Wednesday, 20 January 2016

HANA password security

While creating the new user in HANA studio, we have three types of Authentication.
  • Password
  • Kerberos (Third-party authentication provider)
  • SAML (Security Assertion Markup Language)
                                              Exhibit: 1                                               
SAP, SAP HANA

Every database user is identified with in the database by Authentication based on username and password.
In this document we will be concentrating on password and its policy parameters.

Passwords are subjected to security rules and are configured using the parameters in system properties files indexserver.ini. To have a look, let us open the "Administration Console" perspective -> Configuration tab -> Expand Indexserver.ini -> Expand password policy and you find 11 parameters in it.
   Exhibit: 2 
HANA, SAP HANA

We will focus on all the 11 parameters and referring to this Exhibit 2 many times in this document.

First let us create a new user in HANA studio (Security -> Users -> right click -> New user) and click on   as shown below:
    Exhibit: 3
SAP, SAP HANA Tutorial

The information it is showing as "Password must have at least eight characters" in the first line, refers to the default value (8) in the minimal_password_length of parameter 7 in Exhibit 2. "meet the rule: '"upper-case", "lower-case", "digits"' in the second line, refers to the default value 'A1a' in the password_layout of parameter 10 in Exhibit 2.

One interesting point to know is the default value 'A1a' derives A(upper-case), 1(digit), a(lower-case) which means the password must contain at-least 1 upper-case, at-least 1 digit and at-least 1 lower-case.

This default value is equivalent to 'B2b' or 'C3c' or 'Z1c' etc. as all of these contains upper-case, digit, lower-case. In all of these, special characters (_ , -, etc.) is optional.

In order to include special character as must in password, just include any special character in the default value, example E8s* 

Now let us change these two parameters: length as 6 and also include one special character as must in password.
Exhibit: 4
SAP Certifications

Now let us go back to user creation and click on  and we observe that these changes are reflected.

Exhibit: 5
SAP HANA, SAP

Now let us create the user, say USER1 and when this user log on for the first time, it will ask you to change the password which refers to default value 'true' in force_first_parameter_change of parameter 1 in Exhibit 2.
Exhibit: 6
HANA password security

If this parameter changed to false then when the user log on for the first time, it will not prompt to change password.
Note: Administrators can force a user to change password at any time with SQL command ALTER USER user_name FORCE PASSWORD CHANGE;

What happens when the user forgot his/her password and how many attempts can one make. It depends on the default value (6) in the maximum_invalid_connect_attempts of parameter 3 in Exhibit 2. Let us change this value to a small number, say 3 and give all the invalid passwords for the user USER1.
Exhibit: 7
SAP HANA Certifications

Now the user is locked until some time and this refers to the default value (1440) in the password_lock_time of parameter 11 in Exhibit 2. The value 1440 is in minutes which is equal to (24 * 60 hrs = 1 day). This value can be changed, say 2 hrs (120 min).

Exhibit: 8
SAP HANA

The locked passwords can be reset by administrators with SQL command and/or can assign new password.
ALTER USER user_name RESET CONNECT ATTEMPTS;

Now the user can have the new password but cannot use the previous passwords and this refers to the default value (5) in the last_used_password of parameter 2 in Exhibit 2.

The new password can be subjected to rule of using for minimum and maximum number of days and this refers to the default value (1) in the minimum_password-lifetime of parameter 8, default value (182) in the maximum_password-lifetime of parameter 4 in Exhibit 2 respectively.

These values can be changed, say 3 for last_used_password, 2 for minimum_password-lifetime, and 30 for maximum_password-lifetime respectively.   

    Exhibit: 9 
SAP HANA Password

It is possible to remind the user before the password expiration, and can be done through password_expire_warning_time of parameter 9 in Exhibit 2. The default value is 14 days and can be changed.

When the user has assigned password for the first time, he/she should log in with in a specific number of days and this refers to the default value 28 of  maximum_unused_initial_password_lifetime of parameter 5 in Exhibit 2.

If the user was logged in within the maximum_unused_initial_password_lifetime and not used for a while then there is a restriction that one has to re-log-in and this refers to default value of 365 days of parameter maximum_unused_productive_password_lifetime in Exhibit 2.

Now let us change these values:
password_expire_warning_time to 7 days
maximum_unused_initial_password_lifetime to 15 days
maximum_unused_productive_password_lifetime to 30 days respectively.

 Exhibit: 10
HANA, SAP

However password lifetime check can be disabled by using SQL
ALTER USER user_name DISABLE PASSWORD LIFETIME;

Conclusion: The default values provided by SAP are the best and this document only shows how to change these values.

To reset all the change parameter values, just double click on the parameter  and click "Restore Default" and save it.
Exhibit: 11
HANA password security

We can also query the parameter values of password policy using below SQL's and produce the same result:

SELECT KEY, VALUE FROM M_INIFILE_CONTENTS
WHERE FILE_NAME = 'indexserver.ini'
 AND SECTION = 'password policy' ;
OR
SELECT * FROM M_PASSWORD_POLICY;

SAP HANA Certifications

That's it, we are now aware of different password policy parameters, to view current values, and to change, if necessary.

Source: scn.sap.com

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