We are facing multiple attacks on our website. We are basically classified goods website that helps customers to connect to each other.
Bots are stealing data from our website everyday by giving fake mobile numbers. We don't have login mechanism. User have to share their contact number to get other users contact details.
I read this q/a thread stackoverflow prevent scrapping
An intelligent bot can easily avoid moving to files listed in robots.txt, changing cookies, changing user agents.
Even by using captcha, manually they can steal data by putting any random numbers.
We are planning to flag leads as suspicious if its more than x leads per day. The problem here is that bot can use services like TOR to generate unlimited IPs. How can we solve this i.e. if they have unlimited IPs and unlimited numbers, what can be solution to this?
All suggestions welcome except for putting OTP, as we already have that in mind.