Auto Restore Virtualbox

For the security class I’m teaching we recently had a box to pwn. Problem is, they would sometimes get the address wrong and crash the virtual system. I probably would have just distributed the vdi, but not all of them have machines robust enough to run a vm, so I had to set something up.
First off, I gave the virtual vulnerable box a public IP by bridging.

/etc/network/interfaces

auto eth0
iface eth0 inet manual

auto br0
iface br0 inet static
    address 134.50.1.2
    netmask 255.255.0.0
    gateway 134.50.1.254
    bridge_ports eth0 vbox0 vbox1

# The loopback network interface
auto lo
iface lo inet loopback

/etc/vbox/interfaces

vbox0 lundeen br0
vbox1 lundeen br0

Awesome, now firewall rules work. In the vulnbox, I give myself an ip address. On the host, I set up very strict firewall rules using iptables.

Another big issue is auto-restore. Since the class often gets an address wrong, the vulnbox often crashes.

The following will shut the box down, revert to a snapshot, and turn it back on.

/usr/bin/VBoxManage controlvm vulnxp poweroff;
sleep 5;
/usr/bin/VBoxManage snapshot vulnxp discardcurrent -state
sleep 10;
/usr/bin/VBoxManage startvm vulnxp</pre>

Anyway, I put this in crontab to do every 20 minutes.

0,20,40 * * * * /path/to/virtualscript