I am running ColdFusion MX, so I don't have the possibility of using the built-in cfimage Captcha functionality in my application, before form submitting.
But the problem is without captcha the bots submit the forms.
What will be best way to prevent automatic submitting?
Take a look at cfformprotect - it will work with CFMX 6 and all later engines.
It aims to be fully accessible - and invisible to most users - with an assortment of methods to stop bots and spammers.
Also you might want to look at a CF wrapper for reCaptcha, which is compatible with CFMX 7.