Imagine your first day at a client site and you spend your time figuring out what’s going on with the network. You query passive DNS to find tons of apparently VPN over DNS endpoints on your network. What starts as a simple incident investigation process sees the tables turned on those who used the protocol to hide their tracks. This talk will discuss reverse engineering VPN over DNS (vpnoverdns.com) and how weaknesses in using DNS tunneling makes it trivial to retroactively wiretap all communications over the protocol long after the fact.