Setting up OpenVPN on Kali

Here is how to set-up OpenVPN on Kali. The process is (unsurprisingly the same for Debian), steps below:

Obtain OpenVPN certificates, key and openvpn.ovpn files from the provider

• ca.crt: This is the certificate of the certification authority
• client.crt: This is the user certification file 
• client.key: This is your private key file
• openvpn.ovpn: This is your OpenVPN configuration file
• Rename the openvpn.ovpn config file to something identifiable for the server being used (Server.conf in this example)

Copy the downloaded files to the /etc/openvpn/ directory

• sudo cp Server.conf /etc/openvpn/
• sudo cp ca.cert /etc/openvpn/
• sudo cp client.crt /etc/openvpn/
• sudo cp client.key /etc/openvpn/

Update the  packages on Kali

• sudo apt-get update

Ensure OpenVPN is installed with the required packages

• sudo apt-get install openvpn openssl openresolv

Change directory to /etc/openvpn/

• cd /etc/openvpn

Create a new file for the credentials to access the VPN

• sudo nano user.txt

Enter the credentials in the following format:

• Username
• Password

Open the Server.conf file and make the following changes:

• Change auth-user-pass -> auth-user-pass /etc/openvpn/user.txt

Under comp-lzo add the lines

• up /etc/openvpn/update-resolv-conf
• down /etc/openvpn/update-resolv-conf

Now we need to point OpenVPN to this config file

• sudo nano /etc/default/openvpn
• Add the line AUTOSTART="Server" (without the .conf)

Ensure the DNS resolver is being pointed to your gateway

• Run cat /etc/resolv.conf
• If needed modify the file
• Run the command: sudo update-rc.d openvpn enable
• Now we can start the service with: 
  • sudo service openvpn start

Check the service is running by running: systemctl status openvpn@server

• “Server” being the name of the .conf file being used

If successful the output should look similar to:

openvpn@server.service - OpenVPN connection to server
Loaded: loaded (/lib/systemd/system/openvpn@.service; enabled; vendor preset: enabled)
Active: active (running) since Wed 2019-11-27 00:00:00 GMT; 1h 00min ago
Docs: man:openvpn(8)