Ok, thanks for the clarification, so the key points are, If I understood you correctly:
1.apps and live tiles have some of the powers a regular program has (they can write and read certain files, like the images they are responsible for downloading*) but they are also sandboxed so can't do anything like as much a real programs can?
2.a deliberately malicious app could make some forms of malicious download, but this download might not be able to run itself due to the sandboxing?
3.bundled apps on a new computer and default microsoft apps (things like the app for the store itself) could perhaps deliver infections, but only if the infection first got past vetting my microsoft, and then was downloaded as content by the app (in the same way that the app downloads images and such), and then managed to execute, and then managed to escape the sandbox?
4.microsoft doesn't yet do advertising through the live tiles (the store live tile, the weather live tile, the financial news live tile, the maps live tile...) in the same way that adverts on the norml internet are run. Instead the only adverts here are ones which microsoft themselves have made, and which advertise store apps (I know I have seen atleast one instance of this before I disabled the live function on the store tile), but if they started shwoing third party adverts, then it would open up the risks described in point 3, but only if a malcicous third party advert could get past all those obstacles.
5.I couldn't work this out, but are you saying that the live tiles can be equally vulnerable as IE can? Are you saying that a live tile (the store tile, the news tile, the weather tile...) is like a constant connection via IE to a particular website? or are you saying this is not the case? Because if live tiles ARE equivalent to adverts being shown through IE, then they would surely be guaranteed to infect users, given how vulnerable IE is and how many adverts are malicious.
* to see what images I am talking about search your C:\ drive (through the file explorer, not the search function in the top right corner of the screen) for files with a date modified of today, then look at all the images amongst them, some of those images are clearly backgrounds for adverts in the ms app store. The images will be of things like x-box games, and also title covers of films, and other things like that, title covers of games drawn in cartoon computer graphic style... that sort of stuff, you'll know them when you see them. This will occur on computers where the only live tile is the store, on computers with more live tiles more things might be found. These images will probably only be found if you have live tiles enabled. When searching "show hidden files and folders" might need to be enabled, "show protected operating system files" does not need to be enabled. This happens for windows 8.1 users, it may or may not occur for windows 8 users.
Edited by rp88, 14 August 2015 - 08:03 AM.
Back on this site, for a while anyway, been so busy the last year.
My systems:2 laptops, intel i3 processors, windows 8.1 installed on the hard-drive and linux mint 17.3 MATE installed to USB