The Machine SID Duplication Myth

toppings writes "Microsoft Technical fellow Mark Russinovich explains why he is now retiring NewSID, which has been used by IT departments for years when deploying Windows to new systems from customized clone images. Russinovich writes: 'The reason that I began considering NewSID for retirement is that, although people generally reported success with it on Windows Vista, I hadn't fully tested it myself and I got occasional reports that some Windows component would fail after NewSID was used. When I set out to look into the reports I took a step back to understand how duplicate SIDs could cause problems, a belief that I had taken on faith like everyone else. The more I thought about it, the more I became convinced that machine SID duplication — having multiple computers with the same machine SID — doesn't pose any problem, security or otherwise. I took my conclusion to the Windows security and deployment teams and no one could come up with a scenario where two systems with the same machine SID, whether in a Workgroup or a Domain, would cause an issue. At that point the decision to retire NewSID became obvious.' He concludes: 'It's a little surprising that the SID duplication issue has gone unquestioned for so long, but everyone has assumed that someone else knew exactly why it was a problem. To my chagrin, NewSID has never really done anything useful and there's no reason to miss it now that it's retired. Microsoft's official policy on SID duplication will also now change and look for Sysprep to be updated in the future to skip SID generation.'"

Comments

Go Figure

[Anonymous Coward]

This is coming from the same company that billed my employer to the tune of $250,000 USD in order to create a utility that would move a user profile from the old location to the new one after the user account had been moved to a new NT domain.

And then we found the moveuser.exe utility on the server resource kit and asked them what the $250,000 was for. Not that anyone who pays two hundred and fifty thousand dollars for a few lines of vbscript is smart (the phbs wanted something bonafide), but I'm just sayin'...

In other words...

[jkrise]

Microsoft is now my employer, and I have no reason to cater to the needs of the user community anymore.