title: Programmatically Determine If An Excel File (.xls) Contains Macros
body: <p>Is there any way to programmatically determine if an .xls contains macros, without actually opening it in Excel?</p>
  
  <p>Also are there any methods to examine which certificate (including timestamp cert) these macros are signed with? Again without using Excel.</p>
  
  <p>I'm wondering in particular if there are any strings that always show up in the raw data of an Excel file when macros are present.</p>