M 208: WireGuard VPN on Android (10 pts)

What You Need

• A Google Cloud Debian 10 Linux Server
• An Android device, virtual or real, such as Genymotion machine

Purpose

Server Setup

H 240: WireGuard VPN

Gathering Information

sudo cat /etc/wireguard/publickey

wg genkey | (
  read privk
  echo "android-private-key: $privk"
  echo "android-public-key:  $(echo "$privk" | wg pubkey)"
)

The first one is the server's public key, and the other two will be used to identify the Android client.

Adding the Android Public Key to the Server

sudo systemctl stop wg-quick@wg0
sudo nano /etc/wireguard/wg0.conf

On your Debian server, execute these commands:

sudo systemctl enable wg-quick@wg0
sudo systemctl start wg-quick@wg0

Installing the WireGuard Client on Android

Click the blue + button to add a tunnel.

Click "CREATE FROM SCRATCH".

Fill in the keys and addresses, as shown below.

To paste into Android, click and hold down the mouse button for several seconds.

• Enter an Interface name of wg
• Copy and paste the Android private key into the Interface Private key field. The Public key is automatically calculated.
• Enter the IP address you wish to assign to the Android device into the Interface Addresses field.
• Enter a DNS server of 8.8.8.8
• Click "ADD PEER"
• Paste the server's public key into the Peer Public key field.
• Enter 5 into the Persistent keepalive field.
• Enter the public IP address of your Google Cloud debian server and the port number of your WireGuard VPN into the Endpoint field.
• Enter a specifier for the IP subnet of your VPN into the Allowed IPs field.

At the top right, click the floppy-disk icon to save your configuration.

At the top left, click the slider to activate your VPN interface.

Click wg to show the interface details.

At the bottom right, you should see some bytes received (rx) and transmitted (tx), as shown below.

Testing Networking

ping -c 5 192.168.100.10

Connecting with Android Debug Bridge

sudo apt update
sudo apt install android-tools-adb -y
adb connect 192.168.100.10
adb devices -l

If it fails, check your Android device settings and make sure USB debugging is enabled.

M 208.1: Process (10 pts) On your Debian server, execute this command: adb shell ps | grep wire The flag appears, covered by a green rectangle in the image below.

References