Question:
I'll put this as concretely as I can: For a small business-owning user of a Windows 10 PC who's highest-security-risk activities involve opening plenty of email attachments of PDF and Office documents from sources on the Internet, would uninstalling the traditional desktop Adobe Reader and Microsoft Office 2013 suite programs now used to open & work with those documents and replacing them with the MS Reader and Office for Windows 10 apps from the Windows Store constitute make a sizable difference in the security of that user's PC? (Assuming the user would go along with that.)
Follow-up question: If so, does that have more to do with Windows Store apps (ie. new Windows 10 and arguably Windows 8.1 apps) inherently having stronger security characteristics in the new Windows app model, or with there being so much more attention and effort put into finding weaknesses in & attacking the legacy desktop programs because they are still much, much, much more widely used?
Some Elaboration
Was writing an email to a client of mine (a small business owner) answering a question about matters related to starting to move the PCs in the back offices of the his three stores from Windows 7 to Windows 10. I was mentioning just a bit about the security improvements that might come from that upgrade when I starting trying to describe the possible benefits of using new Windows Store apps to do higher risk things like open documents that arrive in email attachments vs. using traditional Windows legacy desktop programs. I wrote this:
Using Windows Store applications to do risky day-to-day things is much safer than doing them with legacy desktop programs, because a security measure called AppContainer constrains apps that contain programming flaws [ie. security vulnerabilities] and might be hijackable by bad guys from doing a lot of bad things on your PC if that happens, because the new apps are often written in more secure ways [ie. meaning with managed languages like C# and html5/JavaScript, although C: and C++ are certainly still available choices], and because Microsoft verifies the identities of developers and screens the code of apps before they become available in the Store.
I wrote that paragraph, then stopped, thought for a second, then deleted in from my reply. Partly because I was getting more off-track about what the conversation started off being about (Windows 10 compatibility with a creaking old l.o.b. inventory program. Fun.), but also because re-reading it I wasn't totally sure it was correct.
I mean, the P.R. from Redmond certainly has been that they're a big improvement re. application security issues in the new model apps vs. legacy Windows programs. And I haven't read about major attacks occurring against say, Microsoft's official's pdf reader app in the Windows Store or the Office for Windows 10 apps, which obviously is far from the case with the legacy Adobe Reader and Office suite programs. But on the other hand there are a lot fewer installs of the new apps out there than the utterly ubiquitous traditional versions. But on the other, other hand having that AppContainer sandbox + other security technologies & mechanisms that the Windows Store apps probably has to do some good..... Huh.