Doug Barton (dougb) writes: > On 11/13/2011 13:27, Phil Regnauld wrote: > > That's not exactly correct. NAT doesn't imply firewalling/filtering. > > To illustrate this to customers, I've mounted attacks/scans on > > hosts behind NAT devices, from the interconnect network immediately > > outside: if you can point a route with the ext ip of the NAT device > > as the next hop, it usually just forwards the packets... > > Have you written this up anywhere? It would be absolutely awesome to be > able to point the "NAT IS A SECURITY FEATURE!!!" crowd to an actual > demonstration of why it isn't.
Nope, but I could do a quick tut on how to do this against a natd/pf/ iptables or IOS with IP overload. Arguably in *most* cases your CPE or whatever is NATing is behind some upstream device doing ingress filtering, so you still need to be compromising a device fairly close to the target network. P.