[NSE] Detecting IP forwarding

[Patrik Karlsson <patrik () cqure net>]

Hi all,

I had a discussion about ip forwarding and "internet connection sharing"
with a friend the other day.
The discussion was about detecting multi homed laptops having both the
wireless and wired network interfaces active and ip forwarding enabled.
I came up with the attached script which essentially tries to use each
scanned host as a gateway and sends a ping packet to a given target (either
on the same LAN or routed).
It then sees whether it gets a ICMP echo reply or redirect back and
determines whether the packet was forwarded or not.

I've tried it against Windows 7 connection sharing, my home router and a OS
X server with ip forwarding activated and it works as intended.
If there's another more efficient way to discover this, let me know,
otherwise I will commit the script within the next few days.

The script relies on some recent changes to packet.lua, so it needs this to
be updated library as well.

Cheers,
Patrik
-- 
Patrik Karlsson
http://www.cqure.net
http://twitter.com/nevdull77

Attachment: ip-forwarding.nse
Description:

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