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GrapheneOS

GrapheneOS is a private and secure mobile operating system with Android app compatibility. Developed as a non-profit open source project.

GrapheneOS is a private and secure mobile operating system with great functionality and usability. It starts from the strong baseline of the Android Open Source Project (AOSP) and takes great care to avoid increasing attack surface or hurting the strong security model. GrapheneOS makes substantial improvements to both privacy and security through many carefully designed features built to function against real adversaries. The project cares a lot about usability and app compatibility so those are taken into account for all of our features.

GrapheneOS is also hard at work on filling in gaps from not bundling Google apps and services into the OS. We aren't against users using Google services but it doesn't belong integrated into the OS in an invasive way. GrapheneOS won't take the shortcut of simply bundling a very incomplete and poorly secured third party reimplementation of Google services into the OS. That wouldn't ever be something users could rely upon. It will also always be chasing a moving target while offering poorer security than the real thing if the focus is on simply getting things working without great care for doing it robustly and securely.

Features⚑

These are a subset some of the features of GrapheneOS beyond what's provided by version 13 of the Android Open Source Project. It only covers our improvements to AOSP and not baseline features. This section doesn't list features like the standard app sandbox, verified boot, exploit mitigations (ASLR, SSP, Shadow Call Stack, Control Flow Integrity, etc.), permission system (foreground-only and one-time permission grants, scoped file access control, etc.) and so on but rather only our improvements to modern Android.

Defending against exploitation of unknown vulnerabilities⚑

The first line of defense is attack surface reduction. Removing unnecessary code or exposed attack surface eliminates many vulnerabilities completely. GrapheneOS avoids removing any useful functionality for end users, but we can still disable lots of functionality by default and require that users opt-in to using it to eliminate it for most of them. An example we landed upstream in Android is disallowing using the kernel's profiling support by default, since it was and still is a major source of Linux kernel vulnerabilities.

The next line of defense is preventing an attacker from exploiting a vulnerability, either by making it impossible, unreliable or at least meaningfully harder to develop. The vast majority of vulnerabilities are well understood classes of bugs and exploitation can be prevented by avoiding the bugs via languages/tooling or preventing exploitation with strong exploit mitigations. In many cases, vulnerability classes can be completely wiped out while in many others they can at least be made meaningfully harder to exploit. Android does a lot of work in this area and GrapheneOS has helped to advance this in Android and the Linux kernel.

The final line of defense is containment through sandboxing at various levels: fine-grained sandboxes around a specific context like per site browser renderers, sandboxes around a specific component like Android's media codec sandbox and app / workspace sandboxes like the Android app sandbox used to sandbox each app which is also the basis for user/work profiles. GrapheneOS improves all of these sandboxes through fortifying the kernel and other base OS components along with improving the sandboxing policies.

Preventing an attacker from persisting their control of a component or the OS / firmware through verified boot and avoiding trust in persistent state also helps to mitigate the damage after a compromise has occurred.

Attack surface reduction⚑

  • Greatly reduced remote, local and proximity-based attack surface by stripping out unnecessary code, making more features optional and disabling optional features by default (NFC, Bluetooth, etc.), when the screen is locked (connecting new USB peripherals, camera access) and optionally after a timeout (Bluetooth, Wi-Fi)
  • Option to disable native debugging (ptrace) to reduce local attack surface (still enabled by default for compatibility)

Downsides⚑

It looks that the community behind GrapheneOS is not the kindest one, they are sometimes harsh and when they are questioned they enter a defensive position. This can be seen in the discussions regarding whether or not to use the screen pattern lock (1, 2).

They strongly recommend only purchasing one of the following devices for GrapheneOS due to better security and a minimum 5 year guarantee from launch for full security updates and other improvements:

  • Pixel 7 Pro
  • Pixel 7
  • Pixel 6a
  • Pixel 6 Pro
  • Pixel 6

!!! note "Check the source as this section is probably outdated"

Newer devices have more of their 5 year minimum guarantee remaining but the actual support time may be longer than the minimum guarantee.

The Pixel 7 and Pixel 7 Pro are all around improvements over the Pixel 6 and Pixel 6 Pro with a significantly better GPU and cellular radio along with an incremental CPU upgrade. The 7th generation Pixels are far more similar to the previous generation than any prior Pixels.

The Pixel 6 and Pixel 6 Pro are flagship phones with much nicer hardware than previous generation devices (cameras, CPU, GPU, display, battery).

The cheaper Pixel 6 has extremely competitive pricing for the flagship level hardware especially with the guaranteed long term support. Pixel 6 Pro has 50% more memory (12GB instead of 8GB), a higher end screen, a 3rd rear camera with 4x optical zoom and a higher end front camera. Both devices have the same SoC (CPU, GPU, etc.) and the same main + ultrawide rear cameras. The Pixel 6 is quite large and the Pixel 6 Pro is larger.

The Pixel 6a is a budget device with the same 5 years of guaranteed full security support from launch as the flagship 6th generation Pixels. It also has the same flagship SoC as the higher end devices, the same main rear and front cameras as the Pixel 5 and a rear wide angle lens matching the flagship 6th generation Pixels. Compared to the 5th generation Pixels, it has 5 years of full security support remaining instead of less than 2 years and the CPU is 2x faster. We strongly recommend buying the Pixel 6a rather than trying to get a deal with older generation devices. You'll be able to use the Pixel 6a much longer before it needs to be replaced due to lack of support.

It's funny though that in the search for security and privacy you end up buying a Google device. If you also reached this thought, you're not alone. Summing up, the Pixel's are in fact the devices that are more secure and that potentially respect your privacy.

Installation⚑

I was not able to follow the web instructions so I had to follow the cli ones.

Whenever I run a fastboot command it got stuck in < waiting for devices >, so I added the next rules on the udev configuration at /etc/udev/rules.d/51-android.rules

SUBSYSTEM=="usb", ATTR{idVendor}=="18d1", ATTR{idProduct}=="4ee7", MODE="0600", OWNER="myuser"

The idProduct and idVendor were deduced from lsusb. Then after a restart everything worked fine.

Setup Auditor⚑

Auditor provides attestation for GrapheneOS phones and the stock operating systems on a number of devices. It uses hardware security features to make sure that the firmware and operating system have not been downgraded or tampered with.

Attestation can be done locally by pairing with another Android 8+ device or remotely using the remote attestation service. To make sure that your hardware and operating system is genuine, perform local attestation immediately after the device has been setup and prior to any internet connection.

Tips⚑

Add call screening⚑

If you're tired of getting spam calls even if you've signed up in a no-spam list such as the Robinson list, then try out "yetanothercallblocker".

You can also enable the block unknown numbers in the Phone Settings, but it only blocks calls that have an unknown id. Not the ones that are not in your agenda A friend is using "carrion" although he says it's not being very effective.

Disable Bluetooth and Wifi once it's disconnected⚑

If you don't want to go spreading your SSIDs you can configure graphene to disable wifi and bluetooth X minutes after loosing connection.

For Wifi:

  • Go to Settings > network & internet > internet > network preferences
  • Select Turn off Wi-Fi automatically, for example after 2 minutes

For Bluetooth:

  • Go to Settings > connected devices > connection preferences> bluetooth
  • Select Turn Bluetooth off automatically, for example after 2 minutes

Split the screen⚑

Go into app switcher, tap on the app icon above the active app and then select "Split top".

References⚑