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Bekijk Volledige Versie : CSS found in Movable Type



DarkHunter
12/05/03, 22:05
Summary:
Movable Type is a decentralized web-based personal publishing system
designed to ease maintenance of regularly-updated content. This content
can consist of, but is not limited to, entries in a weblog or online
journal, photographs in an online photo gallery, news headlines on a
newspaper site, or articles in an online magazine.

Details:
Vendor's site: www.movabletype.org

Vulnerable systems:
Movable Type version 2.63 and prior.

Cross Site Scripting Vulnerability found in writing the comments, in the
Comments section there is sevral textboxs:
Name, Email Address, URL and Comments.
and all the textboxs allow using the javascript codes.
in order to causes a CSS attack on the target site we need to write a
javascript code in the Name textbox (in some versions u can write the
javascript code in the other textboxs of the Comments).

Examples:
You can use this javascripts codes:
<script>alert(document.cookie)</script>
<script>alert("CSS discovered by DarkHunter")</script>
"DarkHunter><script> .. (This code is so bad :) .. it causes disappering
of all the Comments textboxs and buttons .. in other words every thing
after this code will disapper).
and of course there are many codes that u can use.


Solution:
Edit the source code to strip malicious characters from Name, Email
Address, URL and Comments textboxs or escape malicious characters using
addslashes().
check the vendor's website for new patches.


Additional information:
The information has been provided by DarkHunter.

Jordan Wiens
12/05/03, 22:20
I just tried it on an installed 2.63 MT and was unable to get the XSS to
work. Tried the javascript samples in Name, email, homepage, and comment
field, all with no success. MT properly elminated < > tags and left the
&lt; as &lt, not allowing any execution.

--
Jordan Wiens
UF Network Incident Response Team
(352)392-2061

On Mon, 12 May 2003, DarkHunter wrote:

> Summary:
> Movable Type is a decentralized web-based personal publishing system
> designed to ease maintenance of regularly-updated content. This content
> can consist of, but is not limited to, entries in a weblog or online
> journal, photographs in an online photo gallery, news headlines on a
> newspaper site, or articles in an online magazine.
>
> Details:
> Vendor's site: www.movabletype.org
>
> Vulnerable systems:
> Movable Type version 2.63 and prior.
....
> Examples:
> You can use this javascripts codes:
> &lt;script&gt;alert(document.cookie)&lt;/script&gt;

Jordan Wiens
13/05/03, 00:05
After taking a bit closer look at it, it appears that this is likely
result of the option:

"Allow HTML in comments?"
(Select Weblog Config / Preferences, scroll towards the bottom)

The default is for that option to be disabled.

Additionally, perusing the mt.cfg file yields the following:

# By default, Movable Type cleans up ("sanitizes") any data submitted by
# visitors to your site. This is done to remove any code (HTML or otherwise)
# that could compromise the security of your site. The sanitization code works
# by only allowing certain HTML tags--any other tags, and all processing
# instructions (PHP, for example) are stripped. The GlobalSanitizeSpec
# setting, then, specifies the tags and attributes that are allowed. The
# default setting is "a href,b,br/,p,strong,em,ul,li,blockquote".
#
# GlobalSanitizeSpec br/,p

It seems that only by changing those two options could an installation be
vulnerable to javascript cross-site scripting, though I could be wrong.

--
Jordan Wiens
UF Network Incident Response Team
(352)392-2061

On Mon, 12 May 2003, Jordan Wiens wrote:

> I just tried it on an installed 2.63 MT and was unable to get the XSS to
> work. Tried the javascript samples in Name, email, homepage, and comment
> field, all with no success. MT properly elminated < > tags and left the
> &lt; as &lt, not allowing any execution.
>
>

13/05/03, 00:20
In-Reply-To: <20030512182659.16940.qmail@www.securityfocus.com>

Regarding the potential XSS vulnerability discussed in
DarkHunter's message, Movable Type was updated to prevent this
possible exploit on February 13, with the release of version 2.6 of
the sofware. In addition, all of our users were alerted to the
potential of a security issue and urged to update to the newer
version. Our current version is 2.63, downloadable at http://
www.movabletype.org, and it prevents this exploit by default, as
noted by Jordan Wiens in his follow-up message.