Hey you,
BE IN THE KNOW!

35,000 ransomware infections per month and you still believe you are protected?

Sign up to receive:

  • alerts
  • news
  • free how-to-remove guides

of the newest online threats - directly to your inbox:


Restore Files Encrypted via RSA Encryption. Remove CryptoWall and Other Ransomware Manually

password-brute-force-stforumRansomware encryptions and infections have created havoc worth around 18 million USD. These type of attacks come from Trojan horses with preprogrammed scripts that encrypt the user files in mainly AES and RSA encryption algorithms. Ransomware infections have become a grave danger to inexperienced users who usually open email attachments without carefully thinking about their legitimacy. The threat itself can be removed with a particular anti-malware program, however, the encrypted files remain. This is a tutorial to help users in decrypting RSA encrypted data. The methods below were recommended by experts and were tried several times by users with a good result. However this is no guarantee that it will work for you.

What Is RSA Encryption Algorhytm?

RSA encryption algorithm is a type of language that, in this case, changes the normal code of the file with a unique key. This key can be decrypted via special software, but it requires a powerful machine since it is a time-costly process. RSA algorithm has been employed by the most traditional ransomware viruses that have caused massive devastations on a global scale – The CryptoWall Variants(2.0, 3.0), Bitcrypt and others. In this tutorial, we show you a possible method of decrypting your files and restoring them to their previous working state in case you have no backup on your operating system (OS). After the tutorial, we have provided instructions on how to enable Windows file history so your files can be backed up so you can protect yourself from future attacks. Make sure you take your time and do everything from the steps below and things should be fine for you.

Ransomware Removal Manual

Before doing this, make sure you backup your information on a USB stick or anything of this similarity. After that, make sure you download a reputable anti-malware software that will detect anything out of the ordinary and assist you with the removal of the threat. Download it to a safe PC and put it on yours and boot your computer in Windows online Safe Mode using the following manual:

1. Start Your PC in Safe Mode to Remove Ransomware
2. Remove Ransomware automatically with SpyHunter Removal Tool.

Ransomware Files Restoration

For this particular tutorial, we have used .bitcrypt extension files, encrypted by ransomware, called Bitcrypt. We have also used Ubuntu version 14.04 which assisted us in using special software appropriate for this distribution. You can get it from their website’s download page and you can either:

-Install it along with your operating system by booting a live USB drive.

-Install it on a virtual drive (Recommended).

Here we have brief tutorials for both:

Installation of Ubuntu on your machine:

Step1: Get a USB flash drive that has above 2GB of space.

Step2: Download the free software, called Rufus from here and install it on your windows.

Step3: Configure Rufus by choosing NTFS as a system and selecting the USB drive as the one to be created as a bootable USB. After that boot the Linux image from the following button:

rufus

Make sure you locate it and select it from where you downloaded it.

Step4: After the flash drive is ready, restart your computer, and it should run the Ubuntu installation. If it does not, you should go to the BIOS menu by pressing the BIOS hotkey on startup for your PC (Usually it is F1) and from there select the first boot option to be the USB bootable drive or CD/DVD in case you have burnt Ubuntu on such.

Installation Of Ubuntu on your Virtual Drive

For this installation, you need to download VMware Workstation from their download page or any other Virtual Drive Management program. After installed you should:

Step1: Create a new virtual drive.

Step2: Set the drive size. Make sure you have a minimum of 20 gigabytes of free space fro Ubuntu on your computer. Also choose ‘Run as a single drive’.

Step 3: Select the ISO image. For this option, you should know where it is.

Step 4: After that play the Virtual Machine and it will install automatically.

File Decryption

Once you have Ubuntu or any other Linux distribution on your computer open the terminal by doing the following:

Open-terminal

Then update your Linux and install greater version than Python 3.2 by typing the following in the terminal:

→sudo apt-get update
sudo apt-get install python3.2

Also, if your Linux does not have sqlite3 module, install it by typing:

→sudo apt-get install sqlite3 libsqlite3-dev
sudo gem install sqlite3-ruby

Now after we have Python installed, we need to download a script created by 2014 Airbus Defence and Space Cybersecurity. To do this click on this link. Download the file in your ‘Home’ folder after it prompts you where to save it. Keep this as decrypt.py in case it is not saved in this format.

Now that we have Python and the script, it is time to find out the key of the .bytrcypt encrypted file. To do this move your encrypted files ot the home folder by using the file manager:

File-manager

After you located all of the encrypted files there along with the “decrypt.py” file type the following into the terminal to initiate the script:

→python ./decrypt.py “Your_Encrypted_Document_Name_and_Format”

It will show an error, and this is entirely normal as long as you see this code:

code

This is the RSA code for this file. Now, we need to decrypt it, and we are halfway there. To do this download a program called cado-nfs2.0.tar.gz from their download page here. We recommend the 2.0 version. However, the newest version is also on a good level.

It will download a .tar archive file (.tar files are very similar to .rar or .zip files). Simply open it and click on the Extract button on top and choose the ‘Home’ folder. It should look like this:

Extract

After the we have all the files extracted in the ‘Home’ folder, we need to compile cado-nfs. To do this, open another terminal and type:

→cd cado-nfs-2.0
make

After this is set, it is time to run the key cracker. Important – this process can take from several hours to days to be finished. To begin the process type in your cd cado-nfs terminal:

→./factor.sh YOUR_UNIQUE_KEY_WHICH_IS_LETTERS_OR_NUMBERS_HERE -s 4 -t 6

After the process completes, you should see the following:

→Info:Complete Factorization: Total cpu/real-time for everything: hhhh/dddd
LongNumber1 LongNumber2

After we have the decrypted key, we need to insert in the “decrypt.py” script. Do this by opening decrypt.py in a text editor and finding this part of it:

→known_keys = { many long numbers }

We need to add before the second bracket (“}”) these lines:

The Previous Key, a column, opened parenthesis, LongNumber1, Comma, LongNumber2, closed parenthesis. It should look like this:

→The Previous Key:(LongNumber1,LongNumber2)

Be advised that you should do this only one time. After this it is time to decode the files. To do this type:

→python ./decrypt.py “Your_Encrypted_Document.docx.bitcrypt”

Executing this command will make a file that is called “Your_Encrypted_Document.docx.bitcrypt.CLEAR”

Just rename the file by removing the .clear extension and you should be all set. Repeat the process for your other files as well. But remember that first you should find out their initial keys to decrypt them. You should be able to open them now. We hope this works for you.

Conclusion

The best defense against Ransomware threats is always the user himself. It is crucial to know which files you open and whether or not the locations of those files are safe or not. However if you are in an organization or somewhere where the computer is located in a public or work environment, it always opens it up to a direct attack that is even more dangerous. A real expert will say that the best computer is the one that is switched off, because it may have the best defenses, but the one who makes the errors is not the machine, it’s the man. This is why you should always keep enough knowledge and build up PC usage behavior that is security oriented.

Download

Malware Removal Tool


Spy Hunter scanner will only detect the threat. If you want the threat to be automatically removed, you need to purchase the full version of the anti-malware tool.Find Out More About SpyHunter Anti-Malware Tool / How to Uninstall SpyHunter

Berta Bilbao

Berta is the Editor-in-Chief of SensorsTechForum. She is a dedicated malware researcher, dreaming for a more secure cyber space.

More Posts - Website

  • lucas va

    Good afternoon,

    I get the error : “[-] Error parsing file footer” when I execute decrypt.py on my file encrypted …

    • BertaB

      Hello Lucas,

      This may be due to one of the following reasons:

      1) Old python version.

      sudo apt-get update python

      2) Error in file name or command.

      Check the command you typed carefully. Can you tell me which one is it? If it is this one:

      python ./decrypt.py “MY ENCRYPTED FILE.jpg.bitcrypt”

      it should be typed with the brackets exactly as seen above.

      3)Error in the ‘decrypt.py’ file

      In case it doesnt work you shouldnt try to look for the issue since you may lose a lot of your time in doing so.
      Your best bet is to try DecrypterFixer. You can download it from here:

      https://bitbucket.org/DecrypterFixer/malware_tools-1/get/fa4ec9df293b.zip

      It has a well made ‘decrypt.py’ file and should work for you.

      In case the first web link is broken, try this one:

      https://bitbucket.org/DecrypterFixer/malware_tools-1/get/fa4ec9df293b.zip

      • lucas va

        Hello, thanks you for your reply.
        My file is not in .bitcrypt extension because I was infected by CryptoWall 3.0

        I will try your solutions, thanks you.
        I will come to give you a feedback

  • patrick

    Hi,
    I have the same problem. My files are also infected by the Cryptowall 3.0. And the extension is ccc. Can I use this python script to decrypt ? Are there other possible solutions ?
    thx a lot
    Patrick

    • BertaB

      Hello Patrick,

      We are sorry to hear your files have been encrypted by ransomware. The .ccc extension may not belong to the CryptoWall threat. There are variants of other ransomware that pretend to be Cryptowall 3.0, possibly because it is the most vicious of them all so far. There is a tool that may help you, known as Tesla decryptor. More information in the link below.

      We have started a new topic in our security forum, with the intention to help as many users as possible. There it is: http://sensorstechforum.com/forums/malware-removal-questions-and-guides/my-files-are-encrypted-with-the-ccc-extension-help!/

      • Parawi

        Hi! All my files were encrypted by rsa4096, all has the extension .mp3. What should i do? Thks

  • Brently

    I have a my VP’s computer at my desk right now that has the DecryptorMax ransomware. I have removed the trojan and malware in Safe Mode, but am looking for a way to decrypt the files. This has my VP’s first baby girl’s baby photos from the first couple months of her life, so these files are really important to her. They aren’t providing me the time to do the Linux decrypt, so looking for a tool. Hoping Kaspersky comes out with a tool to decrypt these. They have the crinf extension. Any help is appreciated.

    • Milena Dimitrova

      Hi Brently, we’re about to start a topic in our forum about DecryptorMax, and we’re also going to research it in depth. Can you please clarify what you meant by saying ‘They aren’t providing me the time to do the Linux decrypt’?

      Thx,

      the STF team

  • Gil

    Greetings,

    I am getting the following error when running decrypt.py

    python3.4 ./decrypt.py test.bitcrypt
    File “./decrypt.py”, line 99
    print “usage: %s ” % sys.argv[0]
    ^
    SyntaxError: Missing parentheses in call to ‘print’

    Any help would be great.

    Thank You,

    Gil

  • Gab

    so… just to double check if there’s no restore point and no shadow copy, there’s no way to get the files back from cryptowall 3.0 correct?
    Regards

  • yohji

    do you have a method to decrypt files that is encrypted using cryptowall 4

    • Milena Dimitrova

      Hi yohji,

      Are you dealing with CryptoWall 4.0?

      • Gab

        Would you help me with cryptowall 3.0 please.
        Regards

      • KJ

        Hi,
        My files were infected by cryptowall 4.0 with ‘help_your_files’.
        I removed the cryptowall 4.0 using anti-malware softwares.
        Can I use the “decrypt.py” script to find out the key of the encrypted files by cryptowall 4.0?
        Would you tell me if you have other possible solutions for restoring the encrypted files?

        Regards

      • Mehmet

        Hallo,
        Ich habe auch das selber probleme mit cryptowall virüs aber weiss es nicht genau,welche version das ist.
        Es gibt in jeder ordner einen bild mit HELP_YOUR_FILES

        und folgende dateien formate ; .DZ7 .O1R .7FT .1Q .7429D .0PQGL .BR4 .7UV .2PF Usw…

        Können Sie mir bitte helfen?
        Ich habe sehr wichige fotos und text dokumenten.
        Mfg Mehmet

        • Fran

          Hola Mehmet, has conseguido arreglar los archivos? Mi virus tenia el mismo archivo que el tuyo.

        • Effesse72

          Good morning, my problem is the same of your since 05/01/2016!

  • Hello, KJ as far as we know so far most methods for decrypting files encrypted by cryptowall 4.0 have proven to be unsuccessful even by law enforcement. However what you can try is ask a question in the Cryptowall 4.0 topic in our forum and wait to see if you get any help from other affected users and experts in this subject. Here is the topic link, there are also some instructions included:

    http://sensorstechforum.com/forums/malware-removal-questions-and-guides/how-to-remove-cryptowall-4-0-and-restore-your-data/

  • Marc

    Has anyone been able to decrypt CryptoWall 3.0 encrypted files (2048 bit encryption) using this method?

  • Yannick

    Bonjour,
    Ayant été infecté par l’un de ces virus, je me demande lequel car il a encrypté un grand nombre de fichiers en rajoutant une extension vvv à chaque fois, rendant celui-ci invisible et en mettant dans chaque sous-répertoire plusieurs fichiers appelés “how_recover” ? Donc quel virus est-ce et quelle méthode pour retrouver ses fichiers crypés s’il y en a ?
    Merci beaucoup.

    Cordialement
    Yannick

  • Yannick

    Bonjour,

    Merci beaucoup. Oui, donc il n’y a rien à faire pour récupérer ses fichiers….

  • Cornel Goran

    Hi! I’ve also got some encrypted files that I’d like to decrypt. I have 2 files “5k5m3y.1mm” and “8co7o3co.ze4ha” and they look like this if I try to edit them with notepad: http://i.imgur.com/NIJozDk.png

    First thing first, how do I know what virus caused this?

    • Hello @Corel Goran
      This is typical for Ransomware infections such as CTB Locker and CryptoWall 4.0. In order for me to be able to adequately provide you with assistance I would like you to send me a snip or a screenshot of any ransom message that you may see. It may be a .txt file on your desktop or a picture, named like this, for example:

      • Help_Decrypt_Your_Files
      • Help_Your_Files
      • HELP_DECRYPT

      Attach the screenshots in your reply to this topic in our forum so that our experts may be able to relevantly assist you the best way they can:

      Forum Topic To Attach Your Screenshot

  • Carsten

    Hi.
    Got the same problem since Thursday this week. Encrypted files have .micro extention. Kaspersky Rescue disc reported trojan-ransom.win32.bitman.fay to be the threat.
    Does the above described procedure work for .micro files as well?
    Many thanks for any help.

    • Carsten

      Addition:
      I have found some files in My Documents folder named recover_file_***random_text***.txt that seem to contain keys. May these possibly be the keys to be retrieved by using phyton as described above?

  • Joel

    As Carsten, I have same problem with “.micro” file.
    And as him, I have some file named “recover_file….txt”. Any idea about how to use them and if this solution works with .micro file?
    Thanks

  • Mauzinh0

    Same problem with *.micro file
    Same recover…txt
    Any news?
    Thank you

  • nf

    Hello, I have also the problem with the *.micro extension.

  • William

    Mis archivos han quedado encintados con extension .locky, que virus me ataco? y que guía para recuperarlos me recomiendan

    Atte
    William

  • stef

    Hello, j’ai bien les fichier HELP_FILE*.HTML et PNG
    Mes fichiers ont maintenant des noms et extensions aelatoires.
    Le nettoyage est fait sans probleme.
    Sur leur site où il faut payer, j’ai juste fait decryptage d’un fichier 512 ko max gratuitement, donc maintenant j’ai l’ancien fichier crypté 0sqn1xx.dh1w et le meme fichier decrypté : decrypted-file.jpg
    Ne serait-il pas possible d’apres ces 2 fichiers, d’en reconstruire la clef RSA ?? pour faire les tous les autres fichiers.
    Merci beaucoup, j’aime votre travail.
    Stef

    • Berta Bilbao

      Hello, this appears to be CryptoWall 4.0. It has a very strong encryption, so without the key it’s going to be very hard to decrypt your files. The two files don’t hold a decryption key in themselves, but might help a decryptor program to see a similarity in its database and find a password.

      Try Rakhni Decryptor by Kaspersky – it’s a free tool and with the help of the two files it might find a key file on your computer if it’s not deleted. Also, take a look at the tips about CryptoWall 4.0 in our forum.

  • Vinny

    Hello, I did the commands and I received the page footer error… the file is encrypted with the “.locky” extension. is there something i could do?

  • Oswaldo Leonett

    Hi,
    I have the same problem. My files are also infected by redshitline(at)india.com And the extension is xtbl- Can I use this python script to decrypt ? Are there other possible solutions ?

    Oswaldo

  • Marco

    Hy Berta,
    I infected a month ago by cryptowall 4.0, the same of Oswaldo Leonett and I should know how to do… The instructions in this article are valid also for cryptowall 4? If I run .py script I can hope to decrypt my files of the script operate up to version 3.0 of cryptowall?
    Are There some new information about Cryptowall 4?

  • Marco

    I correct myself, the contracted infection is the same of Stef with some HELP_FILE*.HTML and PNG.

  • Alle dine filer er blevet krypteret med RSA – 2048 og EAS -128 . INFORMATION om SA kan ses på da.Wikipedia. org/wiki/RSA. OG da.Wikipedia. org/wiki/Advanced Encryption Standard
    Dekryptering til hemmelig server på links
    Hw5qrh6fxv2tnaqn.tor2web.org/17572E56401D80
    Jeg tør ikke klikke på dem, måske der er mere virus. De vil nok have betaling for at dekryptere, og få adgang til mit Dankort.

    Kan der gøres noget.
    På forhånd tak
    Mvh. Karl

Share on Facebook Share
Loading...
Share on Twitter Tweet
Loading...
Share on Google Plus Share
Loading...
Share on Linkedin Share
Loading...
Share on Digg Share
Share on Reddit Share
Loading...
Share on Stumbleupon Share
Loading...
Please wait...

Subscribe to our newsletter

Want to be notified when our article is published? Enter your email address and name below to be the first to know.