From owner-freebsd-questions@FreeBSD.ORG Mon May 23 00:31:40 2005 Return-Path: X-Original-To: freebsd-questions@freebsd.org Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 594BB16A41C for ; Mon, 23 May 2005 00:31:40 +0000 (GMT) (envelope-from lists@natserv.com) Received: from mail1.acecape.com (mail1.acecape.com [66.114.74.12]) by mx1.FreeBSD.org (Postfix) with ESMTP id 0C21343D1F for ; Mon, 23 May 2005 00:31:39 +0000 (GMT) (envelope-from lists@natserv.com) Received: from zoraida.natserv.net (p65-147.acedsl.com [66.114.65.147]) by mail1.acecape.com (8.12.11/8.12.11) with ESMTP id j4N0Vceq007210; Sun, 22 May 2005 20:31:38 -0400 Date: Sun, 22 May 2005 20:31:38 -0400 (EDT) From: Francisco Reyes X-X-Sender: fran@zoraida.natserv.net To: Chris In-Reply-To: <4290EEB4.9070502@makeworld.com> Message-ID: <20050522202535.K29197@zoraida.natserv.net> References: <1368.24.99.220.144.1116792799.squirrel@24.99.220.144> <4290EEB4.9070502@makeworld.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Cc: John DeStefano , Jerry Bell , freebsd-questions@freebsd.org Subject: Re: securing SSH, FBSD systems X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 23 May 2005 00:31:40 -0000 On Sun, 22 May 2005, Chris wrote: > 5. (and my favorite) If running IPFW, use something like this if you > don't need ssh open to the whole of the internet. narrow it down to a > range of IP's you need. 6. Don't use passwords at all, but use keys. Not always possible though, but possibly one of the better methods. I personally use a combo 1- Use an AllowUsers clause 2- Every time I see script kiddies I black hole their IPs. I black hole them not only because of ssh, but because, just as they tried to attack ssh the same IPs may try other attacks. I try and stay up to date in patches, but it can not hurt to block known compromised/hacker machines. The IPs can be listed either in the firewall or using route add -host 127.0.0.1 -blackhole I was told that this method of blackholing was more efficient when using a long list of IPs becaues IPFW looks at a linear list while the route list was some sort of tree which is more efficient to search. Over time.. my list of blackholed IPs is 300+ and growing. Every week I add anywhere from 2 to 10 new IPs. :-( Besides ssh I also look for machines trying to attack the web server.. ie a machine looking for files in c:\winnt or any other window directory is a sure sign of a compromised wmachine ith a virus/worm trying to infect more machines.