IP over DNS

Sometimes while you are performing a penetration test, you need to break out from a supposedly isolated network like an internal VLAN in a bank, or a process network full of SCADA equipment. Such networks should be completely isolated from the Internet, so there is no chance that someone who has network access can implant a backdoor and either sneak out information or allow access from the outside. This article demonstrates how the often overlooked DNS service can be used to build a covert channel and why when you configure an isolated network, you shouldn’t allow even name resolution of external hosts. To demonstrate this we will use the NSTX tunnel software to build a dns tunnel and bypass firewall. . . . → Read More: IP over DNS