[erlang-questions] Erlang cookies are secure

[Serge Aleynikov]

I guess it's worth mentioning in the current thread that the present
architecture only supports one distributed protocol in a node at a time.
So using TLS for some nodes over Internet would require all nodes in a
cluster to use TLS, which is a waste of resources and additional latency
for nodes located in the same local network not involving Internet.

I'd love to see some progress by the OTP team in flexing this requirement,
since the patch I submitted a while back that introduced support for
distribution over multiple protocols was not accepted (*).

Serge

(*) http://erlang.org/pipermail/erlang-patches/2014-January/004522.html

On Fri, Jun 10, 2016 at 4:10 PM, Per Hedeland <per@REDACTED> wrote:

> Tony Rogvall <tony@REDACTED> wrote:
> >
> >I am not sure what you mean by sniff cookies?
> >
> >The distribution has been sending blank cookies since first open source
> release.
> >The distribution do not send the cookie in clear text but rely on a MD5
> challenge procedure
> >at connection setup.
>
> Hi Tony!
>
> Indeed - and I will take credit for pestering you to fix that just
> before the first open source release:-) (I will not divulge what it did
> before that...).
>
> >So Erlang is more likely to be vulnerable to connection hijacking since
> not every message
> >is signed.
>
> Yes - the *default* distribution fulfills none of the CIA requirements
> (no, not that evil US thing, but Confidentiality, Integrity, and
> Availability). But this has nothing to do with the authentication
> mechanism as such, and can be fixed by using TLS - which also brings one
> or more other authentication mechanisms, but they are not in any
> fundamental sense more "secure" than the cookie authentication.
>
> >So keep the nodes safe and away from random users. At least until we get
> Safe Erlang ( any decade now )
>
> Sure - but this point is actually also confusing in a cookie discussion,
> as shown by other messages in this thread - it is about the
> *authorization* you automatically get at the point when you have managed
> to break the authentication mechanism - i.e. basically you can do
> "anything". But this is independent of the strength of the
> authentication mechanism itself.
>
> I do find it rather tiresome with this constant ridicule of the cookie
> authentication from people who haven't even bothered to do a basic
> investigation of how it works, let alone done any actual security
> analysis.
>
> And just to put another myth to death, no, you are not required to use
> the same cookie on all your distributed erlang nodes - every node is
> capable of maintaining a specific cookie for every other node, RTFM
> erlang:set_cookie/2.
>
> It is absolutely true that *maintaining* security in a network with
> cookie-based authentication can be troublesome, and that e.g. TLS with
> certificate authentication can do much better in that respect, as long
> as you have mechanisms for certificate revocation properly set up (which
> in turn is not entirely trivial to do).
>
> But again, as long as you do not throw your cookies around, AFAIK no-one
> has demonstrated any fundamental weakness with the mechanism as such.
>
> --Per
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