What are some potential security risks associated with uploading confidential files to a PHP server?

One potential security risk is that the confidential files may be accessible to unauthorized users if proper access controls are not in place. To mitigate this risk, it is important to ensure that the PHP server has secure file permissions and that sensitive files are stored outside of the web root directory. 

// Example code to restrict access to confidential files
$confidentialFilePath = '/path/to/confidential/file.txt';

// Check if the user is authorized to access the file
if (userIsAuthorized()) {
    // Serve the file to the user
    header('Content-Type: application/octet-stream');
    header('Content-Disposition: attachment; filename="' . basename($confidentialFilePath) . '"');
    readfile($confidentialFilePath);
} else {
    // Redirect unauthorized users
    header('Location: /unauthorized.php');
}

Keywords

file upload vulnerability PHP file handling functions server-side file validation cross-site scripting (XSS) SQL injection

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