GNUBoard 4.33.02 - 'tp.php' PATH_INFO SQL Injection

# Exploit Title: Gnuboard <= 4.33.02 PATH_INFO SQL INJECTION Vulnerability

# Google Dork: inurl:gnuboard4/bbs/board.php

# Date: 2011-2-14

# Author: flyh4t

# Software Link: http://sir.co.kr/main/gnuboard4/

# Version: Gnuboard <= 4.33.02

# Tested on: linux+apache

# CVE : CVE-2011-4066





Gnuboard <= 4.33.02 PATH_INFO SQL INJECTION Vulnerability

---------------------------------

Bug found By Flyh4t & alpha.liu

mail:

flyh4t phpsec@hotmail.com

alpha  alpha@patching.net

Site:bbs.wolvez.org

---------------------------------

SIR GNUBoard(http://sir.co.kr) is a widely used bulletin board system of Korea.  

It is freely available for all platforms that supports PHP and MySQL.  

But we find a SQL INJECTION affects SIR GNUBoard version 4.33.02 

The codes can be download here

http://sir.co.kr/main/gnuboard4/

Here is the Vulnerability code in /bbs/tb.php

 

-----------------------vul code-------------------

//bbs/tb.php

$arr = explode("/", $_SERVER[PATH_INFO]);

//$_SERVER[PATH_INFO] is not affected by the magic_quotes_gpc set of php

//we can inject arbitrary sql code include single quotes through $_SERVER[PATH_INFO] 

$bo_table = $arr[1];

$wr_id = $arr[2];

$to_token = $arr[3];

//we can pass arbitrary sql code to $bo_table 

$write_table   = $g4[write_prefix] . $bo_table;

// $write_table can be injected through $bo_table

$sql = " select wr_id, ca_name, wr_email from $write_table where wr_id = '$wr_id' ";

//here $write_table lead to sql injection,and no need of  single quotes

$wr = sql_fetch($sql, FALSE);

if (!$wr[wr_id] || !($_POST[title] && $_POST[excerpt] && $_POST[url] && $_POST[blog_name])) 

{

    $tmp_dir = str_replace("/tb.php", "", $_SERVER[SCRIPT_NAME]);

    header("location:$tmp_dir/board.php?bo_table=$bo_table&wr_id=$wr_id");

    exit;

}

-----------------------vul code end-------------------



-----------------------poc------------------------

bbs/tb.php/[sql]/[sql]

--------------------------------------------------