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Re: Security of BGP Re: Status of the 16-bit AS Number space

2009-05-12 12:45:12
On Tue, 12 May 2009 09:25:07 -0400
Phillip Hallam-Baker <hallam(_at_)gmail(_dot_)com> wrote:

Looks to me that we have an obscurity based 'security' system going
on there.

Everyone in the business understands that there is a routing security
problem.  There is some disagreement about the magnitude of the threat,
and hence about how much one should spend on defense (as opposed to
cleaning up afterwards), but there is no disagreement that there is a
problem.

On the other hand, none of the previous proposals solves it properly;
all of the proposed solutions have their own serious flaws.


At RSA there was a presentation on security holes in IPSEC and SSH. In
the IPSEC case the response 'from the IETF' (i.e. from a well known
individual speaking on his own behalf) was that the security issues
with using IPSEC without authentication were well known and that this
is not new. To which the reply came, well why did you continue to make
support for encryption only mandatory?

Your writing here is unclear.  I assume you mean that current IPsec
standards support encryption-only without authentication.  I agree --
that was a bad decision by the WG.  It was not done blindly, or in
ignorance of the attacks.  The case was made that there are some
situations (video over IP with per-connection keying, for example), when
the attacks are inapplicable and the costs are high.  The WG was
persuaded that this need overrode the potential for misuse.  As I said,
I did and do disagree.


There is unfortunately a naive view that we can solve the BGP security
issue by simply sprinkling some IPSEC pixie dust on it.

I've been working on routing security for >20 years.  I've never heard
*anyone* competent suggest IPsec for this problem.  Next straw man,
please?

I think that
view is based on a profound misunderstanding of what is possible with
a packet layer security protocol. Key agreement and crypto-packaging
are trivial problems that can be solved by a moderately competent grad
student. The hard part is the problem that IPSEC never solved, how to
establish the trust context. And once you look at that problem you
soon realize that IPSEC is the wrong tool entirely as the routing
problem requires you to take an accountability approach which in turn
requires you to work at the message level.

        `May the day not be too long delayed,' said Boromir. 'For
        though I do not ask for aid, we need it.  It would comfort us to
        know that others fought also with all the means that they
        have.'

        `Then be comforted,' said Elrond. `For there are other
        powers and realms that you know not, and they are hidden from
        you.  Anduin the Great flows past many shores, ere it comes to
        Argonath and the Gates of Gondor.'

                        Tolkien, "Lord of the Rings"

There are many people still trying to figure out how to solve this
one.  It's a hard problem.

                --Steve Bellovin, http://www.cs.columbia.edu/~smb
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