Re: Rails and redirections

[Brandon Perry <bperry.volatile () gmail com>]

I agree, an exception is the correct behavior.


On Thu, Mar 6, 2014 at 2:10 PM, Timothy Goddard <tim () goddard net nz> wrote:

> Very interesting, could cause issues. It can't use the value and not
> substitute - that's worse. Have seen response splitting in mod_perl because
> it outputs raw strings in to location headers. In my view it should raise
> an exception if not a valid URI.
>
>
> Sent from Samsung Mobile
>
>
>
> -------- Original message --------
> From: Brandon Perry <bperry.volatile () gmail com>
> Date:
> To: full-disclosure () lists grok org uk
> Subject: [Full-disclosure] Rails and redirections
>
>
>
> Currently, passing \0, \r, or \n into a URL that is passed to redirect_to
> has Rails gsub'ing them out of the URL before completing the redirect.
>
> A programmer that doesn't realise this is happening could easily write a
> regex and logic that says "if url starts with https:// or http:// fail or
> else redirect_to url".
>
> Seems straighforward, but an attacker could simply pass in a url like
> \nhttp://www.google.com and bypass the regex check and be redirected to
> google.com.
>
> The line effecting this is line 106 in redirecting.rb in Rails.
>
>
> https://github.com/rails/rails/blob/3-2-stable/actionpack/lib/action_controller/metal/redirecting.rb#L106
>
> I feel like this is something that Rails should not be doing on behalf of
> the programmer. The programmer should be expected to pass in exactly what
> they want redirected to without Rails changing their data. Should this be
> considered a vulnerability?
>
> Thoughts?
>
> --
> http://volatile-minds.blogspot.com -- blog
> http://www.volatileminds.net -- website



-- 
http://volatile-minds.blogspot.com -- blog
http://www.volatileminds.net -- website

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