ASP.NET - Problema de Seguridad

Public Function GetGroups() As String

Dim search As DirectorySearcher = New DirectorySearcher(_path)
search.Filter = "(cn=" & _filterAttribute & ")"
search.PropertiesToLoad.Add("memberOf")
Dim groupNames As StringBuilder = New StringBuilder()

Try
Dim result As SearchResult = search.FindOne()
Dim propertyCount As Integer = result.Properties
"memberOf").Count

Dim dn As String
Dim equalsIndex, commaIndex

Dim propertyCounter As Integer

For propertyCounter = 0 To propertyCount - 1
dn = CType(result.Properties("memberOf")(propertyCounter), String)

equalsIndex = dn.IndexOf("=", 1)
commaIndex = dn.IndexOf(",", 1)
If (equalsIndex = -1) Then
Return Nothing
End If

groupNames.Append(dn.Substring((equalsIndex + 1), (commaIndex - equalsIndex) - 1))
groupNames.Append("|")
Next

Catch ex As Exception
Throw New Exception("Error obteniendo grupos " & ex.Message)
End Try

Return groupNames.ToString()
End Function