Next Generation Naughtiness at the Dead Beef Cafe
The IPocalypse is nearly upon us. Amongst the FUD, the four horsemen are revving up their steeds, each bearing 32 bits of the IPv6 Global Multicast Address of Armageddon, ff0e::dead:beef:666.
Making sure that the four horsemen don’t bust into our stables undetected is something of a challenge at the moment; IPv6 can represent a definite network monitoring blind spot or, at worst, an unpoliced path right into the heart of your network. Consider the following:
Routers and Firewalls
Although a router may be capable of routing IPv6, are all the features you use on the router IPv6-enabled? Is the firewall process inspecting IPv6 traffic? If it is, is it as feature-rich as the IPv4 equivalent (e.g., does it support application-layer inspection for protocols like FTP, or HTTP protocol compliance checking?)
If you IPv6-enable your infrastructure, you may be inadvertently assigning internal hosts global IPv6 addresses (2001::) via stateless address autoconfiguration. If this happens (deliberately or accidentally), are the hosts reachable from the Internet directly? There’s no safety blanket of NAT for internal hosts like there is in IPv4, and if your network and/or host firewalls aren’t configured for IPv6 you could be wide open.
Do your IDS/IPS boxes support IPv6? Snort’s had IPv6 support since (I think) v2.8; the Cisco IPS products are also IPv6-aware, as I’m sure are many others.
Session tracking tools
Even if all of your all-seeing-eyes support IPv6, they’re of little use if your reporting tools don’t. Can your netflow analyser handle IPv6 exports? What about your IDS reporting tools – are they showing you alerts on IPv6 traffic? What about your expensive SIEM box?
The IPv6 Internet is just as rotten as the IPv4 one
We’ve seen some quite prolific IPv6 port scanning just as described here, complete with scans of addresses like 2001:x:x:x::c0:ffee and 2001:x:x:x::dead:beef:cafe. The same scanning host also targeted UDP/53 trying to resolve ‘localhost’, with the same source port (6689) being used for both TCP and UDP scans. I have no idea if this is reconnaissance or part of some kind of research project, but there were nearly 13000 attempts from this one host in the space of about three seconds.
Due to the current lack of visibility into IPv6, it can also make a great bearer of covert channels for an attacker or pentester. Even if you’re not running IPv6 at all, an attacker who gains a foothold within your network could easily set up a low-observable IPv6-over-IPv4 tunnel using one of the many IPv6 transition mechanisms available, such as 6in4 (uses IPv4 protocol 41) or Teredo (encapsulates IPv6 in UDP, and can increase the host’s attack surface by assigning globally routable IPv6 addresses to hosts behind NAT devices, which are otherwise mostly unreachable from the Internet).
The IPocalypse is coming…
…that’s for certain; we just have to make sure we’re ready for it. Even if you’re not using IPv6 right now, you probably will be to some degree a little way down the road. Now’s the time to check the capability of your monitoring infrastructure, and to conduct a traffic audit looking for tunneled IPv6 traffic. Who knows what you might find!
Alec Waters is responsible for all things security at Dataline Software, and can be emailed at firstname.lastname@example.org