IntraForum Input Validation Flaw Permits Cross-Site Scripting Attacks
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SecurityTracker Alert ID: 1008839 |
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SecurityTracker URL: http://securitytracker.com/id/1008839
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CVE Reference:
GENERIC-MAP-NOMATCH
(Links to External Site)
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Date: Jan 25 2004
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Impact:
Disclosure of authentication information, Disclosure of user information, Execution of arbitrary code via network, Modification of user information
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Exploit Included: Yes
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Description:
Rafel Ivgi (The-Insider) reported a vulnerability in IntraForum. A remote user can conduct cross-site scripting attacks.
It is reported that the 'intraforum.cgi' script does not properly filter HTML code from user-supplied input in the 'use_last_read' and 'forum' variables. A remote user can create a specially crafted URL that, when loaded by a target user, will cause arbitrary scripting code to be executed by the target user's browser. The code will originate from the site running the IntraForum software and will run in the security context of that site. As a result, the code will be able to access the target user's cookies (including authentication cookies), if any, associated with the site, access data recently submitted by the target user via web form to the site, or take actions on the site acting as the target user.
Some demonstration exploit URLs are provided:
http://[target]/cgi-bin/forumsdb/intraforum_db.cgi?forum=<script>alert('sda')<
/script>&read=&alias=&redir_flag=true
http://[target]/cgi-bin/forumsdb/intraforum_db.cgi?forum=7940&alias=dbr&read=0
00965-000964&session=FFFF&use_last_read="><script>alert('XSS')</script>
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Impact:
A remote user can access the target user's cookies (including authentication cookies), if any, associated with the site running the IntraForum software, access data recently submitted by the target user via web form to the site, or take actions on the site acting as the target user.
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Solution:
No solution was available at the time of this entry.
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Vendor URL: diburim.co.il/ (Links to External Site)
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Cause:
Input validation error
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Message History:
None.
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Source Message Contents
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Subject: Inrtra Forum Cross Site Scripting Vulnerabillity
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Software: Inrtra Forum (Perl CGI)
Vendor: http://www.diburim.co.il/
Versions: Single version was created
Bug: Cross Site Scripting Vulnerabillity
Risk: Low
Exploitation: Remote with browser
Date: 24 Jan 2004
Author: Rafel Ivgi, The-Insider
E-Mail: the_insider@mail.com
Web: http://theinsider.deep-ice.com
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1) Introduction
2) Bug
3) The Code
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
===============
1) Introduction
===============
Inrtra Forum is israel's most common free/paid forum service provider.
Forum as important as this cannot have risks such as Cross Site Scripting.
Any attacker can fake messages, and betray the trust of all the people who
belive that links involved with this forum are safe.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
======
2) Bug
======
The Vulnerabillity is Cross Site Scripting.
The vulnerable form fields are "use_last_read" and "forum".
If an attacker will request the following url from the server:
http://<host>/cgi-bin/forumsdb/intraforum_db.cgi?forum=<script>alert('sda')<
/script>&read=&alias=&redir_flag=true
Or
http://<host>/cgi-bin/forumsdb/intraforum_db.cgi?forum=7940&alias=dbr&read=0
00965-000964&session=FFFF&use_last_read="><script>alert('XSS')</script>
XSS appears and the server allows an attacker to inject & execute scripts.
In the words of securityfocus.com :
~~~~~~~~~~~~~~~~~~~~~~~~~~
If all of these circumstances are met, an attacker may be able to exploit
this issue
via a malicious link containing arbitrary HTML and script code as part of
the hostname.
When the malicious link is clicked by an unsuspecting user, the
attacker-supplied HTML
and script code will be executed by their web client. This will occur
because the server
will echo back the malicious hostname supplied in the client's request,
without sufficiently
escaping HTML and script code.
Attacks of this nature may make it possible for attackers to manipulate web
content or to
steal cookie-based authentication credentials. It may be possible to take
arbitrary actions as the victim user.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
===========
3) The Code
===========
Live Example:
http://www4.diburim.co.il/cgi-bin/forumsdb/intraforum_db.cgi?forum=<script>a
lert('XSS')</script>&read=&alias=&redir_flag=true
Code:
http://<host>/cgi-bin/forumsdb/intraforum_db.cgi?forum=7940&alias=dbr&read=0
00965-000964&session=FFFF&use_last_read="><script>alert('XSS')</script>
http://<host>/cgi-bin/forumsdb/intraforum_db.cgi?forum=<script>alert('XSS')<
/script>&read=&alias=&redir_flag=true
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
---
Rafel Ivgi, The-Insider
http://theinsider.deep-ice.com
"Things that are unlikeable, are NOT impossible."
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