安装virtualbox：sudo apt install virtualbox
安装virtualbox-ext-pack : sudo apt install virtualbox-ext-pack
下载Kali镜像：https://www.offensive-security.com/kali-linux-vm-vmware-virtualbox-image-download/
在virtualbox中导入镜像即可
reference:
install virtualbox:https://linuxconfig.org/install-virtualbox-on-ubuntu-18-04-bionic-beaver-linux
install Kali:https://linuxconfig.org/how-to-install-kali-linux-on-virtualbox
