oss-sec mailing list archives
Re: can we talk about secure time?
From: Walter Parker <walterp () gmail com>
Date: Sun, 21 Dec 2014 23:27:19 -0800
On Sun, Dec 21, 2014 at 10:39 PM, Hanno Böck <hanno () hboeck de> wrote:
On Sun, 21 Dec 2014 23:30:10 -0700 Kurt Seifried <kseifried () redhat com> wrote:Having to reconcile multiple logs/events across widely distributed systems, especially in high volume situations, 1-2 seconds is a deal breaker. Or people running SCADA systems for industrial plants. Or people that run financial systems.I don't think this contradicts my statement that average consumer hw doesn't need the high accuracy of ntp :-) This is something that I don't want to see in the Linux/xBSD world. A
split made between the software that the "average consumer" uses and the software that prosumers and professionals use for basic system services like timekeeping. We should all be be using the good stuff...
From what has been said so far, there appears to be two sides:
One that points out that security in ntp is week therefore MITM attacks can be done. So the idea is to remove ntp and replace it something else, which would be using the time field in TLS transactions. Most arguments seem to come from the assuming the TLS servers are secure and have the correct time. Nothing has be said about how well the TLS servers would work as time servers The other points out that ntp is a time protocol that specializes in getting and keeping time correct. It is designed to allow time to be set with high level of precision and accuracy (milliseconds on regular systems, microseconds when it really matters). Has there been any studies on the quality of TLS for a timeserver? From comments, to me, it looks like the TLS side is rationalizing the 1 second limit on TLS because they want want to use TLS as is, without further researching/refining the topic. If we are going to build a secure time protocol, the timekeeping piece is at least as important as the security piece.
So it's not an either/or situation (care about security, or have accurate time, sometimes we need both).Yeah, I totally agree that this would be the desired thing to have. However the facts are that at the moment we don't. And imho for consumer HW the slight inaccuracy of tlsdate doesn't matter, while the insecurity of ntp does (as the very practical hsts attack has shown). I read these days that the Linux foundation is sponsoring some work on NTP. Anyone involved in this and can comment whether secure authentication for NTP is something that's being looked at or if it is only about creating a better implementation of the ntp software?
Given there are 100's of millions of NTP clients in the field right now, where would we get the trusted TLS servers to use as time servers. We can't trust the web server that we are trying to connect to, as if it is a MITM attack, it could also have bad time. Walter -- The greatest dangers to liberty lurk in insidious encroachment by men of zeal, well-meaning but without understanding. -- Justice Louis D. Brandeis
Current thread:
- Re: can we talk about secure time?, (continued)
- Re: can we talk about secure time? ncl () cock li (Dec 20)
- Re: can we talk about secure time? Daniel Micay (Dec 20)
- Re: can we talk about secure time? Florian Weimer (Dec 21)
- Re: can we talk about secure time? Daniel Micay (Dec 21)
- Re: can we talk about secure time? Dave Horsfall (Dec 21)
- leap seconds and security [was: Re: can we talk about secure time?] Daniel Kahn Gillmor (Dec 21)
- Re: can we talk about secure time? Florian Weimer (Dec 21)
- Re: can we talk about secure time? Hanno Böck (Dec 21)
- Re: can we talk about secure time? Kurt Seifried (Dec 21)
- Re: can we talk about secure time? Hanno Böck (Dec 21)
- Re: can we talk about secure time? Walter Parker (Dec 21)
- Re: can we talk about secure time? John Haxby (Dec 22)
- Re: can we talk about secure time? Dave Horsfall (Dec 22)
- Re: can we talk about secure time? Richard Johnson (Dec 25)
- Re: can we talk about secure time? ncl () cock li (Dec 20)