OBIEE Data Security - Column Level Security

Oracle BI aka OBIEE offers a wide variety of data security, of which column level security is a flavor. Consider a column that has sensitive information like Social Security Number. This information should not be presented to all in the organization except the select few who need to have this info. You can actually hide the column in the presentation layer from others. You can use this column in reports on dashboards and people with access to this column will see it in report for others the report will not show this column. To achieve this functionality we need to make changes in two places – Metadata and one time change in NQSConfig.ini.

Let us first see what needs to be done in Metadata. For this example, let us consider that EmployeeID is a scared piece of information that a select few MegaUsers can see and access.

In Metadata on the presentation column, we need to make changes to permission settings. Right click on the column and select “Properties”

By default, the columns will have read access to everyone.

Choose the groups that should have read access rights on the column. The check box here works like a toggle button. Click on it to get a check mark or a red cross mark. A red cross marks explicitly restricts access. While an unchecked/black check box implicitly restricts access to the column.

Now let us log in as a Mega User (Kumar.Kambam, in this case) and create a report using the EmployeeID Column.

In answers, Kumar.Kambam can see the EmployeeID Column. Let us create a simple report using the column with column level security enforced.

Save it and put it on a dashboard to test OBIEE column level security.

Now log on as Basic User

In answers check for EmployeeID column. The column is not visible. This is due to the column level security restriction.

Go to OBIEE Security Dashboard to see the report, and we get an error message. State: HY000. Code: 10058. [NQODBC] [SQL_STATE: HY000] [nQSError: 10058] A general error has occurred. [nQSError: 27005] Unresolved column: "Employees"."EmployeeID". (HY000)

The error is expected. The report contains a column on which the current user does not have access to. So for all practical purposes as far as OBIEE is concerned, the column does not even exist. The default setting in NQSConfig.ini file drives this behavior.

In, NQSConfig.ini change the parameter PROJECT_INACCESSIBLE_COLUMN_AS_NULL which is under security section. By default it is set to No. Set it to yes. And restart the services.

Now logged in as BasicUser1 and access OBIEE Security Dashboard to test OBIEE column level security

The report is presented without the EmployeeID column on which OBIEE column level security was enforced.

So for the same dashboard report, depending on the data level security access permissions in OBIEE for a user, a column visibility can be controlled using column level security feature.

OBIEE and Virtual Private Database (VPD)

What is VPD?

Virtual Private Database is Oracle’s fine grain access control (FGAC) feature that was introduced in Oracle 8i. It helps control data level security on the database side by applying policies, thus data level security in the applications that read from the database is not necessary. The advantage is that if there are multiple applications accessing data from a database, it is not necessary to implement data level security in all those applications.

How does VPD work?

Policies are created in the database that would append a predicate (a WHERE clause) to the query in runtime. Consider a simple example – there exists a policy which would return only the rows attached to a particular user id on the table Orders. If a user “Kumar” were to query data from Orders table, Kumar would enter the following command:

Select * from Orders;

The policy that dictates what information a user can see would append a predicate to the query as follows:

Select * from Orders

where user_name = ‘KUMAR’;

This mechanism of appending the predicate is entirely transparent to the user.

Click here to read more about VPD on Oracle’s OTN.

Configuring VPD in OBIEE

To use the VPD feature in the Database and OBIEE along with its caching capabilities it is important to configure VPD in OBIEE. Failing to configure VPD in OBIEE while caching is enabled (in OBIEE), the request would bypass VPD policies by accessing data from cache and data level security will not be effectively handled by the database’s VPD. Thus, the users will see incorrect results.

To configure VPD in OBIEE, first enable the VPD option in the database’s general tab as shown:

Then enable the “Security Sensitive” option in the security variable:

Normal OBIEE Cache Behavior

To be simple and brief, if caching is enabled, a query that is being run for the first time would create a cache. Subsequent requests that is similar to the query or its subset would hit the cache to retrieve the results. This is true even if the users are different.

Example:

Logged on as Kumar Kambam

Running a request…

… generates the following Query log

The cache is created….

Now any user that issues a similar request or a subset of the request will hit the cache.

Logged on as Power User1

Running a similar request, generates the following log. Notice that OBIEE server found a matching query in the cache that is created by Kumar.Kambam for the query issued by Poweruser1.

OBIEE Cache Behavior with VPD configured

When VPD option is configured in OBIEE, cache is created for each user even though a matching query exists in the cache. This ensures that the data retrieved for a user is not retrieved from the cache created by a different user, thereby ensuring the enforcement of VPD policies. In other words, if Kumar.Kambam were to run a query, the cache is created by the data visibility rules enforced by the VPD for Kumar.Kambam. If Poweruser1 runs a similar request it should bypass the query cache and hit the database to retrieve the data along the policies of the VPD for Poweruser1; if it were to hit the cache created by Kumar.Kambam, the results for Kumar Kambam will be presented to Poweruser1.

After configuring VPD, logged on as Kumar Kambam

Running a query for the first time…

…the following log is generated

The cache is created

Running the same query again, the following log is generated…

OBIEE found a matching query in the cache and uses it.

Now log on as Power User1

By running the same request, the following log is generated…

A new cache entry is created even though a similar request has been issued by a different user and a cache has been created for it

The subsequent requests by Poweruser1 that is similar to the query will hit its own cache. This ensures that a user will only see his/her data.