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BTOS Virus Ransomware

What Is Btos Virus?

Are your files changed with the .btos extension? This change is an example of a ransomware threat that belongs to the STOP/DJVU family. This iteration of the ransomware uses the .btos file extension, which is appended to all encrypted files. If your files are locked and the .btos extension is appended to their filenames, then you have become a victim of the STOP/DJVU ransomware family. Continue reading to learn more about the ransomware, and what steps to take to remediate your system.

btos virus files

Btos Virus – Why Is My PC Infected?

Ransomware such as Btos may end up on your computer via multiple ways, including:

  • By being downloaded from a shady site.
  • If it is sent to you as an e-mail attachment or a URL.

In case the virus is sent to you via email, there is a high chance that it could pretend to be one of the following important documents:

  • Receipts.
  • Work-related files.
  • Invoices.
  • E-Tickets for events or flights.

Btos virus may also be downloaded from some type of a shady software download site, if the victim is looking for files of executable origin, like the following:

  • Cracked portable versions of apps.
  • Software or game cracks.
  • Software patches.
  • Self extracting archives or regular archives.
  • Fake installation files.
  • Key generator (or Keygen).

BTOS Virus – What Does It Do?

The Btos virus may first download its payload files, which are used for its virus activities. They may be located in the following directories of Windows:

  • %Local%
  • %Temp%
  • %Windows%
  • %SystemDrive%
  • %LocalLow%
  • %AppData%
  • %System%
  • %system32%

Btos virus may also use the _readme.txt ransom note which is also among the dropped files:

STOP ransomware virus ransom message

Btos ransomware could also drop value entries in teh Windows Registries, known as Run and RunOnce:

  • HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
  • HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
  • HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunOnce
  • HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnce

What Are .btos Files

The .btos files are encoded using the AES encryption algorithm. What this threat does is scan for the files and then encrypt them based on their file type:

  • Videos (.mp4, .avi, etc.).
  • Audio (.mp3, .wav, etc.).
  • Picture file kinds (.jpg, .png, .etc).
  • Archive file formats (.zip, .rar, etc).
  • Documents of different types (.docx, .pptx, etc.).
  • Others.

How to Open .btos Files

Once the encryption process is completed, Btos leaves your files looking like the following:

Picture.jpg.btos

The files cannot be opened in any way, as their core structure data is changed, since they are encrypted.

What To Do If My Files Are .btos?

If your files are encrypted with the .btos file extension, then their data is changed by the AES cipher

That is why you should not try to change the extension and change it in any way, as it may permanently break the files.

Btos Virus – Details

Name Btos 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 – more detections of this virus on VirusTotal
File Extension .btos
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 Btos ransomware will encrypt your files by appending the .btos extension to them.
Ransom Demanding Note _readme.txt
Distribution Method Spam Emails, Email Attachments
Detection Tool See If Your System Has Been Affected by malware

Download

Malware Removal Tool

How To Protect Windows from Btos In The Future?

Btos ransomware is a dangerous threat and to protect your Windows computer, you will need to learn how to safely store your files to protect them from ransomware viruses after firstly removing the threat safely using the guide here.

How to Remove Btos Virus?

Btos ransomware can be deleted from your device by following the instructions below. They contain methods that will help you get rid of the ransomware either by yourself or automatically. For the best removal and future protection, the automatic method is highly recommended, as it includes scanning your machine using a professional anti-malware program.

How to Decrypt / Fix .btos Files?

The .btos files can be decoded unless you have the decryption key. This can happen if the key is offline-based. In this case, you can use the STOP Ransomware decryption steps or the instructions in the video guide below. See them for more information.

Also note that the chances to get your files restored on your own or with the help of a company/a professional that advertises decryption capabilities are nearly non-existent. What most such companies and professionals do is buy a decryption tool from the ransomware operators, and add a markup to the ransom amount upon charging you for their decryption services. In other words, trusting anyone, other than an officially released decrypter, with the decryption of your files is utterly pointless. We will update this article once we have more information on possible official decryption.

Milena Dimitrova

An inspired writer and content manager who has been with SensorsTechForum since the project started. A professional with 10+ years of experience in creating engaging content. Focused on user privacy and malware development, she strongly believes in a world where cybersecurity plays a central role. If common sense makes no sense, she will be there to take notes. Those notes may later turn into articles! Follow Milena @Milenyim

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  • Step 1
  • Step 2
  • Step 3
  • Step 4
  • Step 5

Step 1: Scan for Btos with SpyHunter Anti-Malware Tool

1. Click on the "Download" button to proceed to SpyHunter's download page.


It is recommended to run a scan before purchasing the full version of the software to make sure that the current version of the malware can be detected by SpyHunter. Click on the corresponding links to check SpyHunter's EULA, Privacy Policy and Threat Assessment Criteria.


2. After you have installed SpyHunter, wait for it to update automatically.

scan for and delete ransomware virus step 2


3. After the update process has finished, click on the 'Malware/PC Scan' tab. A new window will appear. Click on 'Start Scan'.

scan for and delete ransomware virus step 3


4. After SpyHunter has finished scanning your PC for any files of the associated threat and found them, you can try to get them removed automatically and permanently by clicking on the 'Next' button.

scan for and delete ransomware virus step 4

If any threats have been removed, it is highly recommended to restart your PC.

Ransomware Automatic Removal - Video Guide

Step 2: Uninstall Btos and related malware 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:


1. Hold the Windows Logo Button and "R" on your keyboard. A Pop-up window will appear.
delete ransomware from windows step 1


2. In the field type in "appwiz.cpl" and press ENTER.
delete ransomware from windows step 2


3. This will open a window with all the programs installed on the PC. Select the program that you want to remove, and press "Uninstall"
delete ransomware from windows step 3Follow the instructions above and you will successfully delete most unwanted and malicious programs.


Step 3: Clean any registries, created by Btos 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 Btos there. This can happen by following the steps underneath:

1. Open the Run Window again, type "regedit" and click OK.
delete ransomware virus registries step 1


2. When you open it, you can freely navigate to the Run and RunOnce keys, whose locations are shown above.
delete ransomware virus registries step 2


3. You can remove the value of the virus by right-clicking on it and removing it.
delete ransomware virus registries step 3 Tip: To find a virus-created value, you can right-click on it and click "Modify" to see which file it is set to run. If this is the virus file location, remove the value.

IMPORTANT!
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: Boot Your PC In Safe Mode to isolate and remove Btos

OFFER

Manual Removal Usually Takes Time and You Risk Damaging Your Files If Not Careful!
We Recommend To Scan Your PC with SpyHunter

Keep in mind, that SpyHunter’s scanner is only for malware detection. If SpyHunter detects malware on your PC, you will need to purchase SpyHunter's malware removal tool to remove the malware threats. Read our SpyHunter 5 review. Click on the corresponding links to check SpyHunter's EULA, Privacy Policy and Threat Assessment Criteria

1. Hold Windows Key + R.
remove ransomware in safe mode step 1


2. The "Run" Window will appear. In it, type "msconfig" and click OK.
remove ransomware in safe mode step 2


3. Go to the "Boot" tab. There select "Safe Boot" and then click "Apply" and "OK".
remove ransomware in safe mode step 3
Tip: Make sure to reverse those changes by unticking Safe Boot after that, because your system will always boot in Safe Boot from now on.


4. When prompted, click on "Restart" to go into Safe Mode.
remove ransomware in safe mode step 4


5. You can recognise Safe Mode by the words written on the corners of your screen.
remove ransomware in safe mode step 5


Step 5: Try to Restore Files Encrypted by Btos.

Method 1: Use STOP Decrypter by Emsisoft.

Not all variants of this ransomware can be decrypted for free, but we have added the decryptor used by researchers that is often updated with the variants which become eventually decrypted. You can try and decrypt your files using the instructions below, but if they do not work, then unfortunately your variant of the ransomware virus is not decryptable.

Follow the instructions below to use the Emsisoft decrypter and decrypt your files for free. You can download the Emsisoft decryption tool linked here and then follow the steps provided below:

1 Right-click on the decrypter and click on Run as Administrator as shown below:

stop ransomware decryptor step 1

2. Agree with the license terms:

stop ransomware decryptor step 2

3. Click on "Add Folder" and then add the folders where you want files decrypted as shown underneath:

stop ransomware decryptor step 3

4. Click on "Decrypt" and wait for your files to be decoded.

stop ransomware decryptor step 4

Note: Credit for the decryptor goes to Emsisoft researchers who have made the breakthrough with this virus.

Method 2: Use data recovery software

Ransomware infections and Btos 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.

1. Download the recommended Data Recovery software by clicking on the link underneath:

Simply click on the link and on the website menus on the top, choose Data Recovery - Data Recovery Wizard for Windows or Mac (depending on your OS), and then download and run the tool.


Btos-FAQ

What is Btos Ransomware?

Btos 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 algorithms 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.

What Does Btos Ransomware Do?

Ransomware in general is a malicious software that is designed to block access to your computer or files until a ransom is paid.

Ransomware viruses can also damage your system, corrupt data and delete files, resulting in the permanent loss of important files.

How Does Btos Infect?

Via several ways.Btos Ransomware infects computers by being sent via phishing emails, 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.

Another way you may become a victim of Btos 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 .Btos files?

You can't without a decryptor. At this point, the .Btos files are encrypted. You can only open them once they are decrypted using a specific decryption key for the particular algorithm.

What to Do If a Decryptor Does Not Work?

Do not panic, and backup the files. If a decryptor did not decrypt your .Btos files successfully, then do not despair, because this virus is still new.

Can I Restore ".Btos" Files?

Yes, sometimes files can be restored. We have suggested several file recovery methods that could work if you want to restore .Btos files. 

These methods are in no way 100% guaranteed that you will be able to get your files back. But if you have a backup, your chances of success are much greater.

How To Get Rid of Btos Virus?

The safest way and the most efficient one for the removal of this ransomware infection is the use a professional anti-malware program.

It will scan for and locate Btos ransomware and then remove it without causing any additional harm to your important .Btos files.

Can I 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.

Can You Stop Ransomware from Encrypting Your Files?

Yes, you can prevent ransomware. The best way to do this is to ensure your computer system is updated with the latest security patches, use a reputable anti-malware program and firewall, backup your important files frequently, and avoid clicking on malicious links or downloading unknown files.

Can Btos Ransomware Steal Your Data?

Yes, in most cases ransomware will steal your information. It is a form of malware that steals data from a user's computer, encrypts it, and then demands a ransom in order to decrypt it.

In many cases, the malware authors or attackers will threaten to delete the data or publish it online unless the ransom is paid.

Can Ransomware Infect WiFi?

Yes, ransomware can infect WiFi networks, as malicious actors can use it to gain control of the network, steal confidential data, and lock out users. If a ransomware attack is successful, it could lead to a loss of service and/or data, and in some cases, financial losses.

Should I Pay Ransomware?

No, you should not pay ransomware extortionists. Paying them only encourages criminals and does not guarantee that the files or data will be restored. The better approach is to have a secure backup of important data and be vigilant about security in the first place.

What Happens If I Don't Pay Ransom?

If you don't pay the ransom, the hackers may still have access to your computer, data, or files and may continue to threaten to expose or delete them, or even use them to commit cybercrimes. In some cases, they may even continue to demand additional ransom payments.

Can a Ransomware Attack Be Detected?

Yes, ransomware can be detected. Anti-malware software and other advanced security tools can detect ransomware and alert the user when it is present on a machine.

It is important to stay up-to-date on the latest security measures and to keep security software updated to ensure ransomware can be detected and prevented.

Do Ransomware Criminals Get Caught?

Yes, ransomware criminals do get caught. Law enforcement agencies, such as the FBI, Interpol and others have been successful in tracking down and prosecuting ransomware criminals in the US and other countries. As ransomware threats continue to increase, so does the enforcement activity.

About the Btos Research

The content we publish on SensorsTechForum.com, this Btos how-to removal guide included, is the outcome of extensive research, hard work and our team’s devotion to help you remove the specific malware and restore your encrypted files.


How did we conduct the research on this ransomware?

Our research is based on an independent investigation. We are in contact with independent security researchers, and as such, we receive daily updates on the latest malware and ransomware definitions.

Furthermore, the research behind the Btos ransomware threat is backed with VirusTotal and the NoMoreRansom project.

To better understand the ransomware threat, please refer to the following articles which provide knowledgeable details.


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.

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