[conspire] Password permutations

[Nick Moffitt]

On 17Apr2020 09:49pm (-0700), Tony Godshall wrote:
> On Thu, Apr 16, 2020 at 2:04 AM Nick Moffitt <nick at zork.net> wrote:
> > PSA: Disable ssh password access, and keep a passphrase-locked private key
> > on portable media.  This will prevent a number of "joe account" problems,
> > and simplify your threat model considerably.
> ...
> 
> Someone with access to your keyfiles *would* be able to do a
> dictionary attack, since there's no rate-limiter on that.
> 
> So preventing access to your private key on portable media becomes paramount.

I would argue that this is a much simpler threat model in this day and age.  We used to advise strongly that people never write down passwords, and that made a LOT of sense in the era of workstations in an office, where shoulder-surfing is a constant threat.  But we then scolded our grandparents for writing down passwords in the privacy of their own homes, and I feel that that misunderstood the scope of the problem.

I am currently far more worried about distributed armies of uncoordinated attackers throwing spaghetti at the walls of my systems to see what sticks than I am about targeted known-to-me attackers (with a few exceptions).  So I keep my ssh keys in offline storage that is encrypted at rest, and load the keys into RAM by hand on boot.

Even the exceptions to the category of attackers does not include people who have the resources to track me down physically and rob me in a way that would prevent me from contacting trusted parties to revoke my stolen credentials.

If I were feeling like confounding pickpocket-hackers even more, I could employ Shamir sharing and shard my keys into multiple pieces for assembly at load time.  I'm not sure the threat warrants that right now, and I'd be surprised if the benefits of such an approach outweighed the costs even under a persistent targeted threat.