So I've found a way to get the IP address of a user on a popular website without taking them out of said website (i.e. without making them click any links) by making them (the user) send a request to an arbitrary url, and by doing this you are able to get their:
- IP address
- User agent (on mobile it will show their operative system and the version of the app they are using)
And I'm wondering if there are any security issues for this... It is also possible to target a specific user or many users at once.