"Stephen" == Stephen J Turnbull <steve@turnbull.jp> writes:
Stephen> Johannes Rohr via Mailman-users writes:
Last time I tried, [captchas worked well], but maybe that was before AI became ubiquitous.
Stephen> What we saw was that 2005-level machine learning technology Stephen> was producing character recognition good enough to beat the Stephen> distorted character CAPTCHAs in a small number of tries. Stephen> This was readily available to the most persistent spammers, Stephen> so CAPTCHAs were not very successful at reducing such attacks Stephen> to tolerable levels.
I've enabled CAPTCHA in Postorius and Django using the patches in https://github.com/pbiering/mailman3-rpm and have seen a massive reduction in sign-up spam. Just adding an extra step has made us less attractive than other sites.
Is there another approach that you would recommend?
We haven't used it on Mailman, but Anubis has helped with signup spam on our Mattermost server. https://github.com/TecharoHQ/anubis
Peter C