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Remove Kasiski ransomware / virus (updated Mar 2020) - Bonus: Decryption Steps

removal by Gabriel E. Hall - - | Type: Ransomware

Kasiski ransomware is the cryptovirus that uses unusual prefix for renaming encrypted files 

Kasiski ransomwareKasiski ransomware is the virus that gets photos, documents, archives, video files, and other commonly used data encrypted to have the opportunity for a ransom demand. This ransomware spreads around the world and frustrates users with the money demanding message that appears on the desktop as a wallpaper and a text file. Criminals claim to offer the decryption tool, but that is all for faking legitimacy and trust. Cryptovirus creators only care for your money, so don't even consider paying them.

Kasiski virus is created by criminals who speak Spanish and want $500 from each victim. The threat is targetting Hispanic users, so it can be distributed around the world easily. Also, it is possible that some versions of the particular threat can aim to English-speaking users and lock files, demand ransoms. 

Questions about Kasiski ransomware virus

Kasiski virus appears to be a new type of ransomware[1], which, surprisingly, is created for an x64[2] version of Windows. It seems that the threat cannot even work on 32-bit devices. The name of this ransomware is derived from the appendix that the original names of corrupted files get. The virus renames files during the encryption process. Unlike other ransomware, it doesn’t add extensions but appends [KASISKI] prefix to the file names.

Name Kasiski ransomware
File marker [KASISKI] prefix comes at the start of every encoded file and shows which data got locked by the threat
Targets Hispanic users all over the world
Ransom note INSTRUCCIONES.txt – a file that delivers the message from criminals and displays all the needed information for the victim about encrypted files and possible recovery options.
Ransom amount The text file with instructions also offers to decrypt files with a decryptor for $500
Distribution Spam email attachments with malicious macros get delivered to hundreds of users, so when the file is opened, and macros enabled, ransomware can drop straight on the system and start the encryption
Distinct feature The virus is developed for 64-bit systems, so it is not working on 32-bit devices
Elimination Kasiski ransomware removal should be performed with proper anti-malware tools, so all the malicious files get removed and virus terminated
Repair A full system scan with tools like Reimage Reimage Cleaner Intego can significantly improve the state of security because such utilities can repair system files and corrupted registries or functions

The virus can be installed by the user himself, without knowing what kind of file/program it is. As we have already mentioned, Kasiski malware encrypts[3] almost all files with a strong cipher and then changes desktop background with a basic yellow picture with some text written on it.

Then the virus drops a file called INSTRUCCIONES.txt (on the desktop) which is known to be a ransom note – a message from malicious actors. Cybercriminals typically create such files on the system after corrupting victim’s data. They aim to inform the victim of how the corrupted data can be recovered, and usually, they demand money immediately.

In this ransom note, authors of Kasiski ransomware ask the victim to pay a ransom in Bitcoins. They promise to provide a “DECRYPT TOOL” for $500. Here's how the beginning of the ransom note looks:

Informacion importante

Este es su numero personal (NO LO BORRE) =

Todos sus archivos fueron encryptados (bloqueados)/

Para restaurar sus archivos usted necesita un (DECRYPT TOOL)

Nosotros le ofrecemos el (DECRYPT TOOL) para restaurar sus archivos, su costo es de ($500) quinie

However, we never advise victims to pay the ransom because obviously, cybercriminals are not the people you can count on. Therefore, we usually advise victims to remove Kasiski ransomware from the system using anti-malware tools because such software can easily find and remove the malware from the affected device.

Unfortunately, for affected system files, you should install a program designed for system repair such as Reimage Reimage Cleaner Intego that can help with Kasiski virus damage. Then find a backup, which is needed for data recovery. If you do not have a needed backup[4], you can try data recovery methods provided below the article.

However, the virus is under analysis at the moment, researchers might come up with Kasiski decryption tool after a while. Until then, take care of the machine, clean virus traces, try to secure your PC from possible additional malware attacks, and try to restore all the encoded data with files stored on external devices. Make sure to double-check before adding any data on the machine, because you may lose your files if any leftover ransomware files trigger the secondary encryption round.  Kasiski ransomware virusKasiski ransomware is the cryptovirus that shows the ransom demanding message on the wallpaper.

Traditional ransomware distribution techniques

How ransomware crooks distribute their malicious programs depends on their programming skills. More advanced ones employ hacking skills to spread malicious files via ad networks, others use exploit kits[5], and finally, some scammers use Trojans to infect devices with ransomware.

However, the most efficient technique that is the most used by such criminals so far is also a very basic one. Malware authors only need to compose convincing email letters and send them out to hundreds or even thousands of victims. The message typically says that the user needs to view “attached contents.” In most cases, attachments state about some kind of financial data like order information or invoices.

However, we advise users to think whether a) they know the sender personally or not; b) were they expecting to receive such an email or not. If the answer to these questions is no, better stay away from such letters and delete them ASAP. Always do so with emails you were not expecting to get or notifications that contain red flags like typos, grammar mistakes, or shortened hyperlinks. Those can also send you to macro-laced[6] sites or trigger direct downloads of malicious files, malware.

Kasiski ransomware virus termination procedures include AV tools

If your computer was compromised, remove Kasiski ransomware immediately using proper anti-malware tools. Ransomware-type programs often come with various additional features such as an ability to install new malware, transmit personal information, and even more.

To make your PC safe again, it is recommended to use powerful anti-malware software such as SpyHunter 5Combo Cleaner or Malwarebytes. Full Kasiski ransomware removal guidelines are given down below – follow them carefully, do not rush! Using those methods may help you with the proper AV scan too.

You do not want to miss infectious components because if you do so, they might weaken your PC’s security, which would allow other viruses to infiltrate the system easier. When you are done with the proper elimination of all Kasiski virus components, you can go for the data recovery solutions that are also listed below. Make sure to repair system files using Reimage Reimage Cleaner Intego before though.

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What to do if failed?
If you failed to remove virus damage using Reimage Intego, submit a question to our support team and provide as much details as possible.
Reimage Intego has a free limited scanner. Reimage Intego offers more through scan when you purchase its full version. When free scanner detects issues, you can fix them using free manual repairs or you can decide to purchase the full version in order to fix them automatically.
Alternative Software
Different software has a different purpose. If you didn’t succeed in fixing corrupted files with Reimage, try running SpyHunter 5.
Alternative Software
Different software has a different purpose. If you didn’t succeed in fixing corrupted files with Intego, try running Combo Cleaner.

To remove Kasiski virus, follow these steps:

Remove Kasiski using Safe Mode with Networking

Reboot the system in the Safe Mode with Networking and run the AV tool then

  • Step 1: Reboot your computer to Safe Mode with Networking

    Windows 7 / Vista / XP
    1. Click Start Shutdown Restart OK.
    2. When your computer becomes active, start pressing F8 multiple times until you see the Advanced Boot Options window.
    3. Select Safe Mode with Networking from the list Select 'Safe Mode with Networking'

    Windows 10 / Windows 8
    1. Press the Power button at the Windows login screen. Now press and hold Shift, which is on your keyboard, and click Restart..
    2. Now select Troubleshoot Advanced options Startup Settings and finally press Restart.
    3. Once your computer becomes active, select Enable Safe Mode with Networking in Startup Settings window. Select 'Enable Safe Mode with Networking'
  • Step 2: Remove Kasiski

    Log in to your infected account and start the browser. Download Reimage Reimage Cleaner Intego or other legitimate anti-spyware program. Update it before a full system scan and remove malicious files that belong to your ransomware and complete Kasiski removal.

If your ransomware is blocking Safe Mode with Networking, try further method.

Remove Kasiski using System Restore

Make the system virus free by enabling System Restore feature

  • Step 1: Reboot your computer to Safe Mode with Command Prompt

    Windows 7 / Vista / XP
    1. Click Start Shutdown Restart OK.
    2. When your computer becomes active, start pressing F8 multiple times until you see the Advanced Boot Options window.
    3. Select Command Prompt from the list Select 'Safe Mode with Command Prompt'

    Windows 10 / Windows 8
    1. Press the Power button at the Windows login screen. Now press and hold Shift, which is on your keyboard, and click Restart..
    2. Now select Troubleshoot Advanced options Startup Settings and finally press Restart.
    3. Once your computer becomes active, select Enable Safe Mode with Command Prompt in Startup Settings window. Select 'Enable Safe Mode with Command Prompt'
  • Step 2: Restore your system files and settings
    1. Once the Command Prompt window shows up, enter cd restore and click Enter. Enter 'cd restore' without quotes and press 'Enter'
    2. Now type rstrui.exe and press Enter again.. Enter 'rstrui.exe' without quotes and press 'Enter'
    3. When a new window shows up, click Next and select your restore point that is prior the infiltration of Kasiski. After doing that, click Next. When 'System Restore' window shows up, select 'Next' Select your restore point and click 'Next'
    4. Now click Yes to start system restore. Click 'Yes' and start system restore
    Once you restore your system to a previous date, download and scan your computer with Reimage Reimage Cleaner Intego and make sure that Kasiski removal is performed successfully.

Bonus: Recover your data

Guide which is presented above is supposed to help you remove Kasiski from your computer. To recover your encrypted files, we recommend using a detailed guide prepared by security experts.

If your files are encrypted by Kasiski, you can use several methods to restore them:

Data Recovery Pro is the program that can restore your files after encryption and other incidents

You can use Data Recovery pro for encrypted files or for accidentally deleted data

  • Download Data Recovery Pro;
  • Follow the steps of Data Recovery Setup and install the program on your computer;
  • Launch it and scan your computer for files encrypted by Kasiski ransomware;
  • Restore them.

Windows Previous Versions is the feature that can help with affected files

When System Restore gets enabled, you can rely on Windows Previous Versions feature and recover data individualy

  • Find an encrypted file you need to restore and right-click on it;
  • Select “Properties” and go to “Previous versions” tab;
  • Here, check each of available copies of the file in “Folder versions”. You should select the version you want to recover and click “Restore”.

ShadowExplorer restores files affected by Kasiski ransomware

The option can work when Shadow Volume Copies are left untouched

  • Download Shadow Explorer (;
  • Follow a Shadow Explorer Setup Wizard and install this application on your computer;
  • Launch the program and go through the drop down menu on the top left corner to select the disk of your encrypted data. Check what folders are there;
  • Right-click on the folder you want to restore and select “Export”. You can also select where you want it to be stored.

Kasiski ransomware has no decryption tool

Finally, you should always think about the protection of crypto-ransomwares. In order to protect your computer from Kasiski and other ransomwares, use a reputable anti-spyware, such as Reimage Reimage Cleaner Intego, SpyHunter 5Combo Cleaner or Malwarebytes

Access your website securely from any location

When you work on the domain, site, blog, or different project that requires constant management, content creation, or coding, you may need to connect to the server and content management service more often. The best solution for creating a tighter network could be a dedicated/fixed IP address.

If you make your IP address static and set to your device, you can connect to the CMS from any location and do not create any additional issues for the server or network manager that needs to monitor connections and activities. VPN software providers like Private Internet Access can help you with such settings and offer the option to control the online reputation and manage projects easily from any part of the world.


Backup files for the later use, in case of the malware attack

Computer users can suffer from data losses due to cyber infections or their own faulty doings. Ransomware can encrypt and hold files hostage, while unforeseen power cuts might cause a loss of important documents. If you have proper up-to-date backups, you can easily recover after such an incident and get back to work. It is also equally important to update backups on a regular basis so that the newest information remains intact – you can set this process to be performed automatically.

When you have the previous version of every important document or project you can avoid frustration and breakdowns. It comes in handy when malware strikes out of nowhere. Use Data Recovery Pro for the data restoration process.

About the author
Gabriel E. Hall
Gabriel E. Hall - Passionate web researcher

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  1. jake says:
    February 20th, 2017 at 10:23 am

    Kasiski encrypted all of my files, what am I supposed to do now?

  2. Loganberry says:
    February 20th, 2017 at 10:24 am

    Cant run my antivirus… any ideas why?/?

  3. Victory says:
    February 20th, 2017 at 10:24 am

    The virus prevents you from doing so. Just restart your PC into Safe Mode with Networking (instructions are provided in this post, by the way 😉 )

  4. Daniel says:
    February 20th, 2017 at 10:25 am

    Kasiski.ResearchPaper.doc. WELL THANKS RANSOMWARE! I lost hours of hard work in seconds!

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