Situation: An e-commerce system (specifically: PrestaShop) which is used to sell virtual products (specifically: product license keys). To accelerate order processing, a cronjob is supposed to be regularly executed which looks for new orders. Each of this order is checked against a list of criteria, if it passes the test, the ordered product keys will get delivered via E-Mail immediately and automatically, without human interaction.
If there is an exploit in PrestaShop and an attacker gains access to the administration or database, all product information is exposed, which could mean a total loss of all product licenses meant to be sold (along with the possible theft of customer information).
Could I restrict possible damage in case of intrusion in the shop system by storing the product keys including the automation script on another server with another database? So, the script on the other server is frequently querying the shop for new orders and sends out the product information stored on its own database on its own server via E-Mail to the customer. The shop system is unaware of the license keys all the time. Also, possible intruders could not discover the other server (except they gain access to webserver access logs).
By the way: An HTTPS connection between the servers can be regarded as obligatory in this case, right? Because sensible information may be transferred.