadow Copies from the system using the following CMD command:

vssadmin.exe Delete Shadows /All /Quiet

Once removed, the ability to restore the computer to its previous state becomes exceedingly challenging, rendering the use of System Restore Points virtually futile. The predicament arises from the ransomware operators’ deliberate elimination of built-in Windows mechanisms that could facilitate free file recovery for the victim. Furthermore, the perpetrators tamper with the Windows HOSTS file by appending a list of domains and redirecting them to the localhost IP. Consequently, attempting to access any of the blacklisted websites results in a DNS_PROBE_FINISHED_NXDOMAIN error.

We have observed that the ransomware makes a deliberate effort to restrict access to websites that offer diverse how-to guides for computer users. Evidently, by imposing limitations on specific domains, the malicious actors aim to impede the victim’s access to pertinent and helpful information concerning ransomware attacks. This malware also deposits two text files on the victim’s computer, containing crucial details about the attack – the victim’s public encryption key and personal ID. These files are denoted as bowsakkdestx.txt and PersonalID.txt.

Despite these modifications, the malware remains relentless. Variants of the STOP/DJVU ransomware strain exhibit a tendency to install the Vidar password-stealing Trojan onto compromised systems. This insidious threat boasts a wide array of capabilities, including:

Executing malicious software on the victim’s computer to extract sensitive data.
Unauthorized acquisition of login credentials for accounts on platforms such as Steam, Telegram, and Skype.
Covert manipulation and inspection of files on the victim’s computer, operating unbeknownst to them.
Pilfering cryptocurrency wallets stored on the victim’s system.
Granting hackers remote control over the victim’s computer, facilitating a range of malicious activities.
Extraction of sensitive information, encompassing browser cookies, stored passwords, and browsing history.

The cryptographic algorithm employed by the STOP/Djvu ransomware is AES-256. Consequently, if your data has been encrypted using an online decryption key, the prospects of restoring your files without succumbing to the ransom demands are notably slim. The crux of the matter is that this decryption key is distinctive for each victim, and deciphering it entails an exceedingly substantial investment of time.

Securing the online decryption key through alternative means is also an exceedingly arduous task. This key is safeguarded on a server under the control of the hackers who propagated the Yyza infection. To acquire the unlocking key, a payment of $980 is stipulated. For the payment particulars, victims are instructed to establish contact with the hackers via 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

The _readme.txt file also indicates that the user must establish contact with the hackers’ representatives within 72 hours following the attack. Adhering to this 72-hour stipulation results in a 50% discount being granted by the hackers. Consequently, the ransom sum is reduced to $490.

However, it is strongly advised to refrain from capitulating to the ransom demands. I highly recommend that you avoid engaging with these fraudulent individuals and abstain from making any payment. An exceedingly effective course of action to recover the lost data involves utilizing existing backups or employing the Decrypter tool provided by Emsisoft.

The hallmark of these viruses lies in their utilization of a similar sequence of actions to generate the unique decryption key necessary for restoring the encrypted data. As a result, unless the ransomware is still in the developmental phase or exhibits obscure vulnerabilities, manual data recovery remains an unattainable endeavor. The sole recourse to avert the loss of invaluable data is to maintain regular backups of critical files.

It’s important to note that even if you diligently maintain such backups, they should be stored in a dedicated location separate from your primary workstation. For instance, the backup could be stored on a USB flash drive or another external hard drive storage solution. Alternatively, you may opt for the assistance of online (cloud) data storage.

Needless to say, storing your backup on your primary device could render it susceptible to encryption alongside other data. Thus, preserving the backup on your main computer is unquestionably ill-advised.

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, the following are the typical vulnerabilities through which it could infiltrate your PC:

Utilizing online free hosting resources as a concealed means of disseminating the virus.
Concealing the virus installer within various applications, particularly those distributed as freeware or shareware.
Propagating the virus via spam emails containing misleading links that lead to its installation.
Acquiring pirated software from illegal peer-to-peer (P2P) sources, thereby exposing users to potential malware hazards.

Instances have arisen in which the Yyza virus has been camouflaged as a legitimate tool, such as messages insisting on executing a browser update or an ostensibly crucial codec for online media playback. This serves as the modus operandi for certain online deceptions aimed at coercing you into manually installing the ransomware, effectively involving you directly in this process.

Undoubtedly, the fabricated update alert will not disclose that you are inadvertently introducing the virus. Instead, this procedure will be concealed beneath an alert that asserts the necessity to install an urgent security update or some questionable program.

Without question, cracked applications also harbor potential harm. Engaging in P2P activities is not only illegal but can also lead to the introduction of severe malware, including the Yyza ransomware.

In summary, what measures can you take to prevent the ransomware from infiltrating your system? Although there is no foolproof method to guarantee complete immunity from infection, there are certain recommendations I would like to offer to thwart the infiltration of Yyza. Vigilance during the installation of free software is paramount.

Always ensure you carefully review the additional offerings presented by the installer, apart from the primary free program. Exercise caution when dealing with suspicious email attachments. Refrain from executing files from unfamiliar senders. Of course, it’s imperative to keep your current anti-malware program consistently updated.

The malware operates in a covert manner. It won’t manifest openly in your list of available programs. Instead, it remains concealed beneath a malicious process that consistently operates in the background, initiating from the moment your computer is launched.

How To Remove Ransomware?

Video Guide

How To Decrypt .yyza Files?

How to restore big files?

Try deleting .yyza extension on a few big files and opening them. This malware has issues with large files encryption. Either the virus scanned and did not encrypt the file, or it bugged 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 Popn, Poaz, Wspn etc.

As a consequence 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.

Select folders for decryption.

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

Decryptors usually propose several options considering the specific malware family. The present possible options are displayed in the Options tab and can be turned on or disabled there. You may discover 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 does not have a corresponding key in the 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. There is no one to share the decryption key with you. File recovery is only possible through paying the ransom. 🙁

✓ 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). Nonetheless, receiving this message is good news for you, because 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 issues. Try resetting your HOSTS file to default.

How to Restore .yyza Files?

In some case ransomware is not doom for your files…

The Yyza ransomware encryption mechanism algoritm is next: it ciphers every file byte-by-byte, then saves a duplicate, deleting (not overriding!) the initial file. Hence, the information of the file placement on the disk drive is lost, but the original file is not deleted from the physical disk. The cell, or the sector where this file was kept, can still hold this file, but it is not listed by the file system and can be overwritten by data that has been loaded to this drive after the deletion.

This loophole, actually, allows you to restore your files using special software. There could be certain obstacles, especially when you use modern SSDs, but this gives you one more hope for file recovery.

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 Yyza 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 open-source program, which is originally created for data recovery from damaged disks, or for file retrieval in case if they are unintentionally deleted. However, with time flow, this program received the ability to retrieve the files of 400 different formats. Hence, it can be used for file restoration after the Yyza 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 retrieved. PhotoRec is distributed in a pack with other tool of the same developer – TestDisk. The program archive will bear TestDisk name, but don’t worry – PhotoRec files are right inside.

To launch PhotoRec, 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 Yyza ransomware.

After the launch, you will observe the screen showing you the entire list of your disk spaces. However, this details are likely futile, because the required menu is placed a bit higher. Click this menu, then choose the disk which was attacked by ransomware.

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

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

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

Yyza files recovery Video Guide.

Frequently Asked Questions

🤔 How can I open “.yyza” 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 .yyza 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 Yyza. 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 Yyza 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.