[AMENDED] [CVE-2014-7819] Arbitrary file existence disclosure in Sprockets

[Aaron Patterson]

I've updated this advisory to include the correct version numbers in the
"Fixed Versions" section.

Arbitrary file existence disclosure in Sprockets

There is an information leak vulnerability in Sprockets. This vulnerability
has been assigned the CVE identifier CVE-2014-7819.

Versions Affected: ALL
Not affected: NONE
Fixed Versions: 3.0.0.beta.3, 2.12.3, 2.11.3, 2.10.2, 2.9.4, 2.8.3, 2.7.1, 2.5.1, 2.4.6, 2.3.3, 2.2.3, 2.1.4, 2.0.5

Impact
------
Specially crafted requests can be used to determine whether a file exists on
the filesystem that is outside an application's root directory. The files will not be served, but attackers can determine whether or not the file exists.

All users running an affected release should either upgrade or use one of the work arounds immediately.

Releases
--------
The 2.12.X releases are available at the normal locations.

Workarounds
-----------
In Rails applications, work around this issue, set config.serve_static_assets = false in an initializer. This work around will not be possible in all hosting environments and upgrading is advised.

Patches
-------
To aid users who aren't able to upgrade immediately we have provided patches for the two supported release series. They are in git-am format and consist of a single changeset.

* 2-12-sec-static-files.patch - Patch for the 2.12.x release series

Credits
-------

This vulnerability was reported by multiple researchers working independently. Thanks to each of them for reporting the issue to us and verifying the fixes.

* Eaden McKee
* Dennis Hackethal & Christian Hansen of Crowdcurity
* Juan C. Müller & Mike McClurg of Greenhouse.io
* Alex Ianus of Coinbase

--
Aaron Patterson
http://tenderlovemaking.com/