Rails - Aug 2006 - DHH''s Post on Ruby Talk -- Rails 1.1.6: Stronger fix, backports, and full disclosure

The cat is out of the bag, so here''s the full disclosure edition of
the current security vulnerability. With Rails 1.1.0 through 1.1.5
(minus the short-lived 1.1.3), you can trigger the evaluation of Ruby
code through the URL because of a bug in the routing code of Rails.
This means that you can essentially take down a Rails process by
starting something like /script/profiler, as the code will run for a
long time and that process will be hung while it happens. Other URLs
can even cause data loss.

We''ve backported a fix to all the affected versions for those of you
that can''t update. You''ll have to apply the diff for your
version:

* Patch for Rails 1.1.0:
http://www.rubyonrails.org/files/aug_10_security/rel_1-1-0.diff
* Patch for Rails 1.1.1:
http://www.rubyonrails.org/files/aug_10_security/rel_1-1-1.diff
* Patch for Rails 1.1.2:
http://www.rubyonrails.org/files/aug_10_security/rel_1-1-2.diff
* Patch for Rails 1.1.4:
http://www.rubyonrails.org/files/aug_10_security/rel_1-1-4.diff
* Patch for Rails 1.1.5: Upgrade to Rails 1.1.6.

These patches (and 1.1.6) will break applications using the 3rd party
engines idea. So if you can''t upgrade because of dependencies to
those, you can also add the following URL blocking while engines are
being updated. Here''s how to do it with mod_rewrite under Apache:

RewriteRule  
^(app|components|config|db|doc|lib|log|public|script|test|tmp|vendor)/
- [F]

Here''s how to do it under lighttpd:

url.rewrite-once = (
"^/(app|components|config|db|doc|lib|log|public|script|test|tmp|vendor)/"
=> "index.html" )

Unfortunately, the 1.1.5 update from yesterday only partly closed the
hole (getting rid of the worst data loss trigger). After learning more
about the extent of the problem, we''ve now put together a 1.1.6
release that completely closes all elements of the hole (using the
same technique as the backports above).

So if you upgraded to 1.1.5 yesterday, you need to upgrade again. The
approach stays the same:

  sudo gem install rails --include-dependencies

If you''re running of trunk (also known as edge) using revision 4394 or
later, you''re not affected by all this in any form.

We''ll follow up with more information as it becomes available.
Needless to say, this is all the Rails core team is working on right
now and we''ve recruited a whole band of testers to help us play this
out. We''ll make sure to evaluate all the feedback that''s been
coming
in and develop a policy for dealing with security issues in the
future. Thanks for your continued understanding.

We''ve also started #rails-security on Freenet for people with IRC
available to get and share more information.

If you''re floating on gems (don''t have vendor/rails), then
make sure
you update RAILS_GEM_VERSION in your config/environment.rb. Otherwise
you''ll still be bound to that earlier version of Rails even as you
install the new gems.


We continue to update http://weblog.rubyonrails.org/ with the latest
information as it becomes available.
--
David Heinemeier Hansson
http://www.loudthinking.com -- Broadcasting Brain
http://www.basecamphq.com -- Online project management
http://www.backpackit.com -- Personal information manager
http://www.rubyonrails.com -- Web-application framework


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