Excel Spreadsheet (XLS)
The Excel Spreadsheet (XLS) file format has the .xls extension. This file type originates from Microsoft Excel. However, other spreadsheet software can be used to display these files as well. These include:
The object stream of the OLECF containing a Excel spreadsheet contains the string "WorkBook" with some version.
Excel 97-2003 spreadsheets
The Excel 97-2007 Binary File format is stored in the OLECF using multiple streams:
- Workbook stream
See Word Document (DOC). Note: perhaps this section should be moved to a separate section about Microsoft Office encryption