What’s this attack?

Assuming web attack- heavy traffic over 2 hours all to the site login

Various IP’s, various locations, many different user names

1500 failed attempts
50 are successful

All 50 successful just go to index page. Index loads CSS and JavaScript files.

That’s it, 50 unknown users log out.

What do you think this is?
Recon?

attack css cybersecurity files go to javascript log login names page recon traffic web