The Yytw virus, known as ransomware, is part of the STOP family. This malware family is notorious for malicious file ciphering. Once the Yytw virus infects a system, it targets various types of files, such as videos, photos, documents, and more. It modifies the file structure and adds the “.yytw” extension to each encrypted file, making them inaccessible and unusable without the decryptor.
Yytw Virus Overview
Yytw
🤔 Yytw virus is ransomware that originates from the DJVU/STOP family. Its primary purpose is to encrypt files that are important to you. After that ransomware virus asks its victims for a ransom fee – ($490 – $980) in Bitcoin.
The Yytw virus is a malware type that encrypts your files and forces you to pay for their restoration. This ransomware encrypts various file types. Encrypted files can be identified by a distinct “.yytw” extension. As a result, the affected files become impossible to access and use.
Subsequently, the ransomware asks for a file decryption payment in Bitcoin from the victims, ranging from $490 to $980. Typically, a text file with ransom payment guidances is named as “_readme.txt“. Yytw Ransomware works with Salsa20 encryption algorithms to scramble the contents of the targeted files. Since Yytw virus applies such a strong ciphering method, it becomes incredibly difficult, if not impossible, to find the decryption key without the assistance of the attackers.
Once the files are encrypted, the Yytw virus displays a ransom note to the victim, demanding a ransom payment in exchange for the decryption key. The ransom note contains instructions on the ways of making the payment and also often contains threats of system wipeout or ransom amounts surge if the ransom is not paid within a specified timeframe.
I have made a comprehensive list of potential solutions, advice, and approaches to stop the Yytw malware and decrypt and recover your files. In some cases, it may be possible to restore your files, while sometimes, it may be impossible.
📌 Important Note!
It is essential to say that paying off the bill does not guarantee the successful recovery of your files. The scoundrels who stand behind the Yytw virus are known for their untrustworthiness. There were the cases where people have paid the ransom, only to be denied by the cybercriminals with the decryption key provision.
Yytw employs a unique key for each victim, with one exception:
The Yytw virus bears resemblance to other DJVU ransomware samples like Taoy, Tasa, Yyza, and Wspn. This virus encrypts a wide range of common file types and appends its distinct “.yytw” extension to all files. For instance, a file named “1.jpg” would be altered to “1.jpg.yytw” and “2.png” to “2.png.yytw“. Upon successful encryption, the virus creates a special text file named “_readme.txt” and places it in every folder containing the encrypted files.
The image below provides a visual representation of files with the “yytw” extension:
Encrypted Files by STOP/DJVU Ransomware
| Name | Yytw Virus |
| Ransomware family1 | DJVU/STOP2 ransomware |
| Extension | .yytw |
| Ransomware note | _readme.txt |
| Ransom | From $490 to $980 (in Bitcoins) |
| Contact | [email protected], [email protected] |
| Detection | Trojan.Ransom.Poison.B, Win32/Injector.CUYI, VirTool:Win32/CeeInject.ML!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 warning demanding users to pay off the ransom to decrypt the encoded data contains these frustrating admonitions.
Yytw ransomware arrives as a set of tasks that are meant to execute certain activities on a victim’s computer. One of the first processes being launched is winupdate.exe, a tricky process that displays a fraudulent Windows update notification during the attack. Such a trick helps to convince the victim that a sudden system slowdown is caused by a Windows update. But at the same time, the ransomware runs another process (which name commonly consists of 4 random characters) which commences scanning the system for target files and ciphering them. Next, the ransomware deletes Volume Shadow Copies from the disk through the following CMD command:
vssadmin.exe Delete Shadows /All /Quiet
Once removed, it becomes nearly impossible to retrieve the previous computer state using System Restore Points. The concern is, ransomware operators are eliminating any built-in Windows approaches that could help the victim to recover files for free. In addition, the hackers modify the Windows HOSTS file by appending a list of domains to it and mapping them to the localhost IP. As a result, the victim will encounter a DNS_PROBE_FINISHED_NXDOMAIN error when trying to access one of the listed websites.
We’ve observed that ransomware attempts to block websites that publish various how-to guides for computer users. It is clear that by hindering specific domains, the perpetrators are trying to prevent the victim from connecting to relevant and helpful ransomware-attack-related information online. This malware also saves two .txt files on the victim’s computer that present information related to the attack – the victim’s public key and personal ID. These two files are named bowsakkdestx.txt and PersonalID.txt.
After all these alterations, the malware doesn’t stop. Variants of STOP/DJVU tend to release Vidar password-stealing Trojan on compromised systems. This threat has an extensive list of capabilities, including:
- Stealing Steam, Telegram, Skype login / password;
- Stealing cryptocurrency wallets;
- Downloading other malware to the computer and running it;
- Stealing browser cookies, saved passwords, browsing history, and more;
- Viewing and manipulating files on victim’s computer;
- Allowing the hackers to perform other tasks on the victim’s computer remotely.
The cryptography algorithm used by DJVU/STOP virus 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, the key is unique for each victim, and finding a suitable one will take too much time.
Retrieving the online decryption key in another way is also merely impossible. It is kept on a command server owned by the criminals who spread the Yytw malware. For receiving unlocking key the payment should be $980. To see 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 indicates that the computer owner must get in touch with the hackers during 72 hours after the attack. On the condition of getting in touch within 72 hours, hackers grant a 50% discount. Thus the ransom amount will be minimized down to $490. Yet, stay away from paying the ransom! I highly recommend that you do not contact these frauds and do not pay. A highly effective solution to regain the lost data is just using the backups you have, or using Decrypter tool from Emsisoft.
The peculiarity of such malware is the application a similar set of actions for generating the unique decryption key to recover the ciphered data. Thus, unless the ransomware is still in development or exhibits some hard-to-track flaws, 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.
Note that even if you do create such backups regularly, they must be stored 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 rely to the help of online (cloud) information storage.
Unnecessary to mention, when you keep your backup on your regular device, it may be ciphered together with other data. For this reason, storing the backup on your main computer 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.
- Using online free hosting resources as a means to distribute the virus undetected.
- Disguising the virus installer alongside various apps, particularly those offered as freeware or shareware.
- Spreading the virus through spam emails containing deceptive links that lead to its installation.
- Obtaining pirated software from illegal peer-to-peer (P2P) resources, exposing users to potential malware threats.
Instances have been reported when the Yytw virus hiding 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 usually the way how some online scams aim to force you into install the ransomware manually, by actually making you directly participate in this process.
Surely, the bogus update alert will not tell that you are going to actually inject the virus. This process will be hidden under some alert stating that you need to install an urgent security update or some dubious program whatsoever.
Of course, the software cracks represent the harm as well. Using P2P is illegal and may end up with the injection of serious malware, including the Yytw ransomware.
To sum up, what can you do to evade the injection of the ransomware into your computer? Even though there is no 100% guarantee to stop your PC from getting infected, there are some tips I want to give you to prevent the Yytw 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. Keep away from opening dubious email attachments. Do not open files from the unknown addressees. Certainly, your current anti-malware software 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 regularly in the background, that starts at the moment when you launch your computer.
How To Remove Ransomware?
Video Guide
How To Decrypt .yytw Files?
How to restore big files?
Try removing .yytw 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 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 Yyza, Popn, Poaz etc.
As a outcome of the changes made by the criminals, STOPDecrypter is no longer assisted. 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 reachable drives (the connected ones), including the network drives. You can choose additional locations with the “Add” button.
Decryptors usually offer several options considering the specific malware family. The existing possible options are presented in the Options tab and can be turned on or disabled there. You may find a comprehensive 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]
✓ 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 .yytw Files?
In some case ransomware is not doom for your files…
The Yytw ransomware encryption mechanism algoritm is next: it ciphers every file byte-by-byte, then saves a file copy, removing (not overriding!) the original file. Thus, the data of the file location 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 present in the file system and can be rewritten by data that has been loaded to this drive after the deletion. 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 free program, which is initially created for files recovery from damaged disks, or for data recovery 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 data recovery after the Yytw 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 together with another program of the same developer – TestDisk. The resulting 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 setup is needed – the 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 Yytw ransomware.
After the start, you will encounter the screen showing you the full list of your drives. However, this information is probably useless, because the required menu is placed a bit higher. Click this menu, then choose the disk which was attacked by ransomware.
After picking 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 selection is to export them on USB drive or any other type of removable disk.
Then, you need to specify 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 initiate files restoration by pressing the “Search” button. You will observe the screen where the results of the scan and recovery are shown.
Yytw files recovery Video Guide.
Frequently Asked Questions
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