参考网址: http://www.garykessler.net/library/file_sigs.html
Office 07 - 10 以上版本:
50 4B 03 04 14 00 06 00 DOCX, PPTX, XLSX Microsoft Office Open XML Format (OOXML) Document NOTE: There is no subheader for MS OOXML files as there is with DOC, PPT, and XLS files. To better understand the format of these files, rename any OOXML file to have a .ZIP extension and then unZIP the file; look at the resultant file named [Content_Types].xml to see the content types. In particular, look for the <Override PartName= tag, where you will find word, ppt, or xl, respectively. Trailer: Look for 50 4B 05 06 (PK..) followed by 18 additional bytes at the end of the file.
03版本的Excel文件:
[512 byte offset] 09 08 10 00 00 06 05 00 [512 byte offset] ........ XLS Excel spreadsheet subheader (MS Office)
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