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can someone explain me how to protect the profile page from the wrong user editing the URL to see some other users profile page. i am using a token class to generate a random number to protect against Cross Site Request Forgery. for some reason it doesn't work any suggestion or other way to do that
Also i get the following error : Undefined index: token in PhpProject22_CSRF\profile.php on line 12
<?php
session_start();
require_once 'Classes/Token.php';
$tk = new Token();
if(isset($_POST['username'],$_POST['product'],$_POST['token'])){
$username = $_POST['username'];
$product = $_POST['product'];
if(!empty($product) && !empty($username)){
if(Token::check($_POST['token'])){
echo $_POST['token'].'<br>';
$tk->get('username');
$_SESSION['user'] = $tk->name();
echo 'Process Order';
}
}
}
?>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>CSRF Protection</title>
</head>
<body>
<form action="" method="POST">
<div class="product">
<strong>Profile</strong>
<div class='field'>
Username: <input type='text' name='username'>
</div>
<input type='submit' value='Order'>
<input type='hidden' name='product' value='1'>
<input type='hidden' name='token' value='<?php echo Token::generate();?>'>
</div>
</form>
<?php
if(isset($_POST['username'])){
?>
<p>Hello <a href = 'profile.php?user=<?php echo $tk->name();?>'><?php echo $tk- >name();?></a>!</p>
<?php
}
?>
</body>
</html>
<?php
class Token{
private $_data;
public static function generate(){
return $_SESSION['token'] = base64_encode(openssl_random_pseudo_bytes(32));
}
public static function check($token){
if(isset($_SESSION['token']) && $token === $_SESSION['token']){
unset($_SESSION['token']);
return true;
}
return false;
}
public function get($item){
if(isset($_POST[$item])){
$this->_data = $_POST[$item];
}
}
public function name(){
return $this->_data;
}
}
?>
<?php
require_once 'Classes/Token.php';
session_start();
?>
<form action="" method="POST">
<input type='hidden' name='token' value='<?php echo Token::generate();?>'>
</form>
<?php
echo 'Hello '.$_SESSION['user'].'!<br>';
if(isset($_GET['user'])){
if(Token::check($_POST['token'])){
echo $_GET['user'];
}
}
?>
275
asked Feb 21 '26 13:02
When checking post you need to do the following:
if($_POST){
if(isset($_POST['token']) && Token::check($_POST['token']){
code
}else{
error
}
}
If someone spoof the post, and doesn't include the token, you're going to get an undefined index error, because $_POST['token'] doesn't exist and you are referencing it.
88
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