RE: FN-FORUM: form spam block

date posted 4th September 2006 11:27

> If you receive spam sent through an online form
> on your website how do you stop it?

Nigel,

You need to introduce some form of challenge-response as Chris suggested.

On simple "contact-us" style forms which are the most easily abused, we use
a security image script that randomly creates an image with a sequence of
characters and asked the user to enter it. This is then verified when the
user submits the form. The actual value expected is stored in a database to
hide it from clever scripts.

You can see it in action at

http://www.emissary-consulting.co.uk/contact.php

The tutorial for this can be found here:

http://www.devshed.com/c/a/PHP/Security-Images-in-PHP/

HTH

Edward

--
Emissary Consulting
www.emissary-consulting.co.uk