According to the North American IPv6 Task Force over half of U.S. CIOs have IPv6 traffic on their networks, and are not aware of it.  While you may not be aware of IPv6 hackers are fully aware.  IPv6 traffic can be tunneled over IPv4 connections and be reported as normal IPv4 packets unless you have deployed security and monitoring tools that can inspect tunneled traffic.  Here are some key steps to prevent the threat:

• Verify your firewalls, intrusion detection, and network monitoring solutions are IPv6-aware
• If not running IPv6, ensure all equipment has IPv6 turned off
• Consider buying firewalls and intrusion prevention products to block all IPv6 traffic
• Develop policies for handling IPv6 traffic

A fully integrated solution like Network Instruments Observer and GigaStor provide integrated native support for both IPv6 and IPv6 tunnelling over IPv4.

You can read more about IPv6 threats in this  Network World article and see how you can  Configure Network Instruments Observer to show your IPv6 Traffic.