This new found by spammers , in terms of security, does not involve any risk (of course not visiting the sites in question), but obviously it is annoying both to receive mail delivery errors caused by fake emails, and to delete these false registrations. The module for PrestaShop 1.6 and 1.7 is based on a simplification of the doekia user solution which appeared on the PrestaShop forum.
Compared to the version on the forum, we work exclusively on the Validate.php cash register, filtering www and http only, allowing as an option to filter also / * ^  by intervening on the relevant item in the module configuration.
The control function can be activated and deactivated simply by activating and deactivating the module.
It is thus much easier to apply the change to no longer allow these bots to register these bogus users.
Note: once the module has been installed and activated, it will not be possible to delete bogus users already registered, just deactivate it for the time necessary to remove them and then reactivate it to prevent future bogus registrations.