A new variant of the Matrix Ransomware has been discovered that is renaming encrypted files and then appending the .FOX extension to the file name. Of particular interest, this ransomware could have the most exhaustive process of making sure each and every file is not opened and available for encrypting. Thankfully, this also makes its encryption process very slow so it could be easier to detect.

This ransomware variant was first discovered by security researcher MalwareHunterTeam and is installed through computers running Remote Desktop Services and being openly connected to the Internet. The attackers will scan ranges of IP addresses to find open RDP services and then brute force the password.

Once they have access to the computer, they will manually install the ransomware that displays various console windows that show the progress of the encryption of the computer.

Unfortunately, at this time the Matrix Ransomware variants cannot be decrypted for free. If you have any questions or would like to discuss this ransomware, you can use our dedicated Matrix Ransomware Support topic.

How the Fox Ransomware variant encrypts a computer

The Fox Ransomware is variant of the Matrix Ransomware, and like its predecessor, is very chatty as it communicates a lot with its Command & Control server and also displays consoles that provide status updates on the encryption process.

When the Fox Ransomware variant is executed it will connect to a Command & Control server and start logging various stages of the encryption process.  During the encryption process it will communicate often with the C2 to provide status updates.

Network Connection
Adding the Start Phase record to C2

Two console windows will also be opened that display the current progress of the encryption so that the attackers can monitor it. The first window show an updating status of the encryption process, while the other console window displays network addresses that were scanned for open shares.

Encryption Console
Encryption Status Console
Encryption Console
Network Drives Console

The ransomware will now drop a batch file that exhaustively tries to close all open file handles of the file it is about to encrypt. It does this by first removing all attributes from the files, changing permissions, taking ownership, and finally using a renamed version of the Handle.exe program from Sysinternals to close all open handles to the file.

Close open file handles
Close open file handles

For every file that is encrypted, it will first execute the above batch file on it and then encrypt the file. After encrypting the file it will rename it and append the .FOX extension to the encrypted file's name. For example, a file will be encrypted and be renamed to [PabFox@protonmail.com ].cAE5V4FC-wwWa0jxY.FOX.

You can see an example of an encrypted folder below.

Encrypted FOX Folder
Encrypted FOX Folder

In each folder that a file is created, it will create a ransom note named #FOX_README#.rtf that contains instructions on how to contact the attacker for payment instructions. The emails listed in this ransom note are PabFox@protonmail.com, FoxHelp@cock.li, and FoxHelp@tutanota.com. It also contains a Bitmessage id to contact for information as well.

Ransom Note
Ransom Note (Click to Enlarge)

The desktop background will also be changed to a condensed version of the ransom note.

Desktop Wallpaper
Desktop Wallpaper

At the end of the encryption process, a random named .vbs file in the %AppData% folder will be launched that is used to register a scheduled task named DSHCA. This schedule task is used to run a batch file with administrative privileges that will perform a cleanup of the computer and to disable various repair features.

This batch file is located in the %AppData% folder as well and will delete shadow volume copies using WMIC, powershell, and vssadmin, remove Windows recovery startup, and delete the VBS file, scheduled task, and itself.

The good news is that since the ransomware tries so hard to close all file handles associated with the file it is trying to encrypt, the encryption process is very slow. This allows a user to potentially discover that they are infected before the process is fully completed.

As previously stated, though, any files encrypted with this ransomware are secure and cannot be decrypted for free at this time. Once again,  if you have any questions or would like to discuss this ransomware, you can use our dedicated Matrix Ransomware Support topic.

How to protect yourself from the Fox Ransomware 

In order to protect yourself from ransomware it is important that you use good computing habits and security software. First and foremost, you should always have a reliable and tested backup of your data that can be restored in the case of an emergency, such as a ransomware attack.

As the Fox Matrix Ransomware variant is installed via hacked Remote Desktop services, it is very important to make sure its locked down correctly. This includes making sure that no computers running remote desktop services are connected directly to the Internet. Instead place computers running remote desktop behind VPNs so that they are only accessible to those who have VPN accounts on your network.

It is also important to setup proper account lockout policies so that it makes it difficult for accounts to be brute forced over Remote Desktop Services.

You should also have security software that incorporates behavioral detections to combat ransomware and not just signature detections or heuristics.  For example, Emsisoft Anti-Malware and Malwarebytes Anti-Malware both contain behavioral detection that can prevent many, if not most, ransomware infections from encrypting a computer.

Last, but not least, make sure you practice the following good online security habits, which in many cases are the most important steps of all:

  • Backup, Backup, Backup!
  • Do not open attachments if you do not know who sent them.
  • Do not open attachments until you confirm that the person actually sent you them,
  • Scan attachments with tools like VirusTotal.
  • Make sure all Windows updates are installed as soon as they come out! Also make sure you update all programs, especially Java, Flash, and Adobe Reader. Older programs contain security vulnerabilities that are commonly exploited by malware distributors. Therefore it is important to keep them updated.
  • Make sure you use have some sort of security software installed.
  • Use hard passwords and never reuse the same password at multiple sites.
  • If you are using Remote Desktop Services, do not connect it directly to the Internet. Instead make it accessibly only via a VPN.

For a complete guide on ransomware protection, you visit our How to Protect and Harden a Computer against Ransomware article.


IOCs

Hashes:

0b03bf1c7b596a862978999eebfa0703e6de48912c9a57e2fed3ae5cd747bea7

Ransom Note Text:

HOW TO RECOVER YOUR FILES INSTRUCTION
ATENTION!!!
We are realy sorry to inform you that  ALL YOUR FILES WERE ENCRYPTED 
by our automatic software. It became possible because of bad server security.  
ATENTION!!!
Please don't worry, we can help you to RESTORE your server to original
state and decrypt all your files quickly and safely!

INFORMATION!!!
Files are not broken!!!
Files were encrypted with AES-128+RSA-2048 crypto algorithms.
There is no way to decrypt your files without unique decryption key and special software. Your unique decryption key is securely stored on our server. For our safety, all information about your server and your decryption key will be automaticaly DELETED AFTER 7 DAYS! You will irrevocably lose all your data!
* Please note that all the attempts to recover your files by yourself or using third party tools will result only in irrevocable loss of your data!
* Please note that you can recover files only with your unique decryption key, which stored on our side. If you will use the help of third parties, you will only add a middleman.

HOW TO RECOVER FILES???
Please write us to the e-mail (write on English or use professional translator):
PabFox@protonmail.com 
FoxHelp@cock.li
FoxHelp@tutanota.com
You have to send your message on each of our 3 emails due to the fact that the message may not reach their intended recipient for a variety of reasons!
  
In subject line write your personal ID:
[id]
We recommed you to attach 3 encrypted files to your message. We will demonstrate that we can recover your files. 
*   Please note that files must not contain any valuable information and their total size must be less than 5Mb. 

OUR ADVICE!!!
Please be sure that we will find common languge. We will restore all the data and give you recommedations how to configure the protection of your server.

We will definitely reach an agreement ;) !!!

Files:

#FOX_README#.rtf
%AppData%\random.vbs
%AppData%\random.bat
%AppData%\random.bmp
%DownloadedFolder%\.exe
%DownloadedFolder%\.bat

Associated emails:

PabFox@protonmail.com 
FoxHelp@cock.li
FoxHelp@tutanota.com

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