RE: Any way to remove ADMIN$ only?

From: Jim Harrison (SPG) (jmharr@microsoft.com)
Date: 11/07/02


Date: Thu, 7 Nov 2002 10:19:33 -0800
From: "Jim Harrison (SPG)" <jmharr@microsoft.com>
To: "Evan Mann" <emann@questinc.org>, <focus-ms@securityfocus.com>

I'm sorry, but I have to vehemently disagree; there is never a case where a best practice includes "Everyone=full". If you want to simplify your share permissions, then use something along the lines of "authenticated users", "Accounting", "CFolks", or something approppriately restrictive, never "Everyone".
Security is a layered concept; if you restrict the share access as well as the underlying resource access, then you've made it twice as hard to get the "locked" resource.
If the interaction between folder and share permissions confuses you, then I have to respectfully recommend that you refresh your NTFS knowledge.
I'll grant that it can cause occasional confusion, but I consider it to be one of the smarter decisions made by the Windows team.
 
"Best practice" is that which confounds the bad guys while still allowing reasonable access to required resources for a limited user base, ideally for a limited time.
 
Jim

        -----Original Message-----
        From: Evan Mann [mailto:emann@questinc.org]
        Sent: Wed 11/6/2002 05:08
        To: focus-ms@securityfocus.com
        Cc:
        Subject: RE: Any way to remove ADMIN$ only?
        
        

        Could this be elaborated more on the list by others? I do not recall any
        conversations about the practice of which is the "best practice" or "ideal"
        method of setting permissions between share level and file level within the
        past year and a half or so that I've begun monitoring the list. Perhaps its
        a good time to bring the subject up?
        
        -----Original Message-----
        From: Zack Berkovitz [mailto:zberkovitz@pga-inc.com]
        Sent: Tuesday, November 05, 2002 2:27 PM
        To: Jim Harrison (SPG); Eric; Palumbo, Dave (Factiva);
        focus-ms@securityfocus.com
        Subject: RE: Any way to remove ADMIN$ only?
        
        
        The best practice is in fact to use default (Everyone=Full) share
        permissions and to set NTFS security on all drives (with inheritance for
        2K and newer systems running NTFS 5 or greater). Share permissions
        should really only be used when absolutely necessary, such as on FAT
        volumes where ACE's cannot be applied. Conflicts between share and NTFS
        perms always cause headaches down the road, and NTFS perms secure the
        files and directories for locally logged on users as well.
        
        If you are sharing C and D, of which one is the system drive, how will
        removing the admin$ share (winnt) make the system any more secure, if
        the drive it resides on is shared out? NTFS permissions seem like a
        more comprehensive solution. The presence of any of the administrative
        shares is a security hole, regardless.
        
        - Zack
        
        
        
        -----Original Message-----
        From: Jim Harrison (SPG) [mailto:jmharr@microsoft.com]
        Sent: Tuesday, November 05, 2002 9:59 AM
        To: Eric; Palumbo, Dave (Factiva); focus-ms@securityfocus.com
        Subject: RE: Any way to remove ADMIN$ only?
        
        
         The only problem with using "net share" to create shares is that it
         applies default permissions to those shares it creates. These include
         "Everyone=Full"; obviously not an ideal scenario, especially given the
         default security of Windows drives (Everyone=Full). I've written a
         script that will create shares that only allow those accounts listed
         in the local server's administrator's group to have access to the
         share you choose to create.
        
        http://isatools.org/createshare.zip
        
        * Jim Harrison
        MCP(NT4/2K), A+, Network+
        Services Platform Division
        
        The burden of proof is not satisfied by a lack of evidence to the
        contrary..
        
        
        
        -----Original Message-----
        From: Eric [mailto:ews@tellurian.net]
        Sent: Monday, November 04, 2002 11:55 AM
        To: Palumbo, Dave (Factiva); 'focus-ms@securityfocus.com'
        Subject: Re: Any way to remove ADMIN$ only?
        
        
        write a script that will launch each time upon machine bootup that
        'unshares' that share.
        
        'net share admin$ /delete'
        
        I don't know of any registry setting that will remove only that share
        and
        leave the others.
        
        Understand also that anyone with admin privileges to that machine can
        recreate that share at any time.
        
        
        At 01:11 PM 11/4/2002 -0500, Palumbo, Dave (Factiva) wrote:
>Hello,
>
>I have a scenario in which I'd like to remove the ADMIN$ share from a
>Windows 2000 server, but keep the other default shares (c$, d$)
>available for an application...is there any documented/undocumented way
        
>to accomplish this? If this is documented, please forgive me....but I
>sure can't find it. I am aware of the
>HKLM\System\CurrentControlSet\Services\LanmanServer\Parameters\AutoShar
>eServ
>er=0 registry key...but this disables all the default shares (save
        IPC$).
>Again, I'm just looking to remove ADMIN$.
>
>Any ideas?
>
>Thanks,
>
>Dave Palumbo
>http://pgpkeys.mit.edu:11371/pks/lookup?op=get&search=0x41F746F8