<?php // Vulnerable code - PHP Email Form v3.1 if ($_SERVER["REQUEST_METHOD"] == "POST") $name = $_POST['name']; $email = $_POST['email']; $message = $_POST['message']; $to = "admin@example.com"; $subject = "Contact Form Submission from $name"; $headers = "From: $email\r\n"; $headers .= "Reply-To: $email\r\n";
The -X flag tells sendmail to log the entire email traffic to a specific file. php email form validation - v3.1 exploit
If you must use the fifth parameter of mail() , wrap it in escapeshellarg() . Conclusion including command-line arguments.
The moniker "v3.1" in this context is often misleading. In the open-source community, version numbers imply maintenance and security patches. However, scripts labeled this way are frequently abandoned codebases from the early 2000s, circulating on tutorial sites and repositories long after they were deemed insecure. In the open-source community
By putting a PHP shell (e.g., ) in the body of the email, the log file becomes an executable web shell. 3. Vulnerability Indicators
: Allowing an attacker to run arbitrary code on the server, often by writing a to a publicly accessible directory. Critical Mitigation Steps
The vulnerability exists due to the lack of proper input validation in the mail() function, allowing an attacker to inject arbitrary data, including command-line arguments. This can lead to a remote code execution (RCE) vulnerability, enabling an attacker to execute arbitrary system commands.