Date: Mon, 15 Nov 1999 18:47:08 +0000 From: Brian Somers <brian@Awfulhak.org> To: "Francisco Reyes" <fran@reyes.somos.net> Cc: "freebsd-security@FreeBSD.ORG" <freebsd-security@FreeBSD.ORG>, "Brian Somers" <brian@Awfulhak.org>, brian@hak.lan.Awfulhak.org Subject: Re: Is this an attack? ICMP packets coming from my own IP Message-ID: <199911151847.SAA01919@hak.lan.Awfulhak.org> In-Reply-To: Message from "Francisco Reyes" <fran@reyes.somos.net> of "Mon, 15 Nov 1999 06:38:13 EST." <199911151140.GAA50607@sanson.reyes.somos.net>
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> Some days back I ran a news server, Leafnode++, for 2 days. The server got Hijacked because I failed to
> secure it. Ever since I have been paying close attention to my logs.
>
> I have ICMP packets enabled, but I log them. Last night I noticed numerous ICMP packets, but the ones
> that worried me the most were some coming from an IP which is the IP I use on that box: 207.240.212.43
>
> Is this some form of attack?
>
> ipfw: 3100 Accept ICMP:8.0 207.240.212.43 207.240.212.43 out via tun0
> ipfw: 3100 Accept ICMP:8.0 207.240.212.43 207.240.212.43 in via tun0
> ipfw: 3100 Accept ICMP:0.0 207.240.212.43 207.240.212.43 out via tun0
> ipfw: 3100 Accept ICMP:0.0 207.240.212.43 207.240.212.43 in via tun0
> ipfw: 3100 Accept ICMP:8.0 207.240.212.43 207.240.212.43 out via tun0
> ipfw: 3100 Accept ICMP:8.0 207.240.212.43 207.240.212.43 in via tun0
>
> How can they forge my own IP? Should I mention this to my ISP?
I suspect this is the result of pinging 207.240.212.43 from
207.240.212.43 itself. ppp turns the packets 'round so that they
come straight back (see ``enable loopback'' - on by default).
--
Brian <brian@Awfulhak.org> <brian@FreeBSD.org>
<http://www.Awfulhak.org>; <brian@OpenBSD.org>
Don't _EVER_ lose your sense of humour ! <brian@FreeBSD.org.uk>
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