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- Active Directory in a DMZ 3 answers
I want to be specific about terms. When I say DMZ I'm talking about a place where you would put servers that expose a service to untrusted networks like the Internet, or in some cases merely networks that are less trusted.
I am attempting to shore up our network perimeter by auditing what we expose through our firewall. The firewall I am talking about is NOT a Microsoft ISA server and never will be. If any of you are in this situation you know that the ports required to allow a member server to connect to domain controllers is pretty extensive. Microsoft in attempting to address this provides several designs using RODC's to reduce the count of open ports, but even if it were just one port the Active Directory itself is a trove of intel for an unauthorized person who has compromised a DMZ member server.
What is the consensus about AD member servers in a DMZ? Too insecure, or acceptable risk? Assuming the former (where I'm leaning), aside from local account authentication are there any more secure options than AD for authenticating users who sign onto DMZ Windows servers? If not, then is there a mechanism that can associate a local account with a real person at login for auditing purposes? It seems like the only option for tracking users' behaviour in a standalone server DMZ would be to create local machine accounts for every user who logs onto the servers.
Of course, ideally you don't have people logging on to servers for normal operations; the whole thing should be managed by proxy using services accounts (that's a whole 'nother discussion). But right now our operation isn't "there" yet. We're hopeful that DSC makes that feasible.
The focus of Microsoft's recommendations are to me either impractical or missing the point. An Active Directory for just a DMZ reduces an intruder's ability to gather intel, but still leaves the vector pretty much in-place. The best their solutions can do is split the risk baby by limiting that intel to the DMZ (plus whatever else your DMZ AD might service). The trade-off is an AD for every DMZ. So now your admins are managing one account + N DMZ's.
Not that Microsoft is listening, but there needs to be a middle way that auths a windows user but doesn't require the use of credentials that can do things like enum LDAP users.