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Re: [Ntp] Details of the fragmentation attacks against NTP and port randomization

Warner Losh <imp@bsdimp.com> Wed, 05 June 2019 02:53 UTC

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From: Warner Losh <imp@bsdimp.com>
Date: Tue, 04 Jun 2019 20:53:03 -0600
Message-ID: <CANCZdfqYzqeKeKykSdGh1k74jNegSVNhFFo-eWRHA_RNASJbEw@mail.gmail.com>
To: Ask Bjørn Hansen <ask@develooper.com>
Cc: Danny Mayer <mayer@pdmconsulting.net>, NTP WG <ntp@ietf.org>
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Subject: Re: [Ntp] Details of the fragmentation attacks against NTP and port randomization
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On Tue, Jun 4, 2019, 8:45 PM Ask Bjørn Hansen <ask@develooper.com> wrote:

>
>
> On Jun 5, 2019, at 10:41 AM, Danny Mayer <mayer@pdmconsulting.net> wrote:
>
> Furthermore the attacker doesn't know the server being used by the NTP
> client so the IP address of that server will be invalid as well.
>
>
> This doesn’t seem right. There are much much less NTP servers in the world
> than there are clients. Even an attacker wildly guessing will have a
> limited scope of guessing (versus “every possible IP”).
>

Also, the time isn't a random 64 bit number, also limiting the domain to
search, no?

Warner


> Ask
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> ntp@ietf.org
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