SQL> exp sys/sys file=/home/oracle/sys.dmp full=y

Export: Release 11.2.0.3.0 - Production on Wed Apr 30 16:53:47 2014

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EXP-00056: ORACLE error 6550 encountered

ORA-06550: line 1, column 15:

PLS-00201: identifier 'SYS.DBMS_EXPORT_EXTENSION' must be declared

ORA-06550: line 1, column 15:

PL/SQL: Statement ignored

EXP-00000: Export terminated unsuccessfully

执行安全加固后部分权限丢失；

通过以下方法解决：

GRANT EXECUTE ON SYS.DBMS_DEFER_IMPORT_INTERNAL TO <user_name>;

GRANT EXECUTE ON SYS.DBMS_EXPORT_EXTENSION TO <user_name>;