Database security systems that depend on passwords require that passwords be kept secret at all times.

Because passwords are vulnerable to theft and misuse, Oracle Database uses a password management policy. Database administrators and security officers control this policy through user profiles, enabling greater control of database security.

You can use the CREATE PROFILE statement to create a user profile. The profile is assigned to a user with the CREATE USER or ALTER USER statement.

The DBA_USERS_WITH_DEFPWD data dictionary view can find user accounts that use default passwords.

1. Log in to the CDB root or to a PDB by using SQL*Plus with the SYSDBA administrative privilege.

   For example, to log in to a PDB:

   sqlplus sys@pdb_name as sysdba
   Enter password: password
   

   To find the available PDBs in a CDB, log in to the CDB root container and then query the PDB_NAME column of the DBA_PDBS data dictionary view. To check the current container, run the show con_name command.

2. Query the DBA_USERS_WITH_DEFPWD data dictionary view.

   For example, to find both the names of accounts that have default passwords and the status of the account:

   SELECT d.username, u.account_status 
   FROM DBA_USERS_WITH_DEFPWD d, DBA_USERS u 
   WHERE d.username = u.username 
   ORDER BY 2,1;
   
   USERNAME  ACCOUNT_STATUS
   --------- ---------------------------
   SCOTT     EXPIRED & LOCKED
   

3. Change the passwords for any accounts that the DBA_USERS_WITH_DEFPWD view lists.

   Oracle recommends that you do not assign these accounts passwords that they may have had in previous releases of Oracle Database.

   For example:

   ALTER USER SCOTT ACCOUNT UNLOCK IDENTIFIED BY password;
   

   Replace password with a password that is secure.

A profile is a collection of parameters that sets limits on database resources.

If you assign the profile to a user, then that user cannot exceed these limits. You can use profiles to configure database settings such as sessions per user, logging and tracing features, and so on. Profiles can also control user passwords. To find information about the current password settings in the profile, you can query the DBA_PROFILES data dictionary view.

Table 3-1 lists the password-specific parameter settings in the default profile.

You can modify profile limits such as failed login attempts, password lock times, password reuse, and several other settings.

• Use the ALTER PROFILE statement to modify a user's profile limits.
  For example:

  ALTER PROFILE prof LIMIT
   FAILED_LOGIN_ATTEMPTS 9
   PASSWORD_LOCK_TIME 10
   INACTIVE_ACCOUNT_TIME 21;

Oracle provides scripts that you can use to disable and enable the default password security settings.

1. Modify your applications to conform to the password security settings from Oracle Database 11g or later.
2. Update your database to use the security configuration that suits your business needs, using one of the following methods:

   • Manually update the database security configuration.

   • Run the secconf.sql script to apply the default password settings from Oracle Database 11g or later. You can customize this script to have different security settings if you like, but remember that the settings listed in the original script are Oracle-recommended settings.

Oracle Database can lock a user's account after a specified number of consecutive failed log-in attempts.

• To lock user accounts automatically after a specified time interval or to require database administrator intervention to be unlocked, set the PASSWORD_LOCK_TIME profile parameter in the CREATE PROFILE or ALTER PROFILE statement.
  For example, to set the time interval to 10 days:

  CREATE PROFILE prof LIMIT
   ...
   PASSWORD_LOCK_TIME 10;

  Note the following:

  • You can lock accounts manually, so that they must be unlocked explicitly by a database administrator.

  • You can specify the permissible number of failed login attempts by using the CREATE PROFILE statement. You can also specify the amount of time an account remains locked.

  • Each time the user unsuccessfully logs in, Oracle Database increases the delay exponentially with each login failure.

  • If you do not specify a time interval for unlocking the account, then PASSWORD_LOCK_TIME assumes the value specified in a default profile. (The recommended value is 1 day.) If you specify PASSWORD_LOCK_TIME as UNLIMITED, then you must explicitly unlock the account by using an ALTER USER statement. For example, assuming that PASSWORD_LOCK_TIME UNLIMITED is specified for johndoe, then you use the following statement to unlock the johndoe account:

    ALTER USER johndoe ACCOUNT UNLOCK;
    

  • After a user successfully logs into an account, Oracle Database resets the unsuccessful login attempt count for the user. If it is non-zero, then the count is set to zero.

  • A locked CDB common user account will be locked across all PDBs in the CDB. A locked application common user account will be locked across all PDBs that are associated with the application root.

The CREATE PROFILE statement can lock user accounts if a user’s attempt to log in violates the CREATE PROFILE settings.

Example 3-1 sets the maximum number of failed login attempts for the user johndoe to 10 (the default), and the amount of time the account locked to 30 days. The account will unlock automatically after 30 days.

CREATE PROFILE prof LIMIT
 FAILED_LOGIN_ATTEMPTS 10
 PASSWORD_GRACE_TIME 3

ALTER USER johndoe PROFILE prof;

When you explicitly lock a user account, the account cannot be unlocked automatically. Only a security administrator can unlock the account.

ALTER USER susan ACCOUNT LOCK;

You can ensure that users do not reuse previous passwords for an amount of time or for a number of password changes.

• To configure the ability of users to reuse earlier passwords, set the PASSWORD_REUSE_TIME and PASSWORD_REUSE_MAX parameters in the CREATE PROFILE or ALTER PROFILE statement.
  For example, restrict the number of days (or a fraction of a day) between the earlier use of a password and its next use to 30 days and the number of password changes required before a password can be reused to 10:

  CREATE PROFILE prof LIMIT
   ...
   PASSWORD_REUSE_TIME 30
   PASSWORD_REUSE_MAX 10;

  Note the following:

  • If you do not specify a parameter, then the user can reuse passwords at any time, which is not a good security practice.
  • If neither parameter is UNLIMITED, then password reuse is allowed, but only after meeting both conditions. The user must have changed the password the specified number of times, and the specified number of days must have passed since the previous password was last used. For example, suppose that the profile of user A had PASSWORD_REUSE_MAX set to 10 and PASSWORD_REUSE_TIME set to 30. User A cannot reuse a password until he or she has reset the password 10 times, and until 30 days had passed since the password was last used.
  • If either parameter is specified as UNLIMITED, then the user can never reuse a password.
  • If you set both parameters to UNLIMITED, then Oracle Database ignores both, and the user can reuse any password at any time.
  • If you specify DEFAULT for either parameter, then Oracle Database uses the value defined in the DEFAULT profile, which sets all parameters to UNLIMITED. Oracle Database thus uses UNLIMITED for any parameter specified as DEFAULT, unless you change the setting for that parameter in the DEFAULT profile.

You can specify a password lifetime, after which the password expires.

This means that the next time the user logs in with the current, correct password, he or she is prompted to change the password. By default, there are no complexity or password history checks, so users can still reuse any previous or weak passwords. You can control these factors by setting the PASSWORD_REUSE_TIME, PASSWORD_REUSE_MAX, and PASSWORD_VERIFY_FUNCTION parameters.

In addition, you can set a grace period, during which each attempt to log in to the database account receives a warning message to change the password. If the user does not change it by the end of that period, then Oracle Database expires the account.

As a database administrator, you can manually set the password state to be expired, which sets the account status to EXPIRED. The user must then follow the prompts to change the password before the logon can proceed.

For example, in SQL*Plus, suppose user SCOTT tries to log in with the correct credentials, but his password has expired. User SCOTT will then see the ORA-28001: The password has expired error and be prompted to change his password, as follows:

Changing password for scott
New password: new_password
Retype new password: new_password
Password changed.

When you set a lifetime for a password, the user must create a new password when this lifetime ends.

• To specify a lifetime for passwords, set the PASSWORD_LIFE_TIME parameter in the CREATE PROFILE or ALTER PROFILE statement.
  For example, to set the password life time to 180 days:

  CREATE PROFILE prof LIMIT
   ...
   PASSWORD_LIFE_TIME 180;

You can check the status of any account, whether it is open, in grace, or expired.

• To check the status of a user account, query the ACCOUNT_STATUS column of the DBA_USERS data dictionary view.
  For example:

  SELECT ACCOUNT_STATUS FROM DBA_USERS WHERE USERNAME = 'username';

After a password is created, it follows a life cycle and grace period in four phases.

Figure 3-1 shows the life cycle of the password lifetime and grace period.

Figure 3-1 Password Change Life Cycle

Description of "Figure 3-1 Password Change Life Cycle"

In this figure:

• Phase 1: After the user account is created, or the password of an existing account is changed, the password lifetime period begins.

• Phase 2: This phase represents the period of time after the password lifetime ends but before the user logs in again with the correct password. The correct credentials are needed for Oracle Database to update the account status. Otherwise, the account status will remain unchanged. Oracle Database does not have any background process to update the account status. All changes to the account status are driven by the Oracle Database server process on behalf of authenticated users.

• Phase 3: When the user finally does log in, the grace period begins. Oracle Database then updates the DBA_USERS.EXPIRY_DATE column to a new value using the current time plus the value of the PASSWORD_GRACE_TIME setting from the account's password profile. At this point, the user receives an ORA-28002 warning message about the password expiring in the near future (for example, ORA-28002 The password will expire within 7 days if PASSWORD_GRACE_TIME is set to 7 days), but the user can still log in without changing the password. The DBA_USERS.EXPIRY_DATE column shows the time in the future when the user will be prompted to change their password.

• Phase 4: After the grace period (Phase 3) ends, the ORA-28001: The password has expired error appears, and the user is prompted to change the password after entering the current, correct password before the authentication can proceed. If the user has an Oracle Active Data Guard configuration, where there is a primary and a stand-by database, and the authentication attempt is made on the standby database (which is a read-only database), then the ORA-28032: Your password has expired and the database is set to read-only error appears. The user should log into the primary database and change the password there.

During any of these four phases, you can query the DBA_USERS data dictionary view to find the user's account status in the DBA_USERS.ACCOUNT_STATUS column.

In the following example, the profile assigned to johndoe includes the specification of a grace period: PASSWORD_GRACE_TIME = 3 (the recommended value). The first time johndoe tries to log in to the database after 90 days (this can be any day after the 90th day, that is, the 91st day, 100th day, or another day), he receives a warning message that his password will expire in 3 days. If 3 days pass, and if he does not change his password, then the password expires. After this, he receives a prompt to change his password on any attempt to log in.

CREATE PROFILE prof LIMIT
 FAILED_LOGIN_ATTEMPTS 4
 PASSWORD_LIFE_TIME 90
 PASSWORD_GRACE_TIME 3;

ALTER USER johndoe PROFILE prof;

A database administrator or a user who has the ALTER USER system privilege can explicitly expire a password by using the CREATE USER and ALTER USER statements. The following statement creates a user with an expired password. This setting forces the user to change the password before the user can log in to the database.

CREATE USER jbrown 
 IDENTIFIED BY password
 ...
 PASSWORD EXPIRE;

There is no "password unexpire" clause for the CREATE USER statement, but an account can be "unexpired" by changing the password on the account.

Be careful if you set the PASSWORD_LIFE_TIME parameter of CREATE PROFILE or ALTER PROFILE to a low value (for example, 1 day).

The PASSWORD_LIFE_TIME limit of a profile is measured from the last time that an account's password is changed, or the account creation time if the password has never been changed. These dates are recorded in the PTIME (password change time) and CTIME (account creation time) columns of the SYS.USER$ system table. The PASSWORD_LIFE_TIME limit is not measured starting from the timestamp of the last change to the PASSWORD_LIFE_TIME profile parameter, as may be initially thought. Therefore, any accounts affected by the changed profile whose last password change time was more than PASSWORD_LIFE_TIME days ago immediately expire and enter their grace period on their next connection, issuing the ORA-28002: The password will expire within n days warning.

As a database administrator, you can find an account's last password change time as follows:

ALTER SESSION SET NLS_DATE_FORMAT='DD-MON-YYYY HH24:MI:SS';
SELECT PTIME FROM SYS.USER$ WHERE NAME = 'user_name'; -- Password change time

To find when the account was created and the password expiration date, issue the following query:

SELECT CREATED, EXPIRY_DATE FROM DBA_USERS WHERE USERNAME = 'user_name';

If the user who is assigned this profile is currently logged in when you set the PASSWORD_LIFE_TIME parameter and remains logged in, then Oracle Database does not change the user's account status from OPEN to EXPIRED(GRACE) when the currently listed expiration date passes. The timing begins only when the user logs into the database. You can check the user's last login time as follows:

SELECT LAST_LOGIN FROM DBA_USERS WHERE USERNAME = 'user_name';

When making changes to a password profile, a database administrator must be aware that if some of the users who are subject to this profile are currently logged in to the Oracle database while their password profile is being updated by the administrator, then those users could potentially remain logged in to the system even beyond the expiration date of their password. You can find the currently logged in users by querying the USERNAME column of the V$SESSION view.

This is because the expiration date of a user's password is based on the timestamp of the last password change on their account plus the value of the PASSWORD_LIFE_TIME password profile parameter set by the administrator. It is not based on the timestamp of the last change to the password profile itself.

Note the following:

• If the user is not logged in when you set PASSWORD_LIFE_TIME to a low value, then the user's account status does not change until the user logs in.

• You can set the PASSWORD_LIFE_TIME parameter to UNLIMITED, but this only affects accounts that have not entered their grace period. After the grace period expires, the user must change the password.

Complexity verification checks that each password is complex enough to protect against intruders who try to guess user passwords.

Using a complexity verification function forces users to create strong, secure passwords for database user accounts. You must ensure that the passwords for your users are complex enough to provide reasonable protection against intruders who try to break into the system by guessing passwords.

Be aware that if you associate a password verification function with a user's profile, then dropping the password verification function will prevent the user from changing his or her password and cause an ORA-7443: function for password verification not found error.

Oracle Database provides four password verification functions to check password complexity.

These functions are in the catpvf.sql PL/SQL script (located in $ORACLE_HOME/rdbms/admin). When these functions are enabled, they can check whether users are correctly creating or modifying their passwords. When enabled, password complexity checking is not enforced for user SYS; it only applies to non-SYS users. For better security of passwords, Oracle recommends that you associate the password verification function with the default profile.

The password complexity functions enable you to customize how users access your data.

Before you can use the password complexity verification functions in the CREATE PROFILE or ALTER PROFILE statement, you must be granted the EXECUTE privilege on them.

The password verification functions are located in the SYS schema.

The verify_function_11G function originated in Oracle Database Release 11g.

This function checks for the following requirements when users create or modify passwords:

• The password contains no fewer than 8 characters and includes at least one numeric and one alphabetic character.

• The password is not the same as the user name, nor is it the user name reversed or with the numbers 1–100 appended.

• The password is not the same as the server name or the server name with the numbers 1–100 appended.

• The password does not contain oracle (for example, oracle with the numbers 1–100 appended).

• The password is not too simple (for example, welcome1, database1, account1, user1234, password1, oracle123, computer1, abcdefg1, or change_on_install).

• The password differs from the previous password by at least 3 characters.

The following internal check is also applied:

• The password does not contain the double-quotation character ("). However, it can be surrounded by double-quotation marks.

The ora12c_verify_function function fulfills the Department of Defense Database Security Technical Implementation Guide requirements.

This function checks for the following requirements when users create or modify passwords:

• The password contains no fewer than 8 characters and includes at least one numeric and one alphabetic character.

• The password is not the same as the user name or the user name reversed.

• The password is not the same as the database name.

• The password does not contain the word oracle (such as oracle123).

• The password differs from the previous password by at least 8 characters.

• The password contains at least 1 special character.

The following internal check is also applied:

• The password does not contain the double-quotation character ("). However, it can be surrounded by double-quotation marks.

The ora12c_strong_verify_function function fulfills the Department of Defense Database Security Technical Implementation Guide requirements.

This function checks for the following requirements when users create or modify passwords:

• The password must contain at least 2 upper case characters, 2 lower case characters, 2 numeric characters, and 2 special characters. These special characters are as follows:

  ‘ ~ ! @ # $ % ^ & * ( ) _ - + = { } [ ] \ / < > , . ; ? ' : | (space) 

• The password must differ from the previous password by at least 4 characters.

The following internal check is also applied:

• The password does not contain the double-quotation character ("). It can be surrounded by double-quotation marks, however.

The ora12c_stig_verify_function function fulfills the Security Technical Implementation Guide (STIG) requirements.

This function checks for the following requirements when users create or modify passwords:

• The password has at least 15 characters.

• The password has at least 1 lower case character and at least 1 upper case character.

• The password has at least 1 digit.

• The password has at least 1 special character.

• The password differs from the previous password by at least 8 characters.

The following internal check is also applied:

• The password does not contain the double-quotation character ("). However, it can be surrounded by double-quotation marks.

The ora12c_stig_verify_function function is the default handler for the ORA_STIG_PROFILE profile, which is available in a newly-created or upgraded Oracle database.

Oracle Database enables you to customize password complexity for your site.

You can create your own password complexity verification function in the SYS schema, similar to the functions that are defined in admin/catpvf.sql. In fact, Oracle recommends that you do so to further secure your site’s passwords.

Note the following:

• Do not include Data Definition Language (DDL) statements in the custom password complexity verification function. DDLs are not allowed during the execution of password complexity verification functions.

• Do not modify the admin/catpvf.sql script or the Oracle-supplied password complexity functions. You can create your own functions based on the contents of these files.

• If you make no modifications to the utlpwdmg.sql script, then it uses the ora12c_verify_function function as the default function.

The catpvf.sql script can be customized to enable password complexity verification.

1. Log in to SQL*Plus with administrative privileges.

   For example:

   CONNECT SYSTEM
   Enter password: password
   

2. Run the catpvf.sql script (or your modified version of this script) to create the password complexity functions in the SYS schema.

   @$ORACLE_HOME/rdbms/admin/catpvf.sql
   

3. Grant any users who must use this function the EXECUTE privilege on it.

   For example:

   GRANT pmsith EXECUTE ON ora12c_strong_verify_function;
   

4. In the default profile or the user profile, set the PASSWORD_VERIFY_FUNCTION setting to either the sample password complexity function in the catpvf.sql script, or to your customized function. Use one of the following methods:

   • Log in to SQL*Plus with administrator privileges and use the CREATE PROFILE or ALTER PROFILE statement to enable the function. Ensure that you have the EXECUTE privilege on the function.

     For example, to update the default profile to use the ora12c_strong_verify_function function:

     ALTER PROFILE default LIMIT 
      PASSWORD_VERIFY_FUNCTION ora12c_strong_verify_function;
     

   • In Oracle Enterprise Manager Cloud Control, from the Administration menu, select Security, and then Profiles. Select the Password tab. Under Complexity, from the Complexity function list, select the name of the complexity function that you want. Click Apply.

ALTER PROFILE DEFAULT LIMIT PASSWORD_VERIFY_FUNCTION NULL;

Oracle Database ensures that the passwords for secure roles are case sensitive.

If before upgrading to the current release, you created secure roles by using the IDENTIFIED BY clause of the CREATE ROLE statement, and if upon upgrading to Oracle Database 12c release 12.2, you set the SQLNET.ALLOWED_LOGON_VERSION_SERVER parameter to one of the Exclusive Modes 12 or 12a, then you must change the password for these secure roles in order for them to remain usable. Because Exclusive Mode is now the default, secure roles that were created in earlier releases (such as Oracle Database 10g, in which the 10G password version was the default) will need to have their passwords changed. These passwords will automatically be case sensitive.

You can query the PASSWORD_REQUIRED and AUTHENTICATION_TYPE columns of the DBA_ROLES data dictionary view to find any secure roles that must have their password changed after upgrading to the current release, in order to become usable again.

By default, Oracle Database uses Exclusive Mode, which does not permit case-insensitive passwords, to manage password versions.

In a default installation, the SQLNET.ALLOWED_LOGON_VERSION_SERVER parameter is set to 12 to enable Exclusive Mode. Exclusive Mode requires that the password-based authentication protocol use one of the case-sensitive password versions (11G or 12C) for the account that is being authenticated. Exclusive Mode excludes the use of the 10G password version that was used in earlier releases. After you upgrade to Oracle Database 12c release 2 (12.2) or later, accounts that use the 10G password version become inaccessible. This occurs because the server runs in Exclusive Mode by default, and Exclusive Mode cannot use the old 10G password version to authenticate the client. The server is left with no password version with which to authenticate the client.

The user accounts from Release 10g use the 10G password version. Therefore, you should find the user accounts that use the 10G password version, and then reset the passwords for these accounts. This generates the appropriate password version based on the setting of the SQLNET.ALLOWED_LOGON_VERSION_SERVER parameter, as follows:

• SQLNET.ALLOWED_LOGON_VERSION_SERVER=8 generates all three password versions 10G, 11G, and 12C.

• SQLNET.ALLOWED_LOGON_VERSION_SERVER=12 generates both 11G and 12C password versions, and removes the 10G password version.

• SQLNET.ALLOWED_LOGON_VERSION_SERVER=12a generates only the 12C password version.

If you first relax the SQLNET.ALLOWED_LOGON_VERSION_SERVER setting to a more permissive value (such as SQLNET.ALLOWED_LOGON_VERSION_SERVER=8) and then import the user accounts from an Oracle Database release 10g (or earlier) release into the current database release, then because the 10G password version (used in the older release) is not case sensitive, these users will still be able to log into the database using any case for their password. But when such a user changes their password, the new 11G and 12C password versions are generated automatically, and their password will automatically become case sensitive.

For better security, find and reset passwords for user accounts that use the 10G password version so that they use later, more secure password versions.

SELECT USERNAME,PASSWORD_VERSIONS FROM DBA_USERS;

USERNAME                       PASSWORD_VERSIONS
------------------------------ -----------------
JONES                          10G 11G 12C 
ADAMS                          10G 11G
CLARK                          10G 11G
PRESTON                        11G
BLAKE                          10G

1. Query the DBA_USERS view to find users who only use the 10G password version.

   SELECT USERNAME FROM DBA_USERS 
   WHERE ( PASSWORD_VERSIONS = '10G '
   OR PASSWORD_VERSIONS = '10G HTTP ')
   AND USERNAME <> 'ANONYMOUS';
   

2. Configure the database so that it does not run in Exclusive Mode, as follows:
   1. Edit the SQLNET.ALLOWED_LOGON_VERSION_SERVER setting in the sqlnet.ora file so that it is more permissive than the default. For example:

      SQLNET.ALLOWED_LOGON_VERSION_SERVER=11

   2. If you are in the CDB root, then restart the database (for example, SHUTDOWN IMMEDIATE followed by STARTUP). If you are in a PDB, connect to the root using the SYSDBA administrative privilege, and then enter the following statements:

      ALTER PLUGGABLE DATABASE pdb_name CLOSE IMMEDIATE;
      ALTER PLUGGABLE DATABASE pdb_name OPEN;

3. Expire the users that you found when you queried the DBA_USERS view to find users who only use the 10G password version.

   You must expire the users who have only the 10G password version, and do not have one or both of the 11G or 12C password versions.

   For example:

   ALTER USER username PASSWORD EXPIRE;
   

4. Ask the users whose passwords you expired to log in.

   When the users log in, they are prompted to change their passwords. The database generates the missing 11G and 12C password versions for their account, in addition to the 10G password version. The 10G password version continues to be present, because the database is running in the permissive mode.

5. Ensure that the client software with which the users are connecting has the O5L_NP ability.

   All Oracle Database release 11.2.0.3 and later clients have the O5L_NP ability. If you have an earlier Oracle Database client, then you must install the CPUOct2012 patch.

6. After all clients have the O5L_NP capability, set the security for the server back to Exclusive Mode, as follows:
   1. Remove the SQLNET.ALLOWED_LOGON_VERSION_SERVER parameter from the server sqlnet.ora file, or set the value of SQLNET.ALLOWED_LOGON_VERSION_SERVER in the server sqlnet.ora file back to 12, to set it to an Exclusive Mode.

      SQLNET.ALLOWED_LOGON_VERSION_SERVER = 12

   2. If you are in the CDB root, then restart the database (for example, SHUTDOWN IMMEDIATE followed by STARTUP). If you are in a PDB, connect to the root using the SYSDBA administrative privilege, and then enter the following statements:

      ALTER PLUGGABLE DATABASE pdb_name CLOSE IMMEDIATE;
      ALTER PLUGGABLE DATABASE pdb_name OPEN;

7. Find the accounts that still have the 10G password version.

   SELECT USERNAME FROM DBA_USERS
   WHERE PASSWORD_VERSIONS LIKE '%10G%' 
   AND USERNAME <> 'ANONYMOUS';

8. Expire the accounts that still have the 10G password version.

   ALTER USER username PASSWORD EXPIRE;

9. Ask these users to log in to their accounts.

   When the users log in, they are prompted to reset their passwords. The database then generates only the 11G and 12C password versions for their accounts. Because the database is running in Exclusive Mode, the 10G password version is no longer generated.

10. Rerun the following query:

    SELECT USERNAME FROM DBA_USERS
    WHERE PASSWORD_VERSIONS LIKE '%10G%' 
    AND USERNAME <> 'ANONYMOUS';

    If this query does not return any results, then it means that no user accounts have the 10G password version. Hence, the database is running in a more secure mode than in previous releases.

The password file version and whether the password file contains accounts from previous releases affects the case sensitivity of administrative authentication.

Any password file account from a previous release that has only the 10G verifier can only perform case-insensitive administrative authentication.

After a password file has been created (using the orapwd utility), the Oracle database updates it when an administrative privilege is granted to or revoked from the user, or when the password of a user who has an administrative privilege is updated.

The password file is external to the database, allowing the Oracle database to authenticate administrative connections (using the AS administrative_privilege_name clause, for example, AS SYSKM) even when the database is in the CLOSED state.

When an administrative connection is attempted, the Oracle database searches for the user in the password file to verify their password and to ensure that the user has been granted the requested administrative privilege. The Oracle database can use the password file to authenticate an administrative connection even when the database is in the CLOSED state.

The version of the password file and the type of verifier that it contains for the administrative user affects whether the authentication of that administrative user can be done in a case-sensitive fashion.

However, password files from earlier Oracle Database releases will by default retain their original case-insensitive verifiers. Oracle recommends that you force case sensitivity in these older password files by migrating the password file from one format to another and changing the password of any account that has only a 10G verifier, using the following syntax:

orapwd FILE=new_pwd_file_name INPUT_FILE=old_pwd_file_name [FORMAT=12.2]

The FORMAT and FORCE options are not mandatory and can be omitted. If you omit FORMAT, then it defaults to 12.2. If the FILE and INPUT_FILE options are set to the same file, then the FORCE option would be required.

For example:

orapwd FILE='/u01/oracle/dbs/old_pwd_file_name' INPUT_FILE='/u01/oracle/dbs/new_pwd_file_name' FORMAT=12.2 FORCE=y
Enter password for SYS: password

Assuming that the user accounts in the password file have the newer verifiers (11G and 12C), this command creates a case-sensitive password file called new_pwd_file_name that will authenticate administrative connections in a case-sensitive fashion. If any user account in the password file uses only the older 10G verifier, then the password of this account must be changed to enable case-sensitive authentication of administrative connections to that account. Afterward, if you connect using this password, it succeeds—as long as you enter it using the exact case in which it was created. If you enter the same password but with a different case, then the authentication attempt that uses the password fails.

If you imported user accounts from a previous release and these accounts were created with SYSDBA or SYSOPER administrative privilege, then they will be included in the password file. The passwords for these accounts are case insensitive. The next time these users change their passwords, the passwords become case sensitive. For greater security, have these users change their passwords. You can use the ALTER USER PASSWORD EXPIRE statement to expire a user's password. Afterward, ask the user log in again, so that the user will be prompted to change his or her password.

When you create a database link connection, you must define a user name and password for the connection.

When you create the database link connection, the password is case sensitive. How a user enters his or her password for the database link depends on the release to which the database link was created:

• Users can connect from a pre-Oracle Database 12c database to an Oracle Database 12c or later database. Because case sensitivity is enabled, then the user must enter the password using the case that was used when the account was created.

• If the user connects from an Oracle Database 12c or later database to a pre-Oracle Database 12c database, and if the SEC_CASE_SENSITIVE_LOGON parameter in the pre-Release 12c database had been set to FALSE, then the password for this database link can be specified using any case.

You can find the user accounts for existing database links by querying the V$DBLINK view. For example:

SELECT DB_LINK, OWNER_ID FROM V$DBLINK;

The 12C password hash protects against password-based security threats by including support for mixed case passwords.

The cryptographic hash function used for generating the 12C version of the password hash is based on a de-optimized algorithm involving Password-Based Key Derivation Function 2 (PBKDF2) and the SHA-512 cryptographic hash functions. The PBKDF2 algorithm introduces computational asymmetry in the challenge that faces an intruder who is trying to recover the original password when in possession of the 12C version of the password hash. The 12C password generation performs a SHA-512 hash of the PBKDF2 output as its last step. This two-step approach used in the 12C password version generation allows server CPU resources to be conserved when the client has the O7L_MR capability. This is because during authentication, the server only needs to perform a single SHA-512 hash of a value transmitted by the O7L_MR capable client, to validate it against the 12C version of the password hash.

In addition, the 12C password version adds a salt to the password when it is hashed, which provides additional protection. (Salt is a random string that is added to the data before it is encrypted, making it more difficult for attackers to steal the data by matching patterns of ciphertext to known ciphertext samples.) The 12C password version enables your users to create far more complex passwords. The 12C password version's use of sale, its use of PBKDF2 de-optimization, and its support for mixed-case passwords makes it more expensive for an intruder to perform dictionary or brute force attacks on the 12C password version in an attempt to recover the user's password. Oracle recommends that you use the 12C version of the password hash.

The password hash values are considered to be extremely sensitive, because they are used as a "shared secret" between the server and person who is logging in. If an intruder learns this secret, then the protection of the authentication is immediately and severely compromised. Remember that administrative users who have account management privileges, administrative users who have the SYSDBA administrative privilege, or even users who have the EXP_FULL_DATABASE role can immediately access the password hash values. Therefore, this type of administrative user must be trustworthy if the integrity of the database password-based authentication is to be preserved. If you cannot trust these administrators, then it is better to deploy a directory server (such as Oracle Database Enterprise User Security) so that the password hash values remain within the Enterprise User Security directory and are never accessible to anyone except the Enterprise User Security administrator.

By default, Oracle Database generates two versions of the password hash: 11G and 12C.

The version of the password hash that Oracle Database uses to authenticate a given client depends on the client’s ability, and the settings for the SQLNET.ALLOWED_LOGON_VERSION_CLIENT and SQLNET.ALLOWED_LOGON_VERSION_SERVER parameters. See the column “Ability Required of the Client” in the “SQLNET.ALLOWED_LOGON_VERSION_SERVER Settings” table in the SQLNET.ALLOWED_LOGON_VERSION_SERVER parameter description in Oracle Database Net Services Reference for detailed information about how the client authentication works with password versions.

The 10G password version, which was generated in Oracle Database 10g, is not case sensitive. Both the 11G and 12C password versions are case sensitive.

In Oracle Database 12g release 2 (12.2), the sqlnet.ora parameter SQLNET.ALLOWED_LOGON_VERSION_SERVER defaults to 12, which is Exclusive Mode and prevents the use of the 10G password version, and the SQLNET.ALLOWED_LOGON_VERSION_CLIENT parameter defaults to 11. For new accounts, when the client is Oracle Database 12c, then Oracle Database uses the 12C password version exclusively with clients that are running the Oracle Database 12c release software. For accounts that were created before Oracle Database release 12c, logins will succeed as long as the client has the O5L_NP ability, because an 11G password version normally exists for accounts created in earlier releases such as Oracle Database release 11g. For a very old account (for example, from Oracle Database release 10g), the user’s password may need to be reset, in order to create a SHA-1 password version for the account. To configure this server to generate only the 12C password version whenever a new account is created or an existing account password is changed, then set the SQLNET.ALLOWED_LOGON_VERSION_SERVER parameter to 12a. However, if you want your applications to be compatible with older clients, then ensure that SQLNET.ALLOWED_LOGON_VERSION_SERVER is set to 12, which is the default.

How you set the SQLNET.ALLOWED_LOGON_VERSION_SERVER parameter depends on the balance of security and interoperability with older clients that your system requires. You can control the levels of security as follows:

• Greatest level of compatibility: To configure the server to generate all three versions of the password hash (the 12C password version, the 11G password version, and the DES-based 10G password version), whenever a new account is created or an existing account password is changed, set the SQLNET.ALLOWED_LOGON_VERSION_SERVER parameter to the value 11 or lower. (Be aware that earlier releases used the value 8 as the default.)

• Recommended level of security: To configure the server to generate both the 12C password version and the 11G password version (but not the 10G password version), whenever a new account is created or an existing account password is changed, set the SQLNET.ALLOWED_LOGON_VERSION_SERVER parameter to the value 12.

• Highest level of security: To configure the server to generate only the 12C password version whenever a new account is created or an existing account password is changed, set the SQLNET.ALLOWED_LOGON_VERSION_SERVER parameter to the value 12a.

During authentication, the following scenarios are possible, based on the kinds of password versions that exist for the account, and on the version of the client software being used:

• Accounts with only the 10G version of the password hash: If you want to force the server to generate the newer versions of the password hash for older accounts, an administrator must expire the password for any account that has only the 10G password version (and none of the more secure password versions, 11G or 12C). You must generate these password versions because the database depends on using these password versions to provide stronger security. You can find these users as follows.

  SELECT USERNAME FROM DBA_USERS 
  WHERE PASSWORD_VERSIONS LIKE '%10G%
  AND USERNAME <> 'ANONYMOUS';
  

  And then expire each account as follows:

  ALTER USER username PASSWORD EXPIRE;
  

  After you have expired each account, notify these users to log in, in which case they will be prompted to change their password. The version of the client determines the password version that is used. The setting of the SQLNET.ALLOWED_LOGON_VERSION_SERVER parameter determines the password versions that are generated. If the client has the O7L_MR ability (Oracle Database release 12c), then the 12C password version is used to authenticate. If the client has the O5L_NP ability but not the O7L_MR ability (such as Oracle Database release 11g clients), then the 11G password version is used to authenticate. You should upgrade all clients to Oracle Database release 12c so that the 12C password version can be used exclusively to authenticate. (By default, Oracle Database release 11.2.0.3 and later clients have the O5L_NP ability, which enables the 11G password version to be used exclusively. If you have an earlier Oracle Database client, then you must install the CPUOct2012 patch.)

  When an account password is expired and the ALLOWED_LOGON_VERSION_SERVER parameter is set to 12 or 12a, then the 10G password version is removed and only one or both of the new password versions are created, depending on how the parameter is set, as follows:

  • If ALLOWED_LOGON_VERSION_SERVER is set to 12 (the default), then both the 11G and 12C versions of the password hash are generated.

  • If ALLOWED_LOGON_VERSION_SERVER is set to 12a, then only the 12C version of the password hash is generated.

  For more details, see the "Generated Password Version" column in the table in the "Usage Notes" section for the SQLNET.ALLOWED_LOGON_VERSION_SERVER parameter in Oracle Database Net Services Reference.

• Accounts with both 10G and 11G versions of the password hash: For users who are using a Release 10g or later client, the user logins will succeed because the 11G version of the password hash is used. However, to use the latest version, expire these passwords, as described in the previous bulleted item for accounts.

• Accounts with only the 11G version of the password hash: The authentication uses the 11G version of the password hash. To use the latest version, expire the passwords, as described in the first bulleted item.

The Oracle Database 12c default configuration for SQLNET.ALLOWED_LOGON_VERSION_SERVER is 12, which means that it is compatible with Oracle Database 12c release 2 (12.2) authentication protocols and later products that use OCI-based drivers, including SQL*Plus, ODBC, Oracle .NET, Oracle Forms, and various third-party Oracle Database adapters. It is also compatible with JDBC type-4 (thin) versions that have had the CPUOct2012 bundle patch applied or starting with Oracle Database 11g, and Oracle Database Client interface (OCI)-based drivers starting in Oracle Database 10g release 10.2. Be aware that earlier releases of the OCI client drivers cannot authenticate to an Oracle database using password-based authentication.

You should set the SQLNET.ALLOWED_LOGON_VERSION_SERVER parameter to 12a so that only the 12C password hash version is used.

An intruder may try to provision a fake server to downgrade authentication and trick the client into using a weaker password hash version.

You can store password credentials database connections by using a client-side Oracle wallet.

An Oracle wallet is a secure software container that stores authentication and signing credentials. This wallet usage can simplify large-scale deployments that rely on password credentials for connecting to databases. When this feature is configured, application code, scripts no longer need embedded user names and passwords. This reduces risk because the passwords are no longer exposed, and password management policies are more easily enforced without changing application code whenever user names or passwords change.

Users (and applications, batch jobs, and scripts) connect to databases by using a standard CONNECT statement that specifies a database connection string.

This string can include a user name and password, and an Oracle Net service name identifying the database on an Oracle Database network. If the password is omitted, the connection prompts the user for the password.

For example, the service name could be the URL that identifies that database, or a TNS alias you entered in the tnsnames.ora file in the database. Another possibility is a host:port:sid string.

The following examples are standard CONNECT statements that could be used for a client that is not configured to use the external password store:

CONNECT salesapp@sales_db.us.example.com
Enter password: password

CONNECT salesapp@orasales
Enter password: password

CONNECT salesapp@ourhost37:1527:DB17
Enter password: password

In these examples, salesapp is the user name, with the unique connection string for the database shown as specified in three different ways. You could use its URL sales_db.us.example.com, or its TNS alias orasales from the tnsnames.ora file, or its host:port:sid string.

However, when clients are configured to use the secure external password store, applications can connect to a database with the following CONNECT statement syntax, without specifying database login credentials:

CONNECT /@db_connect_string

CONNECT /@db_connect_string AS SYSDBA

CONNECT /@db_connect_string AS SYSOPER

In this specification, db_connect_string is a valid connection string to access the intended database, such as the service name, URL, or alias as shown in the earlier examples. Each user account must have its own unique connection string; you cannot create one connection string for multiple users.

In this case, the database credentials, user name and password, are securely stored in an Oracle wallet created for this purpose. The autologin feature of this wallet is turned on, so the system does not need a password to open the wallet. From the wallet, it gets the credentials to access the database for the user they represent.

If your client is configured to use external authentication, such as Windows native authentication or SSL, then Oracle Database uses that authentication method.

The same credentials used for this type of authentication are typically also used to log in to the database. For clients not using such authentication methods or wanting to override them for database authentication, you can set the SQLNET.WALLET_OVERRIDE parameter in sqlnet.ora to TRUE. The default value for SQLNET.WALLET_OVERRIDE is FALSE, allowing standard use of authentication credentials as before.

You can configure a client to use the secure external password store feature by using the mkstore command-line utility.

1. Create a wallet on the client by using the following syntax at the command line:

   mkstore -wrl wallet_location -create
   

   For example:

   mkstore -wrl c:\oracle\product\20.1.0\db_1\wallets -create
   Enter password: password
   

   wallet_location is the path to the directory where you want to create and store the wallet. This command creates an Oracle wallet with the autologin feature enabled at the location you specify. The autologin feature enables the client to access the wallet contents without supplying a password.

   The mkstore utility -create option uses password complexity verification. See About Password Complexity Verification for more information.

2. Create database connection credentials in the wallet by using the following syntax at the command line:

   mkstore -wrl wallet_location -createCredential db_connect_string username
   Enter password: password
   

   For example:

   mkstore -wrl c:\oracle\product\20.1.0\db_1\wallets -createCredential orcl system
   Enter password: password
   

   In this specification:

   • wallet_location is the path to the directory where you created the wallet earlier in this procedure.

   • db_connect_string is the TNS alias you use to specify the database in the tnsnames.ora file or any service name you use to identify the database on an Oracle network. By default, tnsnames.ora is located in the $ORACLE_HOME/network/admin directory on UNIX systems and in ORACLE_HOME\network\admin on Windows.

   • username is the database login credential. When prompted, enter the password for this user.

   Repeat this step for each database you want accessible using the CONNECT /@db_connect_string syntax. The db_connect_string used in the CONNECT /@db_connect_string statement must be identical to the db_connect_string specified in the -createCredential command.

3. In the client sqlnet.ora file, enter the WALLET_LOCATION parameter and set it to the directory location of the wallet you created in Step 1.

   For example, if you created the wallet in $ORACLE_HOME/network/admin and your Oracle home is set to /private/ora11, then you need to enter the following into your client sqlnet.ora file:

   WALLET_LOCATION =
     (SOURCE =
       (METHOD = FILE)
       (METHOD_DATA =
     (DIRECTORY = /private/ora11/network/admin)
     )
    )
   

4. In the client sqlnet.ora file, enter the SQLNET.WALLET_OVERRIDE parameter and set it to TRUE as follows:

   SQLNET.WALLET_OVERRIDE = TRUE
   

   This setting causes all CONNECT /@db_connect_string statements to use the information in the wallet at the specified location to authenticate to databases.

   When external authentication is in use, an authenticated user with such a wallet can use the CONNECT /@db_connect_string syntax to access the previously specified databases without providing a user name and password. However, if a user fails that external authentication, then these connect statements also fail.

   Note:

   If an application uses SSL for encryption, then the sqlnet.ora parameter, SQLNET.AUTHENTICATION_SERVICES, specifies SSL and an SSL wallet is created. If this application wants to use secret store credentials to authenticate to databases (instead of the SSL certificate), then those credentials must be stored in the SSL wallet. After SSL authentication, if SQLNET.WALLET_OVERRIDE = TRUE, then the user names and passwords from the wallet are used to authenticate to databases. If SQLNET.WALLET_OVERRIDE = FALSE, then the SSL certificate is used.

You can set special parameters in the sqlnet.ora file to control how wallets are managed.

Example 3-2 shows a sample sqlnet.ora file with the WALLET_LOCATION and the SQLNET.WALLET_OVERRIDE parameters.

WALLET_LOCATION =
   (SOURCE =
     (METHOD = FILE)
     (METHOD_DATA =
       (DIRECTORY = /private/ora/network/admin)
     )
    )

SQLNET.WALLET_OVERRIDE = TRUE
SSL_CLIENT_AUTHENTICATION = FALSE
SSL_VERSION = 0

The mkstore command-line utility manages credentials from an external password store.

• Listing External Password Store Contents
  You can view the contents, including specific credentials, of a client wallet external password store.
• Adding Credentials to an External Password Store
  You can store multiple credentials in one client wallet.
• Modifying Credentials in an External Password Store
  You can modify the database login credentials that are stored in the wallet if the database connection strings change.
• Deleting Credentials from an External Password Store
  You can delete login credentials for a database from a wallet if the database no longer exists or to disable connections to a specific database.

Strong authentication lets you centrally control SYSDBA and SYSOPER access to multiple databases.

Consider using this type of authentication for database administration for the following situations:

• You have concerns about password file vulnerability.

• Your site has very strict security requirements.

• You want to separate the identity management from your database. By using a directory server such as Oracle Internet Directory (OID), for example, you can maintain, secure, and administer that server separately.

To enable the Oracle Internet Directory server to authorize SYSDBA and SYSOPER connections, use one of the following methods described in this section, depending on your environment.

Oracle Internet Directory configures directory authentication for administrative users.

1. Configure the administrative user by using the same procedures you would use to configure a typical user.
2. In Oracle Internet Directory, grant the SYSDBA or SYSOPER administrative privilege to the user for the database that this user will administer.

   Grant SYSDBA or SYSOPER only to trusted users.

3. Set the LDAP_DIRECTORY_SYSAUTH initialization parameter to YES:

   ALTER SYSTEM SET LDAP_DIRECTORY_SYSAUTH = YES;
   

   When set to YES, the LDAP_DIRECTORY_SYSAUTH parameter enables SYSDBA and SYSOPER users to authenticate to the database by using a strong authentication method.

4. Set the LDAP_DIRECTORY_ACCESS parameter to either PASSWORD or SSL. For example:

   ALTER SYSTEM SET LDAP_DIRECTORY_ACCESS = PASSWORD;
   

   Ensure that the LDAP_DIRECTORY_ACCESS initialization parameter is not set to NONE. Setting this parameter to PASSWORD or SSL ensures that users can be authenticated using the SYSDBA or SYSOPER administrative privileges through Oracle Internet Directory.

   In an Oracle Real Application Clusters (Oracle RAC) environment, ensure that all instances have the same LDAP_DIRECTORY_ACCESS setting, either through the ALTER SYSTEM statement or through the init.ora file.

   In an Oracle Data Guard or Active Data Guard environment, ensure that the standby database has the same LDAP_DIRECTORY_ACCESS setting as the primary database. In this environment, the ALTER SYSTEM statement propagates its settings from the primary database to the standby database. If you choose to update the init.ora file, remember that the init.ora parameters are used by both the primary database and the standby database, so you do not need to manually propagate this setting from one database to the other.

CONNECT someuser@orcl AS SYSDBA
Enter password: password

Oracle Internet Directory can be used to configure Kerberos authentication for administrative users.

1. Configure the administrative user by using the same procedures you would use to configure a typical user.
2. Configure Oracle Internet Directory for Kerberos authentication.
   Oracle Database Enterprise User Security includes this functionality.
3. In Oracle Internet Directory, grant the SYSDBA or SYSOPER administrative privilege to the user for the database that this user will administer.

   Grant SYSDBA or SYSOPER only to trusted users.

4. Set the LDAP_DIRECTORY_SYSAUTH initialization parameter to YES:

   ALTER SYSTEM SET LDAP_DIRECTORY_SYSAUTH = YES;
   

   When set to YES, the LDAP_DIRECTORY_SYSAUTH parameter enables SYSDBA and SYSOPER users to authenticate to the database by using strong authentication methods.

5. Set the LDAP_DIRECTORY_ACCESS parameter to either PASSWORD or SSL. For example:

   ALTER SYSTEM SET LDAP_DIRECTORY_ACCESS = SSL;
   

   Ensure that the LDAP_DIRECTORY_ACCESS initialization parameter is not set to NONE. Setting this parameter to PASSWORD or SSL ensures that users can be authenticated using SYSDBA or SYSOPER through Oracle Internet Directory.

   In an Oracle Real Application Clusters (Oracle RAC) environment, ensure that all instances have the same LDAP_DIRECTORY_ACCESS setting, either through the ALTER SYSTEM statement or through the init.ora file.

   In an Oracle Data Guard or Active Data Guard environment, ensure that the standby database has the same LDAP_DIRECTORY_ACCESS setting as the primary database. In this environment, the ALTER SYSTEM statement propagates its settings from the primary database to the standby database. If you choose to update the init.ora file, remember that the init.ora parameters are used by both the primary database and the standby database, so you do not need to manually propagate this setting from one database to the other.

CONNECT /@orcl AS SYSDBA

Both the client and server side can authenticate administrative users with Secure Sockets Layer (SSL).

1. Configure the client to use SSL:
   1. Configure the client wallet and user certificate. Update the wallet location in the sqlnet.ora configuration file.
      You can use Wallet Manager to configure the client wallet and user certificate.
   2. Configure the Oracle net service name to include server DNs and use TCP/IP with SSL in tnsnames.ora.
   3. Configure TCP/IP with SSL in listener.ora.
   4. Set the client SSL cipher suites and the required SSL version, and then set SSL as an authentication service in sqlnet.ora.
2. Configure the server to use SSL:
   1. Enable SSL for your database listener on TCPS and provide a corresponding TNS name. You can use Net Configuration Assistant to configure the TNS name.
   2. Store the database PKI credentials in the database wallet. You can use Wallet Manager do this.
   3. Set the LDAP_DIRECTORY_ACCESS initialization parameter to SSL:

      ALTER SYSTEM SET LDAP_DIRECTORY_ACCESS = SSL;
      

      In an Oracle Real Application Clusters (Oracle RAC) environment, ensure that all instances have the same LDAP_DIRECTORY_ACCESS setting, either through the ALTER SYSTEM statement or through the init.ora file.

      In an Oracle Data Guard or Active Data Guard environment, ensure that the standby database has the same LDAP_DIRECTORY_ACCESS setting as the primary database. In this environment, the ALTER SYSTEM statement propagates its settings from the primary database to the standby database. If you choose to update the init.ora file, remember that the init.ora parameters are used by both the primary database and the standby database, so you do not need to manually propagate this setting from one database to the other.

   4. 
      
3. Configure Oracle Internet Directory for SSL user authentications.
4. In Oracle Internet Directory, grant the SYSDBA or SYSOPER privilege to the user for the database that the user will administer.
5. On the server computer, set the LDAP_DIRECTORY_SYSAUTH initialization parameter to YES.

   ALTER SYSTEM SET LDAP_DIRECTORY_SYSAUTH = YES;
   

   When set to YES, the LDAP_DIRECTORY_SYSAUTH parameter enables SYSDBA and SYSOPER users to authenticate to the database by using a strong authentication method.

CONNECT /@orcl AS SYSDBA

You must use third-party network authentication services if you want to authenticate Oracle Database users over a network.

Prominent examples include Kerberos, PKI (public key infrastructure), the RADIUS (Remote Authentication Dial-In User Service), and directory-based services.

If network authentication services are available to you, then Oracle Database can accept authentication from the network service. If you use a network authentication service, then some special considerations arise for network roles and database links.

Kerberos is a trusted third-party authentication system that relies on shared secrets.

Kerberos presumes that the third party is secure, and provides single sign-on capabilities, centralized password storage, database link authentication, and enhanced PC security. It does this through a Kerberos authentication server, or through Cybersafe Active Trust, a commercial Kerberos-based authentication server.

Remote Authentication Dial-In User Service (RADIUS) is a standard lightweight protocol used for user authentication, authorization, and accounting.

RADIUS also enables users to use the RSA One-Time Password Specifications (OTPS) to authenticate to the Oracle database.

Using a central directory can make authentication and its administration efficient.

Directory-based services include the following:

• Oracle Internet Directory, which uses the Lightweight Directory Access Protocol (LDAP), uses a central repository to store and manage information about users (called enterprise users) whose accounts were created in a distributed environment. Although database users must be created (with passwords) in each database that they need to access, enterprise user information is accessible centrally in the Oracle Internet Directory. You can also integrate this directory with Microsoft Active Directory and SunOne.

• Oracle Enterprise Security Manager lets you store and retrieve roles from Oracle Internet Directory, which provides centralized privilege management to make administration easier and increase security levels.

Authentication systems based on public key infrastructure (PKI) issue digital certificates to user clients.

These clients can use these certificates to authenticate directly to servers in the enterprise without directly involving an authentication. Oracle Database provides a PKI for using public keys and certificates, consisting of the following components:

• Authentication and secure session key management using SSL.

• Trusted certificates. These are used to identify third-party entities that are trusted as signers of user certificates when an identity is being validated. When the user certificate is being validated, the signer is checked by using trust points or a trusted certificate chain of certificate authorities stored in the validating system. If there are several levels of trusted certificates in this chain, then a trusted certificate at a lower level is simply trusted without needing to have all its higher-level certificates reverified.

• Oracle Wallet Manager. An Oracle wallet is a data structure that contains the private key of a user, a user certificate, and the set of trust points of a user (trusted certificate authorities).

  You can use Oracle Wallet Manager to manage Oracle wallets. This is a standalone Java application used to manage and edit the security credentials in Oracle wallets. It performs the following operations:

  • Generates a public-private key pair and creates a certificate request for submission to a certificate authority, and creates wallets

  • Installs a certificate for the entity

  • Manages X.509 version 3 certificates on Oracle Database clients and servers

  • Configures trusted certificates for the entity

  • Opens a wallet to enable access to PKI-based services

  Oracle Wallet Manager (OWM) is deprecated with Oracle Database 21c. Instead of using Oracle Wallet Manager, Oracle recommends that you use the command line tools orapki and mkstore.

• X.509 version 3 certificates obtained from (and signed by) a trusted entity, a certificate authority. Because the certificate authority is trusted, these certificates verify that the requesting entity's information is correct and that the public key on the certificate belongs to the identified entity. The certificate is loaded into an Oracle wallet to enable future authentication.

You can create a user account who has a private schema by providing an identifier (distinguished name, or DN) meaningful to the enterprise directory.

Multiple enterprise users can share a single schema in the database.

1. Create a shared schema in the database using the following example:

   CREATE USER appschema IDENTIFIED GLOBALLY AS '';
   

2. In the directory, create multiple enterprise users and a mapping object.

   The mapping object tells the database how you want to map the DNs for the users to the shared schema. You can either create a full distinguished name (DN) mapping (one directory entry for each unique DN), or you can map, for each user, multiple DN components to one schema. For example:

   OU=division1,O=Example,C=US
   

Oracle Database provides proxy authentication in Oracle Call Interface (OCI), JDBC/OCI, or JDBC Thin Driver for database users or enterprise users.

Enterprise users are those who are managed in Oracle Internet Directory and who access a shared schema in the database.

You can design a middle-tier server to authenticate clients in a secure fashion by using the following three forms of proxy authentication:

• The middle-tier server authenticates itself with the database server and a client, in this case an application user or another application, authenticates itself with the middle-tier server. Client identities can be maintained all the way through to the database.

• The client, in this case a database user, is not authenticated by the middle-tier server. The clients identity and database password are passed through the middle-tier server to the database server for authentication.

• The client, in this case a global user, is authenticated by the middle-tier server, and passes one of the following through the middle tier for retrieving the client's user name.

  • Distinguished name (DN)

  • Certificate

In all cases, an administrator must authorize the middle-tier server to act on behalf of the client.

In multitier environments, proxy authentication preserves client identities and privileges through all tiers in middle-tier applications and by auditing client actions.

For example, this feature allows the identity of a user using a Web application (which acts as a proxy) to be passed through the application to the database server.

Three-tier systems provide the following benefits to organizations:

• Organizations can separate application logic from data storage, partitioning the former in application servers and the latter in databases.

• Application servers and Web servers enable users to access data stored in databases.

• Users like using a familiar, easy-to-use browser interface.

• Organizations can also lower their cost of computing by replacing many thick clients with numerous thin clients and an application server.

In addition, Oracle Database proxy authentication provides the following security benefits:

• A limited trust model, by controlling the users on whose behalf middle tiers can connect and the roles that the middle tiers can assume for the user

• Scalability, by supporting user sessions through OCI, JDBC/OCI, or JDBC Thin driver and eliminating the overhead of reauthenticating clients

• Accountability, by preserving the identity of the real user through to the database, and enabling auditing of actions taken on behalf of the real user

• Flexibility, by supporting environments in which users are known to the database, and in which users are merely application users of which the database has no awareness

  Note:

  Oracle Database supports this proxy authentication functionality in three tiers only. It does not support it across multiple middle tiers.

To create proxy user accounts, users must have special privileges.

These privileges are as follows:

• The CREATE USER system privilege to create a database user account that will be used as a proxy user account

• The DV_ACCTMGR role if Oracle Database Vault is enabled, to create the proxy user account

• The ability to grant the CREATE SESSION system privilege to the proxy user account

• The ALTER USER system privilege to enable existing user accounts to connect to the database through the proxy account

Oracle provides special guidelines for when you create proxy user accounts.

• For better security and to adhere to the principle of least privilege, only grant the proxy user account the CREATE SESSION privilege. Do not grant this user any other privileges. The proxy user account is designed to only enable another user to connect using the proxy account. Any privileges that must be exercised during the connection should belong to the connecting user, not to the proxy account.

• As with all passwords, ensure that the password you create for the proxy user is strong and not easily guessed. Remember that multiple users will be connecting as the proxy user, so it is especially important that this password be strong.

• Consider using the Oracle strong authentication network connection features, to prevent network eavesdropping.

• For further fine-tuning of the amount of control that the connecting user has, consider restricting the roles used by the connecting user when he or she is connected through the proxy account. The ALTER USER statement WITH ROLE clause enables you to configure the user to connect using specified roles, any role except a specified role, or with no roles at all. Be aware that the proxy user can only activate those roles that are included in the WITH ROLE clause. The proxy user session will have all the privileges that were directly granted to the client (that is, current) user.

• A proxy user in a proxy session can enable a password-protected role or secure application role only if the role has been allowed to be enabled with the WITH ROLE or WITH ROLE ALL clause. (If this clause is not specified, then WITH ROLE ALL is the default.) If WITH ROLE does not specify the secure roles, then those roles cannot be enabled, even with the correct password.

The CREATE USER and ALTER USER statements can be used to create a proxy user and authorize users to connect through it.

1. Use the CREATE USER statement to create the proxy user account.

   For example:

   CREATE USER appuser IDENTIFIED BY password;
   

2. Use the GRANT CONNECT THROUGH clause of the ALTER USER statement to enable an existing user to connect through the proxy user account.

   For example:

   ALTER USER preston GRANT CONNECT THROUGH appuser;
   

   Be aware that the user name and proxy combination must not exceed 250 characters.

   Suppose user preston has a large number of roles, but you only want her to use one role (for example, the appuser_role) when she is connected to the database through the appuser proxy account. You can use the following ALTER USER statement:

   ALTER USER preston GRANT CONNECT THROUGH appuser WITH ROLE appuser_role;
   

   Any other roles that user preston has will not be available to her as long as she is connecting as the appuser proxy.

CONNECT appuser[preston]
Enter password: appuser_password

The CREATE USER statement enables you to create the several types of user accounts, all of which can be used as proxy accounts.

These accounts are as follows:

• Database user accounts, which are authenticated by passwords

• External user accounts, which are authenticated by external sources, such as Secure Socket Layer (SSL) or Kerberos

• Global user accounts, which are authenticated by an enterprise directory service (Oracle Internet Directory).

Note the following:

• The proxy user can only perform activities that the user preston has privileges to perform. Remember that the proxy user itself, appuser, only has the minimum privileges (CREATE SESSION).

• Using roles with middle-tier clients. You can also specify roles that the middle tier is permitted to activate when connecting as the client. Operations performed on behalf of a client by a middle-tier server can be audited.

• Finding proxy users. To find the users who are currently authorized to connect through a middle tier, query the PROXY_USERS data dictionary view, for example:

  SELECT * FROM PROXY_USERS;
  

• Removing proxy connections. Use the REVOKE CONNECT THROUGH clause of ALTER USER to disallow a proxy connection. For example, to revoke user preston from connecting through the proxy user appuser, enter the following statement:

  ALTER USER preston REVOKE CONNECT THROUGH appuser;
  

• Password expiration and proxy connections. Middle-tier use of password expiration does not apply to accounts that are authenticated through a proxy. Instead, lock the account rather than expire the password.

Use a secure external password store if you are concerned about the password used in proxy authentication being obtained by a malicious user.

1. Configure the proxy authentication account.
2. Configure the secure external password store.

sqlplus [preston]/@db_alias

You can use Oracle Call Interface, JDBC/OCI, or Thin drivers for enterprise users or database users.

These tools enable a middle tier to set up several user sessions within a single database connection, each of which uniquely identifies a connected user (connection pooling)

These sessions reduce the network overhead of creating separate network connections from the middle tier to the database.

If you want to authenticate from clients through a middle tier to the database, then the full authentication sequence from the client to the middle tier to the database occurs as follows:

1. The client authenticates to the middle tier, using whatever form of authentication the middle tier will accept. For example, the client could authenticate to the middle tier by using a user name and password or an X.509 certificate by means of SSL.

2. The middle tier authenticates itself to the database by using whatever form of authentication the database accepts. This could be a password or an authentication mechanism supported by Oracle Database, such as a Kerberos ticket or an X.509 certificate (SSL).

3. The middle tier then creates one or more sessions for users using OCI, JDBC/OCI, or Thin driver.

   • If the user is a database user, then the session must, as a minimum, include the database user name. If the database requires it, then the session can include a password (which the database verifies against the password store in the database). The session can also include a list of database roles for the user.

   • If the user is an enterprise user, then the session may provide different information depending on how the user is authenticated.

     Example 1: If the user authenticates to the middle tier using SSL, then the middle tier can provide the DN from the X.509 certificate of the user, or the certificate itself in the session. The database uses the DN to look up the user in Oracle Internet Directory.

     Example 2: If the user is a password-authenticated enterprise user, then the middle tier must provide, as a minimum, a globally unique name for the user. The database uses this name to look up the user in Oracle Internet Directory. If the session also provides a password for the user, then the database will verify the password against Oracle Internet Directory. User roles are automatically retrieved from Oracle Internet Directory after the session is established.

   • The middle tier may optionally provide a list of database roles for the client. These roles are enabled if the proxy is authorized to use the roles on behalf of the client.

4. The database verifies that the middle tier has the privilege to create sessions on behalf of the user.

   The OCISessionBegin call fails if the application server cannot perform a proxy authentication on behalf of the client by the administrator, or if the application server is not allowed to activate the specified roles.

Least privilege is the principle that users should have the fewest privileges necessary to perform their duties and no more.

As applied to middle tier applications, this means that the middle tier should not have more privileges than it needs.

Oracle Database enables you to limit the middle tier such that it can connect only on behalf of certain database users, using only specific database roles. You can limit the privilege of the middle tier to connect on behalf of an enterprise user, stored in an LDAP directory, by granting to the middle tier the privilege to connect as the mapped database user. For instance, if the enterprise user is mapped to the APPUSER schema, then you must at least grant to the middle tier the ability to connect on behalf of APPUSER. Otherwise, attempts to create a session for the enterprise user will fail.

However, you cannot limit the ability of the middle tier to connect on behalf of enterprise users. For example, suppose that user Sarah wants to connect to the database through a middle tier, appsrv (which is also a database user). Sarah has multiple roles, but it is desirable to restrict the middle tier to use only the clerk role on her behalf.

An administrator can grant permission for appsrv to initiate connections on behalf of Sarah using her clerk role only by using the following SQL statement:

ALTER USER sarah GRANT CONNECT THROUGH appsrv WITH ROLE clerk;

By default, the middle tier cannot create connections for any client. The permission must be granted for each user.

To enable appsrv to use all of the roles granted to the client Sarah, you can use the following statement:

ALTER USER sarah GRANT CONNECT THROUGH appsrv;

Each time a middle tier initiates an OCI, JDBC/OCI, or Thin driver session for another database user, the database verifies that the middle tier is authorized to connect for that user by using the role specified.

You can authorize a middle-tier server to connect as a user.

ALTER USER bill
    GRANT CONNECT THROUGH appserve 
    WITH ROLE ALL EXCEPT payroll;

ALTER USER bill REVOKE CONNECT THROUGH appserve;

You can authorize a middle tier to proxy a user that has been authenticated by other means.

ALTER USER mary
    GRANT CONNECT THROUGH midtier
    AUTHENTICATION REQUIRED;

You can specify that authentication is required by using the AUTHENTICATION REQUIRED proxy clause with the ALTER USER SQL statement.

When you use password-based proxy authentication, Oracle Database passes the password of the client to the middle-tier server.

How the middle-tier responds for proxy authentication depends on how the user is authenticated, either as an enterprise user or a password-authenticated user.

Oracle Database provides the CLIENT_IDENTIFIER attribute of the built-in USERENV application context namespace for application users.

These application users are known to an application but unknown to the database. The CLIENT_IDENTIFIER attribute can capture any value that the application uses for identification or access control, and passes it to the database. The CLIENT_IDENTIFIER attribute is supported in OCI, JDBC/OCI, or Thin driver.

Many applications use session pooling to set up several sessions to be reused by multiple application users.

Users authenticate themselves to a middle-tier application, which uses a single identity to log in to the database and maintains all the user connections. In this model, application users are users who are authenticated to the middle tier of an application, but who are not known to the database. You can use a CLIENT_IDENTIFIER attribute, which acts like an application user proxy for these types of applications.

In this model, the middle tier passes a client identifier to the database upon the session establishment. The client identifier could actually be anything that represents a client connecting to the middle tier, for example, a cookie or an IP address. The client identifier, representing the application user, is available in user session information and can also be accessed with an application context (by using the USERENV naming context). In this way, applications can set up and reuse sessions, while still being able to keep track of the application user in the session. Applications can reset the client identifier and thus reuse the session for a different user, enabling high performance.

The CLIENT_IDENTIFIER predefined attribute of the built-in application context namespace, USERENV, captures the application user name for use with a global application context.

You also can use the CLIENT_IDENTIFIER attribute independently.

When you use the CLIENT_IDENTIFIER attribute independently from a global application context, you can set CLIENT_IDENTIFIER with the DBMS_SESSION interface. The ability to pass a CLIENT_IDENTIFIER to the database is supported in Oracle Call Interface (OCI), JDBC/OCI, or Thin driver.

When you use the CLIENT_IDENTIFIER attribute with global application context, it provides flexibility and high performance for building applications. For example, suppose a Web-based application that provides information to business partners has three types of users: gold partner, silver partner, and bronze partner, representing different levels of information available. Instead of each user having his or her own session set up with individual application contexts, the application could set up global application contexts for gold partners, silver partners, and bronze partners. Then, use the CLIENT_IDENTIFIER to point the session at the correct context to retrieve the appropriate type of data. The application need only initialize the three global contexts once and use the CLIENT_IDENTIFIER to access the correct application context to limit data access. This provides performance benefits through session reuse and through accessing global application contexts set up once, instead of having to initialize application contexts for each session individually.

Using the CLIENT_IDENTIFIER attribute is especially useful for those applications in which the users are unknown to the database.

In these situations, the application typically connects as a single database user and all actions are taken as that user.

Because all user sessions are created as the same user, this security model makes it difficult to achieve data separation for each user. These applications can use the CLIENT_IDENTIFIER attribute to preserve the real application user identity through to the database.

With this approach, sessions can be reused by multiple users by changing the value of the CLIENT_IDENTIFIER attribute, which captures the name of the real application user. This avoids the overhead of setting up a separate session and separate attributes for each user, and enables reuse of sessions by the application. When the CLIENT_IDENTIFIER attribute value changes, the change is added to the next OCI, JDBC/OCI, or Thin driver call for additional performance benefits.

For example, the user Daniel connects to a Web Expense application. Daniel is not a database user; he is a typical Web Expense application user. The application accesses the built-in application context namespace and sets DANIEL as the CLIENT_IDENTIFIER attribute value. Daniel completes his Web Expense form and exits the application. Then, Ajit connects to the Web Expense application. Instead of setting up a new session for Ajit, the application reuses the session that currently exists for Daniel, by changing the CLIENT_IDENTIFIER to AJIT. This avoids the overhead of setting up a new connection to the database and the overhead of setting up a global application context. The CLIENT_IDENTIFIER attribute can be set to any value on which the application bases access control. It does not have to be the application user name.

You can set the CLIENT_IDENTIFIER setting with Oracle Call Interface to be independent of the global application context.

OCIAttrSet (session,

OCI_HTYPE_SESSION,
(dvoid *) "appuser1",
(ub4)strlen("appuser1"),
OCI_ATTR_CLIENT_IDENTIFIER,
*error_handle);

connection.setClientInfo("E2E_CONTEXT.CLIENT_IDENTIFIER", "appuser"); 

The DBMS_SESSION PL/SQL package manages client identifiers on both the middle tier and the database itself.

To use the DBMS_SESSION package to set and clear the CLIENT_IDENTIFIER value on the middle tier, you must use the SET_IDENTIFIER and CLEAR_IDENTIFIER procedures.

The middle tier uses SET_IDENTIFIER to associate the database session with a particular user or group. Then, the CLIENT_IDENTIFIER is an attribute of the session and can be viewed in session information.

If you plan to use the DBMS_SESSION.SET_IDENTIFIER procedure, then be aware of the following:

• The maximum number of bytes for the client_id parameter of DBMS_SESSION.SET_IDENTIFIER is 64 bytes. If it exceeds 64, then the additional bytes are truncated.

• The DBMS_APPLICATION_INFO.SET_CLIENT_INFO procedure can overwrite the value of the client identifier. Typically, these values should be the same, so if SET_CLIENT_INFO is set, then its value can be automatically propagated to the value set by SET_IDENTIFIER if the CLIENTID_OVERWRITE event is set to ON. You can check the status of the CLIENTID_OVERWRITE event by running the SHOW PARAMETER command for the EVENT parameter.

  For example, assuming that CLIENTID_OVERWRITE is enabled:

  SHOW PARAMETER EVENT
  
  NAME                           TYPE               VALUE
  ------------------------------ ------------------ ------------------
  event                          string             clientid_overwrite

The ALTER SYSTEM statement can enable the CLIENTID_OVERWRITE event system-wide.

1. Enter the following ALTER SYSTEM statement:

   ALTER SYSTEM SET EVENTS 'CLIENTID_OVERWRITE';
   

   Or, enter the following line in your init.ora file:

   event="clientid_overwrite"
   

2. Connect to the CDB with the SYSDBA administrative privilege.

   CONNECT / AS SYSDBA

3. Do one of the following:
   • To restart the entire CDB:

     SHUTDOWN IMMEDIATE
     STARTUP

   • To restart a specific PDB:

     ALTER PLUGGABLE DATABASE pdb_name CLOSE IMMEDIATE;
     ALTER PLUGGABLE DATABASE pdb_name OPEN;

   To find the available PDBs, query the DBA_PDBS data dictionary view. To check the current PDB, run the show con_name command.

The ALTER SESSION statement can enable the CLIENTID_OVERWRITE event for the current session only.

1. Use the ALTER SESSION statement to set the CLIENTID_OVERWRITE value for the session only.

   For example:

   ALTER SESSION SET EVENTS 'CLIENTID_OVERWRITE OFF';
   

2. If you set the client identifier by using the DBMS_APPLICATION_INFO.SET_CLIENT_INFO procedure, then run DBMS_SESSION.SET_IDENTIFIER so that the client identifier settings are the same.

   For example:

   DBMS_SESSION.SET_IDENTIFIER(session_id_p);

The ALTER SYSTEM statement can disable the CLIENTID_OVERWRITE event.

1. Enter the following ALTER SYSTEM statement:

   ALTER SYSTEM SET EVENTS 'CLIENTID_OVERWRITE OFF';
   

2. Restart the database.

   For example:

   SHUTDOWN IMMEDIATE
   STARTUP