| Is the backhoe/squirrel/hurricane an attacker thus making this an "attack"? Semantics. Availability is part of the attack _surface_, which if we're being pedantic is what was being discussed. ("Look at the shiny new attack surface!") > different discussion My point is that, no, it's not. The three points of the triad are inextricably linked. More C and/or I means less A (and A tends to be sidelined in favor of C and I these days). > OCSP and CRL is soft-fail by default in all browser I'm aware of. Not on government systems they aren't (STIG id: v-44789). Also, if we're going all in on https we should go all in on https. > ... Stapling How is the server supposed to get a response to staple if the responder is unavailable? Also, time. Also, client root of trust. Also, fat-fingering the hostname when the DNS gets updated. Also, public wifi which does mitm... Bottom line: this is a decision which prioritizes confidentiality and integrity over availability for the entire .gov with (seemingly) no recourse. Edit: quote from upstream, corrected STIG id |
That's a larger moral responsibility, in my opinion. And consider that the fallback to prioritize availability in case of a non-attack cert error (e.g. revocation or expiration) is to ask the user to look at a certificate warning and make a personal trust decision about it. There are precious few users who can safely make that kind of a decision. And even if they "get it right" that time and click through and aren't attacked, you're training users to click through warnings, and helping them subject themselves to attacks in the future.
I would argue that that kind of "availability" is a very weak sort of availability. The government has enough problems with training people to click through certificate warnings (see: https://www.iad.gov) -- intentionally leaving that hole open seems unwise.