==========================================================================================
 BlastChat Chat Client Component version 3.3 <= Cross Script Scripting
(XSS) Vulnerability
==========================================================================================


1. OVERVIEW

The BlastChat's chat client Component of Joomla 1.x, Joomla 1.5.x,
Mambo 4.5, Mambo 4.6, Drupal 6
was vulnerable to Cross Script Scripting (XSS) Vulnerability.


2. PRODUCT DESCRIPTION

The BlastChat Chat Client Component is a widely-used Blastchat chat
client component designed for website communities
from the smallest personal websites to the huge megasites who desire
to provide their members and visitors
with a superb chat experience. The client chat component is available
in multiple CMSes including
Joomla 1.x, Joomla 1.5.x, Mambo 4.5, Mambo 4.6, and Drupal 6.
BlastChat has currently been serving chat to over 50.000+ websites.


3. VULNERABILITY DESCRIPTION

The BlastChat's chat client Component does not properly escape
"Itemid" parameter, which leads to Cross Site Scripting vulnerability.
For more information about this kind of vulnerability, see OWASP Top
10 - A2, WASC-8 and CWE-79: Improper Neutralization of Input During
Web Page Generation ('Cross-site Scripting').


4. VERSIONS AFFECTED

Versions: 3.3 and lower


5. PROOF-OF-CONCEPT/EXPLOIT

URL: /index.php?option=com_blastchatc&Itemid=-999
Affected Parameter: Itemid

http://yehg.net/lab/pr0js/advisories/joomla/com_blastchatc_xss(Itemid).jpg


6. IMPACT

As this is a multi-user chat application "component", the impact of
XSS is huge, ranking from cookie theft to mass client exploits.


7. SOLUTION

Upgrade to version 3.4


8. VENDOR

Blastchat
http://www.blastchat.com


9. CREDIT

This vulnerability was discovered by Aung Khant, http://yehg.net, YGN
Ethical Hacker Group, Myanmar.


10. DISCLOSURE TIME-LINE

08-11-2010: discovered vulnerability
08-11-2010: notified vendor
08-11-2010: vendor fixed vulnerability
08-14-2010: vendor released patched version - 3.4
08-26-2010: vulnerability disclosed


11. REFERENCES

Original Advisory URL:
http://yehg.net/lab/pr0js/advisories/joomla/[com_blastchatc]_cross_site_scripting
What XSS Can Do: http://yehg.net/lab/pr0js/view.php/What%20XSS%20Can%20Do.pdf
XSS FAQs: http://www.cgisecurity.com/articles/xss-faq.shtml
XSS (wiki): http://en.wikipedia.org/wiki/Cross-site_scripting
XSS (owasp): http://www.owasp.org/index.php/Cross-site_Scripting_(XSS)
OWASP Top 10: http://www.owasp.org/index.php/Category:OWASP_Top_Ten_Project
CWE-79: http://cwe.mitre.org/data/definitions/79.html

#yehg [08-26-2010]

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Best regards,
YGN Ethical Hacker Group
Yangon, Myanmar
http://yehg.net
Our Lab | http://yehg.net/lab
Our Directory | http://yehg.net/hwd