Thursday, December 27, 2007

Access Management from the Trenches

Call it user access management, account management, identity management, or whatever else. I am talking about making sure that authorized users, and only authorized users have access to applications, operating systems, and databases.

When new employees are hired, or existing employees leave, or when employee's jobs change, their access privileges have to change. To my mind, this is probably the most fundamental security control you can think of. It is definitely one you want to get right.

Here's a quick roadmap for fixing your company's access management processes. As a big fan of the triage approach to infosec: fix the worst first.

Too many companies don't do a good job of decommissioning user accounts when the user separates from the company. It isn't too difficult to find stories of disgruntled employees causing sabotage after they walk out the door for the last time. Work with Human Resources and access managers (system admins? infosec admins? helpdesk?) and devise a workflow. In most companies, a list of separated employees is sent out weekly and access managers disable accounts for a period of time before removing them altogether. Write up a simple process describing the steps, and a simple policy capturing the strategy, and run it through the appropriate management chains and make it official. You might want to devise a more expedient procedure for separation of higher risk individuals like privileged users, layoffs, termination, etc.

With employee separation in place, another tricky problem to solve is that of user transfers. You want to prevent, for example, Joe who's been transferring around the company for 5 years from accumulating access to everything. In an ideal world, you have beautifully designed processes and identity management technology that readily manage the lifecycle of a user's access. But here in the real world you probably have dozens or hundreds of systems with no real hope of a unified technology or procedure to ensure that when Joe transfers from Marketing to Advertising, his access is instantly changed.

Work with HR and see if you can insert a step into any existing transfer process. Maybe HR can include employee transfers in their weekly list (I've seen this done at a large telco) or in a smaller company maybe they can simply send transfers ad-hoc to system owners or to a mailing list. As with all things infosec, find a creative, practical solution.

Another excellent control to implement is periodic account access reviews conducted by system owners, data owners, managers, etc. This is conceptually simple, fairly simple to implement and better, it is a distributed. Those in the know will be doing the review. I recommend a period of 4, 6 or 12 months for the review. Too frequent and it is a burden and could get skipped. If not frequent enough it won't be very effective. As with all things infosec, it is a balancing act of cost, risk mitigation, and human behavior. And as we all know, we aren't interested in perfect security but practical risk reduction. A company whose managers check accounts of their employees every so often will have reduced risk substantially. You can always compliment this control with others (like logging & monitoring). Document the strategy in your account management policy, and the review process documented as another procedure and run up through the appropriate management chains to make official.

Finally, there's the onboarding process. This is the question of giving users only the access they need. It's been my experience that even in the most security-clueless environments, companies get this right--they have to, if they want their new employees to be productive. Though I haven't seen it or heard of it, if your company gives new hires access to everything, this may be the highest risk. Either find the highest risk business area and fix their onboarding process before moving to the next, or classify users and their access broadly---you can add granularity later. Work with the appropriate management to define appropriate access control.

You need management backing to do any of this. That means it has to be a real problem, even amongst the constellation of business problems senior management faces. In this day and age, unless the company is having big problems, then due care demands that company leaders fix bad access management. Work with management at as high a level as possible (HR? higher if possible) to get done what you can. Keep the scale small, be smart about what you can and can't accomplish, focus on reducing risk not eliminating it, and get the biggest bang for the buck, and you should wind up with significantly less risk in a fairly short timeframe.

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