Authentication Mechanism Assurance

Many people ask me about this feature and how it works. Let me first give an example scenario:


Let's say you have a user named Mark, this user is a member of the department Section5. Section5 deals with classified development. In the classical Windows way, you would create a group, let's name it "S5-Classified" (stupid name but it is just an example) and add the users within the department Section5 to it.

Let's say you have a file server with a share with top secret material, and you want only the members of the group S5-Classified to have access to it. You obviously grant the S5-Classified group the needed access, right?

This is all good, except that you now want them only to be able to access the files when they logon with a certifiacate-based logon. I.e. they should not be able to access it without the smart-card.

So this is what it is all about, granting access based on the logon method. With certificate-based logon you will get a certain access, without a smart-card - you get less access.

What happens behind the GUI:
First, it is not enabled by default in Windows Server 2008 R2 and it requires DFL Windows Server 2008 R2. What happens when you enable it is that authentication mechanism assurance adds a universal group (which you as an admin designate) to the user's access token when the user logon with a certificate-based method.

So if access is granted based on the designated universal group, the user Mark have only access if using a certificate-based logon. If using another logon method the universal group will not be present in the access token, and thus no access.

Powershell script to put migrated users into a group

My friend Tony Murray has written a very good script that helps you keep track of migrated users that I wanted to share:

Note: I couldn't get the tabs in so it looks a little funny :(

-Script Begins-

#########################################################

#
# Name: SIDHistoryBasedGroupMembership.ps1
# Author: Tony Murray
# Version: 1.0
# Date: 11/07/2010
# Comment: PowerShell 2.0 script to
# populate group membership based on sIDHistory values
#
#########################################################


#Import the Active Directory Powershell Module
Import-Module ActiveDirectory -ErrorAction SilentlyContinue


#Create a new Event log source for the script (only needs to be run once)
New-EventLog -logName Application -Source "Legacy Users Group Management" `
-ErrorAction SilentlyContinue


$SearchBase = "OU=User Objects,DC=fabrikam,DC=local"
$OUArr = Get-ADUser -LDAPFilter "(samaccounttype=805306368)" `
-SearchBase $SearchBase -SearchScope SubTree


# Now we need the domain security identifier or at least a portion of it
$DomSID = "S-1-5-21-1584567894-2535104369-4141123456"


$Group = "Legacy Users"
$MbrArr = get-adgroupmember -identity $Group


# Loop through the Users found beneach the OU tree
# and check to see if the user is already
# a member of the group. If so, do nothing.
# If not, then add the user as a member.
Foreach ($User in $OUArr)
{
$object = [ADSI]"ldap://$User/"
$objectsidh = $object.sIDHistory.value
If (!$objectsidh)
{
# write-host "sIDHistory is blank"
}
Else
{
$objectsidh = $Object.getex(�sidhistory�)
trap
{
#write-host "Error: $_"
continue
}
foreach($sid in $objectSidh)
{
$sidh = new-object System.Security.Principal.SecurityIdentifier $sid,0
if ($sidh -Match $DomSID)
{
if ($MbrArr -Match $User.distinguishedName)
{
#The user is already member - do nothing
}
else
{
# We need to add the user as a member
write-eventlog -logname Application `
-source "Legacy Users Group Management" `
-eventID 3001 -entrytype Information -message "$User added to $Group"
Add-ADGroupMember -Identity $Group -Members $User
}
}
else
{
# No match with sidHistory - do nothing
}
}
}
}
 
-Script Ends-

TechEd sessions

If you couldn't attend, you will find the sessions here: http://www.msteched.com/

Tired

And people say I look funny when I'm tired and sleep with the laptop on my knees.....

New member in the Andersson family

Yep, there is a new member in our family. A very charming Boarder Collie that is 8 weeks and 4 days. She will most certainly make me leave the computer once in a while :)

Windows Summit 2010

Attend Windows Summit 2010: May 25�27

This is a special opportunity to learn�straight from the Windows team�how you can best use Windows 7 and Internet Explorer to enable great solutions for your customers. This three day event takes place at the Microsoft Conference Center on Microsoft's campus in Redmond, WA and is designed for people who engineer and test Windows 7 PCs, devices, and software. Take advantage of this uniquely intimate event on the Microsoft campus to network with Microsoft technical experts and leaders at breakout sessions, chalk talks, and an Ask the Experts evening and social event.

More info here.

TechDays

I will speak on TechDays this year together with my colleague Fredrik P�lerud (scroll down and you'll see him). If you want to know what it is, see this. TechDays is a Microsoft Sweden event and is held once per year. This year it is fully booked already so I'm looking forward to it!

Crayon also have a booth that we will spend as much time as possible in, please come and join us! And despite what the Crayon website says - we do have some seriously good consultants (they just haven't updated it with the consultant department yet....).