Packet Timing and Data Leaks

Chris Rapier
Tue, 08 Aug 2023 02:05:03 -0000

Sorry for top posting but I'm on my phone. My colleague just sent me this.
https://www.theregister.com/2023/08/07/audio_keystroke_security/

I don't know how relevant this is as of yet but based on a quick reading it
seems related.

So I fully support this work. If there is anything I can do please let me
know.

On Mon, Aug 7, 2023, 18:30 Damien Miller <djm at mindrot.org> wrote:

> On Mon, 7 Aug 2023, Chris Rapier wrote:
>
> > > The broader issue of hiding all potential keystroke timing is not
yet
> fixed.
> >
> > Could some level of obfuscation come from enabling Nagle for
interactive
> > sessions that has an associated TTY? Though that would be of limited
> > usefulness in low RTT environments. I don't like the idea of
having a
> steady
> > drip of packets as that seems problematic both in terms of code
> complexity and
> > network usage. I also don't like the idea of imposing random
jitter
> though
> > that might be easier to implement. However, without actual modeling I
> have no
> > idea if that would actually improve things.
>
> Nagle is usually turned off because it causes annoying perceptions of
> non-deterministic latency.
>
> For ssh, IMO sending interactive traffic on a fixed clock (e.g. every
> 2-4ms) instead of as soon as possible, and adding fake keystroke packets
> for some interval after the user stops generating traffic is the way to
> fix it. I've slowly been preparing for this by reworking the mainloop
and
> associated timers.
>
>
> > Anyway, I was simply thinking about this because the whole bugging of
> > typewriters thing crossed my mind recently.
> >
> > Chris
> >
>