Spambots suddenly getting past security questions fairly easily

[ClemFandango]

I've changed my security questions around recently but in the past few days, I've been getting a big increase in spambot registration.

How random do i really have to make these questions ?

I've tried things like "Type the word 'green'" or "What is water? (Answer: wet)" which did seem to work but recently it doesn't seem to make a difference.

[Matt]

Are you also using a captcha of some sort? More abstract questions may be required, these wouldn’t be challenging to program a bot to answer.

[HLFadmin]

Bots haven't got past "what is the name of this forum?"
Yet. Although I don't use search engine optimizations and robots.txt deny spiders.

[ClemFandango]

Thanks for the replies. I'll have to think of a few more "out there" questions, but I do like the "what is the name of this forum" question though.

I don't use captcha at the moment, but I'll certainly give it a try if more questions don't work.

If I do think of something quite "out there" is it worth putting the answer in the question or is that also something spambots can work out?

[Matt]

I think a CAPTCHA will be significantly more effective. The problem is that if someone is coding a bot, if they see there's very limited questions being asked, they can just code in the answers.

[ClemFandango]

Well interestingly, I've just checked the stats and the "What is the name of this forum" question has been shown 68 times since yesterday with 38 wrong answers and not a single correct one