Trojan.BAT.BATCLOAK.A

This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It encrypts files found in specific folders. It drops files as ransom note.

Arrival Details

This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

This Trojan adds the following processes:

• copy C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe /y "{File name}.exe"
• {File Name}.exe -noprofile -ep bypass -c {encrypted command}

Other Details

This Trojan does the following:

• It encrypts files using Rjindael (AES) encryption.
• It displays the following screen after it finishes encrypting files:
  
• It contains an encrypted payload and executes it in memory.

Ransomware Routine

This Trojan encrypts files found in the following folders:

• %Desktop%
• %User Profile%\Documents
• %User Profile%\Pictures

(Note: %Desktop% is the current user's desktop, which is usually C:\Documents and Settings\{User Name}\Desktop on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\Desktop on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name} on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It appends the following extension to the file name of the encrypted files:

• {Original filename}.{Original extension}.scytaleSECC

It drops the following file(s) as ransom note:

• \___RECOVER__FILES__.scytaleSECC.txt