Downloading and Using the Trend Micro Ransomware File Decryptor

Select the ransomware name

Most ransomware usually includes a text file or html file to inform the user that his/her system has been infected by a certain type of ransomware. Using this information, an affected user can select the suspected ransomware name to decrypt files. Users having trouble identifying the type of ransomware should contact Trend Micro Technical Support for further assistance.

Note: When selecting the "I don't know the ransomware name" option, the tool will prompt the user to select a target file to be decrypted and will try and automatically identify the ransomware based on the file signature. 

Select the encrypted file or folder

The tool can either attempt to decrypt a single file or all files in a folder and its sub-folders by using recursive mode. By clicking “Select & Decrypt”, choose a folder or a file and click OK to start the decrypting process.

 

Start decrypting files

After the file(s) or folder(s) are selected, the tool will start scanning and decrypting files automatically.

If the scan target is a folder, the tool will collect some file information from the target folder first to help identify which files need to be decrypted. During the scan, a scrollbar will indicate the decrypting progress, and the UI will be updated to indicate how many files are encrypted and the number of files have been decrypted.

The tool can decrypt certain types of ransomware-encrypted files (e.g. TeslaCrypt) files very quickly. However, other file types (e.g. CryptXXX) may take significantly longer. The overall duration also depends on how many files are located in the target folder.

If Stop is clicked during scanning, the process will be interrupted.

 

Decrypting CyptXXX V1, XORIST, XORBAT, NEMUCOD or TeleCrypt (optional)

If the tool identifies files encrypted by one of the ransomware mentioned above, it will ask the user to provide additional information to proceed due to some unique processing required for the specific decryption.

After selecting the “click here” option highlighted above, another dialog will appear asking for a file pair. The user will need to select a infected file and a matching non-infected file if there is an available backup copy (the larger the file size the better).

Finish decrypting files

Once the scan and decryption process is finished, the UI will show the results.

 

By clicking See encrypted files, the tool opens the encrypted file location or folder which was selected for scanning. The decrypted files are resident in opened folder.

The decrypted file name(s) will be the same as the previously encrypted file(s), with the exception being the removal of the extension appended by the ransomware.

For those file(s) encrypted without the file name changing, the decrypted file name will be {original file name} decrypted.{extension}.

By clicking Done, the tool returns to the main UI. Repeat step 1 and 2 to decrypt more files.

Due to the advanced encryption of this particular Crypto-Ransomware, only partial data decryption is currently possible on files affected by CryptXXX V3.

The tool will try and fix certain file formats after the decryption attempt, including DOC, DOCX, XLS, XLSX, PPT, and PPTX (common Microsoft Office) files.  The fixed file will have the same name of the original file with "_fixed" appended to the file name and will be placed in the same location.  When opening the fixed file with Microsoft Office, it may present a message to try and repair the file again, and this process may be able to recover the document.  Please note that due to the different versions of Microsoft Office and particular file behaviors, it is not guaranteed that this method will completely recover the document.

However, for other files after the partial data decryption, users may have to utilize a 3rd party corrupted file recovery tool (such as the open source program JPEGSnoop*) to try and recover the full file.

An example of this would be a photo or image file that is partially recovered to show parts of the image, but not the entire image. A user would then determine if the file is critical enough to utilize a 3rd party tool or seek assistance from an 3rd party professional file recovery service.

Original Photo (before CryptXXX V3 infection)

Photo after partial data decryption

Unfortunately, Trend Micro Technical Support will be extremely limited in any sort assistance that can be provided regarding 3rd party file recovery.

BadBlock can encypt essential system files, which may cause issues like not allowing the operating system (OS) to load properly after a reboot if infected. Because of the sensitivity of these files, when the tool attempts decryption of these files, it will backup selected key originally encrypted PE files and append “_bbbak” to the name. After the decryption, the original PE file name will be restored. For non-PE files, the decrypted names will be the original file name with “_decrypted” appended to the name of the file.

ince there are different ways that BadBlock can affect a system, there are a few different approaches the tool may use to try and decrypt affected files:

1. If the system has been infected and had not yet had a reboot. In this situation, the user may try and run the tool and it will attempt to decrypt affected files.
2. If the system has already been rebooted after an infection and cannot boot successfully into the OS. In this situation it is recommended that the user boot from an OS installation image (such as a Windows Recovery Disk) or other method to try and get to a state where the OS can boot successfully and then try and run the tool to decrypt other files.
3. If the system OS cannot be recovered by an OS installation image as mentioned above. In this case, users may need to physically remove the affected hard disk drive (HDD) and mount it on another known working system as a extra drive and attempt to run the tool from the other system.

CERBER decryption must be executed on the infected machine itself (as opposed to another machine) since the tool needs to try and locate the first infected file for a critical decryption calculation.

Due to the method of decryption for CERBER, the tool may take several hours (average is 4) to complete decryption on a standard Intel i5 dual-core machine.   In addition, the encryption logic for CERBER also is built in such a way that the more cores a CPU has, the lower percentage chance of success for the decryption because of its complexity.

Similar to some other types of ransomware encryption, some files may be only partially decrypted and may require a subsequent file repair.

Because this tool uses brute-force to calculate keys for Globe/Purge, decryption could take more than twenty (20) hours. The average decryption time varies from approximately ten (10) hours with a 4-core CPU machine to thirty (30) hours with a single-core PC machine.

To decrypt Globe/Purge V1, the decryption process must be run on the originally infected machine.

Please note that the tool cannot decrypt files on a FAT32 system due to a bug in the ransomware itself. This is also a limitation of the ransomware author's original decryption tool.

This tool searches for a private key in the ransomware process memory - which means it is only effective if the original WannaCry ransomware process still exists and is actively running. If the infected machine is rebooted, the ransomware process is somehow stopped after the initial infection, or any other situation occurs that would affect the process memory of the infection machine the decryption will fail. It is very important that users do not try and reboot their system before trying the tool.

It is currently unknown how long the prime numbers (related to the private key) will be stored in the memory address space before being reused or overwritten. Therefore it is highly advantageous to run this tool early in the infection chain rather than later.

Based on internal Trend Micro testing, this tool has the highest success rate on Windows XP (x86) machines compared to a very low rate on other versions of Windows - but individual users' success rate will vary.

The Petya tool has a special UI. To boot your OS back to normal, do the following:

1. Select the Petya family on your machine from the ransomware note screen then choose a screen font color from the dropdown option.

2. Enter your personal decryption code in the boxes found on the ransomware note screen.

    

   The decryption code is case sensitive.
3. Click the Decrypt Key button to show the decrypt key in the text box.
4. On the infected machine, enter the decrypt key from the tool and click Enter to reboot the machine and boot your OS back to normal.

Click image to enlarge

The Trend Micro Ransomware File Decryptor tools will extract itself to the following temporary folder during execution:

%User%\AppData\Local\Temp\TMRDTSelfExtract\

After the completion of a scan, a folder titled “log” will appear in this location which contains logs detailing the decryption process with various timestamps.

Example of the temp directory:

Examples of logs in the log subfolder:

Beginning with version 1.0.1657, users may send feedback directly to Trend Micro via the tool by selecting the "Feedback" button from the main menu.  

Users may select one of the pre-populated answers, or select "Other" and add comments as desired.

Trend Micro has created a Computer Based Training (CBT) module for customers with instructions on how to run the tool. Please click here to view the module.

• TeslaCrypt V1, V2 decryption tool now is in a separate package
• CryptXXX V2, V3 decryption does not support plain text files
• CryptXXX V3 decryption does not support archive files or decrypt file sizes larger than 13MB
• IMPORTANT NOTE: Files encrypted by CryptXXX V3 cannot be fully recovered to 100% (partial recovery), please see the notes above under CryptXXX V3 Partial Recovery
• CryptXXX V4, V5 decryption process may not be able to recover the original file name Decryption for each file could potentially take up to 2 hours
• LeChiffre decryption should be done on the original infected machine because it requires machine name and user name
• Teamxrat/Xpan decryption tool must be run on an infected machine
• WannaCry (WCRY) decryption is only effective on an infected machine with the ransomware process still active.  Currently, only Windows XP (x86) has a high success rate of decryption.
• The tool can only decrypt Petya families discovered in 2016 which encrypts NTFS’s MFT. You need another Windows machine to run the tool since the infected machine cannot be booted normally. This Petya family is different from EternalPetya family discovered in 2017.

• RansomwareFileDecryptor 1.0.1668 MUI.exe uploaded on November 16, 2017 at 17:40 GMT
• MD5: 5a64a4425aead92b9d9e1891be7572e3
• SHA-256: db8c550e5d92d913ea84ca29b59342eeba001d9c2beb8c2320f791346c1bc3cc