Remove ISAK Ransomware Virus (+DECRYPT .isak Files)

Isak ransomware is a type of computer virus that injects your PC, encrypts your documents, and then asks to pay the ransom for file decryption. Besides these unwanted actions, that malware also alters some important settings and can even disable your security tool.

Isak Ransomware Summary

NameIsak virus
TypeSTOP/Djvu Ransomware
DamageAll files are encrypted and cannot be opened without paying a ransom. Additional password-stealing trojans and malware infections can be installed together with a ransomware infection.
Isak Removal Tool To use full-featured product, you have to purchase a license. 6 days free trial available.

Isak malware – what is it?

Isak malware can correctly be classified as a STOP/Djvu ransomware family. That type of malware is targeted at individuals. This feature supposes that Isak does not carry any sort of additional malware, which sometimes helps malware of other families to take control of your computer. Since most users do not have anything valuable on their PCs, there is no need to carry additional malware that increases the risk of failure of the whole ransomware operation.

The usual signs of that virus activity is the appearance of .isak files in your folders, instead of the files you used to have. The photo.jpg turns into photo.jpg.isak, report.xlsx – into report.xlsx.isak and so on. You cannot to suspend this action, and can’t open that documents – they are ciphered with pretty strong cipher.

Isak Virus - encrypted .isak files
Isak Encrypted Files

You can also see various other signs of virus activity. Suddenly blocked Microsoft Defender and inability to check the well-known anti-malware forums or web pages, where the virus removal and file decryption guides are published. You will see how it works in the paragraph below. The malware removal and decryption guide are also available – read below how to wipe out Isak malware and get the .isak files back.

How did Isak ransomware encrypt my files?

After the injection, the Isak virus starts a connection with its command and control server. This server is controlled by malware maintainers – fraudsters who manage the distribution of this virus. Another activity which is done by these crooks is answering the emails of sufferers, who intend to get their files back.

The documents are encrypted with one of the strongest encryption algorithm – AES-256. The “256” digit in the name of this algo means the power of two – 2^256 for this case. 78-digit number of possible decryption keys variations – it is unreal to brute force it. As cipher analysts say, it will take more time than our planet can estimate to exist, even when you make use of the most powerful computer system. In each folder that has the encrypted file(s), Isak ransomware leaves the _readme.txt file with the following contents:


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:

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:

Reserve e-mail address to contact us:

Your personal ID:

Nevertheless, you can still run some of your documents. The Isak ransomware encrypts only the first 150 KB of each file, but the other piece of this file can be opened. Primarily, it works best with audio/video files, which are definitely larger than 150 kilobytes. Not every media player is able to open these files – WinAmp is the best option, since it is free and well-tested. First seconds of each recording will be silent – this part is encrypted – but the rest of the video or music will be accessible like nothing happened.

Is Isak ransomware dangerous for my PC?

As it was mentioned several paragraphs above, ransomware is not only about ciphering the files. Isak virus makes the changes in your operating system in order to prevent searching the ransomware removal and file decryption guides. Malware does not create the software obstacle – it just modifies the system settings, primarily – networking and security configurations.

Through the networking configurations, the most changed item is the HOSTS file. This text file contains the DNS-address instructions, which are used by the browsers while sending a request to the server. If you add a specific DNS-address for the certain website, your web browser will connect that page through that DNS next time. Ransomware edits that file, adding the unknown DNS, so any of the web browsers will show you the “Unable to resolve the DNS-address” error.

Error 404

Other alterations done by the virus are targeted on prevention of fast detection of itself, and also preventing the installation of the majority of anti-malware programs. Isak ransomware makes several changes in Group Policies – the system configuration interface which allows to change the abilities of each application. In such a way, ransomware stops the Microsoft Defender and various other security tools, and also disables the launch of antivirus installation files.

How did I get infected?

Throughout the whole term while STOP/Djvu family is active, it was using dubious programs as a primary method of ransomware injection. Under the term of dubious software I mean applications that are already not supported by the maintainer and spread through the third-party websites. These applications may be hacked, to make them possible to use without buying any license. Another example of such a program type is different hacking tools – cheat engines, keygens, Windows activation tools and so on.

This sort of apps may be distributed in different ways – through the website that offers a downloading link, and also through the seeding networks – ThePirateBay, eMule and so on. All these sources are well-known as the biggest computer piracy resources. People use these pages to get various apps or games for free, even if they must be purchased. Nobody can stop the users who hack these programs from adding malware of some sort to the files of the hacked tool. Hacktools, however, are created for outlaw targets, so their developers may easily insert the ransomware under the guise of some program element.

injecting viruses into program
when adding the jumps on license checking, hackers can easily inject malicious code into the program

These hacked programs, regardless of their source, are one of the most often carriers for various viruses, and 100% the most widespread one for Isak malware. It is better to avoid making use of it, and not only because of ransomware spreading risks. Avoiding the license purchase is an outlaw action, and both hackers and users who use hacked apps fall under the charge of piracy.

How do I remove Isak virus?

The Isak virus is really hard to remove manually. In fact, because of the amount of alterations it makes in your system, it is almost unreal to spot them all and fix. The best decision is to make use of antivirus software. But which one to choose?

You can spectate the offers to use Microsoft Defender, which is already inside of your system. However, as it was mentioned earlier, most of STOP/Djvu malware examples stop it even before the ciphering process. Making use of the third-party program is the only option – and I can offer you the GridinSoft Anti-Malware as a solution for that case. It has perfect detection abilities, so the virus will not be missed. It is also capable of system recovery, that is heavily demanded after the Isak virus attack.

To remove Isak malware infections, scan your computer with legitimate antivirus software.

  • Download and install GridinSoft Anti-Malware by the button above. After the installation, you will be offered to start a 6-day free trial. During this term, the security tool has its full functionality, so you will definitely be able to both wipe out the virus and repair your computer. To activate a trial period, you just need to type your email address.
  • Free trial activation GridinSoft Anti-Malware

  • After activating the free trial, launch the full scan of your PC. It will last for about 15-20 minutes, and check each folder you have in your system. Ransomware will not hide!
  • Full scan in GridinSoft Anti-Malware

  • When the scan is finished, press the Clean Now button to wipe out the Isak ransomware and all other malware detected by a program.
  • Clean the viruses

    After the ransomware removal, you can go to file decryption. Virus removal is required to prevent the repeating encryption of your files: while Isak ransomware is active, it will not miss any unencrypted file.

    How to decrypt the .isak files?

    There are two ways to decrypt your files after a Isak virus attack. First one and the most obvious is file decryption. It is performed with a special app, designed by Emsisoft, and called Emsisoft Decryptor for STOP/Djvu. This program is free. Analysts update its decryption keys databases as often as possible, so you will definitely get your files back, sooner or later.

    Another way to get your documents and photos back is to try to recover them from your physical disks. Since Isak virus deletes them and substitutes with an encrypted copy, the residue of the documents are still kept on the disk. After the deletion, the information about them is wiped from the file system, but not from a disk drive. Special programs, like PhotoRec, are able to recover these files. It is free, too, and may also be used for file recovery in case when you have deleted a thing unintentionally.

    Decrypting the .isak files with Emsisoft Decrypter for STOP/Djvu

    Download and install Emsisoft Decrypter tool. Agree with its EULA and continue to the interface.

    Emsisoft Decrypter EULA

    The interface of this program is extremely easy. All you have to do is to select the folder where the encrypted files are stored, and wait. If the program has the decryption key which corresponds to your ransomware case – it will decrypt it.

    Emsisoft Decrypter decryption process

    During the use of Emsisoft Decrypter for STOP/Djvu, you may observe various error messages. Don’t worry, that does not mean that you did something wrong or a program does not work properly. Each of these errors refer to a specific case. Here is the explanation:

    Error: Unable to decrypt file with ID: [your ID]

    The program does not have a corresponding key for your case. You need to wait for some time until the key database will be updated.

    No key for new variant online ID: [your ID]

    Notice: this ID appears to be an online ID, decryption is impossible.

    This error means that your files are encrypted with an online key. In such a case, the decryption key is unique and stored on the remote server, controlled by crooks. Unfortunately, the decryption is impossible.

    Result: No key for new variant offline ID: [example ID]

    This ID appears to be an offline ID. Decryption may be possible in the future.

    Ransomware uses the offline key to encrypt your files. This key is not unique, so you likely have it in common with another victim. Since offline keys must be collected, too, it is important to keep calm and wait until the analysts team finds one which will fit your case.

    Remote name could not be resolved

    This error indicates that the program has problems with DNS on your computer. That’s a clear sign of malicious alterations in your HOSTS file. Reset it using the official Microsoft guide.

    Recovering the .isak files with PhotoRec tool

    PhotoRec is an open-source tool, which is created to recover the deleted or lost files from the disk. It checks each disk sector for the residues of deleted files, and then attempts to recover them. That app is able to recover the files of more than 400 different extensions. Because of the described feature of ransomware encryption mechanism, it is possible to use this tool to get the original, unencrypted files back.

    Download PhotoRec from the official website. It is absolutely free, however, its developer warns that he does not guarantee that this program will be 100% effective for file recovery purposes. Moreover, even paid apps can barely give you such a guarantee, because of the chain of random factors that can make the file recovery harder.

    Unzip the downloaded archive to the folder you like. Don’t worry because of its name – TestDisk – this is the name of the utility developed by the same company. They decided to spread it together since PhotoRec and TestDisk are often used together. Among the unzipped files, search for qphotorec_win.exe file. Run this executable file.

    PhotoRec and TestDisk

    Before you can start the recovery process, you need to specify several settings. In the drop-down list, choose the logic disk where the files were stored before the encryption.

    PhotoRec recovering choose disk drive

    Then, you need to specify the file formats you need to recover. It may be difficult to scroll all 400+ formats, luckily, they are sorted by alphabetical order.

    PhotoRec file formats

    Finally, name the folder you want to use as a container for recovered files. The program will likely dig out a lot of useless files, which were deleted intentionally, so desktop is a bad solution. The best option is to use the USB-drive.

    PhotoRec recovery drive

    After these easy manipulations, you may just press the “Search” button (it turns active if you specified all required parameters). The recovery process may take several hours, so keep patient. It is recommended not to use the computer during this term, since you may overwrite some files you are intending to recover.

    Frequently Asked Questions

    ✔️Are the files encrypted by Isak ransomware dangerous?

    No. Isak files is not a virus, it is not able to inject its code into the files and force them to execute it. The .EXT files are just the same as regular ones, but encrypted and cannot be opened in the usual way. You may store it together with normal files without any fears.

    ✔️Is it possible that antivirus software will delete the encrypted files?

    As I have mentioned in a previous paragraph, encrypted files are not dangerous. Hence, good anti-malware programs like GridinSoft Anti-Malware will not trigger on them. Meanwhile, some of the “disk cleaning tools” may remove them, stating that they belong to the unknown format and are likely broken.

    ✔️The Emsisoft tool says my files are encrypted with the online key and cannot be decrypted. What do I need to do?

    It is very unpleasant to hear that the files you have are likely lost. Ransomware creators lie a lot in order to scare their victims, but they tell the truth in claims about the strength of the encryption. Your decryption key is stored on their servers, and it is impossible to select it because of the strength of the encryption mechanism.

    Try other recovery methods – through the PhotoRec, or using the previously created backups. Search for the previous versions of these files – getting back a part of your dissertation, for example, is better than missing it all.

    Last option is just waiting. When the cyber police caughts the crooks who create and distribute ransomware, first get the decryption keys and publish it. Emsisoft analysts will surely take these keys and add them to the Decryptor databases. In some cases, malware creators may publish the rest of the keys when they stop their activity.

    ✔️Not all of my .isak files are decrypted. What do I need to do?

    The situation when the Emsisoft Decryptor failed to decrypt several files usually happens when you have not added the correct file pair for the certain file format. Another case when this problem may appear is when some problem occurred during the decryption process – for example, RAM limit reached. Try to perform the decryption process once again.

    Another situation when the Decryptor app may leave your files unencrypted is when ransomware uses different keys for certain files. For example, it may use offline keys for a short period of time when it has connection issues. The Emsisoft tool is not able to check both key types simultaneously, so you need to launch the decryption again, in order to repeat the process.

    Helga Smith

    I was always interested in computer sciences, especially data security and the theme, which is called nowadays "data science", since my early teens. Before coming into the Virus Removal team as Editor-in-chief, I worked as a cybersecurity expert in several companies, including one of Amazon's contractors. Another experience: I have got is teaching in Arden and Reading universities.

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