Re: [Ntp] NTP Security (was NTPv5: big picture)

[Miroslav Lichvar <[e-mail]>]

On Tue, Jan 19, 2021 at 01:15:57PM +0000, FUSTE Emmanuel wrote:
> Le 19/01/2021 à 14:04, Miroslav Lichvar a écrit :
> >
> > In this process you have only verified consistency of the time and
> > other data you have received. It was valid some time ago, but it may
> > not be valid now. If the attacker captured all that data, it can be
> > reused later in a MITM attack.
> How ???
> - If it replay my DNS data fine, it will do the work of my DNS servers 
> for me as he could not resign.
> - For the NTS part you are saying that TLS and NTS are subject to MITM 
> attacks ?

Yes, the attacker has the old private key.

The assumption is that both your DNSSEC and NTS was compromised at
some point. You found out and rebuilt your infrastructure from
scratch, but the attacker can still perform a MITM attack on your
device if it doesn't know the current date in order to validate the
certificate/records.

-- 
Miroslav Lichvar