Member registered through Gateway "Admin" yet no admin registered this particular user.

Hello,

Late last night I received notification that a new person registered for one of our 30-day trial memberships. What is strange is that in the All Members list, the Gateway is showing as "Admin" which indicates that his/her account was set up manually by one of our admins. However, for this particular person, no admin created this account.

What's more, the account creation time is listed as 00:00 which seems odd. In addition, the user's email is from hotmail. Both those things are making me suspect that this is a spam signup.

How is it possible that the Gateway is listed as "Admin" if no admins signed this person up?
How could the signup time be incorrect?

We are trying to find out if there was a security breach and how to patch any holes in our system.

Thanks.