Blocking WooCommerce anonymous orders?

We are receiving a lot of spam from anonymous orders (WooCommerce). Since we wouldn’t like to force our customers to register (guest orders), this is not necessary to place an order in our shop.

Is there any known working spam protection pattern to catch these orders? They often look like this:

Herrn aYlNlfdX aYlNlfdX
3137 Laguna Street
94102 San Francisco
5556660606
[email protected]

But their content differs from time to time of course.