Tails

#1 Updated by ioerror 2014-07-27 14:40:55

intrigeri wrote:
> As discussed in the “Risks of enabled/disabled TCP timestamps?” thread on tails-dev, we might want to disable TCP timestamps just to be on the safe side, but stating exactly what kind of attacks this would protect against is not that clear.

OK.

>
> As intrigeri put it:
>
> > I’m still not convinced we can put statements as bold as “tracking the
> > clock down to the millisecond” in there, without thinking a bit about
> > how an attacker is affected by the network lag between the time a TCP
> > timestamp was created, and the time when they get to see the packet.
> >

I think we should say something like the following:
“TCP time stamps allow for tracking clock information with millisecond resolution. This may or may not allow an attacker to learn information about the system clock at such a resolution, depending on various issues such as network lag.”

> > I mean, I’m weak at stats and all and you probably know better, but
> > learning that “some unknown time ago, the system clock was T with
> > a millisecond precision” does not really give me the current system
> > clock with a millisecond precision, does it?
>
> Hence, marking as a research task to start with, and we can turn it into a documentation one once we’ve got the needed data.

I think that it leaks that information and that is clear - I don’t think we need to try to model the attacks in depth at this point. Does what I wrote above provide enough for us to ship the changes?