Merb devel - Aug 2007 - Cookie Sessions in Merb?

I like the cookie sessions that Rails edge has - they make sense,
they''re fast, easy.

For those that don''t know: the default session mechanism is to give
developers a Hash called session. To store this object between
requests it Marshals the session object and sends the object itself
(now as a bitstream) back to clients to store in their cookie file. To
prevent users from tampering with this data, a cryptographic digest
(using HMAC with SHA-1) is sent along with the bitstream).

The major problem with this scheme is that the Marshalled data is not
at all encrypted! Users are free to unmarshal and examine what
websites are storing in their sessions. They cannot change the data,
but nevertheless this is a security problem!

The answers given by the rails developers sound rather
na?ve:
> This is getting into very difficult crypto. Basically, depending on the
cipher, there
> may be cases where you can change one part of the text without changing the
other.
Not that I know much about cryptography, but I''m almost certain that
modifying AES encrypted Marshaled data is quite tamper proof. If not,
one could at least send a digest along with it.

There has been some mention of the extra AES operation slowing down
speed (but it''s been said it''s not much of a slowdown), I
think having
secure cookies would be well worth the cost.

Is there interest in this type of session for Merb?
Related: I''ve just wrote a CookieJar class - perhaps it would be
useful for Merb?
http://rubyforge.org/pipermail/mongrel-users/2007-August/003890.html

ry

Yeah I''d be interested in a cookie store. But th security concerns are
valid so we would need to investigate thouroughly

Ezra

Sent from my iPhone

On Aug 17, 2007, at 10:08 AM, "ry dahl" <ry at tinyclouds.org>
wrote:
> I like the cookie sessions that Rails edge has - they make sense,
> they''re fast, easy.
>
> For those that don''t know: the default session mechanism is to
give
> developers a Hash called session. To store this object between
> requests it Marshals the session object and sends the object itself
> (now as a bitstream) back to clients to store in their cookie file. To
> prevent users from tampering with this data, a cryptographic digest
> (using HMAC with SHA-1) is sent along with the bitstream).
>
> The major problem with this scheme is that the Marshalled data is not
> at all encrypted! Users are free to unmarshal and examine what
> websites are storing in their sessions. They cannot change the data,
> but nevertheless this is a security problem!
>
> The answers given by the rails developers sound rather na?ve:
>> This is getting into very difficult crypto. Basically, depending on  
>> the cipher, there
>> may be cases where you can change one part of the text without  
>> changing the other.
> Not that I know much about cryptography, but I''m almost certain
that
> modifying AES encrypted Marshaled data is quite tamper proof. If not,
> one could at least send a digest along with it.
>
> There has been some mention of the extra AES operation slowing down
> speed (but it''s been said it''s not much of a slowdown), I
think having
> secure cookies would be well worth the cost.
>
> Is there interest in this type of session for Merb?
> Related: I''ve just wrote a CookieJar class - perhaps it would be
> useful for Merb?
> http://rubyforge.org/pipermail/mongrel-users/2007-August/003890.html
>
> ry
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> Merb-devel at rubyforge.org
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