Install Virtualbox 5.2.8 from PPA in Lubuntu 17.10

sudo apt-get update && sudo apt-get upgrade
wget -q http://download.virtualbox.org/virtualbox/debian/oracle_vbox_2016.asc -O- | sudo apt-key add -
sudo sh -c 'echo "deb http://download.virtualbox.org/virtualbox/debian $(lsb_release -cs) contrib" >> /etc/apt/sources.list.d/virtualbox.list'
sudo apt-get update
sudo apt-get install virtualbox-5.2
sudo gpasswd -a <user> vboxusers
(The <user> is the username which is you are using for login and will run the Virtualbox)

Reference:

https://linuxpropaganda.wordpress.com/2016/07/07/install-virtualbox-from-ppa-in-xubuntu-16-04/

Install Virtualbox 5.2.8 from PPA in Lubuntu 17.10