Why are there suddenly new users on our website?

So my boss logged onto his email today to find this:

New user registration on your site Maui Ceramics:

Username: hongxal664472803

Email: [ redacted ]

So I started poking around and you CAN register as a subscriber

but why? There’s nothing set up for subscribers (yet).. and HOW?!?! When I logged into our dashboard to look at the users I saw a whole bunch of new “subscribers” that neither of us recognized. Whats going on?

Sorry I don’t have screen caps. I deleted all the new users but this is the first time ever (that I know of) that new entries started appearing there as subscribers. Some of these entries looked like spam but others had what looked like actual names too.