[Full-disclosure] Serendipity Freetag-plugin XSS vulnerability

2008-02-1300:00:00

vulners.com

JSON

Advisory: Serendipity Freetag-plugin XSS vulnerability
Application: Serendipity Freetag-plugin =< 2.95
Category: Web application
Class: Cross Site Scripting (XSS)
Release date: 08. February 2008
Last updated: 08. February 2008
Remote: Yes
Local: No
CVE: Not yet assigned
Credits: Alexander Brachmann ([email protected])
Author of advisory: Alexander Brachmann ([email protected])
Severity: An XSS flaw was discovered in the optional Freetag-plugin
for Serendipity (popular weblog application). E.g., this could lead to a
hijacked Serendipity account.
Risk: High
Vendor/Project/Programmer(s): Garvin Hicking, Jonathan Arkell, Grischa
Brockhaus
Solution status: The programmers have fixed this flaw in Freetag
version 2.96.
References:
[1]
http://blog.s9y.org/archives/190-Freetag-plugin-updated-to-prevent-XSS.html
[2] http://www.bitsploit.de/uploads/Code/200802080000/
[3] http://www.bitsploit.de/uploads/Bilder/200802101012/s9y-xss.jpg
Overview:
Quote from www.s9y.org:
"Serendipity is a PHP-powered weblog application which gives the user an
easy way to maintain an online diary, weblog or even a complete
homepage. While the default package is designed for the casual blogger,
Serendipity offers a flexible, expandable and easy-to-use framework with
the power for professional applications.
Casual users appreciate the way Serendipity's sophisticated plugin
architecture allows you to easily modify both the appearance of your
blog and its features.
You can install more than 120 plugins with just one click, instantly
enhancing your blog's functionality."

While testing Serendipity an XSS flaw was discovered in the optional
plugin for tagging entries called "Freetag". For example, this could
lead to a hijacked Serendipity account.

Details:
The Freetag-plugin displays the tag name, specified in a URL, back to
the user.
Due to a defective sanitization of the user's input, it is possible to
inject arbitrary code which will be reflected on the website.
Proof of Concept (PoC):
URL:
http://www.example.com/plugin/tag/%3Cdiv%20style=width:expression(alert(document.cookie));%3E
Hint: PoC does currently work in Microsoft Internet Explorer 6,
Microsoft Internet Explorer 7 and Netscape Navigator 8.1+ (in Internet
Explorer rendering mode) only.
Solution:
We strongly recommend you to upgrade to Freetag version 2.96 which fixes
this flaw.
URL:
http://spartacus.s9y.org/cvs/additional_plugins/serendipity_event_freetag.zip
Disclosure timeline:

February 2008 - Flaw was discovered and re-checked.
February 2008 - Programmers have been notified. (Due to responsible
disclosure.)
February 2008 - Fix was committed.
February 2008 - Freetag 2.96 released to the public.
February 2008 - Public disclosure.

GPG:
E-Mail: [email protected]
Public key: http://www.bitsploit.de/gpg/domains/public_key.asc
Key ID: 0x75093340
Key Fingerprint: D542 669B 02F8 7874 F75A A44C AA0B 41FC 7509 3340
Copyright:
Creative Commons - by - Version 3.0
URL: http://creativecommons.org/licenses/by/3.0/deed.en

Full-Disclosure - We believe in it.
Charter: http://lists.grok.org.uk/full-disclosure-charter.html
Hosted and sponsored by Secunia - http://secunia.com/

JSON