From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754638Ab1JASfE (ORCPT ); Sat, 1 Oct 2011 14:35:04 -0400 Received: from 1wt.eu ([62.212.114.60]:33326 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751492Ab1JASfA (ORCPT ); Sat, 1 Oct 2011 14:35:00 -0400 Date: Sat, 1 Oct 2011 20:34:48 +0200 From: Willy Tarreau To: Steven Rostedt Cc: David Miller , greg@kroah.com, linux-kernel@vger.kernel.org Subject: Re: kernel.org status: hints on how to check your machine for intrusion Message-ID: <20111001183448.GD18690@1wt.eu> References: <20110930235924.GA25176@kroah.com> <20111001073533.GA18690@1wt.eu> <20111001180641.GD6309@home.goodmis.org> <20111001.141343.2293070262147973147.davem@davemloft.net> <1317493763.4588.70.camel@gandalf.stny.rr.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1317493763.4588.70.camel@gandalf.stny.rr.com> User-Agent: Mutt/1.4.2.3i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Oct 01, 2011 at 02:29:22PM -0400, Steven Rostedt wrote: > On Sat, 2011-10-01 at 14:13 -0400, David Miller wrote: > > From: Steven Rostedt > > Date: Sat, 1 Oct 2011 14:06:41 -0400 > > > > > For my machine that is connected to the outside world, I have a script > > > that runs every night that checks for attacks. As bots constantly look > > > for port 22 and 80, they find my machine without issue. When my script > > > detects a bunch of ssh login attempts that fail, it will add that ip > > > address to the iptables DROP chain: > > > > By running sshd on a different port, you'll avoid the login attempts > > as well as the overhead of the successful connection attempts. > > > > I haven't allowed sshd to run on port 22 in more than 10 years. > > I use to do that a long time ago, but I ran into issues because of it. > Can't remember the exact problem. Maybe it was places I went to that did > not allow outgoing connections to non official ports. Whatever it was, > it was annoying enough to put sshd back to 22. 443 is pretty nice for connecting from unexpected places ;-) > I probably can go back to a non 22 port without much issue. I have added > a bunch of personal checks to this box that gives a report every day. I > may add more (from what was posted in this thread already). I also have > logwatch and rkhunter running, and just added chkrootkit now. > > But moving the ssh port again may be a good idea. But I like stressing > your net filtering code ;) BTW ipset is particularly suited for this. Regards, Willy