What Is Koom Virus?
The Koom virus is the name of a ransomware infection. This virus belongs to a notorious family of ransomware threats, called STOP/DJVU, which include hundreds of variants with new ones being released every week. The malware aims to encrypt your files, changing their core data structure and adding the .koom file extension after their original names. The main problem this may pose for you is you are forced to pay BitCoin to the criminals after following their instructions on the ransom note they leave, called _readme.txt. They want payment in return for the decryption key which is about $900 to $1000 and depends on your files. They even threaten to double the payoff, something which we still do not recommend doing.
Read this article to understand more about the Koom virus and how to remove it from your computer plus how to get your files to work once again.

Koom virus Virus Summary
Name | Koom Virus, also known as UDS:Trojan.Win32.Chapak.gen, Ransom:Win32/StopCrypt.KM!MTB, Win32:PWSX-gen [Trj], Win32:PWSX-gen [Trj], A Variant Of Win32/GenKryptik.FHJB |
File Extension | .koom |
Type | Ransomware, Cryptovirus |
Short Description | The ransomware encrypts files on your computer system and demands a ransom to be paid to allegedly recover them. |
Symptoms | The Koom Virus ransomware will encrypt your files by appending the .koom extension to them. |
Ransom Demanding Note | _readme.txt |
Distribution Method | Spam Emails, Email Attachments |
Detection Tool |
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Koom Virus – What We Know About It
Koom virus is a STOP Ransomware variant and is a successor to the recently appeared Lqqw Virus, Efdc Virus and Orkf virus ones. These viruses may be spread on your computer mainly via one of the following methods:
- If it is an e-mail attachment.
- If downloaded as a file from a third-party website.
If the virus is sent to you as e-mail, it will most often be a very well masked message that appears to come from some type of legitimate company or organization and may appear like the following e-mail attachments:
- E-receipts.
- Invoices.
- Tickets.
- Work-related files.
Koom virus may also be downloaded from suspicious websites where victims most often complain of getting their PC’s infected by the malware pretending to be the following file:
- Patch.
- Portable app.
- Hoax setup.
- Crack (activators).
- Keygen (key generator activators).
Once an infection occurs, the Koom ransomware virus connects to a remote server, controlled by the criminals from which it downloads its virus files, that are likely located in the following directories:
- %AppData%
- %Temp%
- %Local%
- %LocalLow%
- %SystemDrive%
Then, this variant of STOP Ransomware also leaves the _readme.txt file that contains the ransom payoff instructions set by the criminals:
Paying these crooks to ransom not only supports their organizations but also should not be done because you trust the same people that extort you for your files.
Windows Registry changes may be noticed after infection with Koom ransomware. The following registry keys may be set by the threat to execute malicious commands:
- HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
- HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunOnce
- HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnce
- HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
.koom Files
Once the Koom virus begins encrypting your files, it will scan them based on their file extension to detect which file types are to be encoded. The most often targeted files are the following:
- Archives (.zip, .rar, etc).
- Document file types (.docx, .pptx, etc.).
- Audio (.mp3, .wav, etc.).
- Image files (.jpg, .png, .etc).
- Video files (.mp4, .avi, etc.).
- Other.
When it encrypts your files, the Koom virus may leave them with the following appearance:
Example Picture.jpg.koom

Remove Koom Virus and Try to Restore Files
If your computer has been infected by the Koom virus, then we recommend that you follow the guide below. It has been made to help you delete this virus along with the malware files either manually or automatically and contains some alternative steps that might be able to help with the recovery of your files if a STOP Decryptor is not yet available for it. For the best removal, security experts strongly advise victims to remove the Koom virus using a professional anti-malware program. Such a software will automatically scan your computer and make sure all of the malware is gone from it without causing damage to the .koom files.
Attention! SensorsTechForum strongly recommends that all malware victims should look for assistance only by reputable sources. Many guides out there claim to offer free recovery and decryption for files encrypted by ransomware viruses. Be advised that some of them may only be after your money.
As a site that has been dedicated to providing free removal instructions for ransomware and malware since 2014, SensorsTechForum’s recommendation is to only pay attention to trustworthy sources.
How to recognize trustworthy sources:
- Always check "About Us" web page.
- Profile of the content creator.
- Make sure that real people are behind the site and not fake names and profiles.
- Verify Facebook, LinkedIn and Twitter personal profiles.
How to Remove Koom virus from Windows.
Step 1: Boot Your PC In Safe Mode to isolate and remove Koom virus





Step 2: Uninstall Koom virus and related software from Windows
Here is a method in few easy steps that should be able to uninstall most programs. No matter if you are using Windows 10, 8, 7, Vista or XP, those steps will get the job done. Dragging the program or its folder to the recycle bin can be a very bad decision. If you do that, bits and pieces of the program are left behind, and that can lead to unstable work of your PC, errors with the file type associations and other unpleasant activities. The proper way to get a program off your computer is to Uninstall it. To do that:



Step 3: Clean any registries, created by Koom virus on your computer.
The usually targeted registries of Windows machines are the following:
- HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
- HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunOnce
- HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnce
You can access them by opening the Windows registry editor and deleting any values, created by Koom virus there. This can happen by following the steps underneath:



Before starting "Step 4", please boot back into Normal mode, in case you are currently in Safe Mode.
This will enable you to install and use SpyHunter 5 successfully.
Step 4: Scan for Koom virus with SpyHunter Anti-Malware Tool
Step 5 (Optional): Try to Restore Files Encrypted by Koom virus.
Ransomware infections and Koom virus aim to encrypt your files using an encryption algorithm which may be very difficult to decrypt. This is why we have suggested a data recovery method that may help you go around direct decryption and try to restore your files. Bear in mind that this method may not be 100% effective but may also help you a little or a lot in different situations.
Simply click on the link and on the website menus on top, choose Data Recovery - Data Recovery Wizard for Windows or Mac (depending on your OS), and then download and run the tool.
Get rid of Koom virus from Mac OS X.
Step 1: Uninstall Koom virus and remove related files and objects
1. Hit the ⇧+⌘+U keys to open Utilities. Another way is to click on “Go” and then click “Utilities”, like the image below shows:
- Go to Finder.
- In the search bar type the name of the app that you want to remove.
- Above the search bar change the two drop down menus to “System Files” and “Are Included” so that you can see all of the files associated with the application you want to remove. Bear in mind that some of the files may not be related to the app so be very careful which files you delete.
- If all of the files are related, hold the ⌘+A buttons to select them and then drive them to “Trash”.
In case you cannot remove Koom virus via Step 1 above:
In case you cannot find the virus files and objects in your Applications or other places we have shown above, you can manually look for them in the Libraries of your Mac. But before doing this, please read the disclaimer below:
You can repeat the same procedure with the following other Library directories:
→ ~/Library/LaunchAgents
/Library/LaunchDaemons
Tip: ~ is there on purpose, because it leads to more LaunchAgents.
Step 3 (Optional): Try to Restore Files Encrypted by Koom virus.
Ransomware infections and Koom virus aim to encrypt your files using an encryption algorithm which may be very difficult to decrypt. This is why we have suggested a data recovery method that may help you go around direct decryption and try to restore your files. Bear in mind that this method may not be 100% effective but may also help you a little or a lot in different situations.
Simply click on the link and on the website menus on top, choose Data Recovery - Data Recovery Wizard for Windows or Mac (depending on your OS), and then download and run the tool.
Koom virus FAQ
What is Koom virus ransomware and how does it work?
Koom virus is a ransomware infection - the malicious software that enters your computer silently and blocks either access to the computer itself or encrypt your files.
Many ransomware viruses use sophisticated encryption algorithm how to make your files inaccessible. The goal of ransomware infections is to demand that you pay a ransom payment to get access to your files back.
How does Koom virus ransomware infect my computer?
Via several ways.Koom virus Ransomware infects computers by being sent via phishing e-mails, containing virus attachment.
This attachment is usually masked as an important document, like an invoice, bank document or even a plane ticket and it looks very convincing to users.
After you download and execute this attachment, a drive-by download occurs and your computer is infected with the ransomware virus.
Another way, you may become a victim of Koom virus is if you download a fake installer, crack or patch from a low reputation website or if you click on a virus link. Many users report getting a ransomware infection by downloading torrents.
How to open .Koom virus files?
You can't. At this point the .Koom virus files are encrypted. You can only open them once they are decrypted.
Decryptor did not decrypt my data. What now?
Do not panic and backup the files. If a decryptor did not decrypt your .Koom virus files successfully, then do not despair, because this virus is still new.
One way to restore files, encrypted by Koom virus ransomware is to use a decryptor for it. But since it's a new virus, advised that the decryption keys for it may not be out yet and available to the public. We will update this article and keep you posted as soon as this decryptor is released.
How Do I restore ".Koom virus" files (Other Methods)?
Yes, sometimes files can be restored. We have suggested several file recovery methods that could work if you want to restore .Koom virus files.
These methods are in no way 100% guarantee that you will be able to get your files back. But if you have a backup, your chances of success are much greater.
How do I get rid of Koom virus ransomware virus?
The safest way and the most efficient one for the removal of this ransomware infection is the use a professional anti malware software. It will scan for and locate Koom virus ransomware and then remove it without causing any additional harm to your important .Koom virus files.
Also, keep in mind that viruses like Koom virus ransomware also install Trojans and keyloggers that can steal your passwords and accounts. Scanning your computer with an anti-malware software will make sure that all of these virus components are removed and your computer is protected in the future.
What to Do If nothing works?
There is still a lot you can do. If none of the above methods seem to work for you, then try these methods:
- Try to find a safe computer from where you can can login on your own line accounts like One Drive, iDrive, Google Drive and so on.
- Try to contact your friends, relatives and other people so that they can check if they have some of your important photos or documents just in case you sent them.
- Also, check if some of the files that were encrypted it can be re-downloaded from the web.
- Another clever way to get back some of your files is to find another old computer, a flash drive or even a CD or a DVD where you may have saved your older documents. You might be surprised what will turn up.
- You can also go to your email account to check if you can send any attachments to other people. Usually what is sent the email is saved on your account and you can re-download it. But most importantly, make sure that this is done from a safe computer and make sure to remove the virus first.
More tips you can find on our forums, where you can also asks any questions about your ransomware problem.
How to Report Ransomware to Authorities?
In case your computer got infected with a ransomware infection, you can report it to the local Police departments. It can help authorities worldwide track and determine the perpetrators behind the virus that has infected your computer. Below, we have prepared a list with government websites, where you can file a report in case you are a victim of a cybercrime:
Cyber-security authorities, responsible for handling ransomware attack reports in different regions all over the world:
- Germany - Offizielles Portal der deutschen Polizei
- United States - IC3 Internet Crime Complaint Centre
- United Kingdom - Action Fraud Police
- France - Ministère de l'Intérieur
- Italy - Polizia Di Stato
- Spain - Policía Nacional
- Netherlands - Politie
- Poland - Policja
- Portugal - Polícia Judiciária
- Greece - Cyber Crime Unit (Hellenic Police)
- India - Mumbai Police - CyberCrime Investigation Cell
- Australia - Australian High Tech Crime Center
Reports may be responded to in different timeframes, depending on your local authorities.
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Dear Sir, All my files are encrypted by Koom Ransomware online. Please help me in order to get the decryption key. Thank you