atmosphear

Send an “HTTP/1.1 403 Forbidden” header on a failed login instead of “HTTP/1.1 200 OK”, which is the WordPress default header on failed login. This is a tremendously simple plugin that does only that and absolutely nothing else.
The purpose of this plugin is to provide a way to allow external tools like fail2ban to get a message of a failed login e.g. to prevent a brute-force attack on a firewall level.
For the public domain.
Uses PHP5.3 anonymous functions and will not work on earlier versions of PHP

HTTP/1.1 403 Forbidden header on a failed login

Send an "HTTP/1.1 403 Forbidden" header on a failed login instead of the default "HTTP/1.1 200 OK"

fullworks

Alan Fuller

Stop User Enumeration is a security plugin designed to detect and prevent hackers scanning your site for user login names.
User Enumeration is a type of attack where nefarious parties can probe your website to discover your login name. This is often a pre-cursor to brute-force password attacks. Stop User Enumeration helps block this initial attack and allows you to log IPs launching these attacks to block further attacks in the future.
Tools like WPSCAN are designed for use by ethical hackers and make efforts to find user login names. Ethical hackers ask permission first, this plugin is designed to reduce the tools when used without permission and when used in conjunction with fail2ban can block those attempts at the firewall.
If you are on a VPS or dedicated server, as the attack IP is logged, you can use (optional additional configuration) fail2ban to block the attack directly at your server’s firewall, a very powerful solution for VPS owners to stop brute force attacks as well as DDoS attacks.
If you don’t have access to install fail2ban ( e.g. on a Shared Host ) you can still use this plugin.
The plugin can stop the user id being leaked by the oEmbed API call.
Since WordPress 4.5 user data can also be obtained by API calls without logging in, this is a WordPress feature, but if you don’t need it to get user data, this 
plugin will restrict and log that too.
Since WordPress 5.5 sitemaps are generated by core WP ( wp-sitemap.xml ) which includes a user/author sitemap that exposes the user id. You can enable / disable this in the plugin settings.
<h4>PHP 8.4 compatible</h4>
Tested on PHP 8.4
<h4>Features Include</h4>
<ul>
<li>Blocks user enumeration requests by GET or POST</li>
<li>Syslogs a block so Fail2Ban can be used to block an IP</li>
<li>Optionally blocks REST API user requests for non authorized users</li>
<li>Optionally removes author sitemap</li>
<li>Optionally removes author from OEMBED</li>
<li>Optionally removes numbers from comment authors</li>
</ul>
<h3>Privacy</h3>
This plugin includes an optional email feature for plugin news and updates. When enabled:
<ul>
<li>Your email address may be sent to https://fullworksplugins.com for important plugin updates and security notices</li>
<li>This is completely optional and requires your explicit consent via the opt-in form in the plugin settings</li>
<li>No data is collected or transmitted without your permission</li>
<li>You can opt-out at any time from the plugin settings</li>
<li>No other personal data is collected or transmitted to external services</li>
</ul>
The plugin logs attempted user enumeration attacks locally using WordPress’s standard logging system: 
* IP addresses of potential attackers are logged locally for security monitoring 
* These logs remain on your server and are not transmitted to any external service 
* Logs can be used with fail2ban or similar tools for enhanced security
For more information about data handling, please visit https://fullworksplugins.com/privacy-policy/

Stop User Enumeration

Works as a charm!

Helps secure your site against hacking attacks through detecting  User Enumeration

HTTP/1.1 403 Forbidden header on a failed login vs Stop User Enumeration