Active Directory: Add New User C# / VB - vb.net

Question

I browsed other questions and couldn't find the answer.
What is the appropriate way to add a new user to a active directory specific group when the "current user" running the application does not have access rights to add new users?
I am currently authenticating as the domain Administrator to do it, but obviously that is a security no-no and I don't want the Administrator user's credentials hard-codeded in my code.
I assume the answers is not in my code itself but that I have to create a user in the Active Directory that has privileges to add users.
So my question is a combination of a AD and a Coding question:
1) How do I create a AD user that ONLY has access rights to add users to specific OU and CN security group?
2) Is their any way possible to not hard-code the password for this user?
Or... am I going about this entirely wrong?
Here is my current VB.NET code:
Public Function CreateUser(ByVal UserName As String, ByVal Password As String, ByVal DisplayName As String) As Boolean
Try
'Dim catalog As Catalog = New Catalog()
Dim de As DirectoryEntry = New DirectoryEntry()
de.Path = "LDAP://OU=TS2xUsers,DC=dc,DC=example,DC=com"
de.AuthenticationType = AuthenticationTypes.Secure
de.Username = "Administrator"
de.Password = "foopassword"
'1. Create user accountd
Dim users As DirectoryEntries = de.Children
Dim newuser As DirectoryEntry = users.Add("CN=" & DisplayName, "user")
newuser.Properties("givenname").Value = DisplayName
newuser.Properties("name").Value = DisplayName
newuser.Properties("displayName").Value = DisplayName
newuser.Properties("SAMAccountName").Value = UserName
newuser.Properties("userPrincipalName").Value = UserName & "#dc.example.com"
'newuser.Properties("OU").Value = "TS2xUsers"
newuser.CommitChanges()
Dim ret As Object = newuser.Invoke("SetPassword", Password)
newuser.CommitChanges()
Dim exp As Integer = CInt(newuser.Properties("userAccountControl").Value)
exp = exp And Not &H2 'enable acccount
exp = exp Or &H10000 'dont expire password
newuser.Properties("userAccountControl").Value = exp
newuser.CommitChanges()
''' 5. Add user account to groups
If MakeTSUser(newuser) = False Then
Return False
newuser.Close()
de.Close()
End If
newuser.Close()
de.Close()
Return True
Catch ex As Exception
MsgBox("Failed to create user due to the following reason: " & ex.Message, MsgBoxStyle.Critical)
Return False
End Try
End Function
Private Function MakeTSUser(ByVal deUser As DirectoryEntry) As Boolean
Try
Dim deRBGroup As New DirectoryEntry
deRBGroup.Path = "LDAP://CN=TSUsers,CN=Builtin,DC=dc,DC=example,DC=com"
deRBGroup.AuthenticationType = AuthenticationTypes.Secure
deRBGroup.Username = "Administrator"
deRBGroup.Password = "foopassword"
Dim deDomainUsers As New DirectoryEntry
deDomainUsers.Path = "LDAP://CN=Domain Users,CN=Users,DC=dc,DC=example,DC=com"
deDomainUsers.AuthenticationType = AuthenticationTypes.Secure
deDomainUsers.Username = "Administrator"
deDomainUsers.Password = "foopassword"
Dim primaryGroupToken As Object = Nothing
deRBGroup.Invoke("Add", New Object() {deUser.Path.ToString()})
deRBGroup.CommitChanges()
'Get Primary Group Token of MYGROUP
deRBGroup.Invoke("GetInfoEx", New Object() {New Object() {"primaryGroupToken"}, 0})
primaryGroupToken = deRBGroup.Properties("primaryGroupToken").Value
'Assign Primary Group Token value of MYROUP to the User's PrimaryGroupID
deUser.Properties("primaryGroupID").Value = primaryGroupToken
deUser.CommitChanges()
'Remove the User from "Domain Users" group
deDomainUsers.Invoke("Remove", New Object() {deUser.Path.ToString()})
deDomainUsers.CommitChanges()
Return True
Catch ex As Exception
Return False
End Try
End Function

Answer 1

What is the appropriate way to add a new user to a active directory specific group when the "current user" running the application does not have access rights to add new users?
Run the app as a user that does have those permissions... but you already know this:
I assume the answers is ... to create a user in the Active Directory that has privileges to add users.
Is their any way possible to not hard-code the password for this user?
Good question. One way to do this by setting up a Windows Scheduled Task. You can setup a task to run on demand, with no actual schedule, and to run as any user you want, including your new service account. You will have to put in the password for that user when you setup the task, but only when you first setup the task, and the actual password won't be stored... only the authentication token, which is not transferable. Then your desktop application can trigger the task to start.
Another way to do this is to grant the unprivileged HR or helpdesk users who run your app permissions to create new users just within your specific OU. In the case of a web app, you can also do this for the user account that runs the web site, as long as you have appropriate logging and auditing in place.
The other option is to create a separate service to create the users, which runs as the appropriate user. This could be a web service, where less-privileged authenticated users can post the new account information, or it could be a Windows service doing something like watching a file share, where your unprivileged users then have the ability or write to the file share. Then your program can know how to call the service or write the correct file formats into the share.