3 things you should have on your software update checklist:
Make sure your web host service provider regularly updates the security features on its operating system.
If you subscribe to third-party software, sign up for their mailing list so you can be immediately advised of program updates.
Ask your website designer to conduct a frequent audit on your site. The purpose of the audit is to identify outdated, hardly used and corrupted software programs that put your website at risk.
Use Strong Passwords
Get SSL Certificates
Protect your website as you would your own home. Do not let suspicious characters in and make sure all entry points are tightly secured.
The bad guys are always trying to stay one step ahead of the good guys. As a business owner, your time is best spent focusing on tasks that will help you stay ahead of the competition not worry about what these cyber criminals are plotting to do.
to protect from the spammer you can use captcha email authentication make sure the website you using does not have any venerability which can be use by spammer . also its depend on the server on which your domain is hosted the server should be secure enough to protect from open relay protect using the antihack / anti spam protection.
If you tweak server settings properly, you can easily trace spammer on the server and suspend it. If cPanel is the control panel, you can enabled extended logs in exim it will help you to detect any script or email account sending the spam.