One of the most common ways to prevent this kind of spam is to block the related URLs through your .htaccess file in the root directory of your site domain.
The other type is called Ghost Spam. With this type of spam, they make use of theGoogle Analytics Measurement Protocol. Essentially, this allows them to submit their data to the Google Analytics Servers directly, bypassing your site in the process. This is where blocking the URL in your .htaccess file becomes useless.
Prevent Ghost Spam from pinging your analytics account is to make use of filters.
Attention: "role based name" email prefixes such as support, webmaster, info, contact, forum, service, affiliate, admin, traffic, partners, marketing, etc., for our member accounts are not permitted. They are acceptable for a vendor listing, but not for the member email. This is due to bulk email processors scrubbing them for delivery due to extremely high bounce rates. Please apply for membership using a personalized email prefix. Something like firstname.lastname@example.org.
If we discover you signed up with a role based name we will give you only one message to change it. After 3 days your account will be removed if the email is not changed.