[SCSA-003] Multiple Cross Site Scripting Vulnerabilities in Nuked-Klan

[Grégory Le Bras | Security Corporation <gregory.lebras () security-corp org>]

.: Multiple Cross Site Scripting Vulnerabilities in Nuked-Klan :.

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Security Corporation Security Advisory [SCSA-003]
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PROGRAM: Nuked-Klan
HOMEPAGE: http://www.nuked-klan.org
VULNERABLE VERSIONS: beta 1.2 and prior
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DESCRIPTION
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Nuked Klan is a PHP Gateway for "clans". (direct quote from Nuked Klan
website)


DETAILS & EXPLOITS
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Many Cross-Site Scripting vulnerabilities have been found in Nuked Klan
which allow attackers to inject script codes into the page and use them on
clients browser as if they were provided by the site.


These Cross-Site Scripting vulnerabilities are found in the following
modules : Guestbook, Forum, Shoutbox.

An attacker can input specially crafted links and/or other malicious
scripts.


Guestbook
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A vulnerability was discovered in the page for posting messages, at this
adress :

http://[target]/index.php?file=Guestbook&req=post_book


The vulnerability is at the level of the interpretation of the "Author"
field.

Indeed, the insertion of a hostile code script in this field makes it
possible to a malicious user to carry out this script on the navigator of
the visitors.


The hostile code could be :

[script]alert("Cookie="+document.cookie)[/script]

(open a window with the cookie of the visitor.)

(replace [] by <>)



Forum
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A vulnerability was discovered in the page for posting new messages in the
forum, at this adress :

http://[target]/index.php?file=Forum&op=post_screen&forum_id=0

The vulnerability is at the level of the interpretation of the "Titre" and
"Pseudo" field.

Indeed, the insertion of a hostile code script in this field makes it
possible to a malicious user to carry out this script on the navigator of
the visitors.

The hostile code could be :

[script]alert("Cookie="+document.cookie)[/script]

(open a window with the cookie of the visitor.)

(replace [] by <>)



Shoutbox
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A vulnerability was discovered in the page for posting messages in "La
Tribune Libre".

Indeed, the insertion of a hostile code script in this field makes it
possible to a malicious user to carry out this script on the navigator of
the visitors.

The hostile code could be :

[script]alert("Cookie="+document.cookie)[/script]

(open a window with the cookie of the visitor.)

(replace [] by <>)


-------Vulnerable line in submit.php--------

$shout = str_replace("|","",$SB_text);

--------------------------------------------


Possible solutions: modify the code in order to analyze the whole of the
text sent by the user and to replace the hostile elements.


---------------Code example-----------------
<?
$SB_text = str_replace("<", "[", $SB_text);
$SB_text = str_replace(">", "]", $SB_text);
$SB_text = htmlentities($SB_text);
$shout = str_replace("|","",$SB_text);
?>
--------------------------------------------


SOLUTIONS
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Upgrade your version to beta 1.3


Upgrade Guestbook with the appropriate patch :
http://tomysnockers.net/download/Guestbook.rar

Upgrade Shoutbox with the appropriate patch :
http://www.nuked-klan.org/files/Shoutbox_13.zip



VENDOR STATUS
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The vendor has reportedly been notified.


LINKS
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http://www.security-corp.org/index.php?ink=4-15-1




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Grégory Le Bras aka GaLiaRePt | http://www.Security-Corp.org
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