In order to know how to protect your site, you have to know your weaknesses and know your enemy. Applying the Art of War precepts will help you by giving perspective of the problem and understanding how to act effectively when something bad happens to your website or e-commerce made with WordPress.
Presenting the way a WordPress is usually hacked, the layer-based model of security and some examples I gathered during my years at Sucuri and GoDaddy Security, I’ll try to make you aware of this problem, I’ll give some examples of what could happen and how, and provide you with some countermeasures to avoid this to happen whenever it is possible.