nanog mailing list archives

Re: UDP/123 policers & status


From: Harlan Stenn <stenn () nwtime org>
Date: Sat, 28 Mar 2020 16:35:06 -0700

Ragnar,

On 3/28/2020 4:09 PM, Ragnar Sundblad wrote:

On 28 Mar 2020, at 23:58, Harlan Stenn <stenn () nwtime org> wrote:

Steven Sommars said:
The secure time transfer of NTS was designed to avoid
   amplification attacks.

Uh, no.

Yes, it was.

As Steven said, “The secure time transfer of NTS was designed to
avoid amplification attacks”. I would even say - to make it
impossible to use for amplification attacks.

Please tell me how.  I've been part of this specific topic since the
original NTS spec.  For what y'all are saying to be true, there are some
underlying assumptions that would need to be in place, and they are
clearly not in place now and won't be until people update their
software, and even better, tweak their configs.

If you understand what's going on from the perspective of both the
client and the server and think about the various cases, I think you'll
see what I mean.

Hopefully, no-one exposes mode 6 or mode 7 on the internet anymore
at least not unauthenticated, and at least not the commands that are
not safe from amplification attacks. Those just can not be allowed
to be used anonymously.

But mode 6/7 is completely independent of NTS.

It's disingenuous for people to imply otherwise.

NTS is a task-specific hammer.

Yes.

Ragnar

-- 
Harlan Stenn <stenn () nwtime org>
http://networktimefoundation.org - be a member!


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