Default user privs

I created a new user and by default the user is getting select on all tables of one of the schemas.
Please provide me your feedback as to how to investigate this. When I checked sys.USER_TAB_PRIVS, I don't see anything granted to the new user, however, the new user was able to select data from one of the schemas.
Thanks.

what privileges were granted to the user when it was created? what roles does the user have, and what privileges do the roles have?

SQL> CREATE USER zzz IDENTIFIED BY zzz;
SQL> GRANT create session TO zzz;

Then the user was able to select data from one of the schemas.

are there public synonyms against the tables, by any chance?

Found out that the schema objects have select grant to public, that is why the new user was able to select the data from the existing schema even though there was no explicit grants made to the new user.