I've just released a community site on XOOPS and we're beginning to see a large number of spam bot and automated mass registrations. Another site on an older version of XOOPS has the same problem (without Profile module). I'd implemented reCAPTCHA but that didn't stop it either. And I was having similar problems with the XOOPS CAPTCHA system as well. And I needed to use reCAPTCHA because of a disability requirement.
It does appear that the spammers and blackhats have come up with methods to get around reCAPTCHA. I've found references to both
programmatic methods as well as paying somebody in some foreign country $0.05/submission ($5/100).
I've found several other discussion here on X.o about spammer registrations and posts, and today, wishcraft announced the new
Profile 1.68, which I'll have to try out as well, but it's focus appears to be more on invitations and such.
I've seen a few solutions proposed including the hidden field (not to easy since both the XOOPS register as well as the Profile Module use XOOPS Forms instead of presenting through Smarty which would make it easier to target) but also still requires either special programming, and or human intervention and review, as well as special fields with math or other text identification. I've also seen people that block by IP, country, and such (but we can't do that).
However,
one possible method I found comes from
Stop Forum Spam, and could be integrated into the Profile module to check registrations against an RBL (and perhaps give a success message but not actually add it to the database, or add it but then add it to a special Spammers group). We could even add a link that allows admins to report spammers into this block-list.
Has anyone tried this method? I'm putting it on my list to try it, but I've got too much on my plate at the moment.
I've also found
using Akismet and Defensio to help stop it (from
Rob Mason on how to code to stop spam).
And I found
Xortify which is somehow tied to StopForumSpam, but will have to research it further as well (and it appears to be only good for XOOPS 2.5.x which I've not yet adopted).
Like others suggested, we're adding users to a Spammer group without user rights on the system (to help keep them from coming back), but then we'll have too many folks in the database and to be able to send an occasional system message may be problematic. We've also moved to a 2-page registration, but will see how much that actually helps.
Anyhoos, still working on those bloody b*stards.