BugTraq
Re: ICMP spoofed source tunneling Sep 22 2004 07:24PM
Dave Paris (dparis w3works com)
At the risk of possibly sinking my foot firmly into my mouth, it appears
that you've implemented an unimplemented feature of LOKI2 (circa 1997).
ref: http://www.phrack.org/show.php?p=51&a=6

If you look in the source at the link referenced, specifically the
help() function, you'll find:

%s dest\t- redirect to another client [ UNIMPLIMENTED ]\n",

Nifty none-the-less.

Kind Regards,
-dsp

Max Tulyev wrote:

> ICMP spoofed source payload tunneling
>
> I. ABSTRACT
>
> Almost any device having IP stack with enabled ICMP can be used to
> be a tunnel redirector.
>
> II. DESCRIPTION
>
> Let's imagine in Net a hacker having his source server(S), destination
> server(D), and a ip-capable device - victim(V). S sends to V spoofed ICMP
> echo request packet containing IP source address of D, and the data in
> Payload.
>
> When V receiving that packet, it sends ICMP echo-reply packet to D, AND
> FORWARDS TO D ALL DATA IN PAYLOAD!
>
> Backward is the same.
>
> I spent an only hour to write working exploit attaching this to Linux
> tuntap
> device...
>
> III. ANALYSIS
>
> Where it can be used?
>
> 1. Hacker have a victim traffic to that one cost lesser than to the World.
> That way Victim will pay for traffic with other hacker's server.
>
> 2. Hacker have no access to the world at all, but have external server
> (D). For Victim can be used any neighbour device (I tried IP phone - it
> works!) or even firewall or gateway! This can make a tunnel through a
> server with completely disabled IP forwarding at all.
>
> Very high probability of their attacks is in ISPs that gives a free access
> to some networks (I know that situation exists in Ukraine - to UA Internet
> Exchange access often is free and/or at higher speed, and in home Ethernet
> networks almost all ISPs provides free access to their clients and local
> resources).
>
> IV. DETECTION
> This can be detected by observing an anomally ICMP activity, and if you
> have more than one network interfaces - by presence of spoofed packets
> that can't be in certain interfaces. Or maybe by viewing your Internet
> bill ;-)
>
> V. WORKAROUND
>
> Turning On reverse-path filtering and other antispoofed
> mechanisms. Limiting rates or even denying ICMP type 8 at all.
>
>
>
>
>

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