Securing 'pickle'

[Paul Rubin]

Re: Securing 'pickle'

Nagy László Zsolt <nagylzs@freema il.hu> writes:[color=blue][color=green]
> >Or is the checksum stored on the server, in some form of lookup
> >dictionary keyed by some user session identifier?
> >[/color]
> I think he wanted to write a digital signature instead. Right?[/color]

I used "cryptograp hic checksum" in a broad sense. More specifically
the suggestion is to use a secret-key authentication code like HMAC-MD5.

[Ian Bicking]

Re: Securing 'pickle'

On Fri, 2003-07-11 at 10:00, John J. Lee wrote:[color=blue]
> Ian Bicking <ianb@colorstud y.com> writes:
> [...][color=green]
> > Security isn't a big deal -- or rather, securing cookies isn't a big
> > deal.[/color]
>
> I don't understand. The problem is that pickles can be constructed
> that can damage systems when unpickled, is that right? If that's
> true, then surely unpickling cookie data is unsafe, because stuff
> coming in from the network has to be regarded as malevolent. Are you
> saying that web server environments are sufficiently-well bolted down
> that no pickle attack will work? But belt-and-braces is the best
> policy, isn't it?[/color]

I should have said "securing cookies isn't hard", so that's not the
reason not to use them (though you shouldn't just use plain-vanilla
cookies).

Ian

[Paul Rubin]

Re: Securing 'pickle'

Ian Bicking <ianb@colorstud y.com> writes:[color=blue]
> I should have said "securing cookies isn't hard", so that's not the
> reason not to use them (though you shouldn't just use plain-vanilla
> cookies).[/color]

The signature scheme we've discussed does cause some configuration
hassle. There has to be a host-specific secret key and it has to be
kept secret. If it leaks to an attacker, the attacker can then create
malicious cookies. So the scheme has to be used with care.