Android VPN IP Leak Even If Always-On VPN Enabled | Hacker News Reader

Android VPN IP Leak Even If Always-On VPN Enabled

lowlevel.fun

25 pointsbirdculture9 comments

"PERMISSION_SYSTEM" meaning you can bypass the VPN, with no option to override from the user, looks broken by design to me.

Honestly not sure if Proton or anyone else can fix this client-side on Android. Stuff like this is why people end up moving the VPN to the router.

"I reported this through the Android VRP. Apparently, it is not in their threat model."

According to Netguard logs UID 1000 "Dynamic System" appears to try to use the tunnel in an earlier Android version

Blocking UID 1000 connections, and blocking QUIC, has not caused any problems for me

Yet another example of the relative lack of user control, privacy, etc. in corporate mobile OS

Not to mention undesired "side effects" of default use of QUIC

Do you need a rooted device to block those connections/protocols?

Nope, mitigation below just requires adb connection

Would that be an appropriate mitigation for this issue though, preventing IP leaks?

I use Windscribe vpn and it has an option for a split tunneling of apps, so I have a bunch of apps I just let through. But, when I use the 'block connections without VPN' in always on VPN, it blocks those tunneled apps.

Neither Netguard nor PCAPDroid requires a "rooted device"

Personally I do not rely solely on apps to block connections/protocols. While they may work to some extent for such purposes, they can also be useful for port forwarding, logging and packet captures with trailers/extensions

To block connections and protocols I set the device gateway to a computer running a non-corporate OS compiled by the user where the user can operate firewalls, DNS, etc. No "rooted device" needed

However... If VPN settings in corporate mobile OS such as Android can be undermined via Android "updates", as shown by this example, then it stands to reason that Network settings for a network interface such as gateway, DNS, etc. could also be undermined by "updates"

With respect to user control, privacy, etc., corporate mobile OS all suck. IMHO they will continue to suck even more as the years go by, as history has shown so far. The vendors' and users' interests on these issues are not aligned, they are in conflict with each other

re: "mitigation"

"device_config values persist across reboots, but a Factory Reset clears them, and a future Mainline update from Google could remove the chicken-out flag entirely. Treat this as a current-release mitigation, not a permanent one."

Life has three certainties: death, taxes and "updates" from so-called "tech" companies

> Blocking UID 1000 connections, and blocking QUIC, has not caused any problems for me

By design, the app sandbox isn't applied as strictly on "privileged apps" (like UID 1000). There's nothing NetGuard or any userspace app can do to shore that up. System/privileged apps can bypass most OS-enforced isolation mechanisms at will: https://github.com/celzero/rethink-app/issues/224

This is besides the fact that NetGuard doesn't (yet) support "Block connections without VPN" mode.

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