deb http://http.kali.org kali main contrib non-free
deb http://download.virtualbox.org/virtualbox/debian wheezy contrib non-free
Execute os seguintes comandos:
# wget -q http://download.virtualbox.org/virtualbox/debian/oracle_vbox.asc -O- | sudo apt-key add -
# apt-get update
# apt-get install virtualbox-4.2
Is Nuts!!!