Vulnerabilities in PHP-Nuke 6.x - 7.2

New Member Joined: Oct 23, 2003 Posts: 24

I found in the SecurityFocus Bugtrag supposed vulnerabilities in the versions 6.x to the 7.2

User-level authentication bypass in phpnuke 6.x-7.2
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Admin-level authentication bypass in phpnuke 6.x-7.2
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The last one I imagine that it is solved with the Chatserv's fix in admin.php or it is not thus Question

Site Admin/Owner Joined: Aug 27, 2002 Posts: 17088

This still revolves around the UNION exploit. Just install my hackattempt script and you are safe Wink

Posted: Tue Apr 13, 2004 12:33 am

Thanks, I have installed it in my Web and everything seems to work well.

Posted: Tue Apr 13, 2004 7:09 am

If you use PHP-Nuke Patched you don't need to worry about either, else if you don't and don't wish to for whatever reason use Raven's Hack Alert script to block all UNION exploits, then make the following changes:
admin.php, below the file credits add:

Code:

if(stristr($_SERVER["QUERY_STRING"],'AddAuthor') || stristr($_SERVER["QUERY_STRING"],'UpdateAuthor')) {


die("Illegal Operation");


}

If using Hack Alert make that code:

Code:

if (stristr($_SERVER["QUERY_STRING"],'AddAuthor') || stristr($_SERVER["QUERY_STRING"],'UpdateAuthor')) header("Location: hackattempt.php");

auth.php, find:

Code:

  $admin = base64_decode($admin);

Before add:

Code:

  $admin = addslashes($admin);

mainfile.php, find:

Code:

   $admin = base64_decode($admin);

before add:

Code:

   $admin = addslashes($admin);

also find:

Code:

   $user = base64_decode($user);

before add:

Code:

   $user = addslashes($user);

Posted: Wed Apr 14, 2004 11:37 am

Important update: [ Only registered users can see links on this board! Get registered or login! ]
Patches were updated today, version remains as 2.3 though.

Posted: Sat Apr 17, 2004 12:32 pm

The variable '$aid' in authors.php also is vulnerable? because I have listened that also is weakness in the treatment of that variable. Exclamation

Posted: Sat Apr 17, 2004 9:39 pm

Other hole:

PHP-Nuke CookieDecode Cross-Site Scripting Vulnerability
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Posted: Sat Apr 17, 2004 10:05 pm

Try this from the PostNuke playbook if an official patch isn't available?
Where you able to do anything with the proof of concept?
Honestly I think this is a little far fetched for most people to worry about.
Maybe on the gamer networks or a genuine ecommerce site but...

Anyway there is a slight performance decrease with adding this blanket filter.
Do I do it yes.

In mainfile.php after the other sec filters add this:

Code:




if (isset($_COOKIE)) {


              foreach (($_COOKIE) as $secvalue) {


               if ((eregi("<[^>]*script.*\"?[^>]*>", $secvalue)) ||


                    (eregi(".*[[:space:]](or|and)[[:space:]].*(=|like).*", $secvalue)) ||


                    (eregi("<[^>]*object.*\"?[^>]*>", $secvalue)) ||


                    (eregi("<[^>]*iframe.*\"?[^>]*>", $secvalue)) ||


                    (eregi("<[^>]*applet.*\"?[^>]*>", $secvalue)) ||


                    (eregi("<[^>]*meta.*\"?[^>]*>", $secvalue)) ||


                    (eregi("<[^>]*style.*\"?[^>]*>", $secvalue)) ||


                    (eregi("<[^>]*form.*\"?[^>]*>", $secvalue)) ||


                    (eregi("<[^>]*window.*\"?[^>]*>", $secvalue)) ||


                    (eregi("<[^>]*alert.*\"?[^>]*>", $secvalue)) ||


                    (eregi("<[^>]*document.*\"?[^>]*>", $secvalue)) ||


                    (eregi("<[^>]*cookie.*\"?[^>]*>", $secvalue)) ||


                    (eregi("<[^>]*img.*\"?[^>]*>", $secvalue))) {


                    echo("Forbidden Cookie... Stop Trying To Tamper With This Site!");  


                  exit; 


                   }


              }


        }

Just paste that in right before:

if (eregi("mainfile.php",$_SERVER['PHP_SELF'])) {
Header("Location: index.php");
die();
}

Posted: Sat Apr 17, 2004 10:17 pm

Actually this doesn't address that specific vulnerability either. Grr! But this is another lol!

Posted: Sat Apr 17, 2004 10:25 pm

Then again after reading the full exploit I think it would.

Here is the details

{================================================================================}
{ [waraxe-2004-SA#016] }
{================================================================================}
{ }
{ [ Cross-Site Scripting aka XSS in phpnuke 6.x-7.2 part 3 ] }
{ }
{================================================================================}

Author: Janek Vind "waraxe"
Date: 12. April 2004
Location: Estonia, Tartu
Web: [ Only registered users can see links on this board! Get registered or login! ]

Affected software description:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Php-Nuke is popular freeware content management system, written in php by
Francisco Burzi. This CMS (Content Management System) is used on many thousands
websites, because it`s free of charge, easy to install and has broad set of features.

Homepage: [ Only registered users can see links on this board! Get registered or login! ]

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

Here I am, on the road again, discussing about potential XSS case in phpnuke.
"AGAIN?". Yes, coz phpnuke is surprisingly generous software for finding different
security holes Wink

This XSS case is active, when website uses some specific nuke themes - for example generic
themes "Karate", "Anagram", "Kaput", "Milo", "NukeNews" and many other derivations and
custom themes. By the way, security issues here are phpnuke engine related, not theme related.

Let's be more specific. There is a function in nuke engine, called cookiedecode().
From mainfile.php:

function cookiedecode($user) {
global $cookie, $prefix, $db, $user_prefix;

$user = base64_decode($user);
$cookie = explode(":", $user);
$sql = "SELECT user_password FROM ".$user_prefix."_users WHERE username='$cookie[1]'";
$result = $db->sql_query($sql);
$row = $db->sql_fetchrow($result);
$pass = $row[user_password];
if ($cookie[2] == $pass && $pass != "") {
return $cookie;
} else {
unset($user);
unset($cookie);
}

As we can see, variable $user (from $_COOKIE[], $_GET[] or $_POST[]) gets base64 decoded and then
exploded to array $cookie. Then the code will ask from database the password md5 hash and if retrieved
password matches with browser supplied password, then function returns the array $cookie[] and next
phpnuke theme.php will use this valid username (it's checked in cookidecode) for visual feedback,
for example - "welcome, $username".
So, it seems, that we can't spoof username here, coz we can't fool the checking routine (we dont consider here
sql injection , coz it will be used in my next advisory Wink

). This is, what
code programmer was thinking, but reality is different...

From php manual:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
unset

(PHP 3, PHP 4)
unset -- Unset a given variable

Description
void unset ( mixed var [, mixed var [, ...]])

unset() destroys the specified variables. Note that in PHP 3, unset() will always return TRUE (actually,
the integer value 1). In PHP 4, however, unset() is no longer a true function: it is now a statement.
As such no value is returned, and attempting to take the value of unset() results in a parse error.

The behavior of unset() inside of a function can vary depending on what type of variable you are attempting to destroy.
If a globalized variable is unset() inside of a function, only the local variable is destroyed.
The variable in the calling environment will retain the same value as before unset() was called.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
So, this little code in function cookiedecode():
} else {
unset($user);
unset($cookie);
}
will destroy the array $cookie[] only IN LOCAL CONTEXT, but in global scope it will be UNDESTROYED!

Ok, now let's issue request like this
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to the phpnuke enabled website, using vulnerable themes. And we can see, that XSS works!
What's inside of the "user"? If we base64_decode this variable, we see this:

1:<script>alert(document.cookie);</script>foobar

So, in this way, we can exploit XSS and evade all contrameasures in phpnuke, set up against scripting tags etc.

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

Greets to torufoorum members and to all bugtraq readers in Estonia! Tervitused!
Special greets to Stefano from UT Bee Clan!

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

come2waraxe_yahoo_DOT_com
Janek Vind "waraxe"

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---------------------------------- [ EOF ] ------------------------------------

Posted: Tue Apr 20, 2004 1:29 pm

SQL injection in Private_Messages Module
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Exploit: [ Only registered users can see links on this board! Get registered or login! ]

Exclamation

Posted: Tue Apr 20, 2004 1:41 pm

Been working with this for several hours. I have not been able to reproduce the results, at least in 7.2. In the future you might want to start contacting us via PM with these things to not give the kiddies more to play with Wink

Posted: Tue Apr 20, 2004 1:46 pm

I haven't either but I tried a little too. Wonder if wasn't in reference to the phpbb 2.08 and 2.08a updates? Technically I spose the listed versions weren't patched yet?

Posted: Tue Apr 20, 2004 1:51 pm

Well there are a couple more that I and Chat have reviewed and the proposed solution should work. I have mixed feelings about exposing.