The doc file type is mainly associated with Word, Microsoft Corporation, Word.Document.6 , Word.Document.8 , WordDocument , WordPad.Document.1, Free Microsoft Viewer, Jarte Word Processor, OpenOffice.org, TextMaker Viewer, Zoho Viewer (Web Viewer), and with the following MIME types: application/msword [official] application/doc, appl/text, application/vnd.msword, application/vnd.ms-word, application/winword, application/word, application/x-msw6, application/x-msword

This SonicWALL signature identifies HTTP downloads of Content-Type: application/vnd.msword.