Wednesday, August 27, 2008

Alphablox Cube Security

I really headache when customer want to impose security constraints on Alphablox solution. Here is a simple security problem that I need to solve.

A local bank in Malaysia has 14 main branches throughout the country where each state got one main branch. There is at least 2 groups of users with different level of data access. One group is country wide users who can view the data for all the states. Another group being state manager which can only sees their own cake.

My first attempt is defining a user property called BelongingState and assign it state code that user belongs to, or "ALL" if they are country wide users. Then I would use Java codes to dynamically construct the MDX for the DataBlox. Thought this will solve my problem, but some user actions would causes rewrite of the MDX automatically (Seems like the default behavior). For example, Show Siblings action will display all members on the same level. This totally defeats my aim of controlling view by Malaysia state. Another one is the Drill Up action. I also found Member Filter dialog and Drill Down (There are 5 types of Drill Down available) action can causes exploitation on data.

Due to lack of time to spend on digging deep into Alphablox object model, I revert to a quick resolution: use removeAction attribute to disable Drill Up, Member Filter and Show Siblings for state level users. At the same time, I wrote a filter on Drilldown event to check the drill down option and prevent the drill down to inappropriate data area. This cut off a lot of interactivity from user, but for the sake of security, some trade offs gotta be made.

Giving some faith to developers who wrote Alphablox framework, I believe there should be some methods to disable MDX rewrite due to user activity, thus preventing the underlying data set from changing. One thing to note if that if you are using MSAS or Essbase as cube source, then you can rely on the native security control features of these cube engines for security. Particularly you can use MemberSecurity tag for this purpose. For Cube View based cubes, may be it could be possible to control the view at database level.

Back to square one, my point of bringing this topic up is that it is important to plan for security requirements to match the out of the box security features provided by Alphablox. For my simple security scenario, I personally think that it is more usable to create 14 identical cubes, each for different state. By controlling which cube that users use in their report, you can be sure that the data view doesn't violate the security expectation, yet retaining powerful interactivity actions such as Member Filter and Drill Up. Things can get pretty ugly and complicated when the security requirements are not just on one dimension. In this case, creating separate cube for different data view might not be practical.

Lastly, localization is another aspect of global business intelligence application that can be as tricky as security factor to implement in Alphablox solution. I really need to appraise Microsoft Analysis Services (MSAS) for incorporating security and localization so well in their cubes. Maybe this is what differentiates market leader and players.

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