Hello Flarum,
i've seen lot of spam in flarum boards, also here on discuss.flarum.org. So the following anti spam plugin I would recommend to check it out, if you can implement the same for Flarum:
TPU (Github): https://github.com/W1zzardTPU/XenForo_TPUDetectSpamReg
TPU (Xenforo): https://xenforo.com/community/resources/tpu-detect-and-block-spam-registrations.2973/
What it does: Reverse lookup the user who wants to register himself. It does give them (bad) score points for the following:
Visitor's country
E-Mail address
E-Mail length
Username
IP hostname
Internet Provider name
Open TCP port (requires PHP-sockets extension)
StopForum Spam API
Project Honeyport API
TOR client detection
Example Blocked Registration:
Personally i'm running a xenforo board with 4k users, with this type of antispam technology it feels like 99,8% spam has been intercept. For example: most Xenforo spambots are from VN/IN or use a proxy. Especially scan open tcp port is a funny thing, you will not believe how many spammers have port 8080 open ; ) (proxies)
At the end, this way to catch spammers is like spamassassin/rspamd with some Blacklists additionally (stopforumspam API for example)
Unfortunately I am not (yet) a programmer, but I hope you will find this idea also good. As i said, for me, this is the best antispam tech, mostly you dont need any captcha anymore, and askimet is catching the rest.
