Drupal Username Enumeration
It is possible to enumerate Drupal usernames.
Username enumeration allows an attacker to guess usernames, which may enable them to log in to the application. This attack is often performed in combination with brute force attacks.
Attackers can enumerate Drupal usernames which can be subsequently used for password spraying and other types of brute force attacks.
Consider disabling username enumeration by using specialised security plugins.