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Friday, August 9, 2013

Oracle Password Verification function

Password Verification : Enforcing Password Complexity

Password complexity is enforced using a verification function. Oracle provide an example password verification function in the "$ORACLE_HOME/rdbms/admin/utlpwdmg.sql" file, but you can code a custom one if you prefer. The function must accept three parameters (username, password and old_password) and return a boolean value, where the value TRUE signifies the password is valid. The simple example below just forces the password to be at least 8 characters long.

CREATE OR REPLACE FUNCTION my_verification_function (
  username      VARCHAR2,
  password      VARCHAR2,
  old_password  VARCHAR2)
  RETURN BOOLEAN AS
BEGIN
  IF LENGTH(password) < 8 THEN
    RETURN FALSE;
  ELSE
    RETURN TRUE;
  END IF;
END my_verification_function;
/

In the above we have restricted that password must contain greater that 8 characters.

Once the function is compiled under the SYS schema it can be referenced by the PASSWORD_VERIFY_FUNCTION parameter of a profile.

You can enable Password verify Function as below:
 
ALTER PROFILE my_profile LIMIT
  PASSWORD_VERIFY_FUNCTION my_verification_function;
The code below assigns the completed profile to a user and tests it.
SQL> ALTER USER scott PROFILE my_profile;

User altered.

SQL> ALTER USER scott IDENTIFIED BY small;
ALTER USER scott IDENTIFIED BY small
*
ERROR at line 1:
ORA-28003: password verification for the specified password failed
ORA-28003: password verification for the specified password failed


SQL> ALTER USER scott IDENTIFIED BY much_bigger;

User altered.

SQL>
A more complete example of a password verification function is provided by the "$ORACLE_HOME/rdbms/admin/utlpwdmg.sql" script.

If you have trouble thinking of strong passwords, try using a password generator like RandPass.com. It creates random strong passwords with a phonetic sound, making them easier to remember.
In Oracle 11g the "$ORACLE_HOME/rdbms/admin/utlpwdmg.sql" script has been updated to improve the default password verification function. It also applies the function to the DEFAULT profile, enabling it for all users.


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