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Date: Sat, 26 Jan 2013 15:13:13 -0500
From: Andrew Nacin <nacin@...dpress.org>
To: Kurt Seifried <kseifried@...hat.com>
Cc: oss-security@...ts.openwall.com, Henri Salo <henri@...v.fi>, 
	WordPress Security Team <security@...dpress.org>
Subject: Re: CVE request: WordPress 3.5.1 Maintenance and
 Security Release

On Sat, Jan 26, 2013 at 2:19 AM, Kurt Seifried <kseifried@...hat.com> wrote:

> > - A server-side request forgery vulnerability and remote port
> > scanning using pingbacks. This vulnerability, which could
> > potentially be used to expose information and compromise a site,
> > affects all previous WordPress versions. This was fixed by the
> > WordPress security team. We’d like to thank security researchers
> > Gennady Kovshenin and Ryan Dewhurst for reviewing our work.
>
> Basically it applies filters to pingbacks, things like:
>
> return new IXR_Error(33, __('The specified target URL cannot be used
> as a target. It either doesn't exist, or it is not a pingback-enabled
> resource.')); so I was largely abl to confirm this one.


The primary fix is to better validate a URL before triggering an HTTP
request to it. You can see this with the filter and function
pingback_ping_source_uri in http://core.trac.wordpress.org/changeset/23330.
It blocks credentials, odd ports, RFC1918 IPs, etc. Turning the error
messages into generic errors was an additional defensive measure but due to
the other fixes, does not address a particular vulnerability.

What these fixes target have already been written about publicly:
http://www.acunetix.com/blog/web-security-zone/wordpress-pingback-vulnerability/
http://lab.onsec.ru/2013/01/wordpress-xmlrpc-pingback-additional.html

> - Two instances of cross-site scripting via shortcodes and post
> > content. These issues were discovered by Jon Cave of the WordPress
> > security team.
>

I found one instance of esc_attr() to esc_url() on a url used in
> embedded media, I'm guessing this is the XSS mentioned in the
> description as "post content"?
>

That was one — http://core.trac.wordpress.org/changeset/23322. The other
was http://core.trac.wordpress.org/changeset/23317, which serves to fully
validate HTML tags passed to a shortcode and reject exploitative values.

All I'm seeing for shortcodes related junk is in a big JavaScript blob
> wp-35/wp-includes/js/media-editor.min.js. It looks like this might
> need two CVEs if they are widely different.
>

The changes in media-editor.min.js are bug fixes and not related to
security. They may be seen in uncompressed form here:
http://core.trac.wordpress.org/changeset?old_path=%2Ftags%2F3.5%2Fwp-includes%2Fjs%2Fmedia-editor.js&new_path=%2Ftags%2F3.5.1%2Fwp-includes%2Fjs%2Fmedia-editor.js
.

> - A cross-site scripting vulnerability in the external library
> > Plupload. Thanks to the Moxiecode team for working with us on this,
> > and for releasing Plupload 1.5.5 to address this issue.


> The diff for plupload is a mess of JavaScript/binary files so I can't
> confirm much.
>

The security fix was specific to the Flash binary. Here is the upstream
commit: https://github.com/moxiecode/plupload/commit/2d746ee. Exploit
occurs with uplupload.flash.js?id=XSS, using the attack described here:
http://lcamtuf.blogspot.se/2011/03/other-reason-to-beware-of.html.

Regards,
Andrew Nacin

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