After having to piece together a VirtualBox Guest Addition installation method from some old articles, I decided to put together one for Security Onion 14.05.
Once you have Security Onion 14.05 installed and running, start the Terminal Emulator and walk through the following commands, one-by-one:
sudo apt-get update sudo apt-get upgrade sudo apt-get dist-upgrade sudo shutdown -r now
After the reboots, launch the Terminal Emulator and run the following commands:
sudo apt-get install build-essential module-assistant dkms sudo add-apt-repository universe sudo apt update sudo m-a prepare
In the virtual machine window, select Devices > Insert Guest Additions CD image…
cd /media/%username%/VBOXADDITIONS (tab complete) sudo ./VBoxLinuxAdditions.run sudo shutdown -r now
After the reboot, the VirtualBox Guest Additions should be installed and all features should be available.
As a last step, select Devices > Optical Drives > Remove disk from virtual drive…