I help run quite a Drupal site (up to date) with around a few thousand registered users. More and more frequently I am finding users who have registered with usernames like the following (found 13 so far but I am going back through the history to see if there are anymore):
briantuffddwwjbsao heiditsfacjsheiffg vickikqskaiwlfnxcg
I am 99% certain these are not legit users and I have blocked their accounts for the time being. Oh and they have been authorised (clicking link in email).
When looking at the profile, in every case the first and last names are populated by the same text (the same as the first four or five characters of the username). The last part of the username is seemingly random characters (no numbers/special characters). I also note the address does usually exist (at least on gmaps) but I cant comment on the zip code/telephone being accurate (it doesn't seem so).
We do have a CAPTCHA implemented.
Has anyone else had experience with users registering on Drupal with this type of username? Are they legitimate or is it some sort of "bot"? Am I just being paranoid?