What are some best practices for handling the HTTP_REFERER variable in PHP to mitigate potential security risks?

When handling the HTTP_REFERER variable in PHP, it is important to sanitize and validate the data to mitigate potential security risks such as spoofing or injection attacks. One best practice is to check if the referer URL is from a trusted source before using it in your application. 

if (isset($_SERVER['HTTP_REFERER'])) {
    $referer = $_SERVER['HTTP_REFERER'];
    
    // Validate the referer URL to ensure it is from a trusted source
    if (strpos($referer, 'https://www.example.com') === 0) {
        // Proceed with using the referer URL in your application
    } else {
        // Handle unauthorized referer URLs
    }
}

Keywords

HTTP_REFERER security risks handling PHP mitigation

Related Questions