oss-sec mailing list archives

Re: CVE requests: MediaWiki 1.22.3, 1.21.6 and 1.19.12 release


From: "Vincent Danen" <vdanen () redhat com>
Date: Fri, 28 Feb 2014 11:55:02 -0700

Seems odd to be asking these questions without asking someone from the MediaWiki team involved (I doubt they are 
subscribed to oss-sec).  Given that Murray just posting what was written by upstream and even asked "if CVE worthy" I 
doubt he has the answers you're looking for.  =)

I've cc'd Markus Glaser to this as he sent out the notification to the mediawiki-announce list so he may have the 
insight you're looking for.


On 02/28/2014, at 11:26 AM, cve-assign () mitre org wrote:

Some of this seems straightforward and we will send CVE assignments a
little later. Our first question is about the UploadBase.php diff in:

https://gerrit.wikimedia.org/r/#/q/7d923a6b53f7fbcb0cbc3a19797d741bf6f440eb,n,z

Our first thought is that it might be best to have separate CVEs for
"Disallow uploading non-whitelisted namespaces" and "disallow iframe
elements" because they are distinct types of problems. The first one
seems similar to what is discussed in:

http://en.wikipedia.org/wiki/User:Aarchiba/SVG_sanitizer

The first CVE would, roughly, have a root cause of "does not recognize
that a trust relationship with a specific external site is reasonably
required for use of a namespace." The second CVE would, roughly, have
a root cause of "does not block IFRAME elements."

Does anyone have an opposing view: for example, that adding the
hardcoded $validNamespaces list can't be interpreted as a "normal"
vulnerability fix? Across all products, adding a list of off-site URLs
maintained by various third parties is rarely the essence of a
security patch.

(As a side issue, SVG_sanitizer allows
http://www.w3.org/XML/1998/namespace but the patched UploadBase.php
does not.)


Our second question is about
https://bugzilla.wikimedia.org/show_bug.cgi?id=61346 Comment 9. Do all
valid tokens have the same length, and thus an attacker (if he looked
at the source code) would already know that the wrong-length attempts
would always fail?

If not, a separate CVE would be needed on the basis of different
affected versions.

(This question is only about MediaWiki as shipped. If a system
administrator would need to modify the source code to use a different
length, and an attacker could detect that more easily because of
'strlen( $answer ) !== strlen( $test )' tests, that doesn't qualify
for a CVE.)

- --
CVE assignment team, MITRE CVE Numbering Authority
M/S M300
202 Burlington Road, Bedford, MA 01730 USA
[ PGP key available through http://cve.mitre.org/cve/request_id.html ]


-- 
Vincent Danen / Red Hat Security Response Team

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