As we explained here https://t.co/XE1Zz6BVnQ, we've already acted. We can't intervene in your shop directly. It's up to you to do it.
— PrestaShop (@PrestaShop) April 18, 2018
You can disable the "Sendtoafriend" module in your backoffice but the best solution is to install a captcha module. 1/2
https://goo.gl/EO0ad1
https://goo.gl/xF8heB