Why does Microsoft Word open Word 6.0 Binary Documents and Templates in Protected View by default? Is there a reason I shouldn't turn that off?

Question

I have a .doc file which, because of the format it's saved in, Word 2013 opens in Protected view. I can't edit, save, or print it:

I would like to do at least one of those things with this file. I could change my file block settings, but I'm hesitant to do so because I'm sure there's a good reason why this kind of file is blocked. It's one of the only formats that is blocked by default.

(In this case, I am requesting that the sender re-send me the document in a different doc format.)

Why is this format opened in Protected View by default? Are there security issues with this format which I should care about in modern day? Is there any reason I shouldn't just change my file block settings, so that Word doesn't open these in protected view and instead treats them like any regular .doc format?

I've tried searching, but didn't come across anything indicating what the problem is.

Answer 1

This feature, which switches to Protected View when handling older file formats, is called File Block. According to Microsoft:

The code used to open and save the older formats have vulnerabilities that hackers can exploit. So they are security risks that should be avoided, if possible.

See http://office.microsoft.com/en-ca/excel-help/what-is-file-block-HA010355927.aspx for more information.

I don't know of an example of a publicly known vulnerability in in Word 2013's Word 6.0 file format support. However:

• There are definitely examples of known vulnerabilities for other older formats that Word 2013 can handle, for instance RTF
• Microsoft sometimes indicates that security updates fix privately reported vulnerabilities without giving details