Bugtraq mailing list archives

IPB v2.x up to 3.0.4 XSS vulnerability

From: Xacker <old.good.xacker () gmail com>
Date: Wed, 9 Dec 2009 09:50:13 +0200

[+] Invision Power Board XSS vulnerability

        Software : Invision Power Board (IPB)
        Affected : IPB v2.x up to v3.0.4 (prior versions might be vulnerable as well)
        Remote   : Yes
        Required : Internet Explorer +5.0
        Vendor   : http://www.invisionpower.com/
        Download : Commercially available
        Author   : Xacker
        Contact  : N/A
        Blog     : http://xacker.wordpress.com
        Website  : N/A


[+] Technical details

        IP.Board is prone to XSS attacks through maliciously crafted *.txt
files attachments. An attacker has to convince a user to view the
malicious file in order to run the evil code.

        The only browser found affected is Internet Explorer +5.0, other
browsers (FF/Chrome/Opera..) seems to handle the issue correctly (or
simply blindly?)

        IP.Board v2.x set the MIME-type of *.txt files to
(application/x-dirview). If the *.txt file contains JavaScript/HTML it
will simply be parsed on IE +5.

        IP.Board v3.0.4 (and prior) seems to check the content of the files
before permitting them, tags like "<body> , <script> , etc.." are
flagged *dangerous* any file containing any of them simply fail to be
uploaded. The filter itself is weak, to escape it I provide a
proof-of-concept code below.


[+] Exploit

        --------------------------------->8---------------------------------
        <span onmouseover="javascript:alert('XSS');function
fakeLoginPage(){...}">move your mouse pointer here</span>
        ---------------------------------8<---------------------------------

        fakeLoginPage() function can be used to rewrite the whole page,
faking a login page through an embedded iframe.


[+] Fix

        Simply change MIME-type of *.txt files (and any other similar
formats) to (text/plain).


[+] Note

        IP.Board technical staff has been notified of the issue and a fix has
been released couple of days ago:
        http://community.invisionpower.com/topic/300051-invision-power-board-305-released/

Current thread:

IPB v2.x up to 3.0.4 XSS vulnerability Xacker (Dec 09)
- <Possible follow-ups>
- Re: IPB v2.x up to 3.0.4 XSS vulnerability MustLive (Dec 14)