from the time that blogging was a heat, Wordpress, Drupal and Joomla became more popular and was been used. Question which of the three CMS has a very tight security?
Undoubtable, WordPress is the best option for beginners to design their first blogs, it is extremely easy to setup, maintain and upgrade, but when it comes to ecommerce site, there are heaps of choices out there (magento, codagenic, pretashop) and there are a lot things need to be considered before picking up your platform.
None of the mentioned platforms have special security out of the box, security depends on what you or your admin have done to improve security...