Re: multicast connection trials from a home machine - is it regular?

["GSimmonds" <gsimmonds () primus ca>]

----- Original Message -----
From: "ruben" <rubenb () arnet com ar>
To: <SECURITY-BASICS () securityfocus com>
Sent: Tuesday, April 15, 2003 10:46 AM
Subject: multicast connection trials from a home machine - is it regular?


> > From the firewall log:
> "blocked: Out ICMP;Router solicitation;localhost->224.0.0.2;Owner: Tcpip
> Kernel Driver"
> That is done (as the first outbound communication) every time the machine
is
> connected via dialup to the Internet. Is that a logical part of the
process?
> OS is Win98, firewall is Kerio, the rule CAN be modified, but the blocking
> came as default in the firewall settings. What arises my doubts is that
the
> firewall blocks the attempt to connect to 224.0.0.2 but the http and mail
> service go back and forth as usual. A short Google search shows some info
> about multicast in NT machines, but nothing worthwile. I'm suspecting of
> some backdoor sitting in this machine. Of course it can be a part of a
> legitimate process. Can you enlighten me about this?
> TIA, Ruben.-

Hi Ruben,

You can forego the slash and burn, at least for now. ;) What you're seeing
is ICMP Router Discovery Protocol (IRDP). A "feature" built into MS
winsock2.

It's an unnecessary process with potential problems.
http://www.atstake.com/research/advisories/1999/rdp.txt

I'm not sure if it is routed far enough to be abused on an ISP dialup. Maybe
someone can elaborate. To be on the safe side, either block or disable it.

Cheers
Gary


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