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A comment on Droppers Is How Android Malware Keeps Sneaking into the Play Store. Parent comment

Re:Droppers Is How Android Malware Keeps Sneaking into the P... by amelius on Friday July 20, 2018 @07:47AM (#17574199)
I really hate it when I need to send a single file or photo, an app suddenly "needs access to my filesystem" and I have to grant that access.

OSes should allow me to create a sandbox for an app, so I can grant them access (and the app will not "break"), while still being secure.

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Re:Droppers Is How Android Malware Keeps Sneaking into the P... by cesarb on Friday July 20, 2018 @08:49AM (#17574524)
> I really hate it when I need to send a single file or photo, an app suddenly "needs access to my filesystem" and I have to grant that access.

There's another way: the app could instead use Android's Intent system to request a file chooser. This switches to a separate app which already has access to the filesystem (like the built-in Gallery app), which after the user has chosen the file, returns something which allows the original app access to just that file. This mechanism exists since the first version of Android.

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Re:Droppers Is How Android Malware Keeps Sneaking into the P... by amelius on Friday July 20, 2018 @09:29AM (#17574790)
I think this won't work because the app can get away by asking (insisting) for more permission than it actually needs.
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Re:Droppers Is How Android Malware Keeps Sneaking into the P... by devxpy on Friday July 20, 2018 @09:19AM (#17574712)
exactly.
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Re:Droppers Is How Android Malware Keeps Sneaking into the P... by scarface74 on Friday July 20, 2018 @08:20AM (#17574378)
That shows the larger problem with Android. An app shouldn’t need access to your file system to send a photo. It should bring up a system provided photo picker and once the user chooses a set of files, the OS should give it a read only access to the file.

If a photo management app needs access to your photos, you should be able to give it access to your photo library.

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Re:Droppers Is How Android Malware Keeps Sneaking into the P... by amelius on Friday July 20, 2018 @08:22AM (#17574393)
I don't think that's the solution because apps may easily "bribe" the user into giving the app more access than it strictly needs. The bribing goes like: "sorry, but if you don't give me full access, then you can't use me". Simple, but very effective in most cases.

A better solution (imho) is to make the app think it has access, while in reality its access is limited to a sandbox.

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Re:Droppers Is How Android Malware Keeps Sneaking into the P... by scarface74 on Friday July 20, 2018 @08:41AM (#17574487)
That’s still a problem with the OS. Why does any app need access to the file system instead of the users photo library or access to certain files in a document store where the app only has read access to files that the user explicitly chooses in a system provided file picker or can write files to a location that the user chooses?
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Re:Droppers Is How Android Malware Keeps Sneaking into the P... by devxpy on Friday July 20, 2018 @09:26AM (#17574764)
https://developer.android.com/training/secure-file-sharing/r...

read up!

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Re:Droppers Is How Android Malware Keeps Sneaking into the P... by scarface74 on Friday July 20, 2018 @09:37AM (#17574842)
It’s fine that it’s an option but there is still nothing on the OS stopping an app from getting more permission. Why is the other permission even an option?
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Re:Droppers Is How Android Malware Keeps Sneaking into the P... by devxpy on Sunday July 22, 2018 @03:54PM (#17588592)
Just a matter of freedom vs security I guess?
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Re:Droppers Is How Android Malware Keeps Sneaking into the P... by HappyRobot on Friday July 20, 2018 @08:01AM (#17574275)
I thought Android apps were sandboxed [1]. The "needs access to my file system" is the way for data to transfer into that sandbox.

Android should add the option for temporary data access. I would prefer turning on the access temporarily to send 1 photo, then turning it off a few minutes later.

https://developer.android.com/training/articles/security-tip...

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Re:Droppers Is How Android Malware Keeps Sneaking into the P... by amelius on Friday July 20, 2018 @08:19AM (#17574376)
The problem is that apps want access to my entire filesystem, otherwise they break. So a solution is to make them think they have access, while in reality they only have access to the sandbox filesystem (containing just the files I want to manipulate with that app).
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Re:Droppers Is How Android Malware Keeps Sneaking into the P... by trash_panda on Friday July 20, 2018 @09:25AM (#17574757)
What is the "file system permission" you are referring to?

See: https://developer.android.com/reference/android/Manifest.per...

If you don't mind sharing, what app are you referring to?

The file system itself should be well protected (on a non-rooted phone) as to prevent any unauthorized access to important data. Any app can only do whatever on the SD card if you give it permission to do so, but on the OS file system itself there isn't much they can do (again, on a non-rooted phone).

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Re:Droppers Is How Android Malware Keeps Sneaking into the P... by scarface74 on Friday July 20, 2018 @09:41AM (#17574878)
That doesn’t help. No app should need general access to the sd card.
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Re:Droppers Is How Android Malware Keeps Sneaking into the P... by trash_panda on Friday July 20, 2018 @09:49AM (#17574945)
Completely agree.
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Re:Droppers Is How Android Malware Keeps Sneaking into the P... by devxpy on Friday July 20, 2018 @09:29AM (#17574795)
I believe this is what you're looking for?

https://developer.android.com/training/secure-file-sharing/r...

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Re:Droppers Is How Android Malware Keeps Sneaking into the P... by taneq on Friday July 20, 2018 @08:03AM (#17574286)
That's basically what Privacy Guard does. It was available at one point in stock Android and is a major selling point (IMO) of LineageOS.
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Re:Droppers Is How Android Malware Keeps Sneaking into the P... by felix_nagaand on Friday July 20, 2018 @07:55AM (#17574242)
Your solution is too simple and intuitive.
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Re:Droppers Is How Android Malware Keeps Sneaking into the P... by chasil on Friday July 20, 2018 @08:32AM (#17574438)
Linux does have this feature. It is the chroot() system call.

Linux can also allow limited access to select filesystem data within a chroot() - this is done with a "bind mount."

Why these two security features were not designed around all Android apps from the beginning is beyond me.

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Re:Droppers Is How Android Malware Keeps Sneaking into the P... by TeMPOraL on Friday July 20, 2018 @09:09AM (#17574642)
Didn't chroot() become secure / usable only late in the era of smartphones, way past creation of Android? Containers are a pretty new development, after all.
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Re:Droppers Is How Android Malware Keeps Sneaking into the P... by hedora on Friday July 20, 2018 @09:28AM (#17574783)
Neither linux containers nor linux chroot provide meaningful security. They’re useful for other things, but the kernel itself isn’t particularly well hardened against local privilege escalation attacks.

OpenBSD is one of the best on that front, but it is a defense-in-depth mechanism, not something designed to run known-malicious code.

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Re:Droppers Is How Android Malware Keeps Sneaking into the P... by JTbane on Friday July 20, 2018 @09:08AM (#17574634)
That's no different than running programs in userspace on a PC- if you trust the app, it makes no sense to decline.

At least you can turn it off later.

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Re:Droppers Is How Android Malware Keeps Sneaking into the P... by duiker101 on Friday July 20, 2018 @07:59AM (#17574267)
And then you need to app to the sandbox? Seems even more complex
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Re:Droppers Is How Android Malware Keeps Sneaking into the P... by mobilio on Friday July 20, 2018 @08:04AM (#17574292)
Actually isn't. And this was already implemented in iOS and Windows Mobile.
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