Is it possible to identify a guest of my website as a VK user without authorization through the VK API?

Question

JavaScript

You need to get all or one of them:
- ID
- Name
- Photo (avatar or albums)
- Interests (for displaying thematic ads)
Maybe there are ways using VK iframe widgets (authorization, comments) + XSS?

Answer 1

Write a vk-iframe application that does not draw anything, but on the server side identifies the user's client (think like ip + useragent), requests information about the user via vk-api, and stupidly writes all this to the log in the database.
On the same server side, make an api for accessing this log.
On the site, embed a hidden frame with your application page (vk.com/appXXXX).
Some time after loading with Ajax, ask the backend of the VK application for information about the latest requests corresponding to the client id.

Answer 2

I was thinking about parsing in frame id0 .