27th Jan 2003 [SBWID-5953]
COMMAND
Multiple Cross Site Scripting Vulnerabilities in Nuked-Klan
SYSTEMS AFFECTED
Nuked-Klan beta 1.2 and prior
PROBLEM
Grégory Le Bras aka GaLiaRePt [http://www.Security-Corp.org], in
Security Corporation Security Advisory [SCSA-003] :
http://www.security-corp.org/index.php?ink=4-15-1
French Version : http://www.security-corp.org/advisories/SCSA-003-FR.txt
DETAILS & EXPLOITS
________________________________________________________________________
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
________________________________________________________________________
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
________________________________________________________________________
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
________________________________________________________________________
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);
?>
--------------------------------------------
SOLUTION
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