Does explorere and office use different cookies?

Question

I have a strange issue. I'm logging in to a SharePoint 2010 solution I then have to enter credentials, and check for remember me (fedauth cookie is set). Then is open a document and I get a popup (Office does not use the cookie??) to log in and check for remember me. Then I log out from the browser and close word and IE. Then I open IE I'm logged out (good), then I try to open the document (from document history in word) and I do not need to log in (Hmmm but I logged out). Then I login in IE as a different user, and opens the word document (no log in) edit it and save. When I edited the document, in last edit is set to the first user (not the one I logged in as in IE) not good. I look at the cookies in the "Temporary Internet Files" here I can see a cookie (Cookie:username@sharepointdomain.com) if I delete this I get loggin in Word (but not IE if I check for remember me). To me it looks like IE uses the fedauth cookie but word users the other one.

Does any of you have experience with this issue, should not word also use the same fedauth cookie?

Answer 1

Office and Internet Explorer do use completely isolated sessions when interacting with SharePoint. When opening an Office document from a web site, the instance of IE that is used by Office will attempt to connect to the document using the proper mode for the zone that the site is in. On intranets, this is typically your current Windows Authentication. If that fails then it will prompt the user for authentication in order to access the document. This authenticated session is only available to Office and will stay active as long as the Office App does. Closing the app and then clicking on the document again will force Office to re-authenticate.

Whatever ID you used to browse the site in the instance of Internet Explorer outside of Office makes no difference to Office whatsoever.