建立trigger:
CREATE OR REPLACE TRIGGER logon_denied_write_alertlog AFTER SERVERERROR ON DATABASE
DECLARE
l_message varchar2(2000);
BEGIN
-- ORA-1017: invalid username/password; logon denied
IF (IS_SERVERERROR(1017)) THEN
select 'Failed login attempt to the "'|| sys_context('USERENV' ,'AUTHENTICATED_IDENTITY') ||'" schema'
|| ' using ' || sys_context ('USERENV', 'AUTHENTICATION_TYPE') ||' authentication'
|| ' at ' || to_char(logon_time,'dd-MON-yy hh34:mi:ss' )
|| ' from ' || osuser ||'@'||machine ||' ['||nvl(sys_context ('USERENV', 'IP_ADDRESS'),'Unknown IP')||']'
|| ' via the "' ||program||'" program.'
into l_message
from sys .v_$session
where sid = to_number(substr(dbms_session.unique_session_id,1 ,4), 'xxxx')
and serial# = to_number(substr(dbms_session.unique_session_id,5 ,4), 'xxxx');
-- write to alert log
sys.dbms_system.ksdwrt( 2,l_message );
END IF;
END;
