[SA23669] Movable Type "nofollow" Plugin Comment Script Insertion

TITLE:
Movable Type "nofollow" Plugin Comment Script Insertion

SECUNIA ADVISORY ID:
SA23669

VERIFY ADVISORY:
http://secunia.com/advisories/23669/

CRITICAL:
Less critical

IMPACT:
Cross Site Scripting

WHERE:
>From remote

SOFTWARE:
Movable Type 3.x
http://secunia.com/product/5753/

DESCRIPTION:
A vulnerability has been discovered in Movable Type, which can be
exploited by malicious people to conduct cross-site scripting
attacks.

Input passed in the "Comments" form field when posting comments to
blog entries is not properly sanitised before being stored. This can
be exploited to insert arbitrary HTML and script code, which is then
executed in a user's browser session in context of an affected site
when the comment is viewed.

Successful exploitation requires that the "nofollow" plugin is
disabled, which is not its default state, and that "Immediately
publish comments from" is set to a value such that the comment does
not require moderation.

The vulnerability is confirmed in version 3.33. Other versions may
also be affected.

SOLUTION:
Enable the "nofollow" plugin.

Fixed in version 3.34b1.

PROVIDED AND/OR DISCOVERED BY:
Mike Stay, Jacques Distler and Zack Ajmal

ORIGINAL ADVISORY:
Jacques Distler:
http://golem.ph.utexas.edu/~distler/blog/archives/001102.html

Zack Ajmal:
http://www.zackvision.com/weblog/2007/01/movabletype-security-bug.html

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