[Ruby on Rails] [CVE-2014-3514] Strong Parameter bypass with create_with

[Rafael Mendonça França]

There is a vulnerability in the create_with method in Active Record. This vulnerability has been assigned the CVE identifier CVE-2014-3514.

Versions Affected:  4.0.0 and All Later Versions.

Not affected:       Versions earlier than 4.0.0

Fixed Versions:     4.0.9 4.1.5

Impact

------

The create_with functionality in Active Record was implemented incorrectly and completely bypasses the strong parameters protection.  Applications which pass user-controlled values to create_with could allow attackers to set arbitrary attributes on models.

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

Releases

--------

The 4.0.9 and 4.1.5 releases are available at the normal locations.

Workarounds

-----------

To avoid this vulnerability you will have to either remove all calls to create_with, or carefully audit your codebase to ensure it sanitizes the input first.  For example you should replace code like this:

  user.blog_posts.create_with(params[:blog_post]).create

with either:

  user.blog_posts.create(params[:blog_post])

or:

  user.blog_posts.create_with(params[:blog_post].permit(:title, :body, :etc)).create

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.

* 4-1-create_with.patch - Patch for 4.1 series

* 4-0-create_with.patch - Patch for 4.0 series

Please note that only the 4.0.x and 4.1.x series receive regular security updates at present.  Users of earlier unsupported releases are advised to upgrade as soon as possible as we cannot guarantee the continued availability of security fixes for earlier releases.

Credits

-------

Thanks to Stephen Touset of Square for reporting the vulnerability to us, and to Jeff Jarmoc of Matasano and Charlie Somerville of GitHub for helping verify the patches and advisories.

Rafael Mendonça França
http://twitter.com/rafaelfranca
https://github.com/rafaelfranca

[Rafael Mendonça França]

These are the attached patches.

Rafael Mendonça França
http://twitter.com/rafaelfranca
https://github.com/rafaelfranca