Fighting Contact Form SPAM
If you use a Contact Form plugin to build and manage forms on your site, you may get a LOT of SPAm thr0ough those forms. To fight this, the best solution is installing an additional plugin to handle detecting and filtering spam form submissions.
There are numerous plugins available:
Add a CAPTCHA block to forms that require users to enter text from an image, or to solve a math problem, before submitting form. (The downside of this is that CAPTCHA can be defeated by more advanced spambots, plus CAPTCHA is annoying to users.)
- Analyze form submission data, and if data matches known spam patterns flag submission for review or dispose of submission automatically. (Akismet is a great example of this.)
Check the WordPress Support for more info, as well as links to popular plugins: https://wordpress.org/plugins/tags/anti-spams