Migration zu PHPMailer: Sicherer E-Mail-Versand mit externen Credentials

.gitignore

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+# Sensible Konfigurationsdateien
+forms/config.php
+
+# Logs und temporäre Dateien
+forms/error_log
+*.log
+
+# System-Dateien
+.DS_Store
+Thumbs.db
+
+# IDE-Dateien
+.vscode/
+.idea/
+*.swp
+*.swo
+*~
+
+# Backup-Dateien
+*.bak
+*.backup

assets/vendor/phpmailer/DSNConfigurator.php

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+<?php
+
+/**
+ * PHPMailer - PHP email creation and transport class.
+ * PHP Version 5.5.
+ *
+ * @see https://github.com/PHPMailer/PHPMailer/ The PHPMailer GitHub project
+ *
+ * @author    Marcus Bointon (Synchro/coolbru) <phpmailer@synchromedia.co.uk>
+ * @author    Jim Jagielski (jimjag) <jimjag@gmail.com>
+ * @author    Andy Prevost (codeworxtech) <codeworxtech@users.sourceforge.net>
+ * @author    Brent R. Matzelle (original founder)
+ * @copyright 2012 - 2023 Marcus Bointon
+ * @copyright 2010 - 2012 Jim Jagielski
+ * @copyright 2004 - 2009 Andy Prevost
+ * @license   http://www.gnu.org/copyleft/lesser.html GNU Lesser General Public License
+ * @note      This program is distributed in the hope that it will be useful - WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+namespace PHPMailer\PHPMailer;
+
+/**
+ * Configure PHPMailer with DSN string.
+ *
+ * @see https://en.wikipedia.org/wiki/Data_source_name
+ *
+ * @author Oleg Voronkovich <oleg-voronkovich@yandex.ru>
+ */
+class DSNConfigurator
+{
+    /**
+     * Create new PHPMailer instance configured by DSN.
+     *
+     * @param string $dsn        DSN
+     * @param bool   $exceptions Should we throw external exceptions?
+     *
+     * @return PHPMailer
+     */
+    public static function mailer($dsn, $exceptions = null)
+    {
+        static $configurator = null;
+
+        if (null === $configurator) {
+            $configurator = new DSNConfigurator();
+        }
+
+        return $configurator->configure(new PHPMailer($exceptions), $dsn);
+    }
+
+    /**
+     * Configure PHPMailer instance with DSN string.
+     *
+     * @param PHPMailer $mailer PHPMailer instance
+     * @param string    $dsn    DSN
+     *
+     * @return PHPMailer
+     */
+    public function configure(PHPMailer $mailer, $dsn)
+    {
+        $config = $this->parseDSN($dsn);
+
+        $this->applyConfig($mailer, $config);
+
+        return $mailer;
+    }
+
+    /**
+     * Parse DSN string.
+     *
+     * @param string $dsn DSN
+     *
+     * @throws Exception If DSN is malformed
+     *
+     * @return array Configuration
+     */
+    private function parseDSN($dsn)
+    {
+        $config = $this->parseUrl($dsn);
+
+        if (false === $config || !isset($config['scheme']) || !isset($config['host'])) {
+            throw new Exception('Malformed DSN');
+        }
+
+        if (isset($config['query'])) {
+            parse_str($config['query'], $config['query']);
+        }
+
+        return $config;
+    }
+
+    /**
+     * Apply configuration to mailer.
+     *
+     * @param PHPMailer $mailer PHPMailer instance
+     * @param array     $config Configuration
+     *
+     * @throws Exception If scheme is invalid
+     */
+    private function applyConfig(PHPMailer $mailer, $config)
+    {
+        switch ($config['scheme']) {
+            case 'mail':
+                $mailer->isMail();
+                break;
+            case 'sendmail':
+                $mailer->isSendmail();
+                break;
+            case 'qmail':
+                $mailer->isQmail();
+                break;
+            case 'smtp':
+            case 'smtps':
+                $mailer->isSMTP();
+                $this->configureSMTP($mailer, $config);
+                break;
+            default:
+                throw new Exception(
+                    sprintf(
+                        'Invalid scheme: "%s". Allowed values: "mail", "sendmail", "qmail", "smtp", "smtps".',
+                        $config['scheme']
+                    )
+                );
+        }
+
+        if (isset($config['query'])) {
+            $this->configureOptions($mailer, $config['query']);
+        }
+    }
+
+    /**
+     * Configure SMTP.
+     *
+     * @param PHPMailer $mailer PHPMailer instance
+     * @param array     $config Configuration
+     */
+    private function configureSMTP($mailer, $config)
+    {
+        $isSMTPS = 'smtps' === $config['scheme'];
+
+        if ($isSMTPS) {
+            $mailer->SMTPSecure = PHPMailer::ENCRYPTION_STARTTLS;
+        }
+
+        $mailer->Host = $config['host'];
+
+        if (isset($config['port'])) {
+            $mailer->Port = $config['port'];
+        } elseif ($isSMTPS) {
+            $mailer->Port = SMTP::DEFAULT_SECURE_PORT;
+        }
+
+        $mailer->SMTPAuth = isset($config['user']) || isset($config['pass']);
+
+        if (isset($config['user'])) {
+            $mailer->Username = $config['user'];
+        }
+
+        if (isset($config['pass'])) {
+            $mailer->Password = $config['pass'];
+        }
+    }
+
+    /**
+     * Configure options.
+     *
+     * @param PHPMailer $mailer  PHPMailer instance
+     * @param array     $options Options
+     *
+     * @throws Exception If option is unknown
+     */
+    private function configureOptions(PHPMailer $mailer, $options)
+    {
+        $allowedOptions = get_object_vars($mailer);
+
+        unset($allowedOptions['Mailer']);
+        unset($allowedOptions['SMTPAuth']);
+        unset($allowedOptions['Username']);
+        unset($allowedOptions['Password']);
+        unset($allowedOptions['Hostname']);
+        unset($allowedOptions['Port']);
+        unset($allowedOptions['ErrorInfo']);
+
+        $allowedOptions = \array_keys($allowedOptions);
+
+        foreach ($options as $key => $value) {
+            if (!in_array($key, $allowedOptions)) {
+                throw new Exception(
+                    sprintf(
+                        'Unknown option: "%s". Allowed values: "%s"',
+                        $key,
+                        implode('", "', $allowedOptions)
+                    )
+                );
+            }
+
+            switch ($key) {
+                case 'AllowEmpty':
+                case 'SMTPAutoTLS':
+                case 'SMTPKeepAlive':
+                case 'SingleTo':
+                case 'UseSendmailOptions':
+                case 'do_verp':
+                case 'DKIM_copyHeaderFields':
+                    $mailer->$key = (bool) $value;
+                    break;
+                case 'Priority':
+                case 'SMTPDebug':
+                case 'WordWrap':
+                    $mailer->$key = (int) $value;
+                    break;
+                default:
+                    $mailer->$key = $value;
+                    break;
+            }
+        }
+    }
+
+    /**
+     * Parse a URL.
+     * Wrapper for the built-in parse_url function to work around a bug in PHP 5.5.
+     *
+     * @param string $url URL
+     *
+     * @return array|false
+     */
+    protected function parseUrl($url)
+    {
+        if (\PHP_VERSION_ID >= 50600 || false === strpos($url, '?')) {
+            return parse_url($url);
+        }
+
+        $chunks = explode('?', $url);
+        if (is_array($chunks)) {
+            $result = parse_url($chunks[0]);
+            if (is_array($result)) {
+                $result['query'] = $chunks[1];
+            }
+            return $result;
+        }
+
+        return false;
+    }
+}

assets/vendor/phpmailer/Exception.php

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+<?php
+
+/**
+ * PHPMailer Exception class.
+ * PHP Version 5.5.
+ *
+ * @see       https://github.com/PHPMailer/PHPMailer/ The PHPMailer GitHub project
+ *
+ * @author    Marcus Bointon (Synchro/coolbru) <phpmailer@synchromedia.co.uk>
+ * @author    Jim Jagielski (jimjag) <jimjag@gmail.com>
+ * @author    Andy Prevost (codeworxtech) <codeworxtech@users.sourceforge.net>
+ * @author    Brent R. Matzelle (original founder)
+ * @copyright 2012 - 2020 Marcus Bointon
+ * @copyright 2010 - 2012 Jim Jagielski
+ * @copyright 2004 - 2009 Andy Prevost
+ * @license   http://www.gnu.org/copyleft/lesser.html GNU Lesser General Public License
+ * @note      This program is distributed in the hope that it will be useful - WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+namespace PHPMailer\PHPMailer;
+
+/**
+ * PHPMailer exception handler.
+ *
+ * @author Marcus Bointon <phpmailer@synchromedia.co.uk>
+ */
+class Exception extends \Exception
+{
+    /**
+     * Prettify error message output.
+     *
+     * @return string
+     */
+    public function errorMessage()
+    {
+        return '<strong>' . htmlspecialchars($this->getMessage(), ENT_COMPAT | ENT_HTML401) . "</strong><br />\n";
+    }
+}

assets/vendor/phpmailer/OAuth.php

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+<?php
+
+/**
+ * PHPMailer - PHP email creation and transport class.
+ * PHP Version 5.5.
+ *
+ * @see       https://github.com/PHPMailer/PHPMailer/ The PHPMailer GitHub project
+ *
+ * @author    Marcus Bointon (Synchro/coolbru) <phpmailer@synchromedia.co.uk>
+ * @author    Jim Jagielski (jimjag) <jimjag@gmail.com>
+ * @author    Andy Prevost (codeworxtech) <codeworxtech@users.sourceforge.net>
+ * @author    Brent R. Matzelle (original founder)
+ * @copyright 2012 - 2020 Marcus Bointon
+ * @copyright 2010 - 2012 Jim Jagielski
+ * @copyright 2004 - 2009 Andy Prevost
+ * @license   http://www.gnu.org/copyleft/lesser.html GNU Lesser General Public License
+ * @note      This program is distributed in the hope that it will be useful - WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+namespace PHPMailer\PHPMailer;
+
+use League\OAuth2\Client\Grant\RefreshToken;
+use League\OAuth2\Client\Provider\AbstractProvider;
+use League\OAuth2\Client\Token\AccessToken;
+
+/**
+ * OAuth - OAuth2 authentication wrapper class.
+ * Uses the oauth2-client package from the League of Extraordinary Packages.
+ *
+ * @see     http://oauth2-client.thephpleague.com
+ *
+ * @author  Marcus Bointon (Synchro/coolbru) <phpmailer@synchromedia.co.uk>
+ */
+class OAuth implements OAuthTokenProvider
+{
+    /**
+     * An instance of the League OAuth Client Provider.
+     *
+     * @var AbstractProvider
+     */
+    protected $provider;
+
+    /**
+     * The current OAuth access token.
+     *
+     * @var AccessToken
+     */
+    protected $oauthToken;
+
+    /**
+     * The user's email address, usually used as the login ID
+     * and also the from address when sending email.
+     *
+     * @var string
+     */
+    protected $oauthUserEmail = '';
+
+    /**
+     * The client secret, generated in the app definition of the service you're connecting to.
+     *
+     * @var string
+     */
+    protected $oauthClientSecret = '';
+
+    /**
+     * The client ID, generated in the app definition of the service you're connecting to.
+     *
+     * @var string
+     */
+    protected $oauthClientId = '';
+
+    /**
+     * The refresh token, used to obtain new AccessTokens.
+     *
+     * @var string
+     */
+    protected $oauthRefreshToken = '';
+
+    /**
+     * OAuth constructor.
+     *
+     * @param array $options Associative array containing
+     *                       `provider`, `userName`, `clientSecret`, `clientId` and `refreshToken` elements
+     */
+    public function __construct($options)
+    {
+        $this->provider = $options['provider'];
+        $this->oauthUserEmail = $options['userName'];
+        $this->oauthClientSecret = $options['clientSecret'];
+        $this->oauthClientId = $options['clientId'];
+        $this->oauthRefreshToken = $options['refreshToken'];
+    }
+
+    /**
+     * Get a new RefreshToken.
+     *
+     * @return RefreshToken
+     */
+    protected function getGrant()
+    {
+        return new RefreshToken();
+    }
+
+    /**
+     * Get a new AccessToken.
+     *
+     * @return AccessToken
+     */
+    protected function getToken()
+    {
+        return $this->provider->getAccessToken(
+            $this->getGrant(),
+            ['refresh_token' => $this->oauthRefreshToken]
+        );
+    }
+
+    /**
+     * Generate a base64-encoded OAuth token.
+     *
+     * @return string
+     */
+    public function getOauth64()
+    {
+        //Get a new token if it's not available or has expired
+        if (null === $this->oauthToken || $this->oauthToken->hasExpired()) {
+            $this->oauthToken = $this->getToken();
+        }
+
+        return base64_encode(
+            'user=' .
+            $this->oauthUserEmail .
+            "\001auth=Bearer " .
+            $this->oauthToken .
+            "\001\001"
+        );
+    }
+}

assets/vendor/phpmailer/OAuthTokenProvider.php

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+<?php
+
+/**
+ * PHPMailer - PHP email creation and transport class.
+ * PHP Version 5.5.
+ *
+ * @see https://github.com/PHPMailer/PHPMailer/ The PHPMailer GitHub project
+ *
+ * @author    Marcus Bointon (Synchro/coolbru) <phpmailer@synchromedia.co.uk>
+ * @author    Jim Jagielski (jimjag) <jimjag@gmail.com>
+ * @author    Andy Prevost (codeworxtech) <codeworxtech@users.sourceforge.net>
+ * @author    Brent R. Matzelle (original founder)
+ * @copyright 2012 - 2020 Marcus Bointon
+ * @copyright 2010 - 2012 Jim Jagielski
+ * @copyright 2004 - 2009 Andy Prevost
+ * @license   http://www.gnu.org/copyleft/lesser.html GNU Lesser General Public License
+ * @note      This program is distributed in the hope that it will be useful - WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+namespace PHPMailer\PHPMailer;
+
+/**
+ * OAuthTokenProvider - OAuth2 token provider interface.
+ * Provides base64 encoded OAuth2 auth strings for SMTP authentication.
+ *
+ * @see     OAuth
+ * @see     SMTP::authenticate()
+ *
+ * @author  Peter Scopes (pdscopes)
+ * @author  Marcus Bointon (Synchro/coolbru) <phpmailer@synchromedia.co.uk>
+ */
+interface OAuthTokenProvider
+{
+    /**
+     * Generate a base64-encoded OAuth token ensuring that the access token has not expired.
+     * The string to be base 64 encoded should be in the form:
+     * "user=<user_email_address>\001auth=Bearer <access_token>\001\001"
+     *
+     * @return string
+     */
+    public function getOauth64();
+}

assets/vendor/phpmailer/POP3.php

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+<?php
+
+/**
+ * PHPMailer POP-Before-SMTP Authentication Class.
+ * PHP Version 5.5.
+ *
+ * @see https://github.com/PHPMailer/PHPMailer/ The PHPMailer GitHub project
+ *
+ * @author    Marcus Bointon (Synchro/coolbru) <phpmailer@synchromedia.co.uk>
+ * @author    Jim Jagielski (jimjag) <jimjag@gmail.com>
+ * @author    Andy Prevost (codeworxtech) <codeworxtech@users.sourceforge.net>
+ * @author    Brent R. Matzelle (original founder)
+ * @copyright 2012 - 2020 Marcus Bointon
+ * @copyright 2010 - 2012 Jim Jagielski
+ * @copyright 2004 - 2009 Andy Prevost
+ * @license   http://www.gnu.org/copyleft/lesser.html GNU Lesser General Public License
+ * @note      This program is distributed in the hope that it will be useful - WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+namespace PHPMailer\PHPMailer;
+
+/**
+ * PHPMailer POP-Before-SMTP Authentication Class.
+ * Specifically for PHPMailer to use for RFC1939 POP-before-SMTP authentication.
+ * 1) This class does not support APOP authentication.
+ * 2) Opening and closing lots of POP3 connections can be quite slow. If you need
+ *   to send a batch of emails then just perform the authentication once at the start,
+ *   and then loop through your mail sending script. Providing this process doesn't
+ *   take longer than the verification period lasts on your POP3 server, you should be fine.
+ * 3) This is really ancient technology; you should only need to use it to talk to very old systems.
+ * 4) This POP3 class is deliberately lightweight and incomplete, implementing just
+ *   enough to do authentication.
+ *   If you want a more complete class there are other POP3 classes for PHP available.
+ *
+ * @author Richard Davey (original author) <rich@corephp.co.uk>
+ * @author Marcus Bointon (Synchro/coolbru) <phpmailer@synchromedia.co.uk>
+ * @author Jim Jagielski (jimjag) <jimjag@gmail.com>
+ * @author Andy Prevost (codeworxtech) <codeworxtech@users.sourceforge.net>
+ */
+class POP3
+{
+    /**
+     * The POP3 PHPMailer Version number.
+     *
+     * @var string
+     */
+    const VERSION = '6.9.1';
+
+    /**
+     * Default POP3 port number.
+     *
+     * @var int
+     */
+    const DEFAULT_PORT = 110;
+
+    /**
+     * Default timeout in seconds.
+     *
+     * @var int
+     */
+    const DEFAULT_TIMEOUT = 30;
+
+    /**
+     * POP3 class debug output mode.
+     * Debug output level.
+     * Options:
+     * @see POP3::DEBUG_OFF: No output
+     * @see POP3::DEBUG_SERVER: Server messages, connection/server errors
+     * @see POP3::DEBUG_CLIENT: Client and Server messages, connection/server errors
+     *
+     * @var int
+     */
+    public $do_debug = self::DEBUG_OFF;
+
+    /**
+     * POP3 mail server hostname.
+     *
+     * @var string
+     */
+    public $host;
+
+    /**
+     * POP3 port number.
+     *
+     * @var int
+     */
+    public $port;
+
+    /**
+     * POP3 Timeout Value in seconds.
+     *
+     * @var int
+     */
+    public $tval;
+
+    /**
+     * POP3 username.
+     *
+     * @var string
+     */
+    public $username;
+
+    /**
+     * POP3 password.
+     *
+     * @var string
+     */
+    public $password;
+
+    /**
+     * Resource handle for the POP3 connection socket.
+     *
+     * @var resource
+     */
+    protected $pop_conn;
+
+    /**
+     * Are we connected?
+     *
+     * @var bool
+     */
+    protected $connected = false;
+
+    /**
+     * Error container.
+     *
+     * @var array
+     */
+    protected $errors = [];
+
+    /**
+     * Line break constant.
+     */
+    const LE = "\r\n";
+
+    /**
+     * Debug level for no output.
+     *
+     * @var int
+     */
+    const DEBUG_OFF = 0;
+
+    /**
+     * Debug level to show server -> client messages
+     * also shows clients connection errors or errors from server
+     *
+     * @var int
+     */
+    const DEBUG_SERVER = 1;
+
+    /**
+     * Debug level to show client -> server and server -> client messages.
+     *
+     * @var int
+     */
+    const DEBUG_CLIENT = 2;
+
+    /**
+     * Simple static wrapper for all-in-one POP before SMTP.
+     *
+     * @param string   $host        The hostname to connect to
+     * @param int|bool $port        The port number to connect to
+     * @param int|bool $timeout     The timeout value
+     * @param string   $username
+     * @param string   $password
+     * @param int      $debug_level
+     *
+     * @return bool
+     */
+    public static function popBeforeSmtp(
+        $host,
+        $port = false,
+        $timeout = false,
+        $username = '',
+        $password = '',
+        $debug_level = 0
+    ) {
+        $pop = new self();
+
+        return $pop->authorise($host, $port, $timeout, $username, $password, $debug_level);
+    }
+
+    /**
+     * Authenticate with a POP3 server.
+     * A connect, login, disconnect sequence
+     * appropriate for POP-before SMTP authorisation.
+     *
+     * @param string   $host        The hostname to connect to
+     * @param int|bool $port        The port number to connect to
+     * @param int|bool $timeout     The timeout value
+     * @param string   $username
+     * @param string   $password
+     * @param int      $debug_level
+     *
+     * @return bool
+     */
+    public function authorise($host, $port = false, $timeout = false, $username = '', $password = '', $debug_level = 0)
+    {
+        $this->host = $host;
+        //If no port value provided, use default
+        if (false === $port) {
+            $this->port = static::DEFAULT_PORT;
+        } else {
+            $this->port = (int) $port;
+        }
+        //If no timeout value provided, use default
+        if (false === $timeout) {
+            $this->tval = static::DEFAULT_TIMEOUT;
+        } else {
+            $this->tval = (int) $timeout;
+        }
+        $this->do_debug = $debug_level;
+        $this->username = $username;
+        $this->password = $password;
+        //Reset the error log
+        $this->errors = [];
+        //Connect
+        $result = $this->connect($this->host, $this->port, $this->tval);
+        if ($result) {
+            $login_result = $this->login($this->username, $this->password);
+            if ($login_result) {
+                $this->disconnect();
+
+                return true;
+            }
+        }
+        //We need to disconnect regardless of whether the login succeeded
+        $this->disconnect();
+
+        return false;
+    }
+
+    /**
+     * Connect to a POP3 server.
+     *
+     * @param string   $host
+     * @param int|bool $port
+     * @param int      $tval
+     *
+     * @return bool
+     */
+    public function connect($host, $port = false, $tval = 30)
+    {
+        //Are we already connected?
+        if ($this->connected) {
+            return true;
+        }
+
+        //On Windows this will raise a PHP Warning error if the hostname doesn't exist.
+        //Rather than suppress it with @fsockopen, capture it cleanly instead
+        set_error_handler([$this, 'catchWarning']);
+
+        if (false === $port) {
+            $port = static::DEFAULT_PORT;
+        }
+
+        //Connect to the POP3 server
+        $errno = 0;
+        $errstr = '';
+        $this->pop_conn = fsockopen(
+            $host, //POP3 Host
+            $port, //Port #
+            $errno, //Error Number
+            $errstr, //Error Message
+            $tval
+        ); //Timeout (seconds)
+        //Restore the error handler
+        restore_error_handler();
+
+        //Did we connect?
+        if (false === $this->pop_conn) {
+            //It would appear not...
+            $this->setError(
+                "Failed to connect to server $host on port $port. errno: $errno; errstr: $errstr"
+            );
+
+            return false;
+        }
+
+        //Increase the stream time-out
+        stream_set_timeout($this->pop_conn, $tval, 0);
+
+        //Get the POP3 server response
+        $pop3_response = $this->getResponse();
+        //Check for the +OK
+        if ($this->checkResponse($pop3_response)) {
+            //The connection is established and the POP3 server is talking
+            $this->connected = true;
+
+            return true;
+        }
+
+        return false;
+    }
+
+    /**
+     * Log in to the POP3 server.
+     * Does not support APOP (RFC 2828, 4949).
+     *
+     * @param string $username
+     * @param string $password
+     *
+     * @return bool
+     */
+    public function login($username = '', $password = '')
+    {
+        if (!$this->connected) {
+            $this->setError('Not connected to POP3 server');
+            return false;
+        }
+        if (empty($username)) {
+            $username = $this->username;
+        }
+        if (empty($password)) {
+            $password = $this->password;
+        }
+
+        //Send the Username
+        $this->sendString("USER $username" . static::LE);
+        $pop3_response = $this->getResponse();
+        if ($this->checkResponse($pop3_response)) {
+            //Send the Password
+            $this->sendString("PASS $password" . static::LE);
+            $pop3_response = $this->getResponse();
+            if ($this->checkResponse($pop3_response)) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * Disconnect from the POP3 server.
+     */
+    public function disconnect()
+    {
+        // If could not connect at all, no need to disconnect
+        if ($this->pop_conn === false) {
+            return;
+        }
+
+        $this->sendString('QUIT' . static::LE);
+
+        // RFC 1939 shows POP3 server sending a +OK response to the QUIT command.
+        // Try to get it.  Ignore any failures here.
+        try {
+            $this->getResponse();
+        } catch (Exception $e) {
+            //Do nothing
+        }
+
+        //The QUIT command may cause the daemon to exit, which will kill our connection
+        //So ignore errors here
+        try {
+            @fclose($this->pop_conn);
+        } catch (Exception $e) {
+            //Do nothing
+        }
+
+        // Clean up attributes.
+        $this->connected = false;
+        $this->pop_conn  = false;
+    }
+
+    /**
+     * Get a response from the POP3 server.
+     *
+     * @param int $size The maximum number of bytes to retrieve
+     *
+     * @return string
+     */
+    protected function getResponse($size = 128)
+    {
+        $response = fgets($this->pop_conn, $size);
+        if ($this->do_debug >= self::DEBUG_SERVER) {
+            echo 'Server -> Client: ', $response;
+        }
+
+        return $response;
+    }
+
+    /**
+     * Send raw data to the POP3 server.
+     *
+     * @param string $string
+     *
+     * @return int
+     */
+    protected function sendString($string)
+    {
+        if ($this->pop_conn) {
+            if ($this->do_debug >= self::DEBUG_CLIENT) { //Show client messages when debug >= 2
+                echo 'Client -> Server: ', $string;
+            }
+
+            return fwrite($this->pop_conn, $string, strlen($string));
+        }
+
+        return 0;
+    }
+
+    /**
+     * Checks the POP3 server response.
+     * Looks for for +OK or -ERR.
+     *
+     * @param string $string
+     *
+     * @return bool
+     */
+    protected function checkResponse($string)
+    {
+        if (strpos($string, '+OK') !== 0) {
+            $this->setError("Server reported an error: $string");
+
+            return false;
+        }
+
+        return true;
+    }
+
+    /**
+     * Add an error to the internal error store.
+     * Also display debug output if it's enabled.
+     *
+     * @param string $error
+     */
+    protected function setError($error)
+    {
+        $this->errors[] = $error;
+        if ($this->do_debug >= self::DEBUG_SERVER) {
+            echo '<pre>';
+            foreach ($this->errors as $e) {
+                print_r($e);
+            }
+            echo '</pre>';
+        }
+    }
+
+    /**
+     * Get an array of error messages, if any.
+     *
+     * @return array
+     */
+    public function getErrors()
+    {
+        return $this->errors;
+    }
+
+    /**
+     * POP3 connection error handler.
+     *
+     * @param int    $errno
+     * @param string $errstr
+     * @param string $errfile
+     * @param int    $errline
+     */
+    protected function catchWarning($errno, $errstr, $errfile, $errline)
+    {
+        $this->setError(
+            'Connecting to the POP3 server raised a PHP warning:' .
+            "errno: $errno errstr: $errstr; errfile: $errfile; errline: $errline"
+        );
+    }
+}

forms/config.php.example

@@ -0,0 +1,21 @@
+<?php
+/**
+ * SMTP Configuration Example
+ * 
+ * Kopieren Sie diese Datei zu config.php und tragen Sie Ihre SMTP-Zugangsdaten ein.
+ * Die config.php wird von Git ignoriert und enthält sensible Daten.
+ */
+
+return [
+    'smtp_host' => 'mail.webfarben.net',
+    'smtp_username' => 'ihre-email@domain.de',
+    'smtp_password' => 'ihr-passwort',
+    'smtp_port' => 587,
+    'smtp_encryption' => 'tls', // 'tls' oder 'ssl'
+    
+    'from_email' => 'ihre-email@domain.de',
+    'from_name' => 'Buckenleib Finanzen',
+    
+    'to_email' => 'info@buckenleib-finanzen.de',
+    'to_name' => 'Benno Buckenleib',
+];

forms/contact.php

@@ -1,41 +1,134 @@
 <?php
 /**
-  * Requires the "PHP Email Form" library
-  * The "PHP Email Form" library is available only in the pro version of the template
-  * The library should be uploaded to: vendor/php-email-form/php-email-form.php
-  * For more info and help: https://bootstrapmade.com/php-email-form/
+ * Kontaktformular mit PHPMailer
+ * Sicherer und moderner E-Mail-Versand
  */
 
-  // Replace contact@example.com with your real receiving email address
-  $receiving_email_address = 'info@buckenleib-finanzen.de';
-
-  if( file_exists($php_email_form = '../assets/vendor/php-email-form/php-email-form.php' )) {
-    include( $php_email_form );
-  } else {
-    die( 'Unable to load the "PHP Email Form" Library!');
+// Nur POST-Requests erlauben
+if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
+    http_response_code(405);
+    die('Methode nicht erlaubt');
 }
 
-  $contact = new PHP_Email_Form;
-  $contact->ajax = true;
+// CSRF-Schutz durch Ajax-Anforderung
+if (!isset($_SERVER['HTTP_X_REQUESTED_WITH']) || 
+    strtolower($_SERVER['HTTP_X_REQUESTED_WITH']) !== 'xmlhttprequest') {
+    http_response_code(403);
+    die('Nur Ajax-Anfragen erlaubt');
+}
 
-  $contact->to = $receiving_email_address;
-  $contact->from_name = $_POST['name'];
-  $contact->from_email = $_POST['email'];
-  $contact->subject = $_POST['subject'];
+// Konfiguration laden
+if (!file_exists(__DIR__ . '/config.php')) {
+    http_response_code(500);
+    die('Konfigurationsdatei nicht gefunden');
+}
+$config = require __DIR__ . '/config.php';
 
-  // Uncomment below code if you want to use SMTP to send emails. You need to enter your correct SMTP credentials
+// PHPMailer laden
+require_once __DIR__ . '/../assets/vendor/phpmailer/PHPMailer.php';
+require_once __DIR__ . '/../assets/vendor/phpmailer/SMTP.php';
+require_once __DIR__ . '/../assets/vendor/phpmailer/Exception.php';
 
-  $contact->smtp = array(
-    'host' => 'mail.webfarben.net',
-    'username' => 'benno@traidendorf.de',
-    'password' => 'b9ojR8*1',
-    'port' => '587'
-  );
+use PHPMailer\PHPMailer\PHPMailer;
+use PHPMailer\PHPMailer\Exception;
 
+// Eingaben validieren und säubern
+$name = filter_var($_POST['name'] ?? '', FILTER_SANITIZE_STRING);
+$email = filter_var($_POST['email'] ?? '', FILTER_SANITIZE_EMAIL);
+$subject = filter_var($_POST['subject'] ?? '', FILTER_SANITIZE_STRING);
+$message = filter_var($_POST['message'] ?? '', FILTER_SANITIZE_STRING);
 
-  $contact->add_message( $_POST['name'], 'From');
-  $contact->add_message( $_POST['email'], 'Email');
-  $contact->add_message( $_POST['message'], 'Message', 10);
+// Validierung
+if (empty($name) || strlen($name) < 2) {
+    die('Bitte geben Sie Ihren Namen ein');
+}
 
-  echo $contact->send();
+if (empty($email) || !filter_var($email, FILTER_VALIDATE_EMAIL)) {
+    die('Bitte geben Sie eine gültige E-Mail-Adresse ein');
+}
+
+if (empty($subject) || strlen($subject) < 3) {
+    die('Bitte geben Sie ein Thema ein');
+}
+
+if (empty($message) || strlen($message) < 10) {
+    die('Ihre Nachricht ist zu kurz (mindestens 10 Zeichen)');
+}
+
+try {
+    $mail = new PHPMailer(true);
+    
+    // Server-Einstellungen
+    $mail->isSMTP();
+    $mail->Host = $config['smtp_host'];
+    $mail->SMTPAuth = true;
+    $mail->Username = $config['smtp_username'];
+    $mail->Password = $config['smtp_password'];
+    $mail->SMTPSecure = $config['smtp_encryption'];
+    $mail->Port = $config['smtp_port'];
+    $mail->CharSet = 'UTF-8';
+    
+    // Absender
+    $mail->setFrom($config['from_email'], $config['from_name']);
+    $mail->addReplyTo($email, $name);
+    
+    // Empfänger
+    $mail->addAddress($config['to_email'], $config['to_name']);
+    
+    // Inhalt
+    $mail->isHTML(true);
+    $mail->Subject = 'Kontaktformular: ' . $subject;
+    
+    $htmlMessage = "
+    <html>
+    <head>
+        <style>
+            body { font-family: Arial, sans-serif; line-height: 1.6; color: #333; }
+            .container { max-width: 600px; margin: 0 auto; padding: 20px; }
+            .header { background: #37517e; color: white; padding: 15px; border-radius: 5px 5px 0 0; }
+            .content { background: #f8f9fa; padding: 20px; border-radius: 0 0 5px 5px; }
+            .field { margin-bottom: 15px; }
+            .label { font-weight: bold; color: #37517e; }
+        </style>
+    </head>
+    <body>
+        <div class='container'>
+            <div class='header'>
+                <h2>Neue Kontaktanfrage</h2>
+            </div>
+            <div class='content'>
+                <div class='field'>
+                    <div class='label'>Name:</div>
+                    <div>" . htmlspecialchars($name) . "</div>
+                </div>
+                <div class='field'>
+                    <div class='label'>E-Mail:</div>
+                    <div>" . htmlspecialchars($email) . "</div>
+                </div>
+                <div class='field'>
+                    <div class='label'>Thema:</div>
+                    <div>" . htmlspecialchars($subject) . "</div>
+                </div>
+                <div class='field'>
+                    <div class='label'>Nachricht:</div>
+                    <div>" . nl2br(htmlspecialchars($message)) . "</div>
+                </div>
+            </div>
+        </div>
+    </body>
+    </html>
+    ";
+    
+    $mail->Body = $htmlMessage;
+    $mail->AltBody = "Name: $name\nE-Mail: $email\nThema: $subject\n\nNachricht:\n$message";
+    
+    // E-Mail senden
+    $mail->send();
+    echo 'OK';
+    
+} catch (Exception $e) {
+    error_log('PHPMailer Error: ' . $mail->ErrorInfo);
+    http_response_code(500);
+    die('Fehler beim Senden der Nachricht. Bitte versuchen Sie es später erneut.');
+}
 ?>