Thanks for engaging with me on this topic. I understand that usernames are made to be shared and email addresses are not generally secret (on an individual basis). However, I still think it’s wrong that anyone on the internet can get a clean .csv of users and user ID for any WordPress website.
I’m also still looking for the WP team’s rationale on this. I see the fact that you don’t consider this a vuln but I don’t see why. Considering it takes under 10 lines of code to fix I feel that “we don’t think it’s necessary” is a bit of a cop-out.
Also, I would argue that just by displaying the username on a webpage we are violating the GDPR. Let’s assume I operate an adult entertainment website. Anyone who enumerates my userlist is going to get very personal information about my users (IE: The fact they’re using my website in the first place).
Obviously contributors are a bit different, as they would be aware that this information gets shared.
But what if Google gave you a .csv of all accountholders usernames just because you poked around a bit. Don’t you think they would consider that a vulnerability?
Also, you’re literally giving away the tools a hacker needs to pull off a brute force attack. Strong passwords are great, but if you have a list of usernames in hand brute forcing becomes a joke anyway. There are hundreds of word lists out there. If we disable enumeration an attacker now has to not only guess a password, but a username too.
The work of writing 10 LOC to harden millions of websites seems trivial. I am just having a hard time understanding why WP wants to invite so much risk for literally no reward and zero development costs. Perhaps you could elaborate?