Hello,
A recent very serious security flaw has been discovered in several prestashop versions
The solution is explained below, manual, or by a specific module :
https://soluka.fr/blog/prestashop/prestashop-faille-phpunit-xsamxadoo-bot/
We recommend that you read and understand well, and possibly let your webmaster secure your site if he finds the files to delete, and check if you have already been impacted.
YOORshop team