Posts tagged #LDAP

Domain User Membership check via LDAP

When you are using LDAP to determine Windows Active Directory group membership, and the group you are aiming for is the Domain Users group, than you're in for a surprise. It turns out that the LDAP interface doesn't have the Domain Users group listed for a user. It's missing the memberOf attribute for Domain Users. Just compare the following screenshots. The first screenshot shows the Active Directory user interface for the user Administrator, and the second shows the LDAP equivalent of that same user.

Active Directory group memberships

LDAP group memberships

The LDAP output doesn't show a 'memberOf: CN=Domain Users, CN=Users, DC=testdomain, DC=local' attribute.

The reason is that Active Directory has a so-called Primary Group attribute, and this is by default the Domain Users group. With that piece of information you might see a LDAP attribute called 'primaryGroupID' with a number. That number represents the Domain Users group.

So if you need to check for Domain User membership with LDAP, you should check the value of the primaryGroupID attribute. This value is (for as far as I know) always the same (513).

So if you're using Certificate based authentication on a Juniper Pulse Access Gateway or Pulse Access Control Service, and you need to check Windows Domain User group membership the primaryGroupID is the way to go.

B.t.w., if you're looking for a good cross-platform LDAP browser, I can recommend the Apache Directory Studio. It's intuitive, has a good interface and just works (oh... and it's free).

Cisco Secure ACS 5.x and Apple OSX Directory (LDAP)

For testing and development purposes I run a Cisco Secure ACS 5.x in a virtual machine at home. In this environment I also run an Apple Directory Service. I'll be using this setup to test several 802.1x and RADIUS authentication schemes.

To get things going I needed to connect to the ACS to my LDAP Directory. The Apple Directory Service is a bit different from the regular LDAP implementations. They seem to add the 'apple' reference in a lot of attribute values. Thankfully the ACS has a very versatile configuration interface.

Apple references in attribute valuesNormally, the group definition would be 'group' instead of 'apple-group'. So the configuration of the ACS should reflect these variations to the standard.

Posted on March 1, 2011 and filed under Apple, Security, Software, Tips'n Tricks.