[MajorSecurity SA-081]Contao CMS 2.9.2 - Persistent Cross Site Scripting Issue

Details

Product: Contao CMS 2.9.2
Security-Risk: moderated
Remote-Exploit: yes
Vendor-URL: http://www.contao.org/
Advisory-Status: published

Credits

Discovered by: David Vieira-Kurz

Affected Products:

Contao CMS 2.9.2
Prior versions may also be vulnerable

Description

"Contao is an open source content management system (CMS) for people who want a
professional internet presence that is easy to maintain." - from www.contao.org

More Details

I have discovered some vulnerabilities in Contao CMS 2.9.2, which can be exploited
by malicious people to conduct persistent cross-site scripting attacks. Input
passed directly over the "HTTP_X_FORWARDED_FOR" header in
"/system/libraries/Environment.php" is not properly sanitised before being stored
and returned to the user out from the "/system/modules/comments/Comments.php" file
when the user browses the "/contao/main.php?do=comments" site. This can be
exploited to execute arbitrary HTML and script code in a user's browser session in
context of an affected site.

Solution

Update to the patched version 2.9.3.

Timeline

2010-12-24, vendor informed ( see ticket 2751 )
2011-01-01, vendor confirmed the issue
2011-01-06, vendor relased a patched version(2.9.3)
2011-01-12, advisory published

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