The Kaaa virus, also known as a ransomware infection, belongs to the STOP/DJVU family. This malware is notorious for malicious file ciphering. When the Kaaa virus gets into a computer, it scans the system for files like photos, videos, documents, and more. It modifies the file structure and appends the “.kaaa” extension to each file, making them inaccessible and unusable without the decryption.
Kaaa Virus Overview
Kaaa
🤔 Kaaa virus can be classified as ransomware that originates from the DJVU/STOP family. Its main target is to cipher your files. Then, ransomware virus asks its victims to pay the ransom – ($499 – $999) in Bitcoin.
The Kaaa virus is a type of malware that ciphers your files and forces you to pay for their decryption. This malware ciphers various file types. Encrypted files can be identified by a distinct “.kaaa” extension. The affected files become impossible to access and use.
After that, the ransomware demands a ransom payment in Bitcoin from the victims, that ranges from $499 to $999, depending on the time passed after the attack. Usually, a text file with ransom payment guidances is named as “_readme.txt“.
Kaaa Ransomware uses Salsa20 encryption algorithms to scramble the contents of the targeted files. Since Kaaa virus uses such a robust ciphering method, it becomes particularly hard, if even possible, to find the decryption key without cooperating with the attackers.
Once the files are encrypted, the Kaaa virus displays a ransom note to the victim, demanding a ransom payment for the decryption key. The ransom note contains instructions on the ways of making the payment and often includes threats of system wipeout or ransom amounts surge if the demands are not met within a specified timeframe.
I have created an all-encompassing list of potential solutions, tips, and methods to remove the Kaaa malware and recover your files. In some cases, it may be feasible to restore your files, while sometimes, it may be impossible.
📌 Important Note!
It is important to note that paying the ransom does not guarantee the successful recovery of your files. The cybercriminals behind the Kaaa 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.
Kaaa uses a unique key for every victim, with one exception:
- If Kaaa fails to connect the command and control server (C2) before starting the encryption process, it uses offline keys as a fallback option. This key is not unique and is the same for all users, allowing for the decryption of files encrypted by the ransomware.
The Kaaa virus bears resemblance to other DJVU ransomware samples such as Uajs, Uazq, Vook, and Looy. This virus encrypts a wide range of common file types and appends its distinct “.kaaa” extension to all files. For instance, a file named “1.jpg” would be altered to “1.jpg.kaaa” and “2.png” to “2.png.kaaa“.
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 “kaaa” extension:
Encrypted Files by STOP/DJVU Ransomware
| Name | Kaaa Virus |
| Ransomware family1 | DJVU/STOP2 ransomware |
| Extension | .kaaa |
| Ransomware note | _readme.txt |
| Ransom | From $499 to $999 (in Bitcoins) |
| Contact | [email protected], [email protected] |
| Detection | Ransom:Win32/Filecoder.DLK!MTB Virus Removal, VirTool:Win32/CeeInject.CF Virus Removal, MSIL/TrojanDownloader.Agent.PYG Virus Removal |
| 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 scary notification requesting users to pay the ransom to decrypt the encoded data contains these annoying cautions.
Kaaa ransomware arrives as a set of actions that are used to carry out certain tasks on a victim’s computer. One of the initial processes being launched is winupdate.exe, a tricky process that shows a fake Windows update prompt during the attack. This is meant to convince the victim that a sudden computer slowdown is caused by a Windows update.
At the same time, the ransomware runs another process (named as 4 random chars) which starts scanning the computer for target files and ciphering them. Next, the ransomware removes Volume Shadow Copies from the system disk by the following CMD command:
vssadmin.exe Delete Shadows /All /Quiet
Once deleted, it becomes impossible to recover the previous computer state using System Restore Points. The issue is, ransomware operators are getting rid of any built-in Windows methods that could assist the victim to regain files for free. In addition, the hackers modify the Windows HOSTS file by including a list of domains to it and directing them to the localhost IP. As a result, the victim will encounter a DNS_PROBE_FINISHED_NXDOMAIN error when trying to open one of the listed websites.
It has come to our attention that ransomware attempts to restrict websites that promote various how-to guides for computer users. It is obvious that by limiting specific domains, the crooks are trying to hinder the victim from reaching relevant and helpful ransomware-attack-related information online. Malware also stores two text files on the victim’s computer that present details 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 changes, the malware doesn’t cease. Variants of STOP/DJVU are inclined to release Vidar password-stealing Trojan on compromised systems. This threat carries an large 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 cryptography algorithm in STOP/Djvu ransomware is AES-256. So, once your data is encrypted with an online decryption key, the chances to get your files back without paying the ransom are quite low. Thing is, this key is unique for each victim, and picking it will take too much time.
Retrieving the online decryption key in any other way is also nearly impossible. It is kept on a remote server owned by the crooks who promote the Kaaa infection. For receiving decrypting code the payment should be $999. 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 pictures, 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. Do not ask assistants from youtube and recovery data sites for help in recovering your data. They can use your free decryption quota and scam you. Our contact is emails in this text document only. You can get and look video overview decrypt tool: https://we.tl/t-hPAqznkJKD Price of private key and decrypt software is $999. Discount 50% available if you contact us first 72 hours, that's price for you is $499. 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?
Remove Kaaa 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 Kaaa 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 “Kaaa 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 Kaaa 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 .kaaa Files?
How to restore big files?
Try deleting .kaaa 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 you have files that are very large (2GB+), such a situation is highly probable. Please, text me in the comments whether this helped you or not.
The newest extensions released around the end of August 2019 after the criminals made changes. This includes Uajs, Uazq, Vook etc.
As a outcome of the modifications 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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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:
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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 other locations with the “Add” button.
Decryptors typically offer several options considering the specific malware family. The existing possible options are presented in the Options tab and can be enabled or deactivated there. You may discover 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
Your original files were encrypted with an online key. There is no one to share the decryption key with you. 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). Nonetheless, receiving this message is good news for you, because 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
It’s an indication of a DNS issue on your PC. Our first recommendation is to reset your HOSTS file back to default.
How to Restore .kaaa Files?
In some case ransomware is not doom for your files…
The Kaaa ransomware encryption mechanism is next: it encrypts every file byte-by-byte, then saves a file copy, removing (not overriding!) the original file. Hence, the information of the file location on the disk drive is lost, but the original file is not erased from the physical disk. The cell, or the sector where this file was stored, can still hold this file, but it is not listed by the file system and can be rewritten by data that has been loaded to this drive after the removal. 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 open-source program, which is initially created for file retrieval from damaged disks, or for data recovery in case if they are unintentionally deleted. However, with time flow, this program adopted the ability to recover the files of 400 different extensions. Hence, it can be used for file recovery after the Kaaa attack.
First, you need to download this app. It is 100% free, but the developer notifies that there is no guarantee that your files will be recovered. PhotoRec is spread in a pack with other program of the same developer – TestDisk. The downloaded archive will have TestDisk name, but don’t worry. PhotoRec files are right inside.
To launch PhotoRec, you need to find and open “qphotorec_win.exe” file. No setup is required – the program has all the files it need inside of the archive, hence, you can mount it on your USB drive, and help your friends/parents/anyone who has been attacked by Kaaa ransomware.
Upon the start, you will observe the screen showing you the full list of your disks. However, this details are presumably futile, because the required menu is placed a bit higher. Click this bar, then choose the disk which was attacked by ransomware.
After opting for the disk, you need to opt for the destination folder for the restored files. This menu is located at the lower part of the PhotoRec window. The best option 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 regain the files of about 400 different formats.
Finally, you can begin files retrieval by pressing the “Search” button. You will see the screen where the outcomes of the scan and recovery are shown.
Kaaa 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.
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 Kaaa 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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