This is how. The value returned will be 1 to 4.
Sub ReadSecurityLevel()
On Error Resume Next
Dim i_RegKey As String
Dim myWS As Object
i_RegKey = "HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Excel\Security\Level"
'access Windows scripting
Set myWS = CreateObject("WScript.Shell")
'read key from registry
RegKeyRead = myWS.RegRead(i_RegKey)
On Error GoTo 0
End Sub