From owner-freebsd-security Mon Nov 15 16: 0:10 1999 Delivered-To: freebsd-security@freebsd.org Received: from awfulhak.org (dynamic-69.max4-du-ws.dialnetwork.pavilion.co.uk [212.74.9.197]) by hub.freebsd.org (Postfix) with ESMTP id 47DE214BD0 for ; Mon, 15 Nov 1999 16:00:05 -0800 (PST) (envelope-from brian@Awfulhak.org) Received: from hak.lan.Awfulhak.org (root@hak.lan.Awfulhak.org [172.16.0.12]) by awfulhak.org (8.9.3/8.9.3) with ESMTP id SAA02547; Mon, 15 Nov 1999 18:42:51 GMT (envelope-from brian@lan.awfulhak.org) Received: from hak.lan.Awfulhak.org (brian@localhost.lan.Awfulhak.org [127.0.0.1]) by hak.lan.Awfulhak.org (8.9.3/8.9.3) with ESMTP id SAA01919; Mon, 15 Nov 1999 18:47:08 GMT (envelope-from brian@hak.lan.Awfulhak.org) Message-Id: <199911151847.SAA01919@hak.lan.Awfulhak.org> X-Mailer: exmh version 2.1.0 09/18/1999 To: "Francisco Reyes" Cc: "freebsd-security@FreeBSD.ORG" , "Brian Somers" , brian@hak.lan.Awfulhak.org Subject: Re: Is this an attack? ICMP packets coming from my own IP In-Reply-To: Message from "Francisco Reyes" of "Mon, 15 Nov 1999 06:38:13 EST." <199911151140.GAA50607@sanson.reyes.somos.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Mon, 15 Nov 1999 18:47:08 +0000 From: Brian Somers Sender: owner-freebsd-security@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org > 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 Don't _EVER_ lose your sense of humour ! To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-security" in the body of the message