Microsoft Compound File

Microsoft Compound File is a complex container format used by some versions of Microsoft Office, and other Microsoft applications. It has features similar to those of a filesystem format.

It is also known as Compound File Binary File Format (CFBF or CFB), Microsoft Compound Document File Format, OLE Compound Document Format, OLE2 Compound Document Format, etc.

The format was not publicly documented by Microsoft until 2008.

Identification
Files begin with signature bytes.

Specifications

 * MSDN: Compound File Binary File Format → [MS-CFB] PDF
 * OpenOffice.org's documentation

Links

 * Wikipedia article
 * Joel on Software: Why are the Microsoft Office file formats so complicated?