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Center for Education and Research in Information Assurance and Security

On standard configurations


[tags]monocultures, compliance, standard configurations, desktops, OMB[/tags]

Another set of news items, and another set of “nyah nyah” emails to me.  This time, the press has been covering a memo out of the OMB directing all Federal agencies to adopt a mandatory baseline configuration for Windows machines.  My correspondents have misinterpreted the import of this announcement to mean that the government is mandating a standard implementation of Windows on all Federal machines.  To the contrary, it is mandating a baseline security configuration for only those machines that are running Windows.  Other systems can still be used (and should be).

What’s the difference? Quite a bit. The OMB memo is about ensuring that a standard, secure baseline is the norm on any machine running Windows.  This is because there are so many possible configuration options that can be set (and set poorly for secure operation), and because there are so many security add-ons, it has not been uncommon for attacks to occur because of weak configurations.  As noted in the memo, the Air Force pioneered some work in decreeing security baseline configurations.  By requiring that certain minimum security configuration settings were in place on every Windows machines, there was a reduction in incidents.

From this, and other studies, including some great work at NIST to articulate useful policies, we get the OMB memo.

This is actually an excellent idea.  Unfortunately, the minimum is perhaps a bit too “minimum.”  For instance, replacing IE 6 under XP with Firefox would probably be a step up in security.  However, to support common applications and uses, the mandated configuration can only go so far without requiring lots of extra (costly) work or simply breaking things.  And if too many things get broken, people will find ways around the secure configuration—after all, they need to get their work done!  (This is often overlooked by novice managers focused on “fixing” security.)

Considering the historical problems with Linux and some other systems, and the complexity of their configuration, minimum configurations for those platforms might not be a bad idea, either.  However, they are not yet used in large enough numbers to prompt such a policy.  Any mechanism or configuration where the complexity is beyond the ken of the average user should have a set, minimum, safe configuration. 

Note my use of the term “minimum” repeatedly.  If the people in charge of enforcing this new policy prevent clueful people from setting stronger configurations, then that is a huge problem.  Furthermore, if there are no provisions for understanding when the minimum configuration might lead to weakness or problems and needs to be changed, that would also be awful.  As with any policy, implementation can be good or be terrible.

Of course, mandating the use of Windows (2000, XP, Vista or otherwise) on all desktops would not be a good idea for anyone other than Microsoft and those who know no other system.  In fact, mandating the use of ANY OS would be a bad idea.  Promoting diversity and heterogeneity is valuable for many reasons, not least of which are:

  1. limit the damage possible from attacks targeting a new or unpatched vulnerability
  2. limit the damage possible from a planted vulnerability
  3. limit the spread of automated attacks (malware)
  4. increase likelihood of detection of attacks of all kinds
  5. provide incentive in the marketplace for competition and innovation among vendors & solutions
  6. enhance capability to quickly switch to another platform in the event a vendor takes a turn harmful to local interests
  7. encourages innovation and competition in design and structure of 3rd-party solutions
  8. support agility—allow testing and use of new tools and technologies that may be developed for other platforms

These advantages are not offset by savings in training or bulk purchasing, as some people would claim.  They are 2nd order effects and difficult to measure directly, but their absence is noted….usually too late.

But what about interoperability?  That is where standards and market pressure come to bear.  If we have a heterogeneous environment, then the market should help ensure that standards are developed and adhered to so as to support different solutions.  That supports competition, which is good for the consumer and the marketplace.

And security with innovation and choice should really be the minimum configuration we all seek.

[posted with ecto]


Posted by Steve Lodin
on Friday, April 13, 2007 at 04:25 PM

Well, the devil is in the details.  At the very high level, the scope has not been defined.

- which agencies and departments are covered by this?
- what types of systems are covered, only general purpose desktop platforms?

Mandating that every piece of computing equipment that runs Windows (R) regardless of its computing mission must comply will cause a severe shortage of available solutions, especially in my industry.  Thankfully, my colleagues in the DoD and VA have recognized the potential problem and started working on their exception granting approval process.

I’m not sure that Alan and his cohorts at SANS are helping here either.


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