I find that on a jailbroken device I can access /Applications/ in a normal app from app store, although I thought due to the sandbox I shouldn't.
Maybe I should write an app to determine what sections of the filesystem are accessible and run it on a normal iPhone and a jailbroken one, to see if this is true.
So my question is, will jailbreaking affect file system accessibility (bypassing the sandbox) for all apps?
Let me try to break down what you're asking.
I find when use a jailbreak device I can access
/Applications/.
Yes, that's correct. A jailbroken device can access an iOS device's root file system from a shell or any application (such as iFile). As of iOS 8, the Applications directory has changed to /var/mobile/Containers/Bundle/Application.
But from this, I shouldn't?
Well, not necessarily. If the application is running as root (think iFile or Filza), you can have read and write access to any directory on the device.
Maybe I should write a App to scan the FileSystem on a normal iPhone and a jailbreak one.
In theory, any application can ask to read or write a file to any directory. This is frequently how jailbreak checks are done in production apps. If the file manager does not return an error when trying to read from /var/mobile, then you know the application is being run as root on a jailbroken device.
