# AVD - Android Virtual Device {{#include ../../banners/hacktricks-training.md}} Thank you very much to [**@offsecjay**](https://twitter.com/offsecjay) for his help while creating this content. ## What is Android Studio allows to **run virtual machines of Android that you can use to test APKs**. In order to use them you will need: - The **Android SDK tools** - [Download here](https://developer.android.com/studio/releases/sdk-tools). - Or **Android Studio** (with Android SDK tools) - [Download here](https://developer.android.com/studio). In Windows (in my case) **after installing Android Studio** I had the **SDK Tools installed in**: `C:\Users\\AppData\Local\Android\Sdk\tools` In mac you can **download the SDK tools** and have them in the PATH running: ```bash brew tap homebrew/cask brew install --cask android-sdk ``` Or from **Android Studio GUI** as indicated in [https://stackoverflow.com/questions/46402772/failed-to-install-android-sdk-java-lang-noclassdeffounderror-javax-xml-bind-a](https://stackoverflow.com/questions/46402772/failed-to-install-android-sdk-java-lang-noclassdeffounderror-javax-xml-bind-a) which will install them in `~/Library/Android/sdk/cmdline-tools/latest/bin/` and `~/Library/Android/sdk/platform-tools/` and `~/Library/Android/sdk/emulator/` For the Java problems: ```java export JAVA_HOME=/Applications/Android\ Studio.app/Contents/jbr/Contents/Home ``` ## GUI ### Prepare Virtual Machine If you installed Android Studio, you can just open the main project view and access: _**Tools**_ --> _**AVD Manager.**_
Then, click on _**Create Virtual Device**_
_**select** the phone you want to use_ and click on _**Next.**_ > [!WARNING] > If you need a phone with Play Store installed select one with the Play Store icon on it! > > In the current view you are going to be able to **select and download the Android image** that the phone is going to run:
So, select it and if it isn't downloaded click on the _**Download**_ symbol next to the name (**now wait until the image is downloaded).**\ Once the image is downloaded, just select **`Next`** and **`Finish`**. The virtual machine will be created. Now **every time that you access AVD manager it will be present**. ### Run Virtual Machine In order to **run** it just press the _**Start button**_. ![](<../../images/image (518).png>) ## Command Line tool > [!WARNING] > For macOS you can find the `avdmanager` tool in `/Users//Library/Android/sdk/tools/bin/avdmanager` and the `emulator` in `/Users//Library/Android/sdk/emulator/emulator` if you have them installed. First of all you need to **decide which phone you want to use**, in order to see the list of possible phones execute: ``` C:\Users\\AppData\Local\Android\Sdk\tools\bin\avdmanager.bat list device d: 0 or "automotive_1024p_landscape" Name: Automotive (1024p landscape) OEM : Google Tag : android-automotive-playstore --------- id: 1 or "Galaxy Nexus" Name: Galaxy Nexus OEM : Google --------- id: 2 or "desktop_large" Name: Large Desktop OEM : Google Tag : android-desktop --------- id: 3 or "desktop_medium" Name: Medium Desktop OEM : Google Tag : android-desktop --------- id: 4 or "Nexus 10" Name: Nexus 10 OEM : Google [...] ``` Once you have decide the name of the device you want to use, you need to **decide which Android image you want to run in this device.**\ You can list all the options using `sdkmanager`: ```bash C:\Users\\AppData\Local\Android\Sdk\tools\bin\sdkmanager.bat --list ``` And **download** the one (or all) you want to use with: ```bash C:\Users\\AppData\Local\Android\Sdk\tools\bin\sdkmanager.bat "platforms;android-28" "system-images;android-28;google_apis;x86_64" ``` Once you have downloaded the Android image you want to use you can **list all the downloaded Android images** with: ``` C:\Users\\AppData\Local\Android\Sdk\tools\bin\avdmanager.bat list target ---------- id: 1 or "android-28" Name: Android API 28 Type: Platform API level: 28 Revision: 6 ---------- id: 2 or "android-29" Name: Android API 29 Type: Platform API level: 29 Revision: 4 ``` At this moment you have decided the device you want to use and you have downloaded the Android image, so **you can create the virtual machine using**: ```bash C:\Users\\AppData\Local\Android\Sdk\tools\bin\avdmanager.bat -v create avd -k "system-images;android-28;google_apis;x86_64" -n "AVD9" -d "Nexus 5X" ``` In the last command **I created a VM named** "_AVD9_" using the **device** "_Nexus 5X_" and the **Android image** "_system-images;android-28;google_apis;x86_64_".\ Now you can **list the virtual machines** you have created with: ```bash C:\Users\\AppData\Local\Android\Sdk\tools\bin\avdmanager.bat list avd Name: AVD9 Device: Nexus 5X (Google) Path: C:\Users\cpolo\.android\avd\AVD9.avd Target: Google APIs (Google Inc.) Based on: Android API 28 Tag/ABI: google_apis/x86_64 The following Android Virtual Devices could not be loaded: Name: Pixel_2_API_27 Path: C:\Users\cpolo\.android\avd\Pixel_2_API_27_1.avd Error: Google pixel_2 no longer exists as a device ``` ### Run Virtual Machine > [!WARNING] > For macOS you can find the `avdmanager` tool in `/Users//Library/Android/sdk/tools/bin/avdmanager` and the `emulator` in `/Users//Library/Android/sdk/emulator/emulator` if you have them installed. We have already seen how you can list the created virtual machines, but **you can also list them using**: ```bash C:\Users\\AppData\Local\Android\Sdk\tools\emulator.exe -list-avds AVD9 Pixel_2_API_27 ``` You can simply **run any virtual machine created** using: ```bash C:\Users\\AppData\Local\Android\Sdk\tools\emulator.exe -avd "VirtualMachineName" C:\Users\\AppData\Local\Android\Sdk\tools\emulator.exe -avd "AVD9" ``` Or using more advance options you can run a virtual machine like: ```bash C:\Users\\AppData\Local\Android\Sdk\tools\emulator.exe -avd "AVD9" -http-proxy 192.168.1.12:8080 -writable-system ``` ### Command line options However there are **a lot of different command line useful options** that you can use to initiate a virtual machine. Below you can find some interesting options but can [**find a complete list here**](https://developer.android.com/studio/run/emulator-commandline) **Boot** - `-snapshot name` : Start VM snapshot - `-snapshot-list -snapstorage ~/.android/avd/Nexus_5X_API_23.avd/snapshots-test.img` : List all the snapshots recorded **Network** - `-dns-server 192.0.2.0, 192.0.2.255` : Allow to indicate comma separated the DNS servers to the VM. - **`-http-proxy 192.168.1.12:8080`** : Allow to indicate an HTTP proxy to use (very useful to capture the traffic using Burp) - If the proxy settings aren't working for some reason, try to configure them internally or using an pplication like "Super Proxy" or "ProxyDroid". - `-netdelay 200` : Set the network latency emulation in milliseconds. - `-port 5556` : Set the TCP port number that's used for the console and adb. - `-ports 5556,5559` : Set the TCP ports used for the console and adb. - **`-tcpdump /path/dumpfile.cap`** : Capture all the traffic in a file **System** - `-selinux {disabled|permissive}` : Set the Security-Enhanced Linux security module to either disabled or permissive mode on a Linux operating system. - `-timezone Europe/Paris` : Set the timezone for the virtual device - `-screen {touch(default)|multi-touch|o-touch}` : Set emulated touch screen mode. - **`-writable-system`** : Use this option to have a writable system image during your emulation session. You will need also to run `adb root; adb remount`. This is very useful to install a new certificate in the system. ## Linux CLI setup (SDK/AVD quickstart) The official CLI tools make it easy to create fast, debuggable emulators without Android Studio. ```bash # Directory layout mkdir -p ~/Android/cmdline-tools/latest # Download commandline tools (Linux) wget https://dl.google.com/android/repository/commandlinetools-linux-13114758_latest.zip -O /tmp/cmdline-tools.zip unzip /tmp/cmdline-tools.zip -d ~/Android/cmdline-tools/latest rm /tmp/cmdline-tools.zip # Env vars (add to ~/.bashrc or ~/.zshrc) export ANDROID_HOME=$HOME/Android export PATH=$ANDROID_HOME/cmdline-tools/latest/bin:$ANDROID_HOME/platform-tools:$ANDROID_HOME/emulator:$PATH # Install core SDK components sdkmanager --install "platform-tools" "emulator" # Install a debuggable x86_64 system image (Android 11 / API 30) sdkmanager --install "system-images;android-30;google_apis;x86_64" # Create an AVD and run it with a writable /system & snapshot name avdmanager create avd -n PixelRootX86 -k "system-images;android-30;google_apis;x86_64" -d "pixel" emulator -avd PixelRootX86 -writable-system -snapshot PixelRootX86_snap # Verify root (debuggable images allow `adb root`) adb root adb shell whoami # expect: root ``` Notes - System image flavors: google_apis (debuggable, allows adb root), google_apis_playstore (not rootable), aosp/default (lightweight). - Build types: userdebug often allows `adb root` on debug-capable images. Play Store images are production builds and block root. - On x86_64 hosts, full-system ARM64 emulation is unsupported from API 28+. For Android 11+ use Google APIs/Play images that include per-app ARM-to-x86 translation to run many ARM-only apps quickly. ### Snapshots from CLI ```bash # Save a clean snapshot from the running emulator adb -s emulator-5554 emu avd snapshot save my_clean_setup # Boot from a named snapshot (if it exists) emulator -avd PixelRootX86 -writable-system -snapshot my_clean_setup ``` ## ARM→x86 binary translation (Android 11+) Google APIs and Play Store images on Android 11+ can translate ARM app binaries per process while keeping the rest of the system native x86/x86_64. This is often fast enough to test many ARM-only apps on desktop. > Tip: Prefer Google APIs x86/x86_64 images during pentests. Play images are convenient but block `adb root`; use them only when you specifically require Play services and accept the lack of root. ## Rooting a Play Store device If you downloaded a device with Play Store you are not going to be able to get root directly, and you will get this error message ``` $ adb root adbd cannot run as root in production builds ``` Using [rootAVD](https://github.com/newbit1/rootAVD) with [Magisk](https://github.com/topjohnwu/Magisk) I was able to root it (follow for example [**this video**](https://www.youtube.com/watch?v=Wk0ixxmkzAI) **or** [**this one**](https://www.youtube.com/watch?v=qQicUW0svB8)). ## Install Burp Certificate Check the following page to learn how to install a custom CA cert: {{#ref}} install-burp-certificate.md {{#endref}} ## Nice AVD Options ### Take a Snapshot You can **use the GUI** to take a snapshot of the VM at any time: ![](<../../images/image (234).png>) ## References - [Build a Repeatable Android Bug Bounty Lab: Emulator vs Magisk, Burp, Frida, and Medusa](https://www.yeswehack.com/learn-bug-bounty/android-lab-mobile-hacking-tools) - [Android Emulator command line](https://developer.android.com/studio/run/emulator-commandline) - [Run ARM apps on the Android Emulator (x86 translation)](https://android-developers.googleblog.com/2020/03/run-arm-apps-on-android-emulator.html) {{#include ../../banners/hacktricks-training.md}}