DOSing Windows Vista

Chris Samual writes a good summary of Peter Gutmann's analysis of the cost of Vista (in terms of DRM).

The following paragraph in the article however seemed more interesting to me:
Once a weakness is found in a particular driver or device, that driver will have its signature revoked by Microsoft, which means that it will cease to function (details on this are a bit vague here, presumably some minimum functionality like generic 640x480 VGA support will still be available in order for the system to boot). This means that a report of a compromise of a particular driver or device will cause all support for that device worldwide to be turned off until a fix can be found.

Now just imagine that you want to cause widespread disruption - a DOS (Denial Of Service) attack against Windows users. What better option than to cause most of them to have hardware that's not acceptable to the OS? I expect that there will be many instances of security holes in drivers and hardware being concealed by MS because they can't afford the PR problems resulting from making millions of machines cease functioning. But just imagine that someone finds hardware vulnerabilities in a couple of common graphics drivers or pieces of hardware and publicly releases exploits shortly before a major holiday. If it's public enough (EG posted to a few mailing lists and faxed to some major newspapers) then MS would be forced to invoke the DRM measures or lose face in a significant way. Just imagine the results of stopping 1/3 of machines working just before Christmas!

Of course after the first few incidents people will learn. It shouldn't be difficult to configure a firewall to prevent all access to MS servers so that they can't revoke access, after all our PCs are important enough to us that we don't want some jerk in Redmond just turning them off. Of course disabling connections to MS would also disable security updates - but we all know that usability is more important than security to the vast majority of users (witness the number of people who happily keep using a machine that they know to be infected with a virus or trojan).

If this happens and firewalling MS servers becomes a common action, I wonder if MS will attempt the typical malware techniques of using servers in other countries with random port numbers to get past firewalls. Maybe Windows updates could be spread virally between PCs, this method would allow infecting machines that aren't connected to the net via laptops.

Finally, I recommend that people who are interested in such things read Eastern Standard Tribe by Cory Doctorow, he has some interesting ideas about people DOSing corporations that they work for which seem surprisingly similar to what MS is doing to itself. I'll post about my own observations of corporations DOSing themselves in the near future.