Determining members of local groups via C#

Question

I wondered whether anybody knows how to obtain membership of local groups on a remote server programmatically via C#. Would this require administrator permissions? And if so is there any way to confirm the currently logged in user's membership (or not) of these groups?

Answer 1

Perhaps this is something that can be done via WMI?

Answer 2

@Unkwntech: That's extremely unhelpful. Last time I checked this was a programming Q&A site where I can ask questions about... programming?!

I know googling can give me an answer, but I respect the opinions of people on here and the perspective they can provide. Obviously you didn't consider that possibility, perhaps you should think a little more before shooting down my question like that - elitism is not going to help stack overflow become the awesome success it's almost certainly going to be. Remember being a humble programmer is very important, that applies to the way you interact with other members of the industry too you know :-)

Answer 3

It appears there is a new Assembly in .net 3.5 called System.DirectoryServices.AccountManagement which gives a cleaner implementation than System.DirectoryServices. Dominick Baier blogs about a couple of simple operations including checking membership of a group:-

public static bool IsUserInGroup(string username, string groupname, ContextType type)
{
    PrincipalContext context = new PrincipalContext(type);

    UserPrincipal user = UserPrincipal.FindByIdentity(
        context,
        IdentityType.SamAccountName,
        username);
    GroupPrincipal group = GroupPrincipal.FindByIdentity(
        context, groupname);

    return user.IsMemberOf(group);
}

I think I will use this approach, thanks for the suggestions though however! :-)

Answer 4

I asked a similar question, and ended up writing an answer which used WMI to enum the group members. I had real problems with authentication in the system.directoryservices.accountmanagement stuff. YMMV, of course.

Answer 5

I'd be curious if the System.DirectoryServices.AccountManagement is fully managed. I've used System.DirectoryServices.ActiveDirectory which is a wrapper for COM Interop which has led to many headaches...

Answer 6

This may possibly help. I had to develop an app where we want to authenticate against active directory, and also examine the groups strings that the user is in.

For a couple of reasons we don't want to use windows authentication, but rather have our own forms based authentication. I developed the routine below to firstly authenticate the user, and secondly examine all the groups that the user belongs to. Perhaps it may help. The routine uses LogonUser to authenticate, and then gets the list of numerical guid-like group ids (SIDs) for that user, and translates each one to a human readable form.

Hope this helps, I had to synthesise this approach from a variety of different google searches.

private int validateUserActiveDirectory()
{
    IntPtr token = IntPtr.Zero;
    int DBgroupLevel = 0;

    // make sure you're yourself -- recommended at msdn http://support.microsoft.com/kb/248187
    RevertToSelf();

    if (LogonUser(txtUserName.Value, propDomain, txtUserPass.Text, LOGON32_LOGON_NETWORK, LOGON32_PROVIDER_DEFAULT, token) != 0) {
        // ImpersonateLoggedOnUser not required for us -- we are not doing impersonated stuff, but leave it here for completeness.
        //ImpersonateLoggedOnUser(token);
        // do impersonated stuff
        // end impersonated stuff

        // ensure that we are the original user
        CloseHandle(token);
        RevertToSelf();

        System.Security.Principal.IdentityReferenceCollection groups = Context.Request.LogonUserIdentity.Groups;
        IdentityReference translatedGroup = default(IdentityReference);

        foreach (IdentityReference g in groups) {
            translatedGroup = g.Translate(typeof(NTAccount));
            if (translatedGroup.Value.ToLower().Contains("desired group")) {
                inDBGroup = true;
                return 1;
            }
        }
    }
    else {
        return 0;
    }
}