Re: Dynamic DNS "Spoofing" & IRC

[Niels Bakker <niels=bugtraq () bakker net>]

* 0x90 () invisiblenet net (Intel Nop) [Fri 02 May 2003, 17:10 CEST]:
> This is a trivial "feature/flaw" I've been holding onto for a bit, and it's
> probably commonly known, but I haven't seen it posted anywhere, more of a
> neat little thing in taking advantage of IRC and it's treatment of dyndns
> within DNS if reverse lookup is possible.
[..]
> By this time, your dyndns should have updated and changed your ip address to
> 127.0.0.1, and irc servers don't re-check after you've connected (so anyone
> resolving your hostname will come up with 127.0.0.1).

You can retrieve the IP address of any user on irc via the STATS L
command (the uppercase L is important).

For privacy reasons some networks (most notably Undernet but also
Freenode) have disabled this command for users that do not have IRC
Operator status.


        -- Niels.

-- 
Note: some countries impose serious penalties for a conspiracy to overthrow
      the political system. THIS DOES NOT FIX THE VULNERABILITY.