title: Security Issue in my Mail-Function. What could it be?
body: <p>i used a simple php mail function on my Website for several weeks. Today it started sending SPAM and i dont know whats the issue. </p>
  
  <p>Im using the Honeypot-Method and I dont allow sending the form when the user spent less than 3 seconds on the form. 
  Here is my php code for processing the form:</p>
  
  <pre><code>    if ($_SERVER["REQUEST_METHOD"] == "POST") {
          $name = htmlspecialchars(trim($_POST["name"]));
          $email = htmlspecialchars(trim($_POST["email"]));
          $message = htmlspecialchars(trim($_POST["message"]));
          $phone = htmlspecialchars(trim($_POST["phone"]));
          $time = $_POST["time"];
          $timenow = time();
          $time_difference = $timenow - $time;
  
      // FILL OUT ALL FORMDATA
          if ($name == "" OR $email == "" OR $message == "" OR $phone == "") {
              $error_message = "Bitte füllen Sie alle Felder aus!";
          }
  
          if (!isset($error_message)) {
              foreach( $_POST as $value ){
                  if( stripos($value,'Content-Type:') !== FALSE ){
                      $error_message = "Es gab ein Problem bei der Dateneingabe. ";
                  }
              }
  
          }
          // HONEYPOT
          if(!isset($error_message) &amp;&amp; $_POST["adress"] != "") {
              $error_message = "Netter Versuch!";
          }
          // TIMESTAMP_CHECK
          if($time_difference &lt; 3) {
              $error_message = "Zu schnell";
          }
  
  }
  if (!isset($error_message) &amp;&amp; isset($name)){EMAILSENDING STUFF} 
  </code></pre>
  
  <p>The rest is simple use of the famous phpmailer and a simple html-form. Is there an issue I am not seeing? Or how else could they make use of my site? </p>