> On Oct 21, 2019, at 3:25 PM, Brandon Martin <lists.na...@monmotha.net> wrote:
>
> On 10/21/19 11:30 AM, Keith Medcalf wrote:
>> Why cannot one just put the MD5 authenticated connection inside a TLS
>> connection? What is the advantage to be gained by replacing the
>> authentication mechanism with weaker certificate authentication method
>> available with TLS?
>
> Self-issued certificates with either CA pinning or end-certificate hash
> pinning is arguably more secure than a shared passphrase as used by TCP-MD5
> in that someone with knowledge of the secrets of one end cannot use it to
> impersonate the other end whereas a shared passphrase is inherently shared
> and symmetric in that respect. Whether that really provides much value in
> the context of a BGP session is perhaps questionable.
Considering a lot of hand-wringing from the various security conscious folk is
over the ability to easily re-key, I think it mostly just complicates things.
Certs are effectively a much nicer single use key. Exactly how the cert
lifetime interacts with peering sessions is likely to be several flavors of
ugly.
>
> Wouldn't ipsec be a "cleaner" solution to this (buginess of implementations
> and difficulty of configuration aside)? It would also solve the TCP-RST
> injection issues that TCP-MD5 was intended to resolve. You can use null
> encryption with ESP or even just AH if you want authentication without
> confidentiality, too. Or are we all going to admit that ipsec is almost dead
> in that it's just too darned complex? Just run BGP over TCP as normal and
> install a security policy that says it must use ipsec with appropriate
> (agreed-upon) authentication. "Just", right?
BGP over ipsec works fine. But that said, it's mostly done with pre-shared
keys.
The ugly issue of ipsec is that the ecosystem really wants IKE to do the good
things people associate with long lived sessions. I don't even vaguely pretend
to be an ipsec/ike expert, but the wrangling over this and router bootstrapping
issues generated a lot of heat and a small amount of light in IETF a while back.
And if you have a rather scaled out router, imagine the cpu melting that goes
with a cold startup scenario where you have to get all of those IKE sessions up
to start up your BGP. Now think what that does to your restart time.
-- Jeff
