Oracle 11g "password delayed verification" feature

The goal of the experiment ： test oracle 11g “ Password delay verification ” characteristic .

Oracle 11g Introduced “ Password delay verification ” New features , If you enter the wrong password to log in , With the increase of login times with wrong password , The verification time before each login will increase accordingly , The purpose of this function is to prevent hackers from breaking the database password .

But for normal systems , Due to the change of password , Especially from 10g( The default password is case insensitive ) Upgrade to 11g( The default password is case sensitive ), The client keeps repeating the wrong password to try to log in , At this point, it will cause a long time of Library Cache Lock wait for , This abnormal state is not uncommon in production environments .

The following simulates this scenario ：

database ：oracle 11.2.0.4

Log in and copy

      
      

       
       20:32:18 SQL> conn liujun/leo ( Login consumption 3 second )
       
       
ERROR:
       
       
ORA-01017: invalid username/password; logon denied
       
       

       
       

       
       
Warning: You are no longer connected to ORACLE.
       
       
20:32:21 SQL> conn liujun/leo ( Login consumption 2 second )
       
       
ERROR:
       
       
ORA-01017: invalid username/password; logon denied
       
       

       
       

       
       
20:32:23 SQL> conn liujun/leo ( Login consumption 4 second )
       
       
ERROR:
       
       
ORA-01017: invalid username/password; logon denied
       
       

       
       

       
       
20:32:27 SQL> conn liujun/leo ( Login consumption 3 second )
       
       
ERROR:
       
       
ORA-01017: invalid username/password; logon denied
       
       

       
       

       
       
20:32:30 SQL> conn liujun/leo ( Login consumption 4 second )
       
       
ERROR:
       
       
ORA-01017: invalid username/password; logon denied
       
       

       
       

       
       
20:32:34 SQL> conn liujun/leo ( Login consumption 5 second )
       
       
ERROR:
       
       
ORA-01017: invalid username/password; logon denied
       
       

       
       

       
       
20:32:39 SQL> conn liujun/leo ( Login consumption 5 second )
       
       
ERROR:
       
       
ORA-01017: invalid username/password; logon denied
       
       

       
       

       
       
20:32:44 SQL> conn liujun/leo ( Login consumption 7 second )
       
       
ERROR:
       
       
ORA-01017: invalid username/password; logon denied
       
       

       
       

       
       
20:32:51 SQL> conn liujun/leo
       
       
ERROR:
       
       
ORA-01017: invalid username/password; logon denied
       
       

       
       

       
       
20:33:00 SQL> conn liujun/leo ( Login consumption 9 second )
       
       

       
       
ERROR:
       
       
ORA-28000: the account is locked
      
      
      
      

       
       
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The experimental environment is session Even so , If the production environment , Hundreds of session All use the wrong password to connect , It will cause serious Library Cache Lock Waiting events for . Front end users log in too many with wrong passwords , It will lead to a long wait for entering the correct password , It feels like a database hang live . However, once the correct password is entered into the account , The delay will clear 0.

When it comes to this problem , Can pass event 28401 Turn off the feature ：

Log in and copy

      
      

       
       alter system set event='28401 trace name context forever,level 1' scope=spfile;
      
      
      
      

       
       
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explain ： Parameters SEC_CASE_SENSITIVE_LOGON Control password case sensitivity

Refer to the website ：​ ​https://blog.csdn.net/zhang123456456/article/details/80983352​​

Mos file ：【Doc ID 1309738.1】