"UNLIMITED TABLESPACE" is revoked - don't know who did that

Question

I got call from developer they encountered error from insert statement stating
ERROR at line 1:
ORA-01536: space quota exceeded for tablespace 'XXXXXXXX'
I went there and found that "unlimited tablespace" is revoked from that user.
I can not explain how it happened since I am the only DBA for this database. Although one of the developers has DBA privilege, I don't think he has the ability to do so. There is no reason for anybody to do so.
The database is 9.2.0.7 with 2nd Quarter CPU patch.
My question is that is there any other mechanism to make this happen? This is really strange to me.
jzc

Answer 1

This is most curious.
It turns out that granting resource also grants unlimited tablespace and revoking resource also revokes unlimited tablespace. However, unlimited tablespace is not a privilege granted to resource, rather it is granted to the user.
If I grant unlimited tablespace, I can see the user has it.
If I then grant resource, the user keeps unlimited tablespace -- of course.
If I revoke resource, unlimited tablespace goes away.
If I then grant resource, unlimited tablespace comes back.
resource has an interesting property in this -- at least in 10.2
SQL> create user test01 identified by test01;
User created.
SQL> grant unlimited tablespace to test01;
Grant succeeded.
SQL> @privs_all
Enter User ID: test01
                                          System Priveleges Granted to test01.
Privilege                                           Via Role?
UNLIMITED TABLESPACE                      No Admin
SQL> grant resource to test01;
Grant succeeded.
SQL> @privs_all
Enter User ID: test01
                                          System Priveleges Granted to test01.
Privilege                                           Via Role?
CREATE CLUSTER                            No Admin  RESOURCE
CREATE INDEXTYPE                          No Admin  RESOURCE
CREATE OPERATOR                           No Admin  RESOURCE
CREATE PROCEDURE                          No Admin  RESOURCE
CREATE SEQUENCE                           No Admin  RESOURCE
CREATE TABLE                              No Admin  RESOURCE
CREATE TRIGGER                            No Admin  RESOURCE
CREATE TYPE                               No Admin  RESOURCE
UNLIMITED TABLESPACE                      No Admin
SQL> revoke resource from test01;
Revoke succeeded.
SQL> @privs_all
Enter User ID: test01
SQL> grant resource to test01;
Grant succeeded.
SQL> @privs_all
Enter User ID: test01
                                          System Priveleges Granted to test01.
Privilege                                           Via Role?
CREATE CLUSTER                            No Admin  RESOURCE
CREATE INDEXTYPE                          No Admin  RESOURCE
CREATE OPERATOR                           No Admin  RESOURCE
CREATE PROCEDURE                          No Admin  RESOURCE
CREATE SEQUENCE                           No Admin  RESOURCE
CREATE TABLE                              No Admin  RESOURCE
CREATE TRIGGER                            No Admin  RESOURCE
CREATE TYPE                               No Admin  RESOURCE
UNLIMITED TABLESPACE                      No Admin