What is CTB-Locker

CTB-Locker or Critroni is very wide-spread and dangerous ransomware virus. It uses RSA-2048 encryption to encrypt various types of files stored on users computers (documents, images, photos, music, videos). Then CTB-Locker demands the ransom of $120 – $300 and shows message on your desktop: “Your personal files are encrypted by CTB-Locker”. Ransomware also creates text file with instructions DecryptAllFiles.txt in every affected folder. The virus itself is rather simple to remove, however we recommend you to use removal tool. Decryption of .ctb files is very complex task as there is no decryption tool developed by antivirus companies yet. Still we recommend you to use instructions below to remove CTB-Locker and decrypt .ctb or .ctb2 files.

ctb-locker virus

How CTB-Locker infected your PC

CTB-Locker uses fake UPS notification e-mails with malicious attachments to infect users computers. Attachments are usually made in form of MS Office document. When user tries to view the document, it asks user to enable macros. After enabling macros downloads virus executable and runs it. This process starts encryption of your files. This makes the virus hard to detect for antivirus programs. After this ransomware modifies the desktop using the image AllFilesAreLocked.bmp that contains instructions and links to decryption services.

ctb-locker desktop instructions

Download CTB-Locker Removal Tool

Download Removal Tool

To remove CTB-Locker completely we recommend you to use SpyHunter 5 from EnigmaSoft Limited. It detects and removes all files, folders and registry keys of CTB-Locker.

Alternative remover

Download Malwarebytes Anti-Malware

As a good free alternative to remove CTB-Locker use Malwarebytes Anti-Malware. It will detect core files and processes of CTB-Locker ransomware and eliminate them to allow you start decryption of your files.

How to remove CTB-Locker manually

It is not recommended to remove CTB-Locker manually, for safer solution use Removal Tools instead.

CTB-Locker files:


%Temp%\{randomname}.exe
%MyDocuments%\AllFilesAreLocked.bmp
%MyDocuments%\DecryptAllFiles.txt
%MyDocuments%\{randomname}.html
%WinDir%\Tasks\{randomname}.job

CTB-Locker reg keys:


HKEY_CURRENT_USER\Control Panel\Desktop "Wallpaper" = "%MyDocuments%\AllFilesAreLocked{user_id}.bmp"

How to decrypt and restore .ctb files

Use automated decryptors

kaspersky rannoh decryptor

Ransomware decryptor from Kaspersky may be useful in this case. It is free and easy to use. Download Kaspersky Ransomware Decryptor here:

Download Kaspersky Ransomware Decryptor

There is no purpose to pay the ransom, because there is no guarantee you will receive the key, but you will put your bank credentials at risk.

If you are infected with CTB-Locker ransomware and removed it from your computer you can try to decrypt your files. Antivirus vendors and individuals create free decryptors for some crypto-lockers. However, there is currently no automatic decryption tool for .ctb files. To attempt to remove them you can do the following:

Using Windows Previous Versions option:

  1. Right-click on infected file and choose Properties.
  2. Select Previous Versions tab.
  3. Choose particular version of the file and click Copy.
  4. To restore the selected file and replace the existing one, click on the Restore button.
  5. In case there is no items in the list choose alternative method.

Using Shadow Explorer:

  1. Download Shadow Explorer program.
  2. Run it and you will see screen listing of all the drives and the dates that shadow copy was created.
  3. Select the drive and date that you want to restore from.
  4. Right-click on a folder name and select Export.
  5. In case there are no other dates in the list, choose alternative method.

If you are using Dropbox:

  1. Login to the DropBox website and go to the folder that contains encrypted files.
  2. Right-click on the encrypted file and select Previous Versions.
  3. Select the version of the file you wish to restore and click on the Restore button.

How to protect computer from viruses like CTB-Locker in future

Use Malwarebytes Anti-Ransomware Beta

Famous anti-malware vendor Malwarebytes along with EasySync Solutions created tool that will help you with active anti-ransomware protection as additional shield to your current protection.

Download Malwarebytes Anti-Ransomware Beta

Use HitmanPro.Alert with CryptoGuard

Dutch vendor of legendary cloud-based scanner HitmanPro – Surfright released active antivirus solution HitmanPro.Alert with CryptoGuard feature that effectively protects from latest versions of cryptoviruses.

Download HitmanPro.Alert with CryptoGuard 5/5 (1)

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