Look, we can debate the proper and private way to do Captchas all day, but if we remove the existing implementation we will be plunged into a world of hurt.
I run tucson.social - a tiny instance with barely any users and I find myself really ticked off at other Admin's abdication of duty when it comes to engaging with the developers.
For all the Fediverse discussion on this, where are the github issue comments? Where is our attempt to convince the devs in this.
No, seriously WHERE ARE THEY?
Oh, you think that just because an "Issue" exists to bring back Captchas is the best you can do?
NO it is not the best we can do, we need to be applying some pressure to the developers here and that requires EVERYONE to do their part.
The Devs can't make Lemmy an awesome place for us if us admins refuse to meaningfully engage with the project and provide feedback on crucial things like this.
So are you an admin? If so, we need more comments here: https://github.com/LemmyNet/lemmy/issues/3200
We need to make it VERY clear that Captcha is required before v0.18's release. Not after when we'll all be scrambling...
EDIT: To be clear I'm talking to all instance admins, not just Beehaw's.
UPDATE: Our voices were heard! https://github.com/LemmyNet/lemmy/issues/3200#issuecomment-1600505757
The important part was that this was a decision to re-implement the old (if imperfect) solution in time for the upcoming release. mCaptcha and better techs are indeed the better solution, but at least we won't make ourselves more vulnerable at this critical juncture.
Fun fact, I purposefully goaded the bots into attacking my instance.
Turns out they aren't even using the web form, they're going straight to the register api endpoint with python. The api endpoint lives at a different place from the signup page and putting a captcha in front of that page was useless in stopping the bots. Now, we can't just challenge requests going to the API endpoint since it's not an interactive session - it would break registration for normal users as well.
The in-built captcha was part of the API form in a way that prevented this attack where the standard Cloudflare rules are either too weak (providing no protection) or too strong (breaking functionality).
In my case I had to create some special rules to exclude python clients and other bots while making sure to keep valid browser attempts working. It was kind of a pain, actually. There's a lot of Lemmy that seems to trip the optional OWASP managed rules so there's a lot of "artisanally crafted" exclusions to keep the site functional.
Anyways, I guess my point is form interaction is just one way to spam sites, but this particular attacker is using the backend API and forgoing the sign-up page entirely. Hidden fields wouldn't be useful here, IMO.