一、帐号失败登录记录

当用户输入错误的密码失败登录的次数超过限定后，Oracle会自动将该帐号锁住。在dba_profiles中，FAILED_LOGIN_ATTEMPTS参数会记录口令失败尝试次数。

SYS@MTH> select * from dba_profiles where resource_name='FAILED_LOGIN_ATTEMPTS';

PROFILE                        RESOURCE_NAME                             RESOURCE            LIMIT
------------------------------ ----------------------------------------- ---------------     ----------------------------------------
DEFAULT                        FAILED_LOGIN_ATTEMPTS                     PASSWORD            10

可以通过以下的命令将失败次数修改为无限制：

SYS@MTH> alter profile default limit FAILED_LOGIN_ATTEMPTS unlimited;

Profile altered.

修改失败登录尝试次数：

SYS@MTH> alter profile default limit FAILED_LOGIN_ATTEMPTS 20;

Profile altered.

SYS@MTH> select * from dba_profiles where resource_name='FAILED_LOGIN_ATTEMPTS';

PROFILE                        RESOURCE_NAME                           RESOURCE         LIMIT
------------------------------ --------------------------------------- --------------   ----------------------------------------
DEFAULT                        FAILED_LOGIN_ATTEMPTS                   PASSWORD         20

可以通过以下语句查看哪个帐号，在哪台server，已经失败登录过多少次：

SYS@MTH> select username,os_username,userhost,client_id,trunc(timestamp),count(*) failed_logins
  2  from dba_audit_trail
  3  where returncode=1017 and timestamp >sysdate -1
  4  group by username,os_username,userhost,client_id,trunc(timestamp)；

USERNAME                       OS_USERNAME                    USERHOST                       CLIENT_ID         TRUNC(TIMESTAMP)             FAILED_LOGINS
------------------------------ ------------------------------ ------------------------------ ----------------  -------------------------    -------------
MTH                            oracle                         C01TEST03                      23-MAY-17                                      3
MTH                            oracle                         C01TEST03                      22-MAY-17                              1

二、口令是否区分大小写

Oracle 11g之前，帐号的密码是不区分大小写的，11g之后，口令开始区分大小写。

下面进行测试：

SYS@MTH> show parameter sec_case_sensitive_logon

NAME                                 TYPE                             VALUE
------------------------------------ -------------------------------- ------------------------------
sec_case_sensitive_logon             boolean                          TRUE

SYS@MTH> alter user mth identified by mth;

User altered.

SYS@MTH> conn mth/MTH;
ERROR:
ORA-01017: invalid username/password; logon denied

Warning: You are no longer connected to ORACLE.
@>
@> conn mth/mth
Connected.

修改参数sec_case_sensitive_logon值为false.

MTH@MTH> conn / as sysdba
Connected.

SYS@MTH> alter system set sec_case_sensitive_logon=false;

System altered.

SYS@MTH>
SYS@MTH> show parameter sec_case_sensitive_logon

NAME                                 TYPE                             VALUE
------------------------------------ -------------------------------- ------------------------------
sec_case_sensitive_logon             boolean                          FALSE
SYS@MTH>
SYS@MTH> conn mth/MTH
Connected.