Posts Tagged ‘ACLS’

Too many permissions in AD

Friday, May 6th, 2011

From MSKB 2001769: When you propagate the permissions on an object such as an organizational unit (OU), group, user, or computer in Active Directory, you may receive the following error:

“Unable to save permission changes on ObjectName. A constraint violation occurred.”

Cause: This will happen when the Access Control List (ACL) size on the object exceeds 64 KB, or approximately 1,820 Access Control Entries (ACEs) depending on the size of the ACEs.

What is the best practice here?  This is what our lead AD admin said:

The way I cleaned this up was as follows:

  • Review the individual accounts on all the OUs to get a list of the permissions those folks were granted.
    • As you might expect, they were granted FULL (for both their admin and regular accounts)
    • PLUS they were granted additional, specific sets (as if FULL didn’t already grant them that)
  • I then created a brand new OUAdministrator group (it covers more than one site, so I figured OU was the best I could do) and plunked only their admin account in that group
    • I gave that group FULL control
    • Then I went through the OUs as follows:
    • Turned on inheritance & applied that change
    • Added the OUAdministrator group to the top OU and granted it FULL (generic)
  • Then on each OU, I went through and deleted the following:
    • All individual user accounts (‘cause they were included in the group)
    • All duplicative permission sets for other groups they had already granted FULL (generic) permissions—they have about 3 or 4 admin groups on the ACLS. Most had FULL (generic) PLUS individual sets of ACLS on long lists of 50 or more attributes for individual objects)
  • I would also have removed broken SIDS at this point, but there weren’t any

Technically, I could also have removed the additional admin groups since they were redundant, but I just needed to get the ACLs down to a manageable size.

This is why granting generic permissions can be a good thing. For example, for folks like workstation/server admins, just grant them FULL (generic) on computer objects. There’s no point in trying to be more specific since they can’t “do” anything bad with computer accounts and it reduces the number of permissions required on the ACL.

The problem is definitely a case of “being too specific”.