Re: [Ntp] Antw: Re: Antw: Re: New rev of the NTP port randomization I-D (Fwd: New Version Notification for draft-gont-ntp-port-randomization-01.txt)
"Ulrich Windl" <Ulrich.Windl@rz.uni-regensburg.de> Wed, 29 May 2019 10:13 UTC
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Date: Wed, 29 May 2019 12:13:45 +0200
From: Ulrich Windl <Ulrich.Windl@rz.uni-regensburg.de>
To: "ntp@ietf.org" <ntp@ietf.org>, stenn@nwtime.org
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Subject: Re: [Ntp] Antw: Re: Antw: Re: New rev of the NTP port randomization I-D (Fwd: New Version Notification for draft-gont-ntp-port-randomization-01.txt)
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>>> Harlan Stenn <stenn@nwtime.org> schrieb am 29.05.2019 um 12:02 in Nachricht <92e2c1f9-a745-c182-6194-c7ce819c8a3c@nwtime.org>: [...] > That also assumes the client has the correct time. If somebody is using > SNTP, this assumption may be wrong, and the client's time could well be > off by much more. At 33 bits, we're talking about 2 seconds. If the > client might be off by 4-8 minutes then we're talking about 41 bits. Do you really think someone planning to attack NTP will start with a clock that is minutes off the correct time? > >>> >>> And remember that: >>> >>> - the window of time where an attack is possible starts when the client >>> sends its request, and ends when a valid response is received. >> >> An attacker will probably "spray" attacking packets. > > OK, so what? Low end normal machines might handle 2k packets/second, > and low end slow machines are lucky to be able to handle 200 packets per > second. It there a difference between the client being overloaded with attack packets that are "wrong" or attack packets that are "correct"? I was arguing that "enough packets" could easily be created, while you argue the client can't handle them. > >>> - a competent client will log bogus responses, at least during this >>> window, and if the client is NTP as opposed to SNTP, will log >>> *any* bogus received packets. >> >> The point is whether logging unexpected packets actually opens a DoS > windows. > > That's something logging systems can reasonably be expected to handle, > and it's also reasonable to assume that if somebody goes to the trouble > to log these events they're also alerting on them. Yeah: Filesystem full ;-) [...]
- [Ntp] New rev of the NTP port randomization I-D (… Fernando Gont
- Re: [Ntp] New rev of the NTP port randomization I… Danny Mayer
- Re: [Ntp] New rev of the NTP port randomization I… Fernando Gont
- Re: [Ntp] New rev of the NTP port randomization I… Gary E. Miller
- Re: [Ntp] New rev of the NTP port randomization I… Fernando Gont
- Re: [Ntp] New rev of the NTP port randomization I… Majdi S. Abbas
- Re: [Ntp] New rev of the NTP port randomization I… Fernando Gont
- Re: [Ntp] New rev of the NTP port randomization I… Fernando Gont
- Re: [Ntp] New rev of the NTP port randomization I… Harlan Stenn
- Re: [Ntp] New rev of the NTP port randomization I… Harlan Stenn
- Re: [Ntp] New rev of the NTP port randomization I… tglassey@earthlink.net
- Re: [Ntp] New rev of the NTP port randomization I… tglassey@earthlink.net
- Re: [Ntp] New rev of the NTP port randomization I… Harlan Stenn
- Re: [Ntp] New rev of the NTP port randomization I… Harlan Stenn
- Re: [Ntp] New rev of the NTP port randomization I… Fernando Gont
- Re: [Ntp] New rev of the NTP port randomization I… Fernando Gont
- Re: [Ntp] New rev of the NTP port randomization I… Fernando Gont
- Re: [Ntp] New rev of the NTP port randomization I… Fernando Gont
- Re: [Ntp] New rev of the NTP port randomization I… Miroslav Lichvar
- Re: [Ntp] New rev of the NTP port randomization I… Harlan Stenn
- Re: [Ntp] New rev of the NTP port randomization I… Fernando Gont
- Re: [Ntp] New rev of the NTP port randomization I… Danny Mayer
- Re: [Ntp] New rev of the NTP port randomization I… Danny Mayer
- Re: [Ntp] New rev of the NTP port randomization I… Danny Mayer
- [Ntp] Antw: Re: New rev of the NTP port randomiza… Ulrich Windl
- [Ntp] Antw: Re: New rev of the NTP port randomiza… Ulrich Windl
- Re: [Ntp] New rev of the NTP port randomization I… Harlan Stenn
- Re: [Ntp] New rev of the NTP port randomization I… Fernando Gont
- Re: [Ntp] Antw: Re: New rev of the NTP port rando… Harlan Stenn
- Re: [Ntp] New rev of the NTP port randomization I… Fernando Gont
- Re: [Ntp] Antw: Re: New rev of the NTP port rando… Miroslav Lichvar
- Re: [Ntp] New rev of the NTP port randomization I… Harlan Stenn
- Re: [Ntp] Antw: Re: Antw: Re: New rev of the NTP … Ulrich Windl
- Re: [Ntp] Antw: Re: New rev of the NTP port rando… Harlan Stenn
- Re: [Ntp] Antw: Re: Antw: Re: New rev of the NTP … Harlan Stenn
- Re: [Ntp] Antw: Re: Antw: Re: New rev of the NTP … Hal Murray
- Re: [Ntp] Antw: Re: Antw: Re: New rev of the NTP … Harlan Stenn
- Re: [Ntp] New rev of the NTP port randomization I… tglassey@earthlink.net
- Re: [Ntp] New rev of the NTP port randomization I… tglassey@earthlink.net
- Re: [Ntp] Antw: Re: Antw: Re: New rev of the NTP … Hal Murray
- Re: [Ntp] New rev of the NTP port randomization I… Danny Mayer
- Re: [Ntp] New rev of the NTP port randomization I… Fernando Gont
- Re: [Ntp] New rev of the NTP port randomization I… Harlan Stenn
- Re: [Ntp] New rev of the NTP port randomization I… Fernando Gont
- Re: [Ntp] New rev of the NTP port randomization I… Fernando Gont
- Re: [Ntp] New rev of the NTP port randomization I… Watson Ladd
- Re: [Ntp] New rev of the NTP port randomization I… Ask Bjørn Hansen
- Re: [Ntp] Antw: Re: Antw: Re: New rev of the NTP … tglassey@earthlink.net
- Re: [Ntp] New rev of the NTP port randomization I… Fernando Gont
- Re: [Ntp] New rev of the NTP port randomization I… Fernando Gont
- [Ntp] Antw: Re: New rev of the NTP port randomiza… Ulrich Windl
- Re: [Ntp] New rev of the NTP port randomization I… Miroslav Lichvar
- Re: [Ntp] New rev of the NTP port randomization I… Fernando Gont
- Re: [Ntp] New rev of the NTP port randomization I… Harlan Stenn
- Re: [Ntp] Antw: Re: Antw: Re: New rev of the NTP … Tony Finch
- [Ntp] New rev of the NTP port randomization I-D (… Loganaden Velvindron
- Re: [Ntp] New rev of the NTP port randomization I… Fernando Gont
- Re: [Ntp] New rev of the NTP port randomization I… Aanchal Malhotra