ENC Ransomware actively spreading in the wild

February 7, 2020

The SonicWall Capture Labs Threat Research Team observed reports of a new variant family of ENC ransomware [ENC.RSM] actively spreading in the wild.

The ENC  ransomware encrypts the victim’s files with a strong encryption algorithm until the victim pays a fee to get them back.

Infection Cycle:

The ransomware adds the following files to the system:

  • Malware.exe
    • % App.path%\ HOW TO RECOVER ENCRYPTED FILES.txt
      • Instruction for recovery
    • %App.path%\ [Name]. <cryptopatronum@protonmail.com.enc>

Once the computer is compromised, the ransomware runs the following commands: (Actual Source code)

When ENC is started it will create and assign a unique 16 hexadecimal number to the victim then scan all local drives for data files to encrypt.

When encrypting files it will use the AES encryption algorithm and only encrypt those files that match the following extensions:

 

The ransomware encrypts all the files and appends the [cryptopatronum@protonmail.com.enc]  extension onto each encrypted file’s filename.

After encrypting all personal documents, the ransomware shows the following text file containing a message reporting that the computer has been encrypted and to contact its developer for unlock instructions.

 

We have been monitoring varying hits over the past few days for the signature that blocks this threat:

SonicWall Capture Labs provides protection against this threat via the following signature:

  • GAV: Filecoder.RSM_60 (Trojan)

This threat is also detected by SonicWALL Capture ATP w/RTDMI and the Capture Client endpoint solutions.