Ich würde dieses Tutorial streichen, Login-Sicherheit sollte nicht auf die leichte Schulter genommen werden, Sie sollten keine Klartext-Passwörter in der Datenbank haben, sie sollten mit einem Salt gehasht werden und beide sollten sich nach erfolgreicher Anmeldung ändern.

Hier ist ein sicheres Anmeldeskript:

Es verwendet PDO für die Datenbankverbindung, das eigentliche Anmeldeformular verwendet zufällige Schlüssel für die Anmeldung, z. nicht Benutzername/Passwort. Passwörter werden mit sha512 x 25k-mal und mit einem 16-Byte-Schlüsselsalz gehasht, Brute-Force-Schutz. Ich hoffe es hilft.

<?php
session_start();

/**
 * Table

CREATE TABLE IF NOT EXISTS `users` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `username` varchar(45) DEFAULT NULL,
  `pass_hash` varchar(255) DEFAULT NULL,
  `pass_salt` varchar(255) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=0 ;

 */

//DB Stuff
define('DBHOST','localhost');
define('DBNAME','yourdb');
define('DBUSER','root');
define('DBPASS','');
//End Config:---


//Open a PDO Database connection
try {
    $db = new PDO("mysql:host=".DBHOST.";dbname=".DBNAME, DBUSER, DBPASS);
    $db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    $db->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
}catch (Exception $e){
    die('Cannot connect to mySQL server.');
}


class Login{
    public $db;
    public $user;
    public $pass;
    public $error;
    // sha512
    public $algo = '$6';
    // Cost parameter, 25k iterations
    public $cost = '$rounds=25000$';

    function __construct(PDO $db){
        $this->db = $db;
        $this->global_salt = sha1($_SERVER['HTTP_HOST']);
    }

    /**
     * Return a random seed for the mt_rand function
     */
    function make_seed(){
        list($usec, $sec) = explode(' ', microtime());
        return (float) $sec + ((float) $usec * 100000);
    }

    /**
     * Return a random unique salt for new created hash/crypt function salts
     */
    function unique_salt(){
        $salt = null;
        mt_srand($this->make_seed());
        for($i=0;$i < mt_rand(1,10);$i++){
            $salt = sha1($this->global_salt.$salt.mt_rand().uniqid().microtime(true));
        }
        return substr($salt,0,16);
    }

    /**
     * Hash a given password and store parts in:
     * $this->salt = a unique 16 byte salt
     * $this->hash = The full crypted hash sting including algo/cost/salt/crytedpassword
     * $this->full_salt = Just algo/cost/salt section, the first 33 bytes 
     * $this->hashed_password = Just crytedpassword section, proceeding bytes after first 33 bytes
     * 
     */
    function hash($password){
        $this->salt = $this->unique_salt();
        $this->full_hash = crypt($password, $this->algo.$this->cost.$this->salt);
        $this->full_salt = substr($this->full_hash, 0, 33);
        $this->hashed_password = substr($this->full_hash, 33);
        return $this->full_hash;
    }

    /**
     * Method to validate the given crypto hash against the given password
     */
    function check_password($hash, $salt, $password){
        $hash = ($this->algo.$this->cost.$salt.'$'.$hash);
        if($hash == crypt($password, substr($hash, 0, 33))){
            //Regenerate new hash and salt for given password
            $this->update_keys();
            $this->status = true;
            $_SESSION['logged_in']=true;
            return true;
        }else{
            $this->status = false;
            return false;
        }
    }

    /**
     * Set error
     */
    function set_error($type,$value){
        $this->error[$type]=$value;
    }

    /**
     * Output error
     */
    function error($type){
        echo (isset($this->error[$type]))?$this->error[$type]:null;
    }

    /**
     * Logout and regenirate session and redirect to index
     */
    static function logout(){
        unset($_SESSION['logged_in']);
        session_regenerate_id(true);
        exit(header('Location: ./index.php'));
    }

    function anti_brute($intval){
        if(!isset($_SESSION['access_time'])){
            $_SESSION['access_time']=time();
        }else{
            $t = time()-$_SESSION['access_time'];
            if($t <= $intval){
                $this->set_error('global','Time violation');
                $_SESSION['access_time']=time();
                return true;
            }
            $_SESSION['access_time']=time();
            return false;
        }
    }

    function process_login(){
        if($_SERVER['REQUEST_METHOD']=='POST'){

            $this->user   = (isset($_SESSION['userParam']) && isset($_POST[$_SESSION['userParam']]))?$_POST[$_SESSION['userParam']]:null;
            $this->pass   = (isset($_SESSION['passParam']) && isset($_POST[$_SESSION['passParam']]))?$_POST[$_SESSION['passParam']]:null;
            $this->create = (isset($_SESSION['createParam']) && isset($_POST[$_SESSION['createParam']]))?$_POST[$_SESSION['createParam']]:null;

            $cont = true;
            if($this->user == null || strlen($this->user) <= 2){$this->set_error('user','Please enter a username!'); $cont=false;}
            if($this->pass == null || strlen($this->pass) <= 2){$this->set_error('pass','Please enter a password!'); $cont=false;}


            if($cont==true){
                //Alls good continue
                if($this->create != null && $this->create=='1'){
                    //Check user for new account
                    if($this->check_user()==true){$this->set_error('user','Username already taken.');return;}
                    //Create account
                    $this->create_account();
                }else{
                    //Stop really fast request 2 seconds
                    if($this->anti_brute(2)==false){
                        //Attempt to login
                        $this->check_login();
                    }
                }
            }else{
                //Error with form
                $this->set_error('global','Please fill in login form!');
            }
        }
    }

    function check_user(){
        $sql = 'SELECT 1 FROM users WHERE username=:username';
        $statement = $this->db->prepare($sql);
        $statement->bindParam(':username', $this->user, PDO::PARAM_STR);
        $statement->execute();
        $result = $statement->fetch(PDO::FETCH_ASSOC);

        if(!empty($result)){return true;}else{return false;}
    }

    function check_login(){
        $sql = 'SELECT pass_hash, pass_salt FROM users WHERE username=:username';
        $statement = $this->db->prepare($sql);
        $statement->bindParam(':username', $this->user, PDO::PARAM_STR);
        $statement->execute();
        $result = $statement->fetch(PDO::FETCH_ASSOC);

        $this->check_password($result['pass_hash'], $result['pass_salt'], $this->pass);
    }

    function create_account(){
        //Create new account
        $this->hash($this->pass);
        $sql = 'INSERT into users (username, pass_hash, pass_salt) VALUES (:username, :pass_hash, :pass_salt)';
        $statement = $this->db->prepare($sql);
        $statement->bindParam(':username', $this->user, PDO::PARAM_STR);
        $statement->bindParam(':pass_hash', $this->hashed_password, PDO::PARAM_STR);
        $statement->bindParam(':pass_salt', $this->salt, PDO::PARAM_STR);
        $statement->execute();

        $this->status = true;
        $_SESSION['logged_in']=true;
    }

    function update_keys(){
        //Update account password hash & salt
        $this->hash($this->pass);
        $sql = 'UPDATE users SET pass_hash=:pass_hash, pass_salt=:pass_salt WHERE username=:username';
        $statement = $this->db->prepare($sql);
        $statement->bindParam(':username', $this->user, PDO::PARAM_STR);
        $statement->bindParam(':pass_hash', $this->hashed_password, PDO::PARAM_STR);
        $statement->bindParam(':pass_salt', $this->salt, PDO::PARAM_STR);
        $statement->execute();

        $this->status = true;
        $_SESSION['logged_in']=true;
    }

}//END Login class

//Logout handler
if(isset($_GET['logout'])){ Login::logout(); }

$login = new Login($db);

//Login handler
$login->process_login();

//Debug
echo '<pre>';
print_r($login);
echo '</pre>';


//Check login status
if(isset($_SESSION['logged_in']) && $_SESSION['logged_in']==true){
    //Logged in
    echo '<a href="?logout">Logout</a>';
}else{
    //Not Logged In

    //Show login form & create uniqie parrams for user/pass/create post keys
    $_SESSION['userParam']   = sha1(uniqid().microtime(true));
    $_SESSION['passParam']   = sha1(uniqid().microtime(true));
    $_SESSION['createParam'] = sha1(uniqid().microtime(true));
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Secure Login</title>
</head>

<body>
<h1>Secure Login Example</h1>
<h3>Please login:</h3>

<?php $login->error('global'); ?>

<form method="POST" action="">
  <label for="user">Username :&nbsp; </label>
  <input type="text" name="<?=$_SESSION['userParam'];?>" size="29"> <?php $login->error('user'); ?>
  <br />
  <label for="pass">Password :&nbsp; </label>
  <input type="text" name="<?=$_SESSION['passParam'];?>" size="29"> <?php $login->error('pass'); ?>
  <br /> 
  <input type="submit" value="Login">&nbsp; and create my account:<input type="checkbox" name="<?=$_SESSION['createParam'];?>" value="1">
</form>
</body>
</html>
<?php } ?>

Beispiel für sichere Anmeldung

Bitte melden Sie sich an: