We have several Marketo forms on external pages of our corporate website. Occassionally we have spam bot form submissions, but it is rare. We posted a new form last week and it has been fine/spam free, up until yesterday when several spam submissions started coming through and creating new leads - the spam varies from submissions that have lots of repeated words and foreign language symbols, to submissions that are English but clearly spam. In terms of the form fields and Java script, everything is identical to our other published forms that aren receiving spam.
Any ideas on why this would happen - and how we can stop it? We have tried taking down the form for several hours and reposting it, but as soon as we reposted it, we started receiving spam again.