Email Form Validation - V3.1 Exploit — Php

$to = "admin@site.com"; $subject = $_POST['subject']; // Vulnerable point $message = $_POST['message']; $headers = "From: " . $_POST['email']; // Vulnerable point mail($to, $subject, $message, $headers); Use code with caution. 3. The Execution

The server interprets the %0A as a line break, creating a new header line. The mail server now sees a valid Cc or Bcc instruction, sending the message to thousands of unauthorized recipients using your server's reputation. Beyond Spam: Escalating to RCE php email form validation - v3.1 exploit

Never let users define the From or Reply-To headers directly without strict white-listing. $to = "admin@site

In some configurations, this leads to the server executing unintended commands. Anatomy of the V3.1 Exploit $to = "admin@site.com"