Step 1 - Download dependencies :
wget http://http.us.debian.org/debian/pool/main/libv/libvpx/libvpx1_1.3.0-3_amd64.deb
wget http://http.us.debian.org/debian/pool/main/o/openssl/libssl1.0.0_1.0.1k-3+deb8u2_amd64.deb
Step 2 - Create Virtualbox repos :
echo "deb http://download.virtualbox.org/virtualbox/debian jessie contrib" > /etc/apt/sources.list.d/vbox.list
Step 3 - Install Virtualbox public key :
wget -q https://www.virtualbox.org/download/oracle_vbox.asc -O- | sudo apt-key add -
Step 4 - Install it now :
dpkg -i libvpx1_1.3.0-3_amd64.deb
dpkg -i libssl1.0.0_1.0.1k-3+deb8u2_amd64.deb
apt-get update
apt-get -y install linux-headers-amd64 dkms libsdl-ttf2.0-0 virtualbox-5.0
Step 5 - Install Virtualbox Extension Pack :
wget http://download.virtualbox.org/virtualbox/5.0.14/Oracle_VM_VirtualBox_Extension_Pack-5.0.14-105127.vbox-extpack
VBoxManage extpack install Oracle_VM_VirtualBox_Extension_Pack-5.0.14-105127.vbox-extpack
Step 6 - Clean up :
rm *.deb
rm *.vbox-extpack
Step 7 - Reboot :
reboot
Bonus
When install Kali Linux as guest on VirtualBox, you may need to install "Guest Additions CD Image".
apt-get update
apt-get -y install dkms
Then mount the "Guest Additions CD Image" from the VirtualBox menu.
cd /media/cdrom0
cp VBoxLinuxAdditions.run /tmp/
cd /tmp
./VBoxLinuxAdditions.run
That's all! See you.