alt Hacker NewsAs others have mentioned, it comes down to the threat model, but sometimes the threat model itself is uncomfortable to talk about.
It’s sad to think about, but in my recollection a lot of intra-building badge readers went up in response to the 2018 active shooter situation at the YouTube HQ[1]. In cases like this, the threat model is “confine a hostile person to a specific part of the building once they’ve gotten in while law enforcement arrives,” less than preventing someone from coat tailing their way into the building at all.
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No, the model there is something bad happened, we must do something. This is something, so we will do it.
I’m not saying that to diminish the value of the actual solution, but what the people want is literally something to make them feel better about a situation that is mostly out of their control.
Someone showed up to their workplace with a fucking gun. And now they have to go there every day, and hope it doesn’t happen again. They want and need the theater.
If an active shooter is the anticipated threat, how does a turnstile effectively stop that? Many of these turnstiles are specifically meant to allow people through in emergencies, and aren't strong enough to withstand bullets or even a sturdy kick. The elevator restrictions would be a better chokepoint, but as the article noted they didn't turn those back on.
If forced partition of a building were the primary goal, that goal could be achieved without badges. Or, at least, without having to badge into every door. Just have locks on every door that are normally disengaged, but which can be locked remotely and promptly.
(While at it, I once worked on an access control system. It was aeons ago; the system ran under OS/2. We installed it on a factory. It worked well, until we ran it in demo mode under production load, that is, the stream of morning shift turnstile registration events. The DB melted. I solved the problem trivially: I noticed that the DB was installed on a FAT volume for unknown reasons, so I moved it to an HPFS volume, and increased the RAM cache for the disk to maximum. Everything worked without a hitch then.)
I doubt these card readers would prevent someone leaving the part of their building they’re in, as that’s a lesson written in charred corpses and was a foundational aspect of health and safety becoming a thing: https://en.wikipedia.org/wiki/Triangle_Shirtwaist_Factory_fi...
In theory it might prevent access to other buildings, but equally often the card readers are around doors of mostly standard glass or near internal windows of the same.
So if that’s the motivation, it doesn’t seem like a particularly effective mitigation