When you share Microsoft Word files with others you may unintentionally leak sensitive corporate or personal information, including, but not limited to, the names of authors and reviewers, text deleted during the revision cycle, private comments, and information from other Microsoft Word, Excel and PowerPoint files that were open at the same time.

Simon Byers, security researcher at AT&T’s US laboratory, conducted a survey of 100,000 Word documents he located online. Byers was able to unearth hidden information in nearly all of the files by utilizing software tools and some basic programming. Real world examples of this problem abound and are not limited to Microsoft files—unprotected Adobe PDF files are also suspect. Tony Blair’s government has been bitten, as has The New York Times, and The Washington Post.