Suddenly I started getting one of these users per day signing into my web app. Here is an example email: xfwpqahlcl_1576843160@tfbnw.net
They only sign in with Facebook and do some minor activity. Not harmful, but quite annoying to be honest, they screw up my metrics.
Are they legit somehow? Is there any way to stop them?
I exclude any malicious activity https://www.whois.com/whois/tfbnw.net
Those seem to be a genuine internal Facebook QA team test.
I had a similar episode today where two of suspicious user accounts have been created with apparently randomly generated data on iwillfindyou.love using emails from domain tfbnw.net.
Due to the fact that I have not been informed about this Facebook activity beforehand, I had to suspend these users as they violate my website rules.
It may well be a malicious activity third party is conducting through the Facebook platform, so I would be very careful here.
To answer question whether this is legit, I would say no.
Those are test users created by facebook you can create them yourself on the app settings, no need to worry.
