The Isak virus, also known as a ransomware infection, is part of the STOP/DJVU family. This malware is known for malignant file encryption operations. When the Isak virus gets into a computer system, it scans the system for files like photos, videos, documents, and more. It modifies the file structure and adds the “.isak” extension to each encrypted file, making them unusable without the decryptor.
Isak Virus Overview
Isak
🤔 Isak malware belongs to ransomware that belongs to the DJVU/STOP family. Its primary purpose is to encrypt your files. After that ransomware virus asks for a ransom fee – ($490 – $980) in Bitcoin.
The Isak virus is a type of malware that encrypts your files and makes you pay for their recovery. This malware encrypts a wide selection of file types. ciphered files are identifiable by a distinct “.isak” extension. As a result, the files touched by ransomware become impossible to access and use.
Then, the ransomware demands a ransom payment in Bitcoin from the victims, ranging from $490 to $980. Usually, a ransom text file is named as “_readme.txt“.
Isak Ransomware uses Salsa20 encryption algorithms to cipher the files. Since Isak virus uses such a strong encryption method, it becomes pretty difficult, if even possible, to find the decryption key without the assistance of the attackers.
Once Isak malware finishes the encryption, it shows 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 also often contains threats of permanent data loss or increased ransom amounts if the demands are not met within a specified timeframe.
I have created an all-encompassing list of the solutions, tips, and methods to stop the Isak ransomware and recover access to your files. In some cases, it may be feasible to restore your files, while sometimes, it may be impossible.
📌 Important Note!
It is essential to note that paying off the bill does not guarantee the successful files recovery. The hackers who stand behind the Isak virus are not trustworthy. There have been instances where victims have paid the ransom, only to be denied by the cybercriminals with the decryption key provision.
Isak uses a unique key for each victim, with one exception:
- If Isak fails to connect the command and control server (C&C) before starting the encryption process, it uses offline keys. This key is the same for all users, allowing for the decryption of files encrypted by the ransomware.
The Isak virus bears resemblance to other DJVU ransomware samples like Cdmx, Cdqw, Lomx, and Loqw. This virus encrypts a wide range of common file types and appends its distinct “.isak” extension to all files. For instance, a file named “1.jpg” would be altered to “1.jpg.isak” and “2.png” to “2.png.isak“.
Upon 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 user will not miss the attack even without opening folders.
The image below provides a visual representation of files with the “isak” extension:
Encrypted Files by STOP/DJVU Ransomware
| Name | Isak Virus |
| Ransomware family1 | DJVU/STOP2 ransomware |
| Extension | .isak |
| Ransomware note | _readme.txt |
| Ransom | From $490 to $980 (in Bitcoins) |
| Contact | [email protected], [email protected] |
| Detection | UDS:Trojan-Ransom.Win32.PornoAsset, Trojan:MSIL/AgentTesla.EXS!MTB, TrojanDownloader:Win32/Dalexis |
| 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 demanding users to pay off the ransom to decrypt the encoded data contains these frustrating warnings.
Isak ransomware arrives as a set of operations that are needed to carry out different activities on a victim’s computer. One of the primary ones being launched is winupdate.exe, a tricky process that displays a fraudulent Windows update notification during the attack. This is meant to convince the victim that a sudden computer slowdown is caused by a Windows update.
Simultaneously, the ransomware runs another process (named as 4 random chars) which commences scanning the computer for target files and ciphering them. Next, the ransomware removes Volume Shadow Copies from the system disk using the following CMD command:
vssadmin.exe Delete Shadows /All /Quiet
Once erased, it becomes virtually impossible to restore the previous computer state using System Restore Points. The issue is, ransomware operators are getting rid of any built-in Windows techniques that could assist the victim to recover files for free. In addition, the crooks modify the Windows HOSTS file by adding a list of domains to it and directing them to the localhost IP. As a result, the victim will see a DNS_PROBE_FINISHED_NXDOMAIN error when trying to access one of the listed websites.
We noticed that ransomware attempts to block websites that developed various how-to guides for computer users. It is obvious that by restricting specific domains, the perpetrators are trying to prevent the victim from reaching relevant and helpful ransomware-attack-related information online. The virus also keeps two text files on the victim’s computer that provide particulars related to the attack – 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 are inclined to install Vidar password-stealing Trojan on compromised systems. This threat has 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, if your data got 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 finding a suitable one will take too much time.
Obtaining the online key in another way is also merely impossible. It is stored on a server controlled by the hackers who spread the Isak malware. For receiving decrypting code 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?
Remove Isak 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 Isak 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 “Isak 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 Isak 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 .isak Files?
How to restore big files?
Try removing .isak extension on a few big files and opening them. This malware has issues with large files encryption. Either the virus read and did not encode the file, or it bugged and did not add the filemarker. If you have files that are very large (2GB+), the latter is most likely. 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 Cdmx, Cdqw, Lomx etc.
As a result of the changes made by the criminals, STOPDecrypter is no longer backed. 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 automatically choose the available directories in order to decode the currently available drives (the connected ones), including the network drives. You can select other locations with the “Add” button.
Decryptors generally offer several options depending on the specific malware family. The existing possible options are displayed in the Options tab and can be turned on or deactivated there. You may find 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]
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
Your original files were encrypted with an online key. Your key is unique and is kept on the command server, controlled by criminals. 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, but files could not be restored (the offline decryption key isn’t available yet). Nonetheless, this message is a good news for you, since 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
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 .isak Files?
In some case ransomware is not doom for your files…
The Isak ransomware encryption algorithm is next: it encrypts every file byte-by-byte, then saves a duplicate, deleting (not overriding!) the original file. Thus, the information of the file location on the physical disk is lost, but the original file is not erased from the disk. The cell, or the sector where this file was stored, can still keep this file, but it is not listed by the file system and can be overwritten by data that has been loaded to this disk after the removal. Hence, it is possible to recover 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 originally created for files recovery from damaged disks, or for files recovery in case if they are unintentionally deleted. However, with time flow, this program got the ability to recover the files of 400 different file types. Hence, it can be used for file recovery after the Isak attack.
First, you need to download this app. It is 100% free, but the developer notifies that there is no assurance that your files will be recovered. PhotoRec is distributed together 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 needed – this 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 Isak ransomware.
Upon the launch, you will witness the screen showing you the entire list of your disk spaces. However, this data is probably futile, 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 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 designate the file formats. This choice is located at the bottom, too. As it was mentioned, PhotoRec can retrieve the files of about 400 different formats.
Finally, you can begin files recovery by pressing the “Search” button. You will view the screen where the findings of the scan and recovery are shown.
Isak 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 Isak 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 .ISAK Files?
Name: ISAK Ransomware
Description: The ISAK 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 isak extension. As a result, the affected files become inaccessible and unusable. Subsequently, the ISAK ransomware demands a ransom payment in Bitcoin from its victims, ranging from $490 to $980.
Operating System: Windows
Application Category: Virus
User Review
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